# textaware_diffusion_for_policy_learning__f9761339.pdf Text-Aware Diffusion for Policy Learning Calvin Luo Mandy He Zilai Zeng Chen Sun Brown University {calvin_luo,mandy_he,zilai_zeng,chensun}@brown.edu Training an agent to achieve particular goals or perform desired behaviors is often accomplished through reinforcement learning, especially in the absence of expert demonstrations. However, supporting novel goals or behaviors through reinforcement learning requires the ad-hoc design of appropriate reward functions, which quickly becomes intractable. To address this challenge, we propose Text-Aware Diffusion for Policy Learning (TADPo Le), which uses a pretrained, frozen text-conditioned diffusion model to compute dense zero-shot reward signals for text-aligned policy learning. We hypothesize that large-scale pretrained generative models encode rich priors that can supervise a policy to behave not only in a text-aligned manner, but also in alignment with a notion of naturalness summarized from internet-scale training data. In our experiments, we demonstrate that TADPo Le is able to learn policies for novel goal-achievement and continuous locomotion behaviors specified by natural language, in both Humanoid and Dog environments. The behaviors are learned zero-shot without ground-truth rewards or expert demonstrations, and are qualitatively more natural according to human evaluation. We further show that TADPo Le performs competitively when applied to robotic manipulation tasks in the Meta-World environment, without having access to any in-domain demonstrations. 1 Introduction Can we train reinforcement learning agents that drive humanoids in a virtual environment [39] to stably stand? How about standing with hands on hips, kneeling, or doing splits? While state-ofthe-art algorithms have shown success on the former scenario (e.g. [14]), the latter (illustrated in Figure 1) remains challenging due to the need for carefully (and often manually) crafted reward functions to specify the desired behaviors. The dependence on ad-hoc designed reward functions renders inscalable the learning of ever-increasing amounts of novel behaviors, which are required in applications ranging from character animation [2] to robotic manipulation [42]. Our work looks towards natural language as a powerful interface through which humans can flexibly specify desired goals or behaviors of interest. We therefore investigate how to construct a zero-shot text-conditioned reward signal, replacing the need for ad-hoc designs, through which text-aligned policies can be learned. We present Text-Aware Diffusion for Policy Learning (TADPo Le), which utilizes a large-scale pretrained, frozen text-conditioned diffusion model to generate a dense reward signal for policy learning. We hypothesize that generative diffusion models, which are pretrained on internet-scale datasets to produce text-aligned, natural-looking images [32, 29] and videos [3, 10, 15], can be utilized to automatically craft a multimodal reward signal that encourages an agent to behave both faithfully with respect to text conditioning and naturally with respect to human perception. Our method is novel in its reward computation, as well as its utilization of a domain-agnostic generative model, rather than one trained from environment-specific or task-specific video demonstrations, as used in prior work [9, 24, 6, 8, 20, 19]. Equal contribution. 38th Conference on Neural Information Processing Systems (Neur IPS 2024). Figure 1: Our proposed Text-Aware Diffusion for Policy Learning (TADPo Le) framework leverages frozen, pretrained text-aware diffusion models to automatically craft dense text-conditioned rewards for policy learning. Here we visualize TADPo Le achieving diverse text-conditioned goals in the Humanoid, Dog, and Meta-World environments. TADPo Le is motivated by the insight that a reinforcement learning policy can be viewed as an agentcentric implicit video representation when operating within an environment with visual rendering capabilities. As illustrated in Figure 2 (left), an agent s video generation process involves the selection of actions following a policy πθ, and the conversion of the action sequence into video subsequences through the environment s rendering function. A policy can therefore be seen as iteratively generating frames conditioned on the actions it selects; on the other hand, a text-to-image diffusion model can also be seen as generating static image frames, but conditioned on natural language instead. A connection can then be established between a policy and a diffusion model, where the frame or video segment generated by the policy can be critiqued by evaluating how likely a text-conditioned diffusion model would generate the same visuals, thus providing dense text-aligned reward signals to guide policy learning (Figure 2 right). Our work is inspired by Dream Fusion [25], where a textconditioned 3D model is learned through rendered views, and where volumetric raytracing ensures spatial consistency. Here, we seek to learn a text-conditioned policy through rendered frames or subsequences, where the environment naturally ensures temporal continuity and consistency with respect to a notion of physics instantiated by the environment. Concretely, TADPo Le achieves text-conditioned policy learning by using a generative diffusion model in a discriminative manner. It computes the reward signal as a weighted combination of two reward terms, which aim to measure the alignment between the rendered observation and text conditioning, and the naturalness of the agent s behaviors, respectively. In this way, we can in effect distill the natural visual and motion priors as well as vision-text alignment understanding captured within the diffusion model into a policy. By default, TADPo Le uses a text-to-image diffusion model [31] to densely compute a reward signal solely from the immediate subsequent frame after each action. We then generalize the framework to Video-TADPo Le, which uses a text-to-video diffusion model [12] to calculate dense rewards as a function of a sliding context window of past as well as future frames achieved. The agent is thus trained to select actions such that arbitrary consecutive subsequences of frames are well-aligned with text as well as natural video (e.g. motion) priors. We highlight TADPo Le as the first approach to leverage domain-agnostic visual generative models for policy learning. Through quantitative and human evaluations on Humanoid [39], Dog [39], and Meta-World [42] environments, we demonstrate that TADPo Le enables the learning of novel, zeroshot policies that are flexibly and accurately conditioned on natural language inputs, across multiple robot configurations and environments, for both goal-achievement and continuous locomotion tasks. TADPo Le therefore provides two main benefits simultaneously: a performant approach towards zero-shot policy learning, where complex reward functions no longer need to be manually specified per task, and a promising path towards distilling priors summarized from large-scale pretraining into policies, ultimately resulting in the learning of more naturally-aligned behavior within arbitrary environments. Visualizations and code are provided at diffusion-supervision.github.io/tadpole/. 2 Related Work Diffusion models [34, 35, 16, 36] have recently demonstrated amazing generative modeling capabilities, particularly in the domain of text-conditioned image generation [5, 29, 32, 31]. Notably, guidance [36, 5, 17] has been shown to be a critical component in producing visual outputs aligned with textual data, enabling the generation of images that accurately match a desired text caption, especially when the models are scaled to utilize large foundation models such as CLIP [27] or T5 [28], and trained on massive image-text datasets [33]. Our work is inspired by Dream Fusion [25], where a Figure 2: A policy πθ that interacts with an environment can be treated as an agent-centric implicit video representation, where the arrow of time is actuated by the agent s actions and the pixels are rendered by the environment. The rendered behaviors can then be evaluated by a text-aware diffusion model to produce dense rewards, thereby providing text-conditioned update signals to the policy. pretrained, frozen text-to-image diffusion model is able to supervise the learning of zero-shot 3D models conditioned on text. We propose leveraging pretrained diffusion models to supervise the learning of flexible, text-conditioned policies in a zero-shot manner over the time dimension. There are numerous works that investigate how interactive agents can learn to perform behaviors specified by textual inputs. Say Can [1] grounds the knowledge of complex, high-level behaviors within an LLM to the context of a robot through pretrained behaviors. This then enables an LLM to instruct and guide a robot, through combining low-level behaviors, to perform complex temporally extended behaviors. Lang Lf P proposes a method for incorporating free-form natural language conditioning into imitation learning by first associating goal images with text captions and training a policy to follow either language or image goals, but only conditioning on natural language during test time inference [4]. The Text-Conditioned Decision Transformer learns a causal transformer to autoregressively produce actions conditioned on both text tokens as well as state and action tokens [26]. Similarly, Hiveformer proposes a unified multimodal Transformer model for robotic manipulation that conditions on natural language instructions, camera views, as well as past actions and observations [11]. However, Lang Lf P, Text-Conditioned Decision Transformer, and Hiveformer, all require training on datasets of trajectories that have been labelled with natural language. In contrast, TADPo Le enables the learning of text-conditioned policies irrespective of visual environment, and without requiring any pretraining dataset of demonstrations or labeling. Similar to our work, Uni Pi [6] treats the sequential decision-making problem as a text-conditioned video generation problem. The authors propose training a video diffusion model to produce a future visual plan for the agent; the subsequent frames are then converted to actions by means of an inverse dynamics model. VLP [7] utilizes text-to-video generative models for planning and goal generation for an agent. Both methods require the video generative models to be trained ad-hoc on the target environments, whereas we directly use frozen general-purpose generative models. Mahmoudieh et al. [21] propose a framework that uses CLIP to generate a reward signal from a text description of a goal state and raw pixel observations from the environment, which is then used to learn a task policy. In VLM-RM [30], the authors also explore utilizing CLIP as the reward model for training humanoids to accomplish complex goal-reaching tasks. In our work, we investigate locomotion tasks on top of goal-achievement, and explore how using diffusion models to produce a reward signal can outperform CLIP-based approaches. Although not conditioned on text, VIPER [8] also aims to harness recent advancements in generative modeling by employing a video prediction model s likelihoods as a reward signal. However, VIPER does not enable the learning of policies conditioned on text, and requires in-domain expert videos for ad-hoc training the video model. Finally, Diffusion Reward [18] also extracts a reward from a diffusion model to train policies; however, it requires training an ad-hoc video model on expert trajectories, the collection of which cannot always be assumed to be trivial, and does not enable text-conditioned policy learning. We propose Text-Aware Diffusion for Policy Learning (TADPo Le) to learn text-aligned policies by leveraging frozen, pretrained text-conditioned diffusion models. An overview of the framework can be found in Figure 3. Figure 3: An illustration of the TADPo Le pipeline, which computes text-conditioned rewards for policy learning through a pretrained, frozen diffusion model. At each timestep, the subsequent frame rendered through the environment is corrupted with a sampled Gaussian source noise vector ϵ0. The pretrained text-conditioned diffusion model then predicts the source noise that was added. The reward is designed to be large when the selected action produces frames well-aligned with the text prompt. 3.1 Text-Aware Diffusion for Policy Learning We first describe how TADPo Le produces text-conditioned rewards from image observations. At each timestep t, reward rt is computed as a score between rendered subsequent image ot+1 and the provided text caption describing the behavior of interest, denoted by y, using a frozen, pretrained textto-image diffusion model. We begin by corrupting the rendered image ot+1 with a sampled Gaussian source noise vector ϵ0 N(ϵ; 0, I) to produce noisy observation ot+1, and use the diffusion model to make an unconditional prediction ˆϵϕ( ot+1; tnoise) as well as a conditional prediction ˆϵϕ( ot+1; tnoise, y). Here ˆϵϕ( ) is a neural network that predicts the source noise given ot+1, the level of noise corruption tnoise, and optionally the text prompt y; we overload notation to have ˆϵϕ represent the source noise prediction in Figure 3. We then compute the mean squared error (MSE) between the two predictions as a reward signal ralign t to be maximized: ralign t = ˆϵϕ( ot+1; tnoise, y) ˆϵϕ( ot+1; tnoise) 2 2 . As investigated in Appendix B.3, we empirically observe that ralign t plays a crucial role on the success of TADPo Le. We hypothesize that for an appropriately-selected noise corruption level tnoise, this term measures the alignment between the environmental observation and the text prompt. Intuitively, for unconditional prediction ˆϵϕ( ot+1; tnoise), the model is incentivized only to bring the noisy input to any arbitrary cleaner image, and makes minimal edits by moving it towards the closest clean mode in data space. On the other hand, if the model recognizes visual features in the noisy image aligned with the text prompt, conditional prediction ˆϵϕ( ot+1; tnoise, y) is incentivized to do extra work and bring it closer to the specific mode described by the text conditioning. We thus expect the MSE to be larger for well-aligned text conditioning. For an unaligned text prompt, the model may have more difficulty in recognizing relevant visual features in the corrupted image, and therefore generally has a lower computed ralign t signal. Therefore maximizing ralign t is a tractable proxy for maximizing the alignment between the rendered observation ot+1 and the provided text prompt y. We also wish to encourage behaviors that are natural to human perception (e.g. a humanoid should walk similar to how a typical pedestrian would walk). We approximate the naturalness of a behavior by how accurately the diffusion model is able to predict the exact source noise vector that was applied. Intuitively, if it voluntarily predicts the exact noise vector with informative text conditioning, thereby perfectly reconstructing the query image, then the diffusion model believes the original rendered frame is reasonably natural (according to the priors captured by the diffusion model). We would therefore like to minimize ˆϵϕ( ot+1; tnoise, y) ϵ0 2 2. We would also like this term to be comparatively closer to the source noise vector than the unconditional prediction is, further reaffirming the benefit of the text conditioning. We therefore seek to also maximize a comparative reconstruction term as below: rrec t = ˆϵϕ( ot+1; tnoise) ϵ0 2 2 ˆϵϕ( ot+1; tnoise, y) ϵ0 2 2 . Algorithm 1 Text-Aware Diffusion for Policy Learning (TADPo Le) 1: prompt = sample(action_phrase) 2: πθ = initialize(θ) 3: D {} 4: while not converged: 5: s0 p(s0) 6: for t in range(episode_length): 7: at πθ(at | st) 8: st+1 P(st+1 | st, at) 9: ϵ0 N(ϵ; 0, I) 10: ot+1 P(ot+1 | st+1) 11: ot+1 noisify(ot+1, ϵ0, tnoise) 12: rt = tadpole_reward( ot+1, ϵ0, prompt) 13: τ τ (st, at, rt, st+1) 14: D D τ 15: loss = policy_loss(D) 16: grads = gradient(loss, θ) 17: opt.apply_gradients(grads, θ) Ultimately, we compose these two terms into a final reward signal rt exposed to the policy during training. We scale each of the individual terms with tunable hyperparameter constants, and apply a symlog [13] transformation operation: rt = symlog(w1 ralign t ) + symlog(w2 rrec t ). The choice of using symlog as a reward normalization technique is thoroughly studied in Section 4.5. TADPo Le is agnostic to the specific choices of policy network architecture and optimization objectives. A pseudocode of the method is provided in Algorithm 1. It is worth emphasizing that tnoise and subscript-less t refer to different notions of time; t indexes the timestep of the agent in the environment, whereas tnoise determines the level of noise to corrupt the raw observed image. 3.2 TADPo Le with Text-to-Video Diffusion Models Conceptually, there exist fundamental limitations to using a text-to-image model to provide a reward signal. As each image is evaluated statically and independently, we are unable to expect the textto-image diffusion model to be able to accurately understand and supervise an agent in learning notions of speed, or in some cases, direction, as such concepts require evaluating multiple consecutive timesteps to deduce. We therefore propose Video-TADPo Le, where a dense text-conditioned reward signal is calculated over sliding windows of consecutive frames through a pretrained text-to-video diffusion model. We extend and generalize the reward formulation from TADPo Le thusly. We can compute reward terms for arbitrary start index i and end index j inclusive, for i j, by considering the sequence of subsequently rendered frames o[i+1:j+1]. We once again utilize source noise vector ϵ0 N(ϵ; 0, Ij i+1) to produce noisy observation o[i+1:j+1]. Then, we can compute a batch of alignment reward terms through one inference step of the text-to-video diffusion model as: ralign [i:j] = ˆϵϕ( o[i+1:j+1]; tnoise, y) ˆϵϕ( o[i+1:j+1]; tnoise) 2 2 , and a batch of reconstruction reward terms as: rrec [i:j] = ˆϵϕ( o[i+1:j+1]; tnoise) ϵ0 2 2 ˆϵϕ( o[i+1:j+1]; tnoise, y) ϵ0 2 2 . For a desired context window of size n, we then calculate the reward at each timestep t utilizing each context window that involves achieved observation ot+1: i=1 symlog w1 ralign [t i+1:t i+n][i 1] + symlog w2 rrec [t i+1:t i+n][i 1] . Intuitively, we seek to calculate an overall reward for an action based off how well the resulting rendered frame aligns with text-conditioning at the beginning of a motion sequence, the end of one, and arbitrarily inbetween. For window size n = 1, this recreates TADPo Le behavior, but using a text-to-video model; for n > 1, we make the computation tractable through dynamic programming. 4 Experiments We now demonstrate the effectiveness of TADPo Le on goal achievement, continuous locomotion, and robotic manipulation tasks. All results are achieved without access to in-domain demonstrations. 4.1 Experimental Setup and Evaluation Benchmarks: We present our main results using the Dog and Humanoid environments from the Deep Mind Control Suite [39], and robotic manipulation tasks from Meta-World [42]. Dog and Humanoid are known to be challenging due to their large action space, complex transition dynamics, and lack of task-specific priors (such as termination conditions). We update the environments by modifying the terrain rendered by Mu Jo Co [38] to have green grass and blue sky. We also limit the number of environment timesteps to be 300, which is sufficient to demonstrate successful learning of a behavior, rather than the default 1000. The agent s initialized joint configurations are also fixed, as we focus on learning text-conditioned capabilities rather than robustness to initialization conditions. Meta-World was initially designed for multi-task and meta-reinforcement learning, and was later adopted to evaluate language-conditioned imitation learning algorithms [23, 22, 37]. We select a suite of tasks which are balanced for diversity and complexity, and pair each task with a text prompt (see tasks and their corresponding prompts in Appendix C). Following prior design [18] for Meta-World, we also add a sparse success signal to the dense text-conditioned reward signals. Implementation: We use TD-MPC [14] as the reinforcement learning algorithm for all tasks. It is the first documented model to solve Dog tasks when ground truth rewards are available for walking. We fix the hyperparameters to the default ones recommended by the TD-MPC authors (see Table A3 in Appendix) for all experiments unless otherwise mentioned. We train Humanoid and Dog agents for 2M steps, and Meta-World agents for 700K steps. For Meta-World experiments, we scale the sparse success signal by 2. Visualizations and quantitative evaluations are reported using the last checkpoint achieved at the end of training. We use Stable Diffusion 2.1 [31] as the text-to-image diffusion model ( 1.3B parameters), and Animated Diff [12] v2 ( 1.5B parameters) as the text-to-video diffusion model. Animated Diff is implemented on top of Stable Diffusion 1.5. We fix the reward weights w1 = 2000 and w2 = 200 based on Humanoid standing and walking performance, and study their impact in Appendix B.3. Selection of noise level is discussed in Appendix A. All experiments are performed on a single NVIDIA V100 GPU. Baselines: We compare TADPo Le against other text-to-reward approaches, including VLM-RM [30], LIV [20], and Text2Reward [41], on top of the same underlying TD-MPC architecture, hyperparameters, and optimization scheme for fair comparison. For LIV, we use their provided CLIP-based checkpoint finetuned on robotic demonstration videos. For VLM-RM, we utilize the Vi T-big G-14 CLIP checkpoint ( 1.3B parameters), reported as the best performing in their work. We follow a prompt template provided in the Text2Reward paper to generate reward functions for the Dog and Humanoid agent, interfaced through vanilla Chat GPT using GPT-3.5. Whereas VLM-RM and LIV provide a multimodal reward signal, and are more directly comparable to TADPo Le, it is of note that Text2Reward generates a text-conditioned reward function purely as the output of a pretrained language model. However, Text2Reward does have access to underlying sensor data such as speed and direction in real-time, whereas the visual interface approaches, including TADPo Le, do not. Evaluation Protocols: We benchmark all text-conditioned methods with a corresponding standardized prompt for fair comparison, and report both quantitative as well as qualitative comparisons. We use cumulative ground-truth rewards as quantitative evaluation metrics for Dog and Humanoid when it is available. We note this is a naturally unfavorable comparison for methods that provide a text-conditioned reward signal purely through a visual interface, as the reward the agent receives has no access to the underlying sensors (such as ones that measure speed and energy usage) that the ground-truth reward function uses to evaluate performance. For example, the ground-truth reward function may have an arbitrary threshold on a speed sensor that needs to be hit to constitute successful walking , and a separate threshold for running ; however the detailed characteristics of and even existence of such a sensor, as well as any thresholds surrounding it, are hidden for policies supervised only through vision and language feedback. Nonetheless, it offers a standardized, numerical comparison across all methods. For Meta-World, we report the success rate evaluation metric, computed as the proportion of evaluation rollouts in which the agent successfully completes the given task. Table 1: Results for goal-achievement experiments on Deep Mind Control Suite Dog and Humanoid environments. For rows with an associated ground-truth reward function, numerical results are listed; for performant approaches, we report mean and standard deviation across 5 seeds. For novel zero-shot text-conditioned behavior learning, checkmarks denote if the resulting policy is aligned with the provided text prompt according to human evaluation. Environment Prompt VLM-RM LIV Text2Reward TADPo Le (Ours) Ground-Truth Humanoid a person standing 247.05 ( 16.90) 11.27 10.50 254.43 ( 8.76) 287.68 ( 4.64) Humanoid a person in lotus position Humanoid a person doing splits Humanoid a person kneeling Dog a dog standing Prompt TADPo Le Naturalness ( ) a dog standing 87.5% a person in lotus position 62.5% a person doing splits 62.5% a person kneeling 70.8% a person walking 84.0% a dog walking 76.0% Figure 4: TADPo Le demonstrates sensitivity to subtle variations to the input prompt, learning to stand in different positions with only slight modifications to the text conditioning. Table 2: Qualitative study: percentages denote user preference for the naturalness of the resulting motion produced by TADPo Le over VLMRM (goal-achievement) and Video-TADPo Le over Vi CLIP-RM (continuous locomotion). A main benefit of utilizing a reward signal conditioned flexibly on text is the ability to learn policies with behaviors beyond those defined by existing ground-truth reward functions. As these have no corresponding ground-truth reward functions, quantitative comparison across different textconditioned methods is challenging; we therefore appeal to a qualitative user study. We perform a paid study through the Prolific platform, with a total of 25 anonymous random participants without prior training to estimate a general response from the human population. For a video demonstration from each trained model, selected as the last timestep of policy training without cherry-picking, each participant is asked if it sufficiently aligns with the text prompt it was conditioned on. These results are depicted in tables as checkmarks ( ) and x-marks ( ), where a checkmark denotes if a majority of participants believe it is text-aligned. In Table A7, we provide the fine-grained user study results on what percentage of the users believe the video achieved by the policy is appropriately text-aligned. We then proceed with a user study regarding naturalness. Given a video produced by VLM-RM and TADPo Le, users are given a choice as to which they believed to be the more natural motion or pose. This seeks to approximate how naturally the resulting Humanoid and Dog policies behave, according to human belief over how people and dogs naturally move in the real world. 4.2 Goal Achievement For text-conditioned goal-achievement, the objective is to learn a policy to consistently achieve a particular pose described by a text prompt; as the emphasis is for every frame to match a fixed goal pose rather than performing continuous motion, it is natural to apply TADPo Le with text-to-image diffusion models. We set the noise level tnoise U(400, 500), with intuition provided in Appendix A. In the Humanoid environment, there is a ground-truth reward function that measures standing performance, as a function of the straightness of the agent s spine. We therefore compare all textconditioned methods using the provided reward function as a quantitative metric, with a standard prompt of a person standing ; these results are shown in the first row of Table 1. TADPo Le and VLM-RM achieve competitive quantitative performance with an agent trained on the ground-truth reward function. The following rows show that according to the user study, TADPo Le consistently achieves text-aligned behaviors beyond making the Humanoid stand, whereas other approaches often fail. Table 2 shows that users consistently found TADPo Le to produce more natural-looking motions and poses when compared head-to-head with VLM-RM. Table 3: Results for continuous locomotion experiments. For rows with an associated ground-truth reward function, numerical results are listed; for performant approaches, we report mean and standard deviation across 5 seeds. Evaluation for text-alignment is also reported. Video-TADPo Le greatly outperforms Vi CLIP-RM on both Humanoid and Dog. Environment Prompt LIV Text2Reward Video-TADPo Le (Ours) Vi CLIP-RM Ground-Truth Humanoid a person walking 0.65 3.35 145.60 ( 48.20) 25.51 ( 40.45) 275.06 ( 9.21) Dog a dog walking 16.86 63.15 60.20 ( 8.82) 14.67 ( 9.84) 280.07 ( 3.07) Humanoid a person walking Dog a dog walking We then investigate whether or not TADPo Le is sensitive to subtle variations of the input prompt. We change the text prompt from a person standing to a person standing with hands above head and a person standing with hands on hips . In Figure 4, we visually verify that the resulting Humanoid policy can indeed learn distinct behaviors that respect the different hand placement specifications. We take this as evidence that TADPo Le is capable of respecting fine-grained details and subtleties of the input prompts when learning text-conditioned policies. 4.3 Continuous Locomotion We further explore the ability of TADPo Le to learn continuous locomotion behaviors conditioned on natural language specifications. Such tasks are often difficult to learn purely from static external description, as there is no canonical pose or goal frame that if reached, would denote successful achievement of the task. This is challenging for approaches that statically select a canonical goalframe to achieve, such as CLIP or LIV, and we propose Video-TADPo Le, which leverages large-scale pretrained text-to-video generative models, as a promising direction forward. We utilize a noise level tnoise U(500, 600) in our continuous locomotion experiments. We perform a search over context windows of size n = {1, 2, 4, 8}, and report the best configuration per task. We observe that when the context window is too high (e.g. 8 or higher), the agent has consistently lower performance, and that although the agent learns coherent motion and repeats it, the pose is less text-aligned. For fair comparison against a text-video alignment model trained in a contrastive manner, we extend VLM-RM to Vi CLIP-RM, where a Vi CLIP-L-14 checkpoint [40] finetuned from Vi T-L-14 CLIP is used to compute dense, text-conditioned rewards. At each timestep t, we compute dense rewards as cosine similarity between the encoded representations of video observation up to t + 1 and the text prompt. We ask Vi CLIP to encode 8 video frames at a time, which is adopted by its authors for zero-shot experiments. For the Humanoid task, we find that Video-TADPo Le achieves the best results amongst methods trained purely from visual and/or language feedback as in Table 3. On the other hand, Vi CLIP-RM indeed learns to take steps, but does so sideways while maintaining an unnaturally lopsided pose. Meanwhile, LIV and Text2Reward fail to learn meaningful behaviors. For the Dog task, we notice that the policy learned via Vi CLIP-RM collapses; it learns to strike a particular pose and maintain it for perpetuity. Text2Reward, which does not have access to any visual information, but does have access to ground-truth state information for the Dog including speed, direction, and joint positions, achieves a reward of 63.15. Ultimately, Video-TADPo Le achieves a comparable result using a context window of 4, while also distinguishing itself as the most naturallooking policy in qualitative terms as the Dog agent appears to perform step-taking motions, rather than remain stationary. Table 2 further showcases a higher preference for the naturalness of the learned policies for continuous locomotion achieved by Video-TADPo Le compared to Vi CLIP-RM, in both Dog and Humanoid environments. In Figure 5, we visualize episode return curves achieved by Video-TADPo Le for a Humanoid agent with the prompt a person walking . We visualize how during training, the computed Video-TADPo Le reward shares a positive correlation with the reward computed by a ground-truth function for walking over all episodes, lending confidence to it as a coherent, well-defined reward function. We also visualize the ground-truth evaluation curve. Figure A4 offers another example for a dog walking . 0.0 0.5 1 1.5 2 Environment Steps (1e6) Episode Return (Humanoid Walk) Video-TADPo Le (Train) 0.0 0.5 1 1.5 2 Environment Steps (1e6) Ground-Truth (Train) 0.0 0.5 1 1.5 2 Environment Steps (1e6) Ground-Truth (Evaluation) Figure 5: Episode return curves for a Humanoid agent trained with Video-TADPo Le, using the prompt a person walking . We observe that the Video-TADPo Le reward signal (left) is positively correlated with the agent s performance as measured with ground-truth reward during training (middle) and evaluation (right). Shaded regions denote the standard deviation across five random seeds. Table 4: Average success rate for robotic manipulation tasks in Meta-World [42] over 30 evaluation rollouts. We compare between TADPo Le and VLM-RM, both approaches that do not utilize indomain data or demonstrations, and find TADPo Le significantly outperforms VLM-RM. We report mean performance and standard deviation across 10 seeds for each task. Success Rate (%) Door Open Door Close Drawer Open Drawer Close Window Open Window Close VLM-RM 0 ( 0) 79.7 ( 39.8) 10.0 ( 30.0) 100.0 ( 0) 9.7 ( 29.0) 0 ( 0) TADPo Le 40.0 ( 49.0) 100.0 ( 0) 45.3 ( 46.6) 100.0 ( 0) 74.0 ( 37.9) 30.0 ( 45.8) Success Rate (%) Coffee Push Button Press Soccer Lever Pull Average VLM-RM 4.0 ( 12.0) 30.0 ( 45.8) 5.3 ( 11.6) 11.3 ( 18.3) 25.0 TADPo Le 18.6 ( 20.5) 73.0 ( 38.5) 25.0 ( 15.4) 0 ( 0) 50.6 4.4 Robotic Manipulation We further investigate how well TADPo Le can be applied to learn robotic manipulation tasks through dense text-conditioned feedback. We do so by replacing the manually-designed ground-truth dense reward for each Meta-World task with TADPo Le s text-conditioned reward. Since TADPo Le aims to leverage domain-agnostic diffusion models for policy learning, we focus our evaluation to compare with baseline methods that also do not utilize in-domain (expert) demonstrations for the robotic manipulation tasks. We note that most of the prior methods which report performance on Meta-World rely on (often expert-produced) video demonstrations from a similar domain or the target environment directly for representation learning [23], reward learning [18], or both [20]. They are thus not directly comparable to TADPo Le. We perform thorough comparisons between TADPo Le and VLM-RM by evaluating them on a diverse set of selected Meta-World tasks. Both models reuse the setup in Section 4.2 without modification, with training performed for 700k steps. In Table 4, we report the final success rate for each manipulation task averaged over 30 evaluation rollouts. We highlight that TADPo Le achieves high success rates across a variety of tasks, and significantly exceeds VLM-RM in terms of average overall performance. We take this as a positive signal that TADPo Le can meaningfully provide dense text-conditioned rewards that replace dense ground-truth hand-designed feedback. We also highlight how TADPo Le is able to successfully supervise the learning of policies within the synthetic-looking visual environment of Meta-World without finetuning the pretrained text-to-image diffusion model, despite the visual attributes (such as the appearance of the robotic arm, or the quality of the renderings) being quite dissimilar from the style of images Stable Diffusion was trained on. 4.5 Normalization Study Of interest is what reward normalization technique is most performant for adjusting the raw computed alignment and reconstruction terms into a final reward used for policy learning. We investigate a Table 5: Quantitative results for TADPo Le and Video-TADPo Le with and without the symlog normalization operation, averaged over 3 seeds. Hyperparameters such as weights and noise level were kept the same across all experiments. We discover that not only does using the symlog transformation enable the highest empirical rewards, it also facilitates the reuse of hyperparameters across tasks, environments, and other diffusion models. Environment Method Prompt Sym Log Direct Scaling Sym Exp Min-Max Standardization Humanoid TADPo Le a person standing" 267.23 239.74 241.49 256.81 236.59 Humanoid Video-TADPo Le a person walking" 226.29 4.58 3.68 61.31 134.66 Dog Video-TADPo Le a dog walking" 81.22 35.30 9.46 6.15 5.05 variety of normalization strategies in a quantitative manner in Table 5, reusing parameters w1 = 2000 and w2 = 200 across experiments, the selection of which is detailed in Section B.3 and Table A4. Apart from the symlog transformation, we also compare against using no additional normalization (denoted as Direct Scaling ), and using symexp. We also compare against empirical normalization techniques. This includes min-max rescaling, where an empirically estimated minimum value is subtracted from the achieved reward, which is then divided by an empirically calculated min-max range, and rescaled to [ 1, 1]. This also includes standardization, which subtracts an empirically estimated mean from the achieved reward and then divides it by an empirically estimated standard deviation. We apply these techniques across Humanoid and Dog environments, for both TADPo Le and Video-TADPo Le. We discover that the symlog operation is the reward normalization strategy that achieves the best empirical results across robotic configurations, visual environments, and desired tasks, while reusing the same hyperparameter settings. We hypothesize that it helps to normalize the raw computed reward signals across diffusion models and environments to be roughly on the same scale. Indeed, we showcase how removing the symlog transformation, as well as using other normalization techniques, reduces consistent policy learning performance across environments and diffusion models with the same fixed hyperparameters. We further note that it does not require empirically estimated values, unlike min-max and standardization. 5 Conclusion and Future Work We present Text-Aware Diffusion for Policy Learning (TADPo Le), a framework that optimizes a policy according to a provided natural language prompt through a pretrained text-conditioned diffusion model. TADPo Le enables novel behaviors to be learned in a zero-shot manner purely from text conditioning, and also offers a promising angle to train policies to behave in accordance with natural priors summarized from large-scale pretraining. TADPo Le can be applied across visual environments and different robotic states without modification, and we experimentally demonstrate that TADPo Le is able to learn novel goal-achievement as well as continuous locomotion behaviors conditioned only on text, across Humanoid, Dog, and Meta-World environments. Limitations: An observed limitation of TADPo Le is that it is difficult to explicitly control the weight each individual word of an input text prompt has on the reward provided to the agent. For certain prompts, TADPo Le could potentially cause the agent to remain stationary since it may focus on alignment with the noun in the phrase rather than details of the goal. How to provide fine-grained control over the text-conditioning is an interesting direction to explore in future work. Further interesting future work includes utilizing multiple camera views simultaneously to compute the dense reward, as environments generally allow flexible rendering from arbitrary angles. Another observed limitation is that TADPo Le depends on a highly stochastic operation, namely, repeatedly resampling a Gaussian source noise vector at each timestep. The behavior of the resulting policy, after training for many iterations, can therefore vary for the same input text prompt, and potentially cause high variance in both visual and quantitative performance. How to control the stability of convergence to a consistent policy across repeated runs is an interesting future direction for exploration. Acknowledgements. We would like to thank Amil Merchant, Daniel Ritchie, David Bau, Ben Poole, Ting Chen, Nate Gillman, and Yilun Du for helpful discussions and feedback. This work is supported by Samsung Advanced Institute of Technology, NASA, and a Richard B. Salomon Faculty Research Award for Chen Sun. Our research was conducted using computational resources at the Center for Computation and Visualization at Brown University. [1] Michael Ahn, Anthony Brohan, Noah Brown, Yevgen Chebotar, Omar Cortes, Byron David, Chelsea Finn, Keerthana Gopalakrishnan, Karol Hausman, Alex Herzog, et al. Do as i can, not as i say: Grounding language in robotic affordances. ar Xiv preprint ar Xiv:2204.01691, 2022. [2] Mazen Al Borno, Martin De Lasa, and Aaron Hertzmann. Trajectory optimization for full-body movements with complex contacts. IEEE transactions on visualization and computer graphics, 19(8):1405 1414, 2012. [3] Omer Bar-Tal, Hila Chefer, Omer Tov, Charles Herrmann, Roni Paiss, Shiran Zada, Ariel Ephrat, Junhwa Hur, Yuanzhen Li, Tomer Michaeli, et al. Lumiere: A space-time diffusion model for video generation. ar Xiv preprint ar Xiv:2401.12945, 2024. [4] Lynch Corey and Sermanet Pierre. Language conditioned imitation learning over unstructured data. In Robotics: Science and Systems Conference (RSS), 2020. [5] Prafulla Dhariwal and Alexander Nichol. Diffusion models beat gans on image synthesis. Advances in Neural Information Processing Systems, 34:8780 8794, 2021. [6] Yilun Du, Sherry Yang, Bo Dai, Hanjun Dai, Ofir Nachum, Josh Tenenbaum, Dale Schuurmans, and Pieter Abbeel. Learning universal policies via text-guided video generation. In Conference on Neural Information Processing Systems (Neur IPS), 2023. [7] Yilun Du, Sherry Yang, Pete Florence, Fei Xia, Ayzaan Wahid, brian ichter, Pierre Sermanet, Tianhe Yu, Pieter Abbeel, Joshua B. Tenenbaum, Leslie Pack Kaelbling, Andy Zeng, and Jonathan Tompson. Video language planning. In International Conference on Learning Representations (ICLR), 2024. [8] Alejandro Escontrela, Ademi Adeniji, Wilson Yan, Ajay Jain, Xue Bin Peng, Ken Goldberg, Youngwoon Lee, Danijar Hafner, and Pieter Abbeel. Video prediction models as rewards for reinforcement learning. In Advances in Neural Information Processing Systems, 2023. [9] Torabi Faraz, Warnell Garrett, and Stone Peter. Behavioral cloning from observation. In International Joint Conference on Artificial Intelligence, 2018. [10] Rohit Girdhar, Mannat Singh, Andrew Brown, Quentin Duval, Samaneh Azadi, Sai Saketh Rambhatla, Akbar Shah, Xi Yin, Devi Parikh, and Ishan Misra. Emu video: Factorizing text-tovideo generation by explicit image conditioning. In European Conference on Computer Vision (ECCV), 2024. [11] Pierre-Louis Guhur, Shizhe Chen, Ricardo Garcia Pinel, Makarand Tapaswi, Ivan Laptev, and Cordelia Schmid. Instruction-driven history-aware policies for robotic manipulations. In Conference on Robot Learning, pages 175 187. PMLR, 2023. [12] Yuwei Guo, Ceyuan Yang, Anyi Rao, Zhengyang Liang, Yaohui Wang, Yu Qiao, Maneesh Agrawala, Dahua Lin, and Bo Dai. Animatediff: Animate your personalized text-to-image diffusion models without specific tuning. International Conference on Learning Representations, 2024. [13] Danijar Hafner, Jurgis Pasukonis, Jimmy Ba, and Timothy Lillicrap. Mastering diverse domains through world models. ar Xiv preprint ar Xiv:2301.04104, 2023. [14] Nicklas Hansen, Xiaolong Wang, and Hao Su. Temporal difference learning for model predictive control. In International Conference on Machine Learning (ICML), 2022. [15] Jonathan Ho, William Chan, Chitwan Saharia, Jay Whang, Ruiqi Gao, Alexey Gritsenko, Diederik P Kingma, Ben Poole, Mohammad Norouzi, David J Fleet, et al. Imagen video: High definition video generation with diffusion models. ar Xiv preprint ar Xiv:2210.02303, 2022. [16] Jonathan Ho, Ajay Jain, and Pieter Abbeel. Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840 6851, 2020. [17] Jonathan Ho and Tim Salimans. Classifier-free diffusion guidance. ar Xiv preprint ar Xiv:2207.12598, 2022. [18] Tao Huang, Guangqi Jiang, Yanjie Ze, and Huazhe Xu. Diffusion reward: Learning rewards via conditional video diffusion. European Conference on Computer Vision (ECCV), 2024. [19] Corey Lynch, Ayzaan Wahid, Jonathan Tompson, Tianli Ding, James Betker, Robert Baruch, Travis Armstrong, and Pete Florence. Interactive language: Talking to robots in real time. IEEE Robotics and Automation Letters, 2023. [20] Yecheng Jason Ma, Vikash Kumar, Amy Zhang, Osbert Bastani, and Dinesh Jayaraman. LIV: language-image representations and rewards for robotic control. In International Conference on Machine Learning (ICML), 2023. [21] Parsa Mahmoudieh, Deepak Pathak, and Trevor Darrell. Zero-shot reward specification via grounded natural language. In International Conference on Machine Learning, pages 14743 14752. PMLR, 2022. [22] Yao Mu, Qinglong Zhang, Mengkang Hu, Wenhai Wang, Mingyu Ding, Jun Jin, Bin Wang, Jifeng Dai, Yu Qiao, and Ping Luo. Embodiedgpt: Vision-language pre-training via embodied chain of thought. Advances in Neural Information Processing Systems, 36, 2024. [23] Suraj Nair, Aravind Rajeswaran, Vikash Kumar, Chelsea Finn, and Abhinav Gupta. R3m: A universal visual representation for robot manipulation. In 6th Annual Conference on Robot Learning, 2022. [24] Xue Bin Peng, Ze Ma, Pieter Abbeel, Sergey Levine, and Angjoo Kanazawa. Amp: Adversarial motion priors for stylized physics-based character control. ACM Transactions on Graphics (To G), 40(4):1 20, 2021. [25] Ben Poole, Ajay Jain, Jonathan T. Barron, and Ben Mildenhall. Dream Fusion: text-to-3d using 2d diffusion. In International Conference on Learning Representations (ICLR), 2023. [26] Aaron L Putterman, Kevin Lu, Igor Mordatch, and Pieter Abbeel. Pretraining for language conditioned imitation with transformers. In Offline Reinforcement Learning Workshop at Neural Information Processing Systems, 2021. [27] Alec Radford, Jong Wook Kim, Chris Hallacy, Aditya Ramesh, Gabriel Goh, Sandhini Agarwal, Girish Sastry, Amanda Askell, Pamela Mishkin, Jack Clark, et al. Learning transferable visual models from natural language supervision. In International conference on machine learning, pages 8748 8763. PMLR, 2021. [28] Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan Narang, Michael Matena, Yanqi Zhou, Wei Li, and Peter J Liu. Exploring the limits of transfer learning with a unified text-to-text transformer. The Journal of Machine Learning Research, 21(1):5485 5551, 2020. [29] Aditya Ramesh, Prafulla Dhariwal, Alex Nichol, Casey Chu, and Mark Chen. Hierarchical text-conditional image generation with clip latents. ar Xiv preprint ar Xiv:2204.06125, 2022. [30] Juan Rocamonde, Victoriano Montesinos, Elvis Nava, Ethan Perez, and David Lindner. Visionlanguage models are zero-shot reward models for reinforcement learning. In International Conference on Learning Representations (ICLR), 2024. [31] Robin Rombach, Andreas Blattmann, Dominik Lorenz, Patrick Esser, and Björn Ommer. Highresolution image synthesis with latent diffusion models. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition, pages 10684 10695, 2022. [32] Chitwan Saharia, William Chan, Saurabh Saxena, Lala Li, Jay Whang, Emily L. Denton, Kamyar Ghasemipour, Raphael Gontijo Lopes, Burcu Karagol Ayan, Tim Salimans, Jonathan Ho, David J. Fleet, and Mohammad Norouzi. Photorealistic text-to-image diffusion models with deep language understanding. In Conference on Neural Information Processing Systems (Neur IPS), 2022. [33] Christoph Schuhmann, Richard Vencu, Romain Beaumont, Robert Kaczmarczyk, Clayton Mullis, Aarush Katta, Theo Coombes, Jenia Jitsev, and Aran Komatsuzaki. Laion-400m: Open dataset of clip-filtered 400 million image-text pairs. ar Xiv preprint ar Xiv:2111.02114, 2021. [34] Jascha Sohl-Dickstein, Eric Weiss, Niru Maheswaranathan, and Surya Ganguli. Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256 2265. PMLR, 2015. [35] Yang Song and Stefano Ermon. Generative modeling by estimating gradients of the data distribution. Advances in neural information processing systems, 32, 2019. [36] Yang Song, Jascha Sohl-Dickstein, Diederik P Kingma, Abhishek Kumar, Stefano Ermon, and Ben Poole. Score-based generative modeling through stochastic differential equations. In International Conference on Learning Representations (ICLR), 2021. [37] Sumedh Sontakke, Jesse Zhang, Séb Arnold, Karl Pertsch, Erdem Bıyık, Dorsa Sadigh, Chelsea Finn, and Laurent Itti. Roboclip: One demonstration is enough to learn robot policies. In Conference on Neural Information Processing Systems (Neur IPS), 2023. [38] Emanuel Todorov, Tom Erez, and Yuval Tassa. Mujoco: A physics engine for model-based control. In 2012 IEEE/RSJ international conference on intelligent robots and systems, pages 5026 5033. IEEE, 2012. [39] Saran Tunyasuvunakool, Alistair Muldal, Yotam Doron, Siqi Liu, Steven Bohez, Josh Merel, Tom Erez, Timothy Lillicrap, Nicolas Heess, and Yuval Tassa. dm_control: Software and tasks for continuous control. Software Impacts, 6:100022, 2020. [40] Yi Wang, Yinan He, Yizhuo Li, Kunchang Li, Jiashuo Yu, Xin Ma, Xinhao Li, Guo Chen, Xinyuan Chen, Yaohui Wang, et al. Internvid: A large-scale video-text dataset for multimodal understanding and generation. In The Twelfth International Conference on Learning Representations, 2023. [41] Tianbao Xie, Siheng Zhao, Chen Henry Wu, Yitao Liu, Qian Luo, Victor Zhong, Yanchao Yang, and Tao Yu. Text2reward: Reward shaping with language models for reinforcement learning. In International Conference on Learning Representations (ICLR), 2024. [42] Tianhe Yu, Deirdre Quillen, Zhanpeng He, Ryan Julian, Karol Hausman, Chelsea Finn, and Sergey Levine. Meta-world: A benchmark and evaluation for multi-task and meta reinforcement learning. In Conference on robot learning, pages 1094 1100. PMLR, 2020. A Intuition Regarding A Reasonable Noise Level Range We desire a reward signal that is high when the text prompt is well-aligned with the frame rendered following a well-selected action. However, we find that using too high or too low a noise level will cause the reward computation to ignore or discount the provided text prompt. For a sufficiently low noise value, the conditional and unconditional noise prediction is similar for a particular text prompt and rendered frame that already has high cross-modal alignment. Being already close in data space to the desired mode described by the text prompt, the unconditional prediction will also cheaply seek to denoise the input towards the original input. Therefore, too low a noise value may cause the computed reward signal to decrease as cross-modal alignment increases, which runs counter to what is desirable. This is supported by looking at the left tails of the two graphs depicted in Figure A1, where the difference in computed TADPo Le rewards between well-aligned paired inputs and misaligned paired inputs is small. Similarly, choosing a sufficiently high noise value may also cause unconditional and conditional predictions to be similar. For a given noisy input with virtually all of the spatial structure perturbed, the pretrained denoising model intuitively makes denoising predictions that fill in general structure to the image irrespective of text-conditioning. This is intuitively similar to the behavior of an unconditional prediction. Once again, we can visually observe this in the right tails of both graphs in Figure A1; for high noise values, both misaligned and well-aligned paired inputs have similar computed TADPo Le rewards. Intuitively, TADPo Le is able to meaningfully quantify text-conditioned alignment with rendered observations into a reward signal for a noise level range approximately in the middle. For a balanced level of noise corruption on a text-aligned rendered observation, there is enough existing visual structure to help the denoising model make a meaningful text-conditioned prediction close to the original input, whereas an unconditional prediction may not do so accurately. In Figure A1, we observe that for a noise range in the middle, TADPo Le is able to substantially favor the well-aligned pair over the misaligned pair, respecting changes in both text prompt as well as rendered observations. We verify in our experiments that using a noise level between 400 and 500 works well for TADPo Le, across both Dog and Humanoid environments. Figure A1: Noise range intuition for a fixed image but two distinct prompts (left), and for a fixed prompt but two distinct images (right). Through visualization, we verify that U(400, 500) is a reasonable range from which to sample noise levels that can meaningfully distinguish vision-text alignment for arbitrarily rendered frames. A.1 Noise Level for Video-TADPo Le We discover that Video-TADPo Le achieves better performance with a higher noise level than TADPo Le, and use a range of 500 to 600 in our experiments. We hypothesize that being able to observe multiple frames at once enables the space-time U-Net to exploit uncorrupted (or lesser-corrupted) portions from adjacent frames across the context window to inform how each individual frame should be denoised coherently. Because each frame in a context window has a distinct source noise applied to it, structural information can be leaked from randomly uncorrupted portions of the other frames in the context window when making predictions. Therefore, to make the denoising prediction more challenging, thereby forcing it to rely on the text-conditioning and learned motion priors rather than what is readily extractable from the provided context, generally a higher noise level is acceptable compared to TADPo Le. B Detailed Hyperparameters In our experiments, we place less emphasis on the underlying architecture and optimization scheme, instead comparing our method against other text-conditioned reward functions. We keep the same reinforcement learning architecture, optimization scheme, and text-to-image/text-to-video generative model in all environments, unless otherwise noted. We provide detailed hyperparameters about these existing components below. B.1 Pretrained Text-Conditioned Diffusion Models We utilize a Stable Diffusion v2.1 checkpoint for our TADPo Le experiments. We provide the sizes of the components in Table A1. For Video-TADPo Le experiments, we use a pretrained Animate Diff checkpoint, and provide relevant details in Table A2. We do not update or modify either checkpoint during our training, utilizing them purely for inference. We include the default hyperparameters from the TD-MPC implementation in Table A3 for completeness. We do not modify the default recommended settings for both Humanoid and Dog environments, as well as the Meta-World experiments. Table A1: Stable Diffusion Components. For completeness, we list sizes of the components of the Stable Diffusion v2.1 checkpoint used in TADPo Le experiments. The checkpoint is used purely for inference, and is not modified or updated in any way. Note that the VAE Decoder is not utilized in our framework. Component # Parameters (Millions) VAE (Encoder) 34.16 VAE (Decoder) 49.49 U-Net 865.91 Text Encoder 340.39 Table A2: Animate Diff Components. For completeness, we list sizes of the components of the Animate Diff checkpoint used in Video TADPo Le experiments. The checkpoint is used purely for inference, and is not modified or updated in any way. Note that the VAE Decoder is not utilized in our framework. Component # Parameters (Millions) VAE (Encoder) 34.16 VAE (Decoder) 49.49 U-Net 1312.73 Text Encoder 123.06 Table A3: TD-MPC hyperparameters. We use the official implementation TD-MPC [14] with no adjustments to the hyperparameters, but list it below for completeness. However, we do set the number of training steps to 2 million for all experiments using TD-MPC. Hyperparameter Value Discount factor (γ) 0.99 Seed steps 5, 000 Replay buffer size Unlimited Sampling technique PER (α = 0.6, β = 0.4) Planning horizon (H) 5 Initial parameters (µ0, σ0) (0, 2) Population size 512 Elite fraction 64 Iterations 12 (Humanoid) 8 (Dog) Policy fraction 5% Number of particles 1 Momentum coefficient 0.1 Temperature (τ) 0.5 MLP hidden size 512 MLP activation ELU Latent dimension 100 (Humanoid, Dog) Learning rate 3e-4 (Dog) 1e-3 (Humanoid) Optimizer (θ) Adam (β1 = 0.9, β2 = 0.999) Temporal coefficient (λ) 0.5 Reward loss coefficient (c1) 0.5 Value loss coefficient (c2) 0.1 Consistency loss coefficient (c3) 2 Exploration schedule (ϵ) 0.5 0.05 (25k steps) Planning horizon schedule 1 5 (25k steps) Batch size 2048 (Dog) 512 (Humanoid) Momentum coefficient (ζ) 0.99 Steps per gradient update 1 θ update frequency 2 B.3 Selecting w1 and w2 We select hyperparameters w1 and w2, which scale the alignment term ralign and the reconstruction term rrec respectively, firstly such that the resulting computed reward r has value roughly between 0 and 1 at any arbitrary timestep. This is visualized in Figure A1, where over all noise levels, the computed reward stays roughly between 0 and 1. Because the same pretrained text-conditioned diffusion model is used across all environments without modification, these hyperparameters can be generally reused to achieve the same kind of reward scale across environments. We found that the values of w1 = 2000 and w2 = 200 through a light hyperparameter sweep, reported in Table A4, and indeed verify that they work well without modification across both Humanoid and Dog environments in our main experiments. Table A4: Ablation over w1 and w2 on Humanoid Stand and Walk w1 w2 Humanoid Stand Humanoid Walk 200 2000 249.82 2.72 1000 2000 240.05 121.20 2000 200 262.22 226.29 2000 1000 195.87 152.32 2000 2000 218.22 90.20 C Meta-World Tasks We visualize the complete suite of selected Meta-World tasks in Figure A2 along with the official names of the tasks. In Table A5 we also list the corresponding prompts consistently utilized across all text-conditioned approaches. In Table A6, we list the average success for all 12 robotic manipulation tasks. As we add a sparse success signal to text-conditioned approaches such as VLM-RM and TADPo Le, following prior experimental design [18] for Meta-World, we also list the performance of utilizing the sparse signal only. We first notice that no approach is able to solve two selected tasks, Peg Insert Side and Shelf Place ; these were therefore omitted in Table 4. Furthermore, we observe that utilizing a sparse reward signal only appears to have strong default performance, and achieves a higher overall average success rate than TADPo Le or VLM-RM. This showcases the inherent power of a sparse reward in solving Meta-World tasks. However, there are two additional takeaways; firstly, VLM-RM surprisingly achieves a substantial decrease in performance from the default sparse reward signal, highlighting TADPo Le as a more preferable dense text-conditioned reward provider. Secondly, TADPo Le is able to solve more overall tasks than other approaches. In particular, TADPo Le can solve the Door Open task, which is completely unable to be solved by VLM-RM or using a sparse reward only. We therefore highlight TADPo Le as a promising text-conditioned reward signal in replacing ground-truth hand-designed feedback, particularly as the text-to-image diffusion model utillized was pretrained in a general manner, without finetuning explicitly on Meta-World demonstrations. Table A5: Meta-World Task-Prompt Pairs Task Text Prompt Door Open opening a door Door Close closing a door Drawer Open opening a drawer Drawer Close closing a drawer Window Open opening a window Window Close closing a window Coffee Push pushing a white mug towards the coffee machine Button Press pressing a button Soccer pushing a soccer ball into the net Peg Insert Side inserting a peg into the slot Shelf Place placing an object on the shelf Lever Pull pulling a lever Door Open Door Close Drawer Open Drawer Close Window Open Window Close Coffee Push Button Press Soccer Peg Insert Side Shelf Place Lever Pull Figure A2: Meta-World Tasks. We select 12 robotic arm tasks from Meta-World suite as our evaluation task set, balanced in terms of diversity and complexity. Table A6: Average success rate for 12 robotic manipulation tasks in Meta-World [42] over 30 evaluation rollouts. We compare between TADPo Le and VLM-RM, both approaches that do not utilize in-domain data or demonstrations, and find TADPo Le significantly outperforms VLM-RM. We report mean performance and standard deviation across 10 seeds for each task. Success Rate (%) Door Open Door Close Drawer Open Drawer Close Window Open Window Close Coffee Push Sparse 0 ( 0) 99.7 ( 1.0) 74.7 ( 28.7) 99.3 ( 2.0) 94.3 ( 5.8) 93.0 ( 16.9) 46.3 ( 11.3) VLM-RM 0 ( 0) 79.7 ( 39.8) 10.0 ( 30.0) 100 ( 0) 9.7 ( 29.0) 0 ( 0) 4.0 ( 12.0) TADPo Le 40.0 ( 49.0) 100 ( 0) 45.3 ( 46.6) 100 ( 0) 74.0 ( 37.9) 30.0 ( 45.8) 18.6 ( 20.5) Success Rate (%) Button Press Soccer Peg Insert Side Shelf Place Lever Pull Average Sparse 86.7 ( 29.1) 12.7 ( 14.1) 0 ( 0) 0 ( 0) 0 ( 0) 50.6 VLM-RM 30.0 ( 45.8) 5.3 ( 11.6) 0 ( 0) 0 ( 0) 11.3 ( 18.3) 20.8 TADPo Le 73.0 ( 38.5) 25.0 ( 15.4) 0 ( 0) 0 ( 0) 0 ( 0) 42.2 D Training Curves In our experiments, we compare against other methods that provide text-conditioned rewards. As each of these methods are formulated differently, the difference in scales naturally prevent easy direct comparison. However, plotting the training curves for TADPo Le does yield insights into its speed of convergence, and investigating the visual performance at intermediate steps can be interesting. In Figure A3 we showcase the TADPo Le training curves for a variety of novel text-conditioned policies. We highlight the performance at steps 500k, 1M, 1.5M, and 2M in red; we further visualize the policy achieved at these intermediate steps by showcasing the last frame of the achieved video. In the case of the policy learned for the prompt a person standing with hands on hips", for example, we see that whereas the initial policies fail, the policy first learns to stand up by step 1.5M. Then, by the last training step, the policy has learned to correctly place its hands conspicuously on its hips. Similarly, for the prompt a person kneeling", the policy first learns to kneel on all fours; by the end, the policy learns to successfully kneel on one knee. Figure A3: TADPo Le training curves for a variety of text-conditionings, with intermediate visualizations. The frames displayed are always the last frame achieved by the policy, at that particular training step. 0.0 0.5 1 1.5 2 Environment Steps (1e6) Episode Return (Dog Walk) Video-TADPo Le (Train) 0.0 0.5 1 1.5 2 Environment Steps (1e6) Ground-Truth (Train) 0.0 0.5 1 1.5 2 Environment Steps (1e6) Ground-Truth (Evaluation) Figure A4: Episode return curves of a Dog Walk agent trained with Video-TADPo Le, using the prompt a dog walking . From left to right: the cumulative Video-TADPo Le rewards achieved throughout training, the cumulative ground-truth rewards achieved throughout training, and the cumulative ground-truth rewards achieved during evaluation. Shaded regions denote the standard deviation across five random seeds. Table A7: Numerical results from the user study on text-alignment. Out of 25 anonymous users, for each method, we report the percentage that believe the video achieved by a policy at the end of training is aligned with the provided text prompt. Entries above 50% are displayed in Table 1 as checkmarks ( ); below 50% are displayed as x-marks ( ). Environment Prompt VLM-RM LIV Text2Reward TADPo Le (Ours) Humanoid a person in lotus position" 52% 28% 4% 60% Humanoid a person doing splits" 64% 88% 0% 84% Humanoid a person kneeling" 48% 4% 0% 64% Dog a dog standing" 16% 0% 40% 84% E Motivating Visualizations For further intuition on TADPo Le s behavior, we visualize the complete denoising results for a query video achieved through a Dog policy and corrupted with some level of noise, conditioned on a consistent text prompt of a dog walking". Note that this is purely for visualization purposes; in practice, when training policies, we do not visually denoise over multiple steps but instead extract a reward signal from components of a one-step denoising prediction. However, the multi-step denoising visualizations can offer us a glimpse of intuition into the behavior of the pretrained diffusion model and the properties of its predicted components at one single denoising step. We first find that Stable Diffusion, used in TADPo Le, is able to reconstruct a well-aligned policy rollout (a video of the Dog agent actually walking) relatively accurately frame-by-frame, for a noise level of 500 (Figure A5). However, the predictions can differ substantially for a misaligned policy rollout (a video of the Dog agent falling over rather than walking); for frames where the dog has collapsed on the floor, the Stable Diffusion model still tries to respect the specified input prompt and attempts to predict dogs standing upright or walking, as depicted in Figure A6, resulting in a more noticeable difference between the achieved frame and predicted frame. This difference can be exploited to distinguish between well-aligned and misaligned policy rollouts, lending confidence to Stable Diffusion as a supervisory signal for text-conditioned policy learning. For a higher noise level, Stable Diffusion quickly forms hallucinatory final predictions (depicted in Figures A7, A8), but preserves more of the structure of the original video when the achieved video and provided text prompt is aligned. We also visualize reconstruction predictions using a text-to-video model, namely an Animate Diff v2 checkpoint, in Figures A9 and A10. We find that the motion prior is indeed meaningful, enabling it to reconstruct the Dog with a coherent texture and pose over time. In Figures A11, A12 we highlight how a text-to-video model is more robust in reconstructing the achieved video by the policy at high noise levels compared with Stable Diffusion (Figures A7, A8). This supports the hypothesis outlined in Section A.1. Figure A5: Visualizing the denoising of a good query trajectory from a noise level of 500 to completion using per-frame Stable Diffusion. Figure A6: Visualizing the denoising of a failed query trajectory from a noise level of 500 to completion using per-frame Stable Diffusion. Figure A7: Visualizing the denoising of a good query trajectory from a noise level of 700 to completion using per-frame Stable Diffusion. Figure A8: Visualizing the denoising of a failed query trajectory from a noise level of 700 to completion using per-frame Stable Diffusion. Figure A9: Visualizing the denoising of a good query trajectory from a noise level of 500 to completion using Animate Diff. Figure A10: Visualizing the denoising of a failed query trajectory from a noise level of 500 to completion using Animate Diff. Figure A11: Visualizing the denoising of a good query trajectory from a noise level of 700 to completion using Animate Diff. Figure A12: Visualizing the denoising of a failed query trajectory from a noise level of 700 to completion using Animate Diff. Neur IPS Paper Checklist Question: Do the main claims made in the abstract and introduction accurately reflect the paper s contributions and scope? Answer: [Yes] Justification: In both the abstract and introduction, we state our main contribution we propose Text-Aware Diffusion for Policy Learning (TADPo Le) as the first approach to leverage domain-agnostic visual generative models for policy learning. TADPo Le uses a large-scale pretrained text-conditioned diffusion model in a discriminative manner to enable the learning of novel, zero-shot policies that are flexibly and accurately conditioned on natural language inputs, across multiple robot configurations and environments, for both goal-achievement and continuous locomotion tasks. We conduct thorough qualitative and quantitative evaluations across various benchmarks to experimentally support our claims. Guidelines: The answer NA means that the abstract and introduction do not include the claims made in the paper. The abstract and/or introduction should clearly state the claims made, including the contributions made in the paper and important assumptions and limitations. A No or NA answer to this question will not be perceived well by the reviewers. The claims made should match theoretical and experimental results, and reflect how much the results can be expected to generalize to other settings. It is fine to include aspirational goals as motivation as long as it is clear that these goals are not attained by the paper. 2. Limitations Question: Does the paper discuss the limitations of the work performed by the authors? Answer: [Yes] Justification: We have discussed the limitations of our work in the concluding section of the main paper, where we highlight the lack of fine-grained control over text conditioning and the high variance of the policy performance as two observed shortcomings of our proposed method that are promising future directions to explore. Guidelines: The answer NA means that the paper has no limitation while the answer No means that the paper has limitations, but those are not discussed in the paper. The authors are encouraged to create a separate "Limitations" section in their paper. The paper should point out any strong assumptions and how robust the results are to violations of these assumptions (e.g., independence assumptions, noiseless settings, model well-specification, asymptotic approximations only holding locally). The authors should reflect on how these assumptions might be violated in practice and what the implications would be. The authors should reflect on the scope of the claims made, e.g., if the approach was only tested on a few datasets or with a few runs. In general, empirical results often depend on implicit assumptions, which should be articulated. The authors should reflect on the factors that influence the performance of the approach. For example, a facial recognition algorithm may perform poorly when image resolution is low or images are taken in low lighting. Or a speech-to-text system might not be used reliably to provide closed captions for online lectures because it fails to handle technical jargon. The authors should discuss the computational efficiency of the proposed algorithms and how they scale with dataset size. If applicable, the authors should discuss possible limitations of their approach to address problems of privacy and fairness. While the authors might fear that complete honesty about limitations might be used by reviewers as grounds for rejection, a worse outcome might be that reviewers discover limitations that aren t acknowledged in the paper. The authors should use their best judgment and recognize that individual actions in favor of transparency play an important role in developing norms that preserve the integrity of the community. Reviewers will be specifically instructed to not penalize honesty concerning limitations. 3. Theory Assumptions and Proofs Question: For each theoretical result, does the paper provide the full set of assumptions and a complete (and correct) proof? Answer: [NA] Justification: We do not include any theoretical results in this work. Guidelines: The answer NA means that the paper does not include theoretical results. All the theorems, formulas, and proofs in the paper should be numbered and crossreferenced. All assumptions should be clearly stated or referenced in the statement of any theorems. The proofs can either appear in the main paper or the supplemental material, but if they appear in the supplemental material, the authors are encouraged to provide a short proof sketch to provide intuition. Inversely, any informal proof provided in the core of the paper should be complemented by formal proofs provided in appendix or supplemental material. Theorems and Lemmas that the proof relies upon should be properly referenced. 4. Experimental Result Reproducibility Question: Does the paper fully disclose all the information needed to reproduce the main experimental results of the paper to the extent that it affects the main claims and/or conclusions of the paper (regardless of whether the code and data are provided or not)? Answer: [Yes] Justification: We clearly describe our approach in the Method section (Section 3) and provide implementation details and evaluation protocols in the Experiments section (Section 4. In addition, we provide detailed hyperparameters in the Appendix (Section B). Our experiments are performed using publicly available pretrained diffusion models and algorithms, and our codebase will be released publicly to support full reproducibility. Guidelines: The answer NA means that the paper does not include experiments. If the paper includes experiments, a No answer to this question will not be perceived well by the reviewers: Making the paper reproducible is important, regardless of whether the code and data are provided or not. If the contribution is a dataset and/or model, the authors should describe the steps taken to make their results reproducible or verifiable. Depending on the contribution, reproducibility can be accomplished in various ways. For example, if the contribution is a novel architecture, describing the architecture fully might suffice, or if the contribution is a specific model and empirical evaluation, it may be necessary to either make it possible for others to replicate the model with the same dataset, or provide access to the model. In general. releasing code and data is often one good way to accomplish this, but reproducibility can also be provided via detailed instructions for how to replicate the results, access to a hosted model (e.g., in the case of a large language model), releasing of a model checkpoint, or other means that are appropriate to the research performed. While Neur IPS does not require releasing code, the conference does require all submissions to provide some reasonable avenue for reproducibility, which may depend on the nature of the contribution. For example (a) If the contribution is primarily a new algorithm, the paper should make it clear how to reproduce that algorithm. (b) If the contribution is primarily a new model architecture, the paper should describe the architecture clearly and fully. (c) If the contribution is a new model (e.g., a large language model), then there should either be a way to access this model for reproducing the results or a way to reproduce the model (e.g., with an open-source dataset or instructions for how to construct the dataset). (d) We recognize that reproducibility may be tricky in some cases, in which case authors are welcome to describe the particular way they provide for reproducibility. In the case of closed-source models, it may be that access to the model is limited in some way (e.g., to registered users), but it should be possible for other researchers to have some path to reproducing or verifying the results. 5. Open access to data and code Question: Does the paper provide open access to the data and code, with sufficient instructions to faithfully reproduce the main experimental results, as described in supplemental material? Answer: [Yes] Justification: Our codebase will be publicly released, along with detailed instructions to reproduce the main experimental results. Guidelines: The answer NA means that paper does not include experiments requiring code. Please see the Neur IPS code and data submission guidelines (https://nips.cc/ public/guides/Code Submission Policy) for more details. While we encourage the release of code and data, we understand that this might not be possible, so No is an acceptable answer. Papers cannot be rejected simply for not including code, unless this is central to the contribution (e.g., for a new open-source benchmark). The instructions should contain the exact command and environment needed to run to reproduce the results. See the Neur IPS code and data submission guidelines (https: //nips.cc/public/guides/Code Submission Policy) for more details. The authors should provide instructions on data access and preparation, including how to access the raw data, preprocessed data, intermediate data, and generated data, etc. The authors should provide scripts to reproduce all experimental results for the new proposed method and baselines. If only a subset of experiments are reproducible, they should state which ones are omitted from the script and why. At submission time, to preserve anonymity, the authors should release anonymized versions (if applicable). Providing as much information as possible in supplemental material (appended to the paper) is recommended, but including URLs to data and code is permitted. 6. Experimental Setting/Details Question: Does the paper specify all the training and test details (e.g., data splits, hyperparameters, how they were chosen, type of optimizer, etc.) necessary to understand the results? Answer: [Yes] Justification: We include training and evaluation details in the Experiments section (Section 4), along with detailed hyperparameters for all components of our method in the Appendix (Section B). Furthermore, for user study experiments, we have included the relevant decisions and details surrounding the collection procedure. Guidelines: The answer NA means that the paper does not include experiments. The experimental setting should be presented in the core of the paper to a level of detail that is necessary to appreciate the results and make sense of them. The full details can be provided either with the code, in appendix, or as supplemental material. 7. Experiment Statistical Significance Question: Does the paper report error bars suitably and correctly defined or other appropriate information about the statistical significance of the experiments? Answer: [Yes] Justification: We report error bars for goal achievements, continuous locomotion, and robotic manipulation experimental results, and explicitly state the number of seeds utilized. Guidelines: The answer NA means that the paper does not include experiments. The authors should answer "Yes" if the results are accompanied by error bars, confidence intervals, or statistical significance tests, at least for the experiments that support the main claims of the paper. The factors of variability that the error bars are capturing should be clearly stated (for example, train/test split, initialization, random drawing of some parameter, or overall run with given experimental conditions). The method for calculating the error bars should be explained (closed form formula, call to a library function, bootstrap, etc.) The assumptions made should be given (e.g., Normally distributed errors). It should be clear whether the error bar is the standard deviation or the standard error of the mean. It is OK to report 1-sigma error bars, but one should state it. The authors should preferably report a 2-sigma error bar than state that they have a 96% CI, if the hypothesis of Normality of errors is not verified. For asymmetric distributions, the authors should be careful not to show in tables or figures symmetric error bars that would yield results that are out of range (e.g. negative error rates). If error bars are reported in tables or plots, The authors should explain in the text how they were calculated and reference the corresponding figures or tables in the text. 8. Experiments Compute Resources Question: For each experiment, does the paper provide sufficient information on the computer resources (type of compute workers, memory, time of execution) needed to reproduce the experiments? Answer: [Yes] Justification: In the Experiments section (Section 4) we report that all of our experiments are performed on a single NVIDIA V100 GPU. Guidelines: The answer NA means that the paper does not include experiments. The paper should indicate the type of compute workers CPU or GPU, internal cluster, or cloud provider, including relevant memory and storage. The paper should provide the amount of compute required for each of the individual experimental runs as well as estimate the total compute. The paper should disclose whether the full research project required more compute than the experiments reported in the paper (e.g., preliminary or failed experiments that didn t make it into the paper). 9. Code Of Ethics Question: Does the research conducted in the paper conform, in every respect, with the Neur IPS Code of Ethics https://neurips.cc/public/Ethics Guidelines? Answer: [Yes] Justification: The research conducted in this paper adheres to the Neur IPS Code of Ethics. Guidelines: The answer NA means that the authors have not reviewed the Neur IPS Code of Ethics. If the authors answer No, they should explain the special circumstances that require a deviation from the Code of Ethics. The authors should make sure to preserve anonymity (e.g., if there is a special consideration due to laws or regulations in their jurisdiction). 10. Broader Impacts Question: Does the paper discuss both potential positive societal impacts and negative societal impacts of the work performed? Answer: [NA] Justification: There are no extremely noteworthy positive or negative societal consequences of our work. Guidelines: The answer NA means that there is no societal impact of the work performed. If the authors answer NA or No, they should explain why their work has no societal impact or why the paper does not address societal impact. Examples of negative societal impacts include potential malicious or unintended uses (e.g., disinformation, generating fake profiles, surveillance), fairness considerations (e.g., deployment of technologies that could make decisions that unfairly impact specific groups), privacy considerations, and security considerations. The conference expects that many papers will be foundational research and not tied to particular applications, let alone deployments. However, if there is a direct path to any negative applications, the authors should point it out. For example, it is legitimate to point out that an improvement in the quality of generative models could be used to generate deepfakes for disinformation. On the other hand, it is not needed to point out that a generic algorithm for optimizing neural networks could enable people to train models that generate Deepfakes faster. The authors should consider possible harms that could arise when the technology is being used as intended and functioning correctly, harms that could arise when the technology is being used as intended but gives incorrect results, and harms following from (intentional or unintentional) misuse of the technology. If there are negative societal impacts, the authors could also discuss possible mitigation strategies (e.g., gated release of models, providing defenses in addition to attacks, mechanisms for monitoring misuse, mechanisms to monitor how a system learns from feedback over time, improving the efficiency and accessibility of ML). 11. Safeguards Question: Does the paper describe safeguards that have been put in place for responsible release of data or models that have a high risk for misuse (e.g., pretrained language models, image generators, or scraped datasets)? Answer: [NA] Justification: We do not release data or models with a high risk for misuse. Guidelines: The answer NA means that the paper poses no such risks. Released models that have a high risk for misuse or dual-use should be released with necessary safeguards to allow for controlled use of the model, for example by requiring that users adhere to usage guidelines or restrictions to access the model or implementing safety filters. Datasets that have been scraped from the Internet could pose safety risks. The authors should describe how they avoided releasing unsafe images. We recognize that providing effective safeguards is challenging, and many papers do not require this, but we encourage authors to take this into account and make a best faith effort. 12. Licenses for existing assets Question: Are the creators or original owners of assets (e.g., code, data, models), used in the paper, properly credited and are the license and terms of use explicitly mentioned and properly respected? Answer: [Yes] Justification: We properly credit all publicly available codebases and models used in the paper. Their licenses and terms of use are properly respected. Guidelines: The answer NA means that the paper does not use existing assets. The authors should cite the original paper that produced the code package or dataset. The authors should state which version of the asset is used and, if possible, include a URL. The name of the license (e.g., CC-BY 4.0) should be included for each asset. For scraped data from a particular source (e.g., website), the copyright and terms of service of that source should be provided. If assets are released, the license, copyright information, and terms of use in the package should be provided. For popular datasets, paperswithcode.com/datasets has curated licenses for some datasets. Their licensing guide can help determine the license of a dataset. For existing datasets that are re-packaged, both the original license and the license of the derived asset (if it has changed) should be provided. If this information is not available online, the authors are encouraged to reach out to the asset s creators. 13. New Assets Question: Are new assets introduced in the paper well documented and is the documentation provided alongside the assets? Answer: [Yes] Justification: Along with the release of our codebase, we will provide well-documented instructions for reproducibility. Guidelines: The answer NA means that the paper does not release new assets. Researchers should communicate the details of the dataset/code/model as part of their submissions via structured templates. This includes details about training, license, limitations, etc. The paper should discuss whether and how consent was obtained from people whose asset is used. At submission time, remember to anonymize your assets (if applicable). You can either create an anonymized URL or include an anonymized zip file. 14. Crowdsourcing and Research with Human Subjects Question: For crowdsourcing experiments and research with human subjects, does the paper include the full text of instructions given to participants and screenshots, if applicable, as well as details about compensation (if any)? Answer: [NA] Justification: Although we queried anonymous humans for a user study of our achieved results, there was no direct research on or using human subjects. The anonymous humans in the user study were paid higher than the minimum wage of the country of the data collector. Guidelines: The answer NA means that the paper does not involve crowdsourcing nor research with human subjects. Including this information in the supplemental material is fine, but if the main contribution of the paper involves human subjects, then as much detail as possible should be included in the main paper. According to the Neur IPS Code of Ethics, workers involved in data collection, curation, or other labor should be paid at least the minimum wage in the country of the data collector. 15. Institutional Review Board (IRB) Approvals or Equivalent for Research with Human Subjects Question: Does the paper describe potential risks incurred by study participants, whether such risks were disclosed to the subjects, and whether Institutional Review Board (IRB) approvals (or an equivalent approval/review based on the requirements of your country or institution) were obtained? Answer: [NA] Justification: Although we queried anonymous humans for a user study of our achieved results, we do not perform any direct research with or on human subjects. Guidelines: The answer NA means that the paper does not involve crowdsourcing nor research with human subjects. Depending on the country in which research is conducted, IRB approval (or equivalent) may be required for any human subjects research. If you obtained IRB approval, you should clearly state this in the paper. We recognize that the procedures for this may vary significantly between institutions and locations, and we expect authors to adhere to the Neur IPS Code of Ethics and the guidelines for their institution. For initial submissions, do not include any information that would break anonymity (if applicable), such as the institution conducting the review.