A survey argues embodied agents fail mostly on memory, and benchmarks cannot tell memory use from general skill
AspireAI community · arXiv (cs.RO, cs.AI, cs.LG)
Foundation models have pushed embodied AI into navigation, manipulation and long-horizon tasks, but agents have to act on partial knowledge and retain, retrieve and update information from past observations, actions and experience. This survey organizes embodied memory along two dimensions: six fundamental memory requirements spanning world-state persistence, task progress, belief maintenance and experiential learning, and eight architectural categories including recurrent states, fast weights, visual and symbolic representations, spatial memory and experience-based systems. Its sharpest contribution is methodological: it argues existing benchmarks conflate genuine use of historical information with general task performance, and distinguishes the two. The open problems it flags are selecting relevant experiences, keeping beliefs consistent in changing environments, and consolidating knowledge across episodes. It is a survey, so it reports no new experimental results.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.