Denis Lan

@jonathannicholas.bsky.social

My first PhD paper - with @lhuntneuro.bsky.social and @summerfieldlab.bsky.social - is now out in @plosbiology.org! We ask: how do humans (and deep neural networks) navigate flexibly even in unfamiliar environments, such as a new city? Link: plos.io/45uSwNm 🧵 (1/6)

Denis Lan reposted

Jonathan Nicholas

19 June

We make flexible choices in new situations by knitting together information from separate relevant memories. But what governs which memories are retrieved and when? In a new preprint, we captured how people build decision variables from different memories by tracking their gaze on a blank screen.

biorxiv.orgFlexible decisions arise from resource-rational memory samplingFlexible decision making depends on retrieving and recombining memories. Yet because this process unfolds covertly, its governing principles remain unknown. Here we use gaze reinstatement to uncover t...

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We also identify ‘modules’ that appear causally important for implementing each strategy. These modules represent the environment differently: for eg, ‘vector’ units are more likely to have stable spatial representations, while ‘transition’ units are more likely to carry landmark information (5/6)

Overall, we hope that our paper sheds some light on how we combine strategies for flexible navigation, and how different representations in the brain may support different strategies. + see paper for some additional results about how humans select landmarks! (6/6)

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We find that humans did best when they could freely arbitrate between strategies - preferring vector-based strategies overall but transition-based strategies near learnt landmarks. Interestingly, deep meta-learning models developed strikingly similar behavioural profiles. (3/6)

We examined the representations learnt by networks for hints about how these strategies might be implemented in the brain. We find units that represent the environment in different ways - resembling diverse spatial representations observed in mammalian navigation systems. (4/6)