Angus Chapman
@afchapman.bsky.social
50 followers 100 following 5 posts
postdoc in computational and cognitive neuroscience at Boston University, soup fan
Posts Media Videos Starter Packs
afchapman.bsky.social
interestingly, attention didn't change the total size of the space, compared to perceptual judgements we measured without the interleaved attention task, consistent with normalization of the representations. we think this is a cool and novel way to look at the effects of attention - hope you agree!
afchapman.bsky.social
we measured the local length throughout the orientation space - the distance spanned in windows of the representation - to assess changes induced by attention. lengths were expanded in a narrow window around targets, but compressed in a broad window around distractors.
afchapman.bsky.social
our participants performed interleaved tasks, where they reported the perceived similarity between orientations under different attention conditions (attending 45° CW or CCW). we fit these responses with models based on MDS, finding that orientation representations were best accounted for in 4-D.
afchapman.bsky.social
excited to share this new preprint w/ Melissa and @racheldenison.bsky.social

we measured the representational geometry of orientations using behavioral similarity judgements, and found that attention expanded representations around target orientations with a broader compression around distractors
Attention reshapes the representational geometry of a perceptual feature space
Department of Psychological and Brain Sciences, Boston University Our perception of the world is transformed by attention, both in terms of the efficiency of information processing and the appearance ...
www.biorxiv.org
afchapman.bsky.social
recently posted a new preprint (the first of my postdoc 🎉) where we implemented normalization across space *and* time, allowing us to capture several neural and behavioral findings! I'll be presenting this work at VSS in a couple of months too for those attending
www.biorxiv.org/content/10.1...
A dynamic spatiotemporal normalization model for continuous vision
Perception and neural activity are profoundly shaped by the spatial and temporal context of sensory input, which has been modeled by divisive normalization over space or time. However, theoretical wor...
www.biorxiv.org