Multi-Feature Processing in Brains and Deep Neural Networks

In one of my central lines of work, I've been studying how visual systems, both biological and artificial, encode combinations of multiple visual features, focusing on color and shape representation. I have found that while the human visual system mostly tends to encode these variables in an orthogonal format, convolutional neural networks appear to process these features in an increasingly entangled manner over processing.

Color and form pattern stimuli (pink crosses and teal puzzle pieces) used to probe feature-conjunction coding. Inflated cortical surfaces marking visual areas V1 to V4, LOT, VOT and anterior, central and posterior color patches. Representational dissimilarity matrices across two network layers and the resulting trajectories of colored objects from Conv1 onward.

Taylor, J. & Karakose-Akbiyik, S. (2026). Reimagining the binding problem(s) for the 21st century. 26th annual meeting of the Vision Sciences Society Conference. Symposium organized in St. Pete Beach, FL.

Xu, Y., Swinchoski, B., Taylor, J., & Chun, M. (2025). Interactive shape and color representation in visual working memory for colored objects in the human occipitotemporal cortex. Imaging Neuroscience, 3, IMAG.a.1049.

Taylor, J. & Xu, Y. (2023). Comparing the dominance of color and form information across the human ventral visual pathway and convolutional neural networks. Journal of Cognitive Neuroscience, 35(5), 816-840.

Taylor, J. & Xu, Y. (2022). Representation of color, form, and their conjunction across the human ventral visual pathway. NeuroImage, 251, 118941.

Taylor, J. & Xu, Y. (2021). Joint representation of color and form in convolutional neural networks: A stimulus-rich network perspective. PLOS ONE, 16(6), e0253442.

Taylor, J. & Xu, Y. (2022). Identifying the neural loci mediating conscious object orientation perception using fMRI MVPA. Cognitive Neuropsychology, 39(1-2), 64-67.

Vaziri-Pashkam, M., Taylor, J., & Xu, Y. (2019). Spatial frequency tolerant visual object representations in the human ventral and dorsal visual processing pathways. Journal of Cognitive Neuroscience, 31(1), 49-63.

Taylor, J. & Xu, Y. (2019). The Coding of Color, Shape, and their Conjunction Across the Human Ventral Visual System. 19th annual meeting of the Vision Sciences Society Conference. Talk presented in St. Pete Beach, FL.

NeuroAI Research Methods

I maintain an open-source Python package, TorchLens, for extracting, visualizing, and intervening on the internals of deep neural network models. It remains in active development and I welcome your thoughts on how to improve it.

Additionally, I've developed a method called framed RSA that incorporates mean activation information (e.g., the fact that a region responds more to faces than houses) into standard RSA, enabling richer adjudication of brain-computational models.

vit = ViTForImageClassification.from_pretrained("google/vit-base-patch16-224").eval()
cat = tl.trace(vit, "cat.jpg")
cat["vit.layers.5.attention"].facets.pattern.shape  # torch.Size([1, 12, 197, 197])
cat.draw(direction="leftright", depth=1)
# ablate one attention head: tabby becomes Egyptian cat
ablated = cat.fork().do(tl.module("vit.layers.5.attention") & tl.head(3), tl.zero_ablate())
ablated.output_table(k=3)
#   rank             label   prob
#      1      Egyptian cat  0.489
#      2  tabby, tabby cat  0.341
#      3         tiger cat  0.147
Framed RSA: stimuli placed relative to the origin and an all-c point, and the dissimilarity matrix framed by those two reference points.

Taylor, J., Schütt, H., & Kriegeskorte, N. (2025). Framed RSA: Representational comparisons that honor both geometry and population-mean response preferences. bioRxiv, 2025.07.10.664257.

Taylor, J. & Kriegeskorte, N. (2023). Extracting and visualizing hidden activations and computational graphs of PyTorch models with TorchLens. Scientific Reports, 13(1), 14375.

Task-Relevant Visual Processing and Nonlinear Mixed Selectivity

In one line of work, I've studied how task modulates visual representations in the dorsal and ventral visual pathways. Specifically, I've developed a method called pattern-difference decoding that allows for non-invasively measuring nonlinear mixed selectivity (i.e., interaction effects) in the human brain using fMRI, finding evidence that the human dorsal stream multiplexes stimulus and task information in a nonlinear manner.

Oneback and oddball task stimuli (photographs of animals) used to manipulate task demands during fMRI. Pattern-difference decoding: the oddball minus oneback response pattern for an elephant differs from the same difference for a cat.

Taylor, J. & Xu, Y. (2024). Using fMRI to examine nonlinear mixed selectivity tuning to task and category in the human brain. Imaging Neuroscience, 2, imag-2-00354.

Taylor, J., Vaziri-Pashkam, M., & Xu, Y. (2017). Effect of task on object category representations across human ventral, dorsal, and frontal brain regions. 17th annual meeting of the Vision Sciences Society Conference. Poster presented in St. Pete Beach, FL.

Taylor, J., Vaziri-Pashkam, M., & Xu, Y. (2016). Attention to Object Form Modulates Informational Connectivity Between Dorsal and Ventral Visual Streams. 46th Annual Meeting of the Society for Neuroscience. Poster presented in San Diego, CA.

Face Perception

In past work with Gregory McCarthy, I studied how the electrophysiological markers of face perception varied between faces that were equated for their perceptual familiarity, but that differed in their level of associated semantic knowledge, finding that hallmarks of knowledge for face identity emerged as early as 200ms.

ERP time course and scalp topography showing biographical-knowledge effects during face perception.

Taylor, J., Shehzad, Z., & McCarthy, G. (2016). Electrophysiological correlates of face-evoked person knowledge. Biological Psychology, 118, 136-146.

Shehzad, Z., Taylor, J., & McCarthy, G. (2015). VATL Contributes to Biographical Knowledge of Faces via Feedback to FFA. 45th Annual Meeting of the Society for Neuroscience. Poster presented in Chicago, IL.