Octavio Ocampo (1992) “Equality”. The mirror reflection of the woman's face is perceived as a man's face.

A classic painting from the Mexican artist Octavio Ocampo.

Try rotating the image upside-down if you don't see anything strange at first.

Anyone seriously interested in synesthesia should watch this 1994 BBC programme, not just to see a younger Roger Watt!

archive.org/details/bbch...

And to confirm the end of the video, Kandinsky was indeed a synesthete:

philharmoniedeparis.fr/fr/activite/...

Perceptual multistability: a multifaceted window into brain dysfunctions Perceptual multistability, observed across species and sensory modalities, offers valuable insights into numerous cognitive functions and dysfunctions. For instance, differences in temporal dynamics and information integration during percept formation often distinguish clinical from nonclinical populations. Computational psychiatry can elucidate these variations through two primary approaches: (i) Bayesian modeling, which treats perception as an unconscious inference, and (ii) an active, information-seeking perspective (e.g., reinforcement learning), which frames perceptual switches as internal actions. Our synthesis aims to leverage multistability to bridge these computational psychiatry subfields, linking human and animal studies as well as connecting behavior to underlying neural mechanisms. Perceptual multistability emerges as a promising noninvasive tool for clinical applications, facilitating translational research and enhancing our mechanistic understanding of cognitive processes and their impairments.

Online Now: Perceptual multistability: a multifaceted window into brain dysfunctions

Floor heating elements that have a square shape look like diamond tiles when light grazes the surface.

In this image, the square tiles look like diamond shapes when light grazes the surface.

(The square tiles are actually floor heating elements)

Probably related to the coffer illusion by Anthony Norcia.

Congratulations Karl!

@pec-ipe.bsky.social

Congratulations to Ian Thornton and colleagues who published their Mainz-Linez illusion in i-Perception (@pec-ipe.bsky.social):

the red dots appears to wave left and right when one looks at one of the black dots, but they actually move straight

journals.sagepub.com/doi/10.1177/...

A new Department of Cognitive Science is being created at Bocconi University in Milan, Italy.

Here is the call for a cluster hire (for around 10 faculty) in all areas of cognitive science, at both junior and senior levels:

www.unibocconi.it/en/faculty-a...

Deadline: May 4th, 2026

Congratulations should be directed to Hinnerk Schulz-Hildebrandt who chose "Perception" to publish this effect
(disclaimer: I'm Editor-in-Chief of this journal!).

As to whether it is an "illusion", I think it does fit the definition of Dejan Todorovic
doi.org/10.1177/0301...

Now published in Perception (@pec-ipe.bsky.social)!

Schulz-Hildebrandt, H. (2026). When purple perceived only at fixation: A fixation- and distance-dependent color illusion. Perception, 0(0). doi.org/10.1177/0301...

Flyer for 2026 edition of the European Summer School "Visual Neuroscience" in Rauischholzhausen castle, Germany.

The European Summer School "Visual Neuroscience" in Rauischholzhausen castle, Germany, is coming back in 2026!

Deadline: 8 March 2026

www.allpsych.uni-giessen.de/rauisch/

Visual language models show widespread visual deficits on neuropsychological tests - Nature Machine Intelligence Tangtartharakul and Storrs use standardized neuropsychological tests to compare human visual abilities with those of visual language models (VLMs). They report that while VLMs excel in high-level obje...

Our latest paper, “Visual language models show widespread visual deficits on neuropsychological tests”, is now out in Nature Machine Intelligence: www.nature.com/articles/s42...

Non-paywalled version:
arxiv.org/abs/2504.10786

Tweet thread below from first author @genetang.bsky.social...

UCL launches landmark European collaboration on perception science UCL is working with top French partners CNRS and ENS – PSL on a major European research initiative to advance understanding of human perception and consciousness.

The CNRS (@cnrs.fr) and the Ecole Normale Supérieure/PSL University (@normalesup.bsky.social) is launching a 5-year International Research Project (IRP) with University College London (@ucl.ac.uk) on human perception and consciousness.

www.ucl.ac.uk/global/news/...

We're running a 5th edition of the always-exciting UCL Summer School on Consciousness and Metacognition this year, 8th-10th July 2026 in London. Accommodation and travel expenses are covered.

For more information and how to apply, check out metacoglab.org/summer-schoo...

1/
📢 Come study cognitive science in Paris!
The Master’s program in Cognitive Science at @ENS_ULM, @psl_univ, and @EHESS_fr is now accepting applications for the next academic year.

🗓 Deadline: February 24, 2026
💻 Apply here: master-cognitive-science.ens.psl.eu/en/applicati...

This renewed opportunity to transform our understanding of perceptual organization will require closer integration between segmentation experiments and algorithms. The examples discussed in this paper demonstrate encouraging initial steps towards this goal.

Ironically, this has happened at a time in which artificial networks have revolutionized automatic segmentation. Here we direct the spotlight on the convergence between new algorithms and experimental approaches to study segmentation of natural images.

Perceptual segmentation is central to how visual systems achieve their functional goals, yet research on human segmentation has fallen somewhat out of fashion in the last decade.

An illustration of how human perceptual segmentation and integration (PSI) of natural stimuli and image segmentation algorithms can be bridged.

Are we ready to tackle perceptual segmentation of natural scenes?

Finally the review on perceptual segmentation you’ve been waiting for!

www.sciencedirect.com/science/arti...

Long-term perceptual priors drive confidence bias that favors prior-congruent evidence Author summary Prior expectations play a critical role in shaping not only the perceptual inferences that we make, but also how confident we feel about those inferences. Bayesian confidence models cap...

🎉 Excited to share this! Low-level, naturally formed priors influence our perceptual inferences, but do they impact our confidence in the same way? With @elifilevich.bsky.social and @mamassian.bsky.social we found: they influence confidence even more strongly! More👇 1/5

dx.plos.org/10.1371/jour...

This head is spinning continuously, but we see it rotating back and forth...

...presumably because of our strong prior expectation that faces are convex.

This is a very nice example of the Hollow-Face illusion promoted by Richard Gregory:

www.richardgregory.org/experiments/

Exposition Bridget Riley et Seurat au musée d’Orsay jusqu’au 26 janvier, l’artiste presque centenaire, gloire de l’art cinétique, eu la révélation des interactions des couleurs en copiant Seurat en 1959. L’occasion rare de faire l’expérience sensible des liens reliant ces 2 géants de la perception

Congratulations Sara and Guido!

The two of you look beautiful!

Introducing Philosophy Corner - Tim S. Meese, Pascal Mamassian, Isabelle Mareschal, Frans A.J. Verstraten, 2025

Great new initiative from the editors of Perception: Philosophy Corner. A forum for "accessible reflections on the conceptual foundations of sensory/perception science where empirical insight meets philosophical inquiry". journals.sagepub.com/doi/full/10....

L’ancêtre du camouflage, crée pour la 1ere guerre mondiale, pour des navires de guerre. Les rayures empêchent de déterminer la vitesse, entraine la confusion et rend imprécis les tirs…

Congratulations Dr Nadia Hosseinizaveh!
It was an honour to work with you.

And thank you to your PhD committee for the great discussion,
@nfaivre.bsky.social
Bahador Bahrami
@clairesergent.bsky.social
@opheliaderoy.bsky.social
Frédérique de Vignemont

We will address this through an integrated behavioural, computational, and neurophysiological approach, focusing on how endogenous perceptual traits interact with the external factors.

PhD and postdoctoral positions linked to this project will be advertised in the coming months.
Stay tuned!

(2/2)

Pleased to share that a collaboration project between David Pascucci (UNIL/CHUV) and I has been selected for funding.

Our project asks a central question:
Why do individuals differ in how their perceptual judgments are shaped by temporal context?

(1/2)

L'écriture de mon manuel de psychoacoustique #openaccess avance bien : chapitre 1 (méthodologie de la psychophysique) terminé, chapitre 2 (physiologie du système auditif) terminé pour ce qui concerne le système auditif périphérique, j'attaque le chapitre 4 !
leovarnet.github.io/psychoac-man...

🚨Friends, we’re happy to share that our book is available for pre-order! 🎉
We aimed to cover all the foundations of the topic in an accessible manner for a large audience.
It could help set up a bachelor-level curriculum on the topic.
Pre-orders are very key for the fate of books: shorturl.at/Dxbif

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