PERCEPTION is what we do with sensory stimulation and how we experience THREE SIMULTANEOUS STREAMS of information… from our internal organs (INTEROCEPTION) from our muscles (PROPRIOCEPTION) and from our external environments (EXTEROCEPTION), as detected (and often interpreted by ) our “special senses”–those organs embedded on and in the surface of our body that detects the world outside our bodies.  Read A&O notes on INPUT- STIMULI  Note: interoception provides critical information on the state of the body and can thereby affect physiological processes. It also affects cognitive processes and thereby states of mind–read Camilla Nord’s comments on interoception in Psyche Feb 2022 issue.


PAST and FUTURE of PERCEPTION: “Our perception of the world is not entirely veridical. Instead, theoretical, neuroimaging, and behavioral research has shown that we actively process sensory information, using our prior knowledge to form expectations and influence what we ultimately perceive. One attractive hypothesis regarding why the brain actively interprets the world, rather than senses it as is, is to increase efficiency in perception. Our neural resources are limited; therefore, the brain must decide how to prioritize unexpected input which is likely more informative. To do this, the brain uses prior knowledge to construct internal models and predict what information it may encounter. By comparing these predictions to actual input, we can quickly attend to the most important aspects of our environment, with the ultimate goal of optimizing context-dependent behavior.”  (D’Mello & Rozenkrantz 2020) [i] 


[i] Neural Mechanisms for Prediction: From Action to Higher-Order Cognition.    Anila M. D’Mello and Liron Rozenkrantz (2020)  Journal of Neuroscience 1 July 2020, 40 (27) 5158-5160; DOI: https://doi.org/10.1523/JNEUROSCI.0732-20.2020   https://www.jneurosci.org/content/40/27/5158   Article   Info & Metrics eLetters  PDF 



What can we “really” know: data is inserted into gaps in our flow of information by INTERPOLATION and EXTRAPOLATION.  In neuroscience, interpolation is called “filling in” – the blind spot in our retina is a good metaphor if not an example –look at Spillman (et al’s 2006) paper on “perceptual filling in.”


CONSCIOUSNESS PERCEIVED?  One of the most complex accomplishments of perception may go beyond representations of the world outside us to representations of the one within. (It’s too soon to ask how “does one perceive their organ of perception?”). Read Michael S. A. Graziano and Sabine Kastner’s (2011), “novel hypothesis”

BUT we could argue that consciousness itself is only what we perceive it to be: Graziano argues at greater length that consciousness is a perceptual construct in his book, Consciousness and the Social Brain.  (Read Aaron Schurger’s (2014) review, “Consciousness Perceived,” in SCIENCE.)






We know we are unique – genes are very conservative, but not identical—and even when they are there is variation in development that affects their expression and how they are deployed to communicate with world outside our brains. 

It is common for people to disagree with each other on exactly what they have perceived.  But where do these disagreements arise?  READ Richard Hollingham’s reporting on what we can perceive and whether other people perceive the same thing: “In the Realm of Your Senses”

RELATED:  Of course we are all different; of course we may or may not agree with the assessement of other people.  This platitude is enshrined in the expression, “beauty in the eye of the beholder.”   Assuming we agree about what is objective or subjective in our conceptions, it is still a provocative question.    




“The brain, after all, is sealed in darkness and silence within the solid casing of the skull. It has no direct access to the outside world, and so relies on the information that reaches it via a few electrical cables from our sensory organs What is it we actually perceive? is it real?”


look at Alison George’s essay, “Can We Perceive Reality?”






In 2015, Adam Zeman borrowed Aristotle’s term for the mind’s eye (phantasia) to refer to apparent deficits in visualization aspect of perceptual cognition: he coined the term ‘congenital aphantasia’ to describe those rare people with an inability to visualize. Prof. Zeman estimates that aphantasia occurs in around 3 per cent of the general population, and hyperphantasia in about 6 per cent. In other words, a spectrum phenomenon reflecting the neurodiversity amongst us. [READ Zeman’s short summary from PSYCHE]  How does this ability intersect with dreams? Or or our recollections of real experiences.  With respect to memory of things, researcher Elizabeth Loftus has established the parameters of accurate recollection including its malleability.  Read about her research as it developed and how her findings play out in the real world (as in court testimony based on recollections) (LOFTUS discussed in the New Yorker).