An intuitive and common conception of perception is that our sensory systems accurately represent the external world as it actually is, a view that likens our perception of a visual scene to a photograph of such scene. In contrast with this view, substantial evidence indicates that perception is an idiosyncratic process that does not solely rely on input from the senses but also relies heavily on the context of what is being sensed and the expectations derived from this context.” (from introduction to Duhamel et al. 2023 about top-down versus bottom up baises on hallucination).   


  • signals are transduced, stimuli are transformed; sensations (actions of sensory receptors) that result become percepts

OF COURSE we can only detect a fragment of what is believed to be out there: our sensory competence is a complex amalagam of competencies that were preserevd by natural selection, and those that developed as an individual matures –competencies can be general (ability to communicate with speech) and then shapedto be more specific (the particular language we learned)

  • GNOSIS” has to do with “knowing.” AGNOSIA is a more-or-less specific inability to understand the meaning of what is perceived, most famously known in the clinic with respect to language, but there are other forms, and VISUAL AGNOSIA is of particular interest  in itself as well as for its larger (possibly metaphoric) meaning in the context of art. (read a brief essay on the doors of perception: https://www.brainandlife.org/articles/what-is-agnosia-understanding-causes-symptoms.)
    • see also HYPERGNOSIA, and ANOSOGNOSIA for commentaries about specific kinds of gnosia. … PERCEIVING but not knowing the meaning of what is perceived.

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.

PERCEPTION is thus these streams of information, each multistranded, and their integration in the light of cerebral contexts in which specific elements of the central nervous system–past, presenand anticipated–are acting on them.

The action of PERCEPTS on the CNS is often regarded as BOTTOM-UP (coming from sense organs) and TOP-DOWN (coming from within the brain)

    • .

Discussion of Blake’s poetry and Doors of Perception


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] 



  • PARTS and WHOLES.   Sometimes we see small elements of an art work (read about “Tracking the Gaze“), and other times we pursue a vision of the work as a whole:   Listen to https://www.npr.org/2020/03/28/823071293/art-critic-jerry-saltz-on-his-new-book-how-to-be-an-artist a short interview in which Saltz makes the point that one of the elements of genius in certain paintings (van Gogh, Picasso) is how it helps you see multiple elements simultaneously – we know this can be difficult AND can be learned… remember last week’s notes on Janusian thinking.  (neuro-types amongst you: there is likely a good reason for this that is connected to flicker-fusion creating an illusion of wholeness from separate frames: works in vision and—arguably—consciousness itself)
  • OK, so ARTISTS (all communicators?) seek to manipulate our perceptions and feelings to evoke within us a representation of their perceptions and feelings–at least those they want us to receive–by means of when and where and how they present stimuli.   Stimuli to Feelings.   Okay, I hope it is clear to all of us by now that ART functions as communications when attributes of the physical environment are detected within us and lead to non-physical feelings. Stimuli evoke feelings: pleasure, pain, the sublime, laughing and crying, joy and grief. Artists discover ways in which your environment can be modified to better communicate their feelings. These ways can be learned by intense, dedicated study (e.g., Leonardo da Vinci), others discover some mechanisms spontaneously by endless, even compulsive, tinkering. Even serendipity.  That is, experience—deliberately sought or not—that eventually informs their intuition—connections are made at a subconscious level.  Many artists seem to know this and work to  get access to their subconscious (e.g., the Surrealists). 
    • So, in Art & Organism, we are always on the lookout for examples of how science can explain any part of the process that leads to how we feel. How corporeal physical things become incorporeal feelings.  This is at the heart of all research on the nature (and nurture?) of consciousness. Some say, the greatest unanswered question of our time.  You will get a good feel for how our disposition and experience–feelings and understanding of what evokes them–work together by reading  Read Sarah Scoles on The Strange Blissfulness of Storms in a 2016 issue of Nautilus magazine. [HERE]

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?”



So there are countless THINGS we can perceive, even with our extremely limited sensory apparatus, but can we perceive NOTHING?

look in on A&O IDEA about NOTHING





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  The Psychology of Eye Contact, Digested    Indeed, such is the importance of eye contact to socialising that we tend to form rather low opinions of people who persistently avoid our gaze, assuming that they are less sincere and, at least if they’re female, less conscientious. Conversely, we’re more likely to believe statements made by a person who looks us in the eye. Yet maintaining eye contact with too much intensity is seen as a feature of psychopaths. [another example of the golden mean]

[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).    


[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