The official site of bestselling author Michael Shermer The official site of bestselling author Michael Shermer

Perception Deception

published November 2015
Do we perceive reality as it is?
magazine cover

One of the deepest problems in epistemology is how we know the nature of reality. Over the millennia philosophers have offered many theories, from solipsism (only one’s mind is known to exist) to the theory that natural selection shaped our senses to give us an accurate, or veridical, model of the world. Now a new theory by University of California, Irvine, cognitive scientist Donald Hoffman is garnering attention. (Google his scholarly papers and TED talk with more than 1.4 million views.) Grounded in evolutionary psychology, it is called the Interface Theory of Perception (ITP) and argues that percepts act as a species-specific user interface that directs behavior toward survival and reproduction, not truth.

Hoffman’s computer analogy is that physical space is like the desktop and that objects in it are like desktop icons, which are produced by the graphical user interface (GUI). Our senses, he says, form a biological user interface—a gooey GUI—between our brain and the outside world, transducing physical stimuli such as photons of light into neural impulses processed by the visual cortex as things in the environment. GUIs are useful because you don’t need to know what is inside computers and brains. You just need to know how to interact with the interface well enough to accomplish your task. Adaptive function, not veridical perception, is what is important.

Hoffman’s holotype is the Australian jewel beetle Julodimorpha bakewelli. Females are large, shiny, brown and dimpled. So, too, are discarded beer bottles dubbed “stubbies,” and males will mount them until they die by heat, starvation, or ants. The species was on the brink of extinction because its senses and brain were designed by natural selection not to perceive reality (it’s a beer bottle, you idiot!) but to mate with anything big, brown, shiny, and dimply.

To test his theory, Hoffman ran thousands of evolutionary computer simulations in which digital organisms whose perceptual systems are tuned exclusively for truth are outcompeted by those tuned solely for fitness. Because natural selection depends only on expected fitness, evolution shaped our sensory systems toward fitter behavior, not truthful representation.

ITP is well worth serious consideration and testing, but I have my doubts. First, how could a more accurate perception of reality not be adaptive? Hoffman’s answer is that evolution gave us an interface to hide the underlying reality because, for example, you don’t need to know how neurons create images of snakes; you just need to jump out of the way of the snake icon. But how did the icon come to look like a snake in the first place? Natural selection. And why did some nonpoisonous snakes evolve to mimic poisonous species? Because predators avoid real poisonous snakes. Mimicry works only if there is an objective reality to mimic.

Hoffman has claimed that “a rock is an interface icon, not a constituent of objective reality.” But a real rock chipped into an arrow point and thrown at a four-legged meal works even if you don’t know physics and calculus. Is that not veridical perception with adaptive significance?

As for jewel beetles, stubbies are what ethologists call supernormal stimuli, which mimic objects that organisms evolved to respond to and elicit a stronger response in doing so, such as (for some people) silicone breast implants in women and testosterone- enhanced bodybuilding in men. Supernormal stimuli operate only because evolution designed us to respond to normal stimuli, which must be accurately portrayed by our senses to our brain to work.

Hoffman says that perception is species-specific and that we should take predators seriously but not literally. Yes, a dolphin’s icon for “shark” no doubt looks different than a human’s, but there really are sharks, and they really do have powerful tails on one end and a mouthful of teeth on the other end, and that is true no matter how your sensory system works.

Also, computer simulations are useful for modeling how evolution might have happened, but a real-world test of ITP would be to determine if most biological sensory interfaces create icons that resemble reality or distort it. I’m betting on reality. Data will tell.

Finally, why present this problem as an either-or choice between fitness and truth? Adaptations depend in large part on a relatively accurate model of reality. The fact that science progresses toward, say, eradicating diseases and landing spacecraft on Mars must mean that our perceptions of reality are growing ever closer to the truth, even if it is with a small “t.”

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15 Comments to “Perception Deception”

  1. Timothy Strauss Says:

    “what ethologists call supernormal stimuli”,brings religion to mind

  2. Richard Owings Says:

    I don’t think people perceive reality (whatever it might be)–people perceive the part of reality that is useful for us to perceive and perceive it in ways that are useful to us. I can perceive an attractive female on a beach at 200 yards and can perceive a steak cooking from down the block (given wind direction), but I cannot perceive millions of neutrinos passing through my body every minute. The spectrum of electromagnetic waves people perceive is a very small part of the total spectrum. What we perceive is real (sharks bite, steaks are nourishing, and females are, well, you know), but there are is a lot that’s real that flies past unnoticed. James Gibson used “affordances” to denote what we actually perceive. We don’t perceive a “real” steak–rather we perceive eatability. Science gives us other tools to go beyond our evolutionary useful sensorium to perceive other aspects of reality, though even here affordance may be important. Science helps us to perceive a material as fissile, and we have learned to do this because fissionability has become important to us.

  3. Burton Smith Says:

    One of humanities traits, or sometimes faults, is that we tend to draw a line around a group of similarities, calculate averages of the group, then totally ignore the fact that each and every one of the similarities in that group are unique in and of themselves. In short just about every living organism has a bevy of bell curves that denote not only their physical characteristics but their numerous behaviors as well. We focus on the two or three sigma groupings and ignore the lunatic fringes. And while we may be loath to admit it the fringes are where major changes are conceived. We tend to forget that survival is not a digital operation, it’s analog. For a trait to be passed along only requires that it works most of the time, it’s not necessary that it works all the time. Not all tigers are man-eaters, but some are – hence, its best to avoid all tigers.

    I suspect that Dr. Hoffman is essentially correct, and as Dr. Shermer mentions, we (well maybe not all, but hopefully most of us) are getting closer to reality.

    Burt Smith, PhD, retired (sort of)

  4. Joel Levinson Says:

    I found this article interesting because it generally aligns with my notion of The Illusionistic Nature of Reality, which one can read about in greater depth on my website joellevinson.info Go to Writings; there are two articles – One is called The Mind’s Eye under the Chestnut Hill Local section and another starting with the phrase ‘Phantom Instants’ under the Science section.

    I think that Mr. Shermer and Mr. Hoffman have not gone far enough in setting forth the fundamental nature of perception. We really perceive nothing. We fabricate from energy input streams various qualia which serve the functional needs of the organism. Important to realize is that there is no fixed, certain, and concrete reality upon which these qualia are formed. Reality is a human construct. It is true that man has developed through the scientific method a better grasp of the workings of nature and of the structures that those workings have yielded. Without going deeper into what I mean by what I have written above, my essential message here is that what we call perception is really a cerebral FABRICATION that is so disconnected from the underlying world we think we observe that the term The Illusionistic Nature of Reality should be the operable fundament upon which to understand and discuss the workings of perception.

  5. Richard Morris Says:

    The perceptions are what they are, it is our brain that is able to make sense of the input. The eye is an excellent example. Another good book on the issue is David Kelley’s “Evidence of the Senses.”

  6. Ray Madison Says:

    “Because natural selection depends only on expected fitness, evolution shaped our sensory systems toward fitter behavior, not truthful representation.”
    Heretofore you’ve argued that evolution doesn’t have a purpose. Is this a turnaround? And if there is a purpose, wouldn’t that require an intelligent “purposer”? Which would need to be the entity that does the expecting, no? Leading to the conclusion that entities must do their own selecting to suit their own purposes – no?

  7. Stephen Nowlin Says:

    Our visual perception (one might say icon) of a forest from the distance of a jetliner is very different than from the distance of a ski lift. But if we fall from either, the result is the same and perception didn’t matter. That’s reality.

  8. Ed Kreusser Says:

    A bit more emphasis here on the “species specific” notion: Dogs’ sense of smell is said to be about 10,000 X more sensitive than ours with a large olfactory cortex. They must have a unique, concomitant imagery or world-view that informs them of the relevant aspects of their environment. Bats have echolocation; some marine creatures perceive subtle electro-chemical variations, others… vibrations; some creatures go largely by touch; etc. etc. So, each species has its own very narrow glimpse of “reality”… that which has evolved to give it maximum survival and reproducibility… If any species had the entire gamut that constitutes “full-blown reality” (whatever that is), much of that input would be irrelevant (the scale being too large or small) and all the relevant data would bombard the organism with a confusing and paralyzing avalanche of perceptions, delaying appropriate action (and reducing survivability).

  9. Robert C Says:

    This article and the posted comments remind me of the thoughts I had after seeing the movie, The Matrix. What is really real? Does it matter what is real since we seem focused on individual specific interpretations of their environment. In The Matrix, Cypher is talking to Agent Smith, “You know, I know this steak doesn’t exist. I know that when I put it in my mouth, the Matrix is telling my brain that it is juicy and delicious. After nine years, you know what I realize? [takes a bite of steak] Ignorance is bliss.”

  10. Violet W. Says:

    Does this explain why highly intelligent and educated people who have doctoral degrees in one or more fields can hang on so tenaciously to belief systems that contradict whatever
    scientific evidence has accumulated? They can’t let go because their particular culture/environment requires such a belief because those beliefs are adaptive in their particular and personal emotional life. The reality we perceive does not just affect our physical survivability but our very important emotional survival.

  11. Mark A Says:

    Regarding his computer simulations, he is using equations for modelling evolution that, by definition, favor “fitness”. Then he acts as though it is an unexpected result that simulated organisms that maximize “fitness” are the most successful. Sounds like a bit of a tautology. I’m sure the actual situation is far more complex than his brief summary, but it does seem rather silly.

  12. Stephen Nowlin Says:

    I think it may be true that any reality we conjure can affect our sense of physical and emotional survivability, and that this may account for why supernatural belief systems are so tenacious in spite of contrary scientific evidence.

    But in fact we all practice in the same acknowledged and confirmed reality, even if our perceptions and illusions vary. So-called believers in the power of God to alter the physics of gravity, nonetheless avoid stepping off the edges of cliffs. Regardless of how subjective reality may seem, or how differently individual humans or species may perceive things, the matter that displaces space is real. A solid object hurled through the air will collide with matter in its path, unaffected by how the intended target makes sense of, or “envisions” that incoming object. Every perceiving thing knows this, otherwise we would not have the inter-species phenomenon of ducking!

  13. Todd Freeman Says:

    I think you may be oversimplifying some parts of the argument.
    To begin with, just because there is an objective reality, does not mean anyone experiences it objectively. At the same time, what people do experience, must have some grounding in objective reality for any of their translation or planning mechanisms to work.

    For example, color vision is primarily a function of an individuals imagination, not the electromagnetic wavelengths that bombard the retina. This is why optical illusions work, because the process that translates the nerve impulses from the optic nerve into something as ineffable as the concept of depth within a daydream. These impulses are translated into symbols and the meaning of those symbols is created by the experiential history of the observer. This is why some people are afraid of spiders and others are not, they visualize the spider differently, regardless of the same objective reality.

    Having an objective view of reality is not adaptive, because of information overload. More decisions /references need to be made in order for a translation of information into planning to occur. By creating processing short-cuts that eliminate portions of objective reality as superfluous, those without an objective view are actually more energy efficient in their processing for mechanical fitness. Taking too long to make decisions is evolutionary dis-advantageous. As for the first caveman to kill something with a rock, there was not an explosion of creativity with tool use, it took millennium of tool use to spark the evolutionary urge for creativity, and even diversify the stone tools, let alone switch to something better.

    And one last note, super-normal stimuli I think actually supports the concept of pattern matching gone awry with the mental shortcuts that are used for judging our more “instinctual” or at least more subconscious behaviors. I would defiantly not say they were adaptive twords an objective view of anything, considering how often they lead people to unhappiness instead of happiness as they have valued the wrong things.

  14. James Says:

    I don’t always perceive the world as nothing more than randomly assimilated molecular structures, but since I have that knowledge I can perceive it that way if I choose. Knowledge shapes perception.

  15. Jill Young Gorton Says:

    Another great example of metaphor used to convey abstract theories, showing how the concepts that we use determine the outcomes of our argument.