Print journal: Evolutionary Enquiry into the Structure of Perception

By: Taylor Coplen, writing for The Science in Society Review

Humans are terrible observers.  If a laboratory instrument introduced as much bias as we do, it would be tossed out immediately. We fabricate significant patterns from meaningless data. We see faces everywhere, from pieces of toast to Mars[1]. And every classic rock song, when played backwards, seems to reveal some hidden, often satanic, message. There is little doubt that the human mind plays an active role in structuring perception, but it is unclear how fundamentally active this role is.

lights of ideasThe way we receive information from the external world has traditionally been a topic of purely philosophical concern. However, a consideration of the evolutionary process that shaped the human brain offers an explanation for the specific structure of our perception. Empiricists assert that the mind is originally lacking in ideas and accrues them through experience.  In this theory of knowledge, the mind is likened to a tabula rasa (blank tablet), or in the words of John Locke, “white paper, void of all characters, without any ideas” [2]. Other philosophers hold that the mind has innate ideas, which precede the individual’s experience. Immanuel Kant famously argued that concepts like space, time, and even causality are pure intuitions of the human mind, which we impose upon our experience of the sensible world [3]. If we consider all mental activity as the product of physical cognitive mechanisms, then it seems that this inquiry into the origin of our cognitive framework falls into the realm of evolutionary biology. An epistemological inquiry, centered upon an evolutionary understanding of the human being, reveals two insights: 1) that we are born with these innate concepts that structure our experience, and 2) that these concepts are themselves the product of experience in a general sense—the experience of our biological ancestors.

By the latter half of the 18th century, the epistemologies of European philosophers could be categorized as either empiricist or rationalist.  The rationalists, residing primarily on the European continent, regarded reason as the primary source of knowledge [4].  Alternatively, the empiricists, most of whom were British, argued that experience was the principle source of knowledge [5].  Most epistemologists of the time fit neatly into one of these two categories, until the writings of the Scottish empiricist, David Hume, spurred Immanuel Kant to produce his magnum opus, The Critique of Pure Reason, in which he rejected both of the competing schools.  Kant suggested reason as a solution to the skeptical arguments proposed by Hume’s empiricism.  The resulting theory was referred to as “transcendental idealism”, which argues that causality, space, and time are a priori intuitions, which the human mind imposes upon our perception of the sensible universe [6]. Thus, drastically more significance is placed on the role of the observer. According to transcendental idealism, concepts like space and time can never be learned through experience because the individual must possess these concepts in order for experience to be possible.

To understand why these concepts must be innate to allow for experience to take place, consider the alternative: a mind devoid of innate ideas, an aforementioned tabula rasa.  If a subject were born without an innate idea of space, one may assume that he or she could derive this idea by identifying objects and considering their physical relation to each other.  However, the idea of space must be presupposed in order for the notion of one object’s relation to another to even be conceivable. The concepts of time and causality can be considered in a similar hypothetical situation and the conclusion is always the same: the way that we experience the external world is made possible only if these concepts are presupposed. These innate concepts can be thought of as way for the mind to structure incoming sensory information. Without this structuring framework, the individual would simply receive incoherent stimuli rather than useful, organized information about the external world.  Yet despite the obvious necessity of this cognitive framework, its origin remains obscure.

One major obstacle that has hindered this investigation is the mystery surrounding the mind.   Many philosophers in the past have struggled with the perplexing relationship between the mind and body. Today, however, modern neuroscience has provided considerable evidence that indicates that all mental phenomena are the result of a physical structure [7].  Though the claim that the mind is the product of physical matter is still disputed, there is enough supporting evidence to accept this position as a premise for the following argument.  In humans, all sensation, thought, emotion, and desires are the direct product of neurological activity [8].  This discovery is essential to forming a complete understanding of our innate cognitive framework.  To understand the structure of our perception, we need only understand the origin of the structure of our central nervous system, specifically the brain.  The brain, like all the physical mechanisms that comprise the human body, developed gradually over time through the process of natural selection [9]. Thus, as we trace the evolutionary development of the brain we will be simultaneously witnessing the development of the framework that structures our perception.

Let us first consider the notion of experience—so intimately related to any theory of knowledge.  For Hume and other empiricists, experience is the aggregate of cognitions acquired through the individual’s perception of the external world. While experience clearly requires a subject, there is no reason that it should be considered as restricted to an individual.  For if I could somehow transmit my observation of an object directly to another being by minutely altering the structure of his or her brain to precisely reconstruct my mental image, there would be no way to identify the “true” observer in any epistemological sense.  We would both have acquired the exact same knowledge.  Though this example seems like science fiction, the point is that experience can be transferred from one individual to another by replicating physical conditions of the brain.

Experience, in a more general sense, can be transferred from one individual to another, encoded in DNA.  When a mutation alters a physical characteristic of an organism, the alteration can either positively or negatively contribute to its fitness. The structure of the organism’s neurological system determines the way it perceives.  Physical manifestations of the organism’s genetic structure will either be passed on to the next generation or perish with the organism; the outcome is determined by the organism’s interaction with its environment [10]. Our specific neurological structure, and thus the structure of our perception, is the product of many evolutionary trials and errors.

As information is useful for the survival of an organism, it is a commodity shaped by the process of natural selection. In the same way that our respiratory system structures the way that we receive oxygen from the environment, our complex neurological system dictates the way that we receive information. To gain knowledge of the external world, an organism requires some biological structure that can receive stimuli and trigger a reaction in the organism. For instance, an eyespot apparatus is an organelle found in many unicellular organisms [11], which allows the organism to determine the direction of the light and move accordingly [12]. Though this is one of the most primitive forms of perception, the organism can now distinguish between two states of the external world: light and dark.  This rudimentary process of perception involves chemical messengers that cause an almost instantaneous response in the organism. Further evolutionary modification in more complex multicellular organisms causes these chemical messengers to make permanent alterations to the organism [13], so that organisms become capable of constructing primitive memories [14]. Organisms with the ability to sense change in the external world and record these changes have the rudiments necessary to produce the groundwork for our conception of time.  When organisms become capable of storing multiple pieces of information, memories are structured in sequence.  Thus humans, with extremely complex neurological systems capable of storing countless memories, have an innate temporal intuition, which allows us to structure our experience in chronological order.  While this example is particular to the structure of temporal perception, the structure of spatial or causal perception can be considered in a similar way: as a gradual succession of increasingly complex perceptual structures.

The process of evolution by natural selection can sufficiently account for the specific structural framework of our perception.  Once we accept that our thoughts, sensations, and perceptions are the product of the physical structure of our brain, which is in turn the product of natural selection, this conclusion is inevitable.  In a certain sense, the experience of our biological ancestors, i.e. their interaction with the environment, is the determining force that shaped the outcome of our cognitive structure.  The bias that our particular type of perception introduces is the vestigial baggage of evolution, which was at one point in our evolutionary history conducive to survival.


  1. NASA “Unmasking Mars”
  2. Locke; An Essay Concerning Human Understanding, New York: Prometheus, 1995 2:1:2.
  3. Kant, Immanuel. Critique of Pure Reason. Cambridge: Cambridge University Press, 1998.
  4. Cottingham, John, Rationalism, London: Paladin Books, 1984.
  5. Priest, Stephen. The British Empiricists. 2nd. New York: Routledge , 1990.
  6. Kant, Immanuel. Critique of Pure Reason. Cambridge: Cambridge University Press, 1998.
  7. John C. Eccels  “Evolution of Consciousness” 1992.
  8. Armstrong, D.M.  A Materialist Theory of the Mind, London: Routledge; 1993.
  9. Striedter, Georg. Principals of Brain Evolution. Sunderland: Sinauer, 2005.
  10. Williams, George. Adaptation and Natural Selection. Princeton : Princeton University Press, 1966.
  11. Kreimer, G. “The green algal eyespot apparatus: a primordial visual system and more?” 2009.
  12. Hegemann P “Vision in microalgae”, 1997.
  13. Stanley B. Klein, Leda Cosmides, John Tooby, and Sarah Chance. Decisions and the Evolution of Memory: Multiple Systems, Multiple Functions, 2005.
  14. Chrisantha T Fernando, Anthony M. Liekens, Lewis E. Bingle, Christian Beck, Thorsten Lenser, Dov J Stekel, and Jonathan E. Rowe Molecular Circuits for Associative Learning in Single-Celled Organisms, 2008.
  15. Image credit (Creative Commons): Faruque, S. Lights of ideas. Flickr, 2011.

This is an excerpt of an article that was originally published in The Science in Society Review, a sister publication of The Triple Helix Online. Taylor Coplen is a student at the University of Chicago. Contact us to read the original article, and follow us on Facebook.