The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human

Peak shift

Contrast

Isolation

Peekaboo, or perceptual problem solving

Abhorrence of coincidences

Orderliness

Symmetry

Metaphor

It isn’t enough to just list these laws and describe them; we need a coherent biological perspective. In particular, when exploring any universal human trait such as humor, music, art, or language, we need to keep in mind three basic questions: roughly speaking, What? Why? and How? First, what is the internal logical structure of the particular trait you are looking at (corresponding roughly to what I call laws)? For example, the law of grouping simply means that the visual system tends to group similar elements or features in the image into clusters. Second, why does the particular trait have the logical structure that it does? In other words, what is the biological function it evolved for? And third, how is the trait or law mediated by the neural machinery in the brain?¹ All three of these questions need to be answered before we can genuinely claim to have understood any aspect of human nature.

In my view, most older approaches to aesthetics have either failed or remained frustratingly incomplete with regard to these questions. For example, the Gestalt psychologists were good at pointing out laws of perception but didn’t correctly answer why such laws may have evolved or how they came to be enshrined in the neural architecture of the brain. (Gestalt psychologists regarded the laws as byproducts of some undiscovered physical principles such as electrical fields in the brain.) Evolutionary psychologists are often good at pointing out what function a law might serve but are typically not concerned with specifying in clear logical terms what the law actually is, with exploring its underlying neural mechanisms, or even with establishing whether the law exists or not! (For instance, is there a law of cooking in the brain because most cultures cook?) And last, the worst offenders are neurophysiologists (except the very best ones), who seem interested in neither the functional logic nor the evolutionary rationale of the neural circuits they explore so diligently. This is amazing, given that as Theodosius Dobzhansky famously said, “Nothing in biology makes any sense except in the light of evolution.”

A useful analogy comes from Horace Barlow, a British visual neuroscientist whose work is central to understanding the statistics of natural scenes. Imagine that a Martian biologist arrives on Earth. The Martian is asexual and reproduces by duplication, like an amoeba, so it doesn’t know anything about sex. The Martian dissects a man’s testicles, studies its microstructure in excruciating detail, and finds innumerable sperm swimming around. Unless the Martian knew about sex (which it doesn’t), it wouldn’t have the foggiest understanding of the structure and function of the testes despite all its meticulous dissections. The Martian would be mystified by these spherical balls dangling in half the human population and might even conclude that the wriggling sperm were parasites. The plight of many of my colleagues in physiology is not unlike that of the Martian. Knowing the minute detail doesn’t necessarily mean you comprehend the function of the whole from its parts.

So with the three overarching principles of internal logic, evolutionary function, and neural mechanics in mind, let’s see the role each of my individual laws plays in constructing a neurobiological view of aesthetics. Let’s begin with a concrete example: grouping.

The Law of Grouping

The law of grouping was discovered by Gestalt psychologists around the turn of the century. Take a moment to look again at Figure 2.7, the Dalmatian dog in Chapter 2. All you see at first is a set of random splotches, but after several seconds you start grouping some of the splotches together. You see a Dalmatian dog sniffing the ground. Your brain glues the “dog” splotches together to form a single object that is clearly delineated from the shadows of leaves around it. This is well known, but vision scientists frequently overlook the fact that successful grouping feels good. You get an internal “Aha!” sensation as if you have just solved a problem.

FIGURE 7.3 In this Renaissance painting, very similar colors (blues, dark brown, and beige) are scattered spatially throughout the painting. The grouping of similar colors is pleasing to the eye even if they are on different objects.