Engines of Our Ingenuity

No. 2256:
DARWIN AND EMOTION

by John H. Lienhard

Today, we smile with our animal cousins. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

I spent the morning in one of Charles Darwin's last books, The Expression of Emotions in Man and Animals. What a joy! Darwin does not so much tackle the question of whether animals express emotions, but rather the kinship of animal and human expression.

He begins by suggesting three principles of emotional expression: First, he says, certain expressions spring from habit. If a singer or a speaker becomes hoarse, we often clear our own throat out of habit -- expressing the emotion of empathy. A horse in a stall, eager to get going, will paw the ground as though starting out -- expressing the emotion of excitement.

Second, certain expressions go to their natural opposite when the emotion is reversed. A dog, seeing a potentially dangerous stranger walks stiffly erect, tail pointing upward, gums tightened against the teeth, ears laid back. Ah, but the stranger turns out to be the dog's friendly owner. All those gestures reverse -- belly to the ground, tail down, ears forward, mouth slack. So too with humans. Nodding our head or shaking it have opposite meanings -- likewise looking away or making eye contact.

The third principle of expression is a response of the nervous system. When we're cold or frightened, our body tries to make its hairs stand up. That creates better insulation and makes us look more fierce -- if we have a lot of hair. In most of us relatively-hairless humans, it merely produces goose flesh. Animals and humans alike respond to severe pain by violently tensing their muscles -- as they would in either a fight or a flight.

Darwin's study is very detailed. His was one of the first books to include photos. His many images show the vast range of animal and human emotions, expressed in both body and face. It'd begun as a chapter in another study, then expanded into a book as Darwin collected data and information from all over the world.

frown sadness melancholic

Darwin was not first to look at animal emotional expressions. But, having gained an understanding of our literal kinship to other living creatures, he saw them in a new light. He wrote,

No doubt, as long as man and all other animals are viewed as independent creations, ... our natural desire to investigate ... the causes of expression [is halted].

That's a direct swipe at the early 19th-century psychologist Sir Charles Bell. Bell clearly claimed that we are far more expressive since we rank highest among God's creations. But Darwin knew that it's much harder to torment a cat, boil a lobster alive, or make dogs fight to the death for our entertainment, when we stop seeing them as lesser creatures with small emotional lives.

By clarifying our kinship with animals Darwin leaves us more humane -- more human. No one likes to abandon the arrogance of being first in the class. But that loss of status is beautifully balanced when we see how much we share with the other inhabitants of our small planet in the far corner of the Milky Way.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


C. Darwin, The Expression of the Emotions in Man and Animals. Francis Darwin, ed. (London John Murray, 1904). This is a reprint of the 2nd ed., also edited posthumously by Charles' 3rd son Francis in 1889. Charles Darwin's first edition was published in 1872. All images are from Darwin's book. For more on the book, see: The Expression of Emotions_in Man and Animals.

For more on Francis Darwin see: this Wikipedia article.

cat terrified

affectionate cat


The Engines of Our Ingenuity is Copyright © 1988-2006 by John H. Lienhard.