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Emotion
By Brian Thomas, M.S.
Unlike animals, we communicate all kinds of
information with our eyes. One subtle glance might express doubt and another
joy, all without a word. How did we get this way?
Evolutionary psychologists take Charles Darwin’s
answer seriously.
Supposedly, artful eye expressions evolved from
primates that had no eye expressions.
When psychologists from Cornell and the
University of Colorado in Boulder presented their research results about eye
expressions, they dragged up some evolutionary baggage.
The journal Psychological Science carried
their 2017 report.
The researchers asked study participants to
match 50 words, each describing a mental state like curious or bored to one of
six eye-based expressions: sadness, disgust, anger, joy,
fear, or surprise.
Different participants matched the mental states
to similar expressions, showing they can discern those six basic
emotions from the look of the eyes alone—even when the rest of the face didn’t
match the eyes’ expressions.
Next, they tested the hypothesis that our own
eye expressions affect how we perceive others’ eye expressions.
For example, wide eyes enhance viewer
sensitivity, whereas narrowing our eyes helps us discriminate particulars.
Participants often categorized mental states
related to sensitivity with wide-eyed expressions, and they associated mental
states involving discrimination with narrow eyes. So far, so good.
But then the researchers began crafting stories
about how eye expressions began.
The Cornell University Press Release said, “We
interpret a person’s emotions by analyzing the expression in their eyes—a
process that began as a universal reaction to environmental stimuli and evolved
to communicate our deepest emotions.”
So, some supposed evolutionary ancestor began to
perceive another’s emotional state first by observing their wide or narrow
eyes, then by associating those eye widths with how they themselves felt when
their own eyes were narrow or wide.
Then other, more-complicated, emotional links
supposedly emerged.
But this speculation imports some unmentioned
problems.
First, humans discern eye width and
narrowness by noticing the amount of the whites in the eyes, called sclera.
But apes have no visible sclera! How could any supposed ape-like ancestor
notice or mimic a feature that didn’t exist?
Second, this evolutionary story leapfrogs the
mechanical and informational requirements for discerning any emotion from eye
expressions.
One must first be able to precisely alter the
shape of one’s eye, and that means new muscles. Humans have about 50 separately
controlled facial muscles.
We routinely use many of them to express
emotions. Gorillas, like other apes, have fewer than 30 muscles in their faces.
And even if some supposed ancestor had an extra
set of eye muscles, it would do them no good without the nerves to properly
connect those muscles to the informational signals that specify when, how far,
and how long to stimulate each muscle.
The last problem with this evolutionary scenario
may be the most obvious for those with eyes to see it.
Scientists have not seen evolution make a new
muscle and nerve kit.
Nor have they seen evolution make the new
information needed to stimulate that muscle at just the right time to convey
new emotions, let alone the acute mental programming that notices and
interprets those emotional eye signals in others.
Psychologists who believe that eye expressions
evolved from an ape-like ancestor face difficult problems.
They need to show how natural processes could
craft an all-or-nothing eye expression system.
No aspect of this system would work without
visible sclera, muscles, nerves, and the intricate mental capacities needed to
manage them and interpret emotions in others’ eyes.
We have all these integrated features in place as
though someone put them all there. They allow us to communicate on a uniquely
human level—a level of emotion we share with our Creator.
http://www.icr.org/article/9991
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