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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