Seeing intelligence

I have always said that one can literally see that a person is more intelligent than the norm by looking at their eyes. I wonder if that observation was based on subconsciously picking up on large pupil size:

A person’s intelligence and brain function correlates to the size of their pupils, a new eye-popping study by US researchers suggests. The study claims that the larger the pupil, the smarter its owner. Cognitive abilities like attention control, fluid intelligence and working memory capacity have been linked to baseline pupil size by researchers at Georgia Institute of Technology, who conducted several large-scale studies involving over 500 participants.
First, they calculated the average pupil size of each of the participants — aged between 18 and 35 years old — using a special tracking device with a camera linked to a computer. Normally, a constricted pupil — the black circular aperture in the center of the eye — is two to four millimeters in size, and fully dilates to up to eight millimeters. 
The participants were then offered a series of cognitive tests measuring their abilities to stay focused and control attention while being intentionally distracted, to reason through new problems and remember new information. The laboratory was kept dim in order for the pupils not to constrict in response to light. 
“We found that a larger baseline pupil size was correlated with greater fluid intelligence, attention control and, to a lesser degree, working memory capacity,” researchers concluded, with their findings published in the June issue of the Cognition international journal.

I tend to perceive intelligence in the eyes as an active awareness, or in some cases a liveliness, that doesn’t necessarily translate to the person’s expression, tone, or behavior. Not every intelligent person shows this, but I’ve never met anyone who did who didn’t later prove to be intelligent. It might also explain why people instinctively avoid eye contact when they don’t want to indicate that they are anyone out of the ordinary.