> The study found that the openness of the eye was most closely related to our ability to read others' mental states based on their eye expressions.
which is where you probably drew your conclusion. However, the actual paper goes into more details, and reading it show that conclusion is wrong. It says:
> For these analyses, we extracted seven eye features from each exemplar: vertical eye aperture, eyebrow distance, eyebrow slope, eyebrow curvature, nasal wrinkles, temporal wrinkles, and wrinkles below the eyes (Fig. 1). Euclidean coordinates from the appearance models were used to compute eye aperture (distance from top to bottom of eye), eyebrow distance (distance from top of eye to eyebrow), eyebrow slope (slope from start to end of eyebrow), and eyebrow curvature (angular change from start to end of eyebrow).
Fig. 1 in shows example of how they define eye aperture, and it is NOT the pupil size, but the size from the bottom to top of the center of the eye.
Further, their analysis suggests that eye pupil size is either strongly correlated with the seven components they analyzed, or has relatively small contribution to expressing mental state. They say aperture had the strongest correlation with mental-state, "explaining 61.7% of the variance; the valence dimension was the secondary component, explaining 26.8% of the variance. ... Together, these [seven] components captured 88.8% of the total variance."
That is, your claim about pupil size being an evolutionary benefit due to the increased ability to perceive mental state, appear to be contradicted by the very paper you say supports your hypothesis.
There's a long history where defenders of pseudoscience, including Young Earth Creationism and "scientific racism", of citing papers which supposedly support their claim, only to find that either they are irrelevant or say quite the opposites. If you want to make a solid claim, you need to avoid that style, otherwise you'll draw their pseudoscience stink onto you.
> We also found that blue-eyed people have a stronger pupil response than brown-eyed people when they view a picture that causes pupil dilation or constriction. To be more precise, with respect to the total range of response from the smallest pupil size to the largest the range is greater for blue-eyed people than it is for brown-eyed people. (This statement applies, of course, only to changes in pupil size resulting from emotions or attitudes.)
> It is of course easier to see a pupil surrounded by a blue iris than it is to see one surrounded by a brown iris.
That is the press release for the primary article, which is listed at the bottom of the page: Daniel H. Lee, Adam K. Anderson. Reading What the Mind Thinks From How the Eye Sees. Psychological Science, 2017; 28 (4): 494 DOI: 10.1177/0956797616687364
Lee and Anderson DO NOT talk about pupils. That's why irrational replied to your link with "Did you even read what you linked? The linked article has nothing to do with pupils."
I confirmed that irrational's observation is correct, despite your denial.
Your quote now comes from The Role of Pupil Size in Communication, Eckhard H. Hess, Scientific American, Vol. 233, No. 5 (November 1975), pp. 110-119.
The Lee and Anderson (2017), doesn't contradict Hess (1975). Rather, it says that any effect of pupil dilation size on the ability to perceive mental state is significantly smaller than several other factors related to the eye.
The Hess paper is a woefully inadequate source for your claim that blue eyes are not evolutionarily neutral. How many people were studied? How much stronger was the response? What is the statistical significance and how was it calculated? How does it compare to other ways the eyes signal mood like in Lee and Anderson? Were there conflating social factors, like the blue-eye subjects being from a higher social class on average than the brown-eyed subjects?
The paper doesn't give any of those numbers, which makes sense as Scientific American was on the border between an academic publication and a popular science magazine.
Furthermore, the author characterizes the evolutionary hypothesis as "perhaps it is not unwarranted" - a far more tentative claim than you are trying to push.
You need to fill in the missing steps. How do you get from "perhaps not unwarranted" to "substantive enough to advocate on HN"? Because you appear to be advocating an hypothesis with very little evidence.
There's been 50 years of research since Hess. My sampling of the recent papers citing Hess are completely silent of a blue/brown-eyed distinction, which suggests to me it did not play out.
How did you find the Lee and Anderson paper? When did you read it? Why did you cite it when it doesn't even mention the word "pupil"? Do you understand how it seems to strongly diminish the significance of your evolutionary hypothesis?
> The study found that the openness of the eye was most closely related to our ability to read others' mental states based on their eye expressions.
which is where you probably drew your conclusion. However, the actual paper goes into more details, and reading it show that conclusion is wrong. It says:
> For these analyses, we extracted seven eye features from each exemplar: vertical eye aperture, eyebrow distance, eyebrow slope, eyebrow curvature, nasal wrinkles, temporal wrinkles, and wrinkles below the eyes (Fig. 1). Euclidean coordinates from the appearance models were used to compute eye aperture (distance from top to bottom of eye), eyebrow distance (distance from top of eye to eyebrow), eyebrow slope (slope from start to end of eyebrow), and eyebrow curvature (angular change from start to end of eyebrow).
Fig. 1 in shows example of how they define eye aperture, and it is NOT the pupil size, but the size from the bottom to top of the center of the eye.
Further, their analysis suggests that eye pupil size is either strongly correlated with the seven components they analyzed, or has relatively small contribution to expressing mental state. They say aperture had the strongest correlation with mental-state, "explaining 61.7% of the variance; the valence dimension was the secondary component, explaining 26.8% of the variance. ... Together, these [seven] components captured 88.8% of the total variance."
That is, your claim about pupil size being an evolutionary benefit due to the increased ability to perceive mental state, appear to be contradicted by the very paper you say supports your hypothesis.
There's a long history where defenders of pseudoscience, including Young Earth Creationism and "scientific racism", of citing papers which supposedly support their claim, only to find that either they are irrelevant or say quite the opposites. If you want to make a solid claim, you need to avoid that style, otherwise you'll draw their pseudoscience stink onto you.