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Many Minds

Jun 28, 2023

We're taking a little summer break right now, but we wanted to share a favorite essay from our archives. Enjoy!


Welcome back folks! Today, we’ve got an audio essay for you. I won’t say too too much—don’t want to spoil it—but it’s about pupils. Not as in students, but as in the dark cores of our eyes. This one of those that’s been in the works for a little while. About a year ago I started collecting all the cool new pupil-related stuff coming out. Then at some point this summer some extra cool stuff came out and I said, “That’s it—time to do it, time to pull this material together into some kind of episode.” So that’s what we have for you today. And I hope you find it eye-opening.

Quick reminder before we get to it: As always, we could really use your help in getting the word out about the show. That might mean subscribing, if you don’t already. It might mean rating or reviewing us on Apple Podcasts. It might mean sending the show to a friend or two. I mean honestly it could mean knitting a Many Minds cardigan for the cold months ahead and sporting it around town. Ceaselessly.

Alright all, on to this week’s essay ‘The eye’s mind.’ Enjoy!


A text version of this episode (enriched with images!) is readable on Medium.



2:00 – The eye of the giant squid was described in detail for the first time in 2012, in this paper.

3:10 – On diversity in animal pupils, see this recent paper.

4:40 – Pupil changes to imagined and linguistically encoded light can be read about here and here.

5:30 – Eckherd Hess’s early research on pupils is summarized in his 1965 Scientific American article, ‘Attitude and Pupil Size’.

6:45 – The 1966 paper by Kahneman and Beatty is here. Or see a 2018 review of more recent research on pupils and cognitive effort.

8:10 – Hess’s studies on the social functions of pupils are recounted in his 1975 Scientific American article, ‘The Role of Pupil Size in Communication’. Several of his classic studies have been replicated just this year (with good but not perfect success).

8:50 – Mariska Kret’s suggestion about how pupils fit the baby schema can be found here.

9:45 – Kret’s studies of pupil mimicry include this onethis one, and this one, among others.

10:15 – The 2021 paper by Wohltjen & Wheatley on “pupillary synchrony” is available here.

12:00 – The 1974 Nature article titled ‘Pupils of a talking parrot’ is available here.


Correction: The audio version of this essay misstated the size of the pupil changes in Daniel Kahneman's classic studies. These changes were roughly .2 to .5 mm, not 2 to 5 mm.