Medin and Ortony: "Psychological essentialism" (1989)

This is a contribution by Douglas Medin and Andrew Ortony to the volume Similarity and Analogical Reasoning (1989) edited by Stella Vosniadou and Ortony. Medin and Ortony argue that entities have two distinct sets of features, a shallow and a deep set, that influence similarity judgments in different contexts.

Superficial Attributes and "Essence Slots"
The paper is called "Psychological essentialism" because Medin and Ortony thinks that the context-dependence of similarity judgment can be explained by supposing that ordinary lay folk are metaphysical essentialists. What this means is that the average test subject believes that entities have deep, perhaps unknown, properties in addition to their superficial attributes.

This is supposed to explain why we categorize dolphins with bats and not with sharks. In other cases, like an airplane, a subject's representation of this "essence" make take the form of a theory like "I don't know, but an experts could tell me."

There is something interesting and original about taking a bad philosophical theory and trying to explain it as a psychological phenomenon. However, think their theory hides as much as it shows, as it takes similarity judgment to be divorced from action. I think most of the paradoxical features of similarity judgments (as described by Lawrence Barsalou) would evaporate if we took "being similar" as explained by "treated similarly" rather than the other way around.

A Note on Gender and Style
When I was reading the paper, I was noticing that Medin and Ortony tend to refer to Linda E. Smith by both her first and last name, while they refer to male authors by their last name only. In order to check whether this was actually true, I counted how many times people were mentioned in the text, and whether their first names were mentioned:

Person	+ first name	– first name
Linda B. Smith	4	2
Lawrence W. Barsalou	1	9
Lance J. Rips	1	12
Ryszard Michalski	2	3
Edward E. Smith	2	8
Daniel N. Osherson	2	8
Ludwig Wittgenstein	0	2
John Locke	0	4

The numbers in the table show how often the respective authors occur with their first name spelled out completely. Last names mentioned in references such as "Smith and Medin (1981)" are not counted, since their form is dictated by more rigid style guides. I have not counted names that only occur once (which exlude Elanor Rosch, who is mentioned with first name).

Note that Linda B. Smith is the only woman referred to in the paper. The fact that her first name is mentioned more frequently than, say, Michalski's, may be attributed to the fact that there is another "Smith" frequently referenced in the paper, but note that he is more frequently referred to by his last name only. However, this may partly be due to the fact that his name is disambiguated by the fact that it occurs next to Osherson's as well as more often. A recent mention of a figure does to some extent make the first name obsolete.

Nevertheless, the numbers are quite striking. It would be interesting to do a more thorough investigation of this phenomenon. It would perhaps also be more interesting to investigate whether there is a significant difference in the distance from last mention that warrants reiterating a first name for men and women, respectively.