Defining key terms in Ecological Psychology

Andrew Wilson and I had a tiff on twitter about whether "Affordances" are by-definition "perceivable". Well... backing up... it was a tiff about whether it is fair for a researcher to start talking about something as an example of an affordance, when they have not bothering to demonstrate that the thing in question is perceived. This actually has deep implications for all the key terms in Ecological Psychology. As it is the type of thing you can't really discuss in 240 characters, we decided to return to the blogosphere. Who knows, maybe we can crank out a second blog-driven co-publication when this is done!*

I am extremely sensitive to the problems that occur in a theory when terms start to get mutually inter-defined. You quickly end up with tautologies, and tautologies stop your theory from being a theory in any proper sense. My post-doc advisor and occasional co-author Nick Thompson wrote about this problem extensively in the context of learning theory and evolutionary theory and other contexts in psychology. I don't think any prominent members of the Eco Psych community have such a problem when they are doing research. However, when they start writing theory, the problem pops up fairly often, and it is behind many of the long-term disputes in the literature. The temptation to inter-define terms is strong, because when terms are mutually defined, deduction is easier, and that makes the theory feel intellectually safe and well-founded. However, that feeling is misleading in a scientific context. you can't test things that are deducible from each other, so if you find yourself just stating things that are true by definition, you don't have a theory anymore, because the exact part this is supposed to be testable can't be tested. The way out of this is to rigorously ensure that your terms point to things that can be verified independently of each other, leaving it open for testing whether the things in question relate in the manner proposed. 

Evolution and Homosexuality

For a semester at Clark I was asked to organize the weekly 'recitations' for Introductory Psychology. The course itself was quite large, but the recitations were run by upper-level undergraduates, and contained 20-30 students. I transformed several weeks into lab activities. For others, I organized more formal discussion activities. When the main course was discussing evolutionary psychology, a student asked about how homosexuality could be explained from an evolutionary point of view. This student, and several others in class, seemed to see the existence (or at least the relative normality) of homosexuality as proof against the usefulness of evolutionary theory as an explanation of behavior. For that week, I prepared the following discussion paper for students:

Design, and why we should and shouldn't care about deep theory

Bjoern Bremb, who guy who gave the very cool research talk at WCALB, linked to a good essay on his own blog where he argues that we should banish the term 'design' from our discussions of evolution. I started responding to his comment, but before I knew it, enough was written, and the subject had shifted enough, to justify another post. I appreciate the desire to banish 'design'. I used to hold that view myself, and I think it is a much better position than using the term sloppily. That said, I am now convinced that the current way we discuss evolutionary theory has some deep problems, and that many of those problems could be solved through a fight to reclaim the concept of design. Alas, I'm less convinced that most people should care, e.g., that the work of the day-to-day biologist or psychologist is being negatively impacted by their vague commitment to a problematic version of evolutionary theory. This will not be quite as articulate as I would like, but I will try to explain, in a roundabout way:

William James and the Problem of Design

At William James exhibit in Houghton Library (Harvard), there was a test from 'Philosophy 9' (academic year 1904-1905), one of the questions read:

How far can any state of facts experienced be taken either as proving "design," or as being incompatible therewith?....

This immediately grabbed my attention, as the context was presumably the so-called 'problem of design' that faces evolutionary theorists... and Nick Thompson and I have been wrestling with how to get 'design' back into evolutionary theory (he's been wrestling with it for 40 years, me only for the last 10)... and as I have been trying to convince Nick that his approach derives strongly out of James's late work. 

While the test was staring up at me, I realized that nothing I had read of James dealt with the issue explicitly. How was James trying to deal with the problem of design? What had he told his students? What might his students have replied? This lead to some digging.