Rotating Images

In Sweet Dreams (sorry I’m not giving page numbers in this essay -- Kindle isn’t showing me page numbers) Daniel Dennett argues that practicing experimental psychologists work under the assumptions of heterophenomenology, and not classical phenomenology (which Dennett sometimes calls “autophenomenology”.)  He cites as an example experiments by Roger Shepard where subjects are shown drawings of two three-dimensional shapes and asked if they are actually the same shape in two different positions.  Apparently, the subjects got the correct answer a lot of the time.  Dennett writes:

Most subjects claimed to solve the problem by rotating one of the two figures in their “mind’s eye” or imagination, to see if it could be imposed on the other.

Shepard argued that the subjects actually did solve the problem by rotating the shapes in their imagination, and he supported this claim by trying to show that the time it took to solve the problem correlated well with the “rotation distance” between the two shapes, that is, how many degrees the shape would need to be rotated from the position of the first shape to the position of the second shape.  “This didn’t settle the issue,” Dennett writes, “since Pylyshyn and others were quick to compose alternative hypotheses.”

Pylyshyn, Dennett argues, is clearly practicing heterophenomenology.  The subjects claim to be rotating mental images -- they report a conscious experience -- and Pylyshyn’s hypotheses suggest that no such experience actually happens.  Even Shepard seems to be practicing heterophenomenology.  If he simply assumes that his subjects actually experience what they think they are experiencing, there would be no reason to find further evidence of those experiences.

Dennett writes:

Subjects always say they are rotating their mental images, so if agnosticism were not the tacit order of the day, Shepard and Kosslyn would never have needed to do their experiments to support subjects’ claims that what they were doing (at least if described metaphorically) really was a process of image manipulation.

This doesn’t quite follow, IMAO.  Dennett doesn’t seem to consider the possibility that there is no “order of the day”, that some experimental psychologists identify with heterophenomenolgy and some identify with classical phenomenology.

Furthermore, I don’t think that Pylyshyn’s alternative hypotheses are actually relevant to heterphenomenology.  Dennett assumes that if the alternative hypotheses were true, it would imply that the subjects’ reports were false, but IMAO this doesn’t follow.  It’s possible that the brain subconsciously solved the problem through some non-rotational algorithm, but people still imagined the images rotating -- the experience may have reflected the nature of the problem being solved, rather than the process of the problem being solved.

In general, these image rotation experiments are not phenomenology experiments at all -- their relevance to phenomenology is indirect.  The experiments analyze the brain’s computational competence, rather than the person’s conscious experiences.