[This is a guest post by Paul Kay, responding to an earlier Language Log post.]
My colleagues and I would like to express our appreciation for the nice things Mark Liberman ("What would Whorf say?" Language Log, Jan 3, 2006), had to say about our study (Gilbert, Aubrey L., Terry Regier, Paul Kay and Richard B. Ivry. "Whorf hypothesis is supported in the right visual field but not the left." PNAS. 103, 489-494, 2006). In that paper, we presented evidence for the Whorf hypothesis operating in the right visual field (RVF) but not the left visual field (LVF). This pattern is suggested by the functional organization of the brain, since the RVF furnishes visual input to the left cerebral hemisphere (LH), and the LH is significantly more dedicated to language processing than the right hemisphere (RH). In studies involving visual search for colors, we found that reaction times to target colors in the RVF were faster when the target and distractor colors had different names than when they had the same name; in contrast, reaction times to targets in the LVF were not affected by the names of the target and distractor colors.
Mark’s post gave an excellent description of our experiments and findings, and sparked some very useful email discussion. However, at the risk of seeming ungracious, we wish to contest one part of his interpretation of our results. Our disagreement arises with the following passage of his post:
One [problem] is that the explanation might have worked just as well if the experiment had come out quite a bit differently. […] Other possible results -- basically anything except a situation in which color category makes no difference, or doesn't interact with visual field -- could similarly be given a Whorfian interpretation. [Italics ours]
We think the Whorf hypothesis makes a more specific prediction than this – a prediction that is confirmed by our findings. It has previously been established that (1) other things being equal, stimuli from distinct lexical (thus, linguistic) categories are discriminated faster than stimuli from the same lexical category – a Whorfian finding, since it apparently stems from language, and (2) as mentioned above, language function tends strongly to be biased to the left hemisphere, to which the RVF projects. Under the Whorfian hypothesis that language affects perceptual discrimination, a straightforward extrapolation from (1) and (2) is that cross-category stimulus pairs should be discriminated more readily than within-category pairs to a greater extent in the RVF than the LVF. Our results confirm this specific prediction. More complicated scenarios leading to different predictions are of course possible, but, we submit, less well motivated.
[This post has benefited from email exchanges between some of us and Mark Liberman.]
Paul Kay, January 14, 2006.
Posted by Mark Liberman at January 15, 2006 09:23 AM