Don Dedrick

Colour categorization and the space between perception and language.

We need to reconsider and reconceive the path that will take us from innate perceptual saliencies to basic (and perhaps other) colour language. There is a space between the perceptual and the linguistic levels that needs to be filled by an account of the rules that people use to generate relatively stable reference classes in a social context.

Explanation and Color-Naming Research

Perhaps one of the central assumptions when one comes to think about scientific explanations—an assumption made by philosophers and scientists alike—is that a causal explanation is an optimal explanation. It seems, after all, that an explanation tells us why something happens and that to do so is to specify causes. Although there is nothing wrong with causal explanations per se, many good explanations in science are not in any important sense causal. What I mean by this is that many good explanations in science are compatible with a variety of causal mechanisms and, as such, ignore the details of such mechanisms. I develop this claim in the discussion of color-naming research that follows, where I distinguish between explanation types that are (more) close to causality (actual sequence explanations) and those that are (more) removed from causal details (robust process explanations).

Can Colour Be Reduced to Anything

C. L. Hardin has argued that the colour opponency of the vision system leads to chromatic subjectivism: chromatic sensory states reduce to neurophysiological states. Much of the force of Hardins argument derives from a critique of chromatic objectivism. On this view chromatic sensory states are held to reduce to an external property. While I agree with Hardins critique of objectivism it is far from clear that the problems which beset objectivism do not apply to the subjectivist position as well. I develop a critique of subjectivism that parallels Hardins anti-objectivist argument.

Blindsight and enumeration: A case study

“Blindsight” is a term first coined by Weiskrantz et al. in 1974 to describe residual visual performance in the cortically blind. It has been postulated that blindsight could be due to the retinotectal pathway projecting information past V1 to later cortical structures. Our interest was in whether the pathways responsible for blindsight could also support enumeration. We tested a 53-year-old male, C.H., who had suffered a medial right occipital lobe stroke seven months previous. The stroke resulted in an upper left homonymous quadrantanopia. In order to determine whether there were any residual abilities in the blind field, we first tested basic detection and discrimination skills. C.H. was able to determine whether or not a 7° X 7° visual angle object was presented in his blind field with near perfect accuracy though his accuracy was only 90% for smaller (4.6° X 2.2°) figures. C.H. also discriminated between large X′s and O′s and horizontal and vertical bars with good accuracy when the figures were large (78% for X vs. O and 73% for horizontal vs. vertical bars). Throughout these tests C.H. staunchly maintained that he could not see the stimuli and that he was only guessing. Because it was clear that C.H. had some residual ability in his blind field, we tested his enumeration. The enumeration task involved 1-3 items. These items were 1.5° Blindsight and enumeration: A case study http://www.journalofvision.org/content/10/7/898.short 1 of 2 2015-01-03, 8:42 PM X 1.5° black diamonds, 0-2 in his blind field and 1-3 in his non-blind field. Across all conditions, C.H. was able to use the information in his blind field and identify the total number of items presented at levels of performance that were well above chance. Because C.H. appears to use blind field information to enumerate, we postulate that enumeration ability may be mediated by the same structures that support blindsight. Received June 26, 2010.

Jules Davidoff, Cognition through Color, Issues in the Biology of Language and Cognition Series

These visions of the future – and our responsibility toward it – have a pretty familiar ring, and for the most part they also sound pretty naive. Fortunately, there is a growing abundance of sophisticated literature on computers and society, and anyone wishing to address that topic in some depth will profit from consulting it. Good entry points are Johnson and Nissenbaum 19951 and Kling 1996.2 As for how brains think, a better starting place than this book is William Calvin’s Web page (http://weber.u.washington.edu/∼wcalvin). It’s well done, and it’s free.