Blind to blindsight

Blindsight is a bête noire of Semir Zeki, the reviewer of Out of Mind (Books, THES , April 5). It guarantees a review that is anything but balanced.

Zeki ignores evidence by Petra Stoerig and colleagues of patients such as FS who demonstrate visual discriminations always in the complete absence of acknowledged awareness. He ignores the imaging study by Rainer Goebel et al demonstrating activity in the parietal and temporal lobes in those with visual cortex damage, in the absence of conscious awareness.

He ignores findings in the book. Other pertinent analyses get a passing mention as "erudite". Zeki ignores ten years of work on subject DB reported in Blindsight , making it clear that visual discriminations without any awareness can occur under some stimulus conditions, and that under other conditions they are accompanied by a kind of awareness (typically abnormal in character and content).

Subsequent experimental research has been directed towards defining and measuring these contrasting conditions. The effort to classify them was a natural outcome, and nothing to do with "damage limitation". The states have been seen as providing a privileged basis for functional brain-imaging studies of the neural bases of awareness. Readers will be misled by Zeki's destructive and snide review.

Larry Weiskrantz
Department of experimental psychology
University of Oxford