Selective Attention

[Thomas Hildebrandt]

Paul Kube of UCSD mentions:

   In a recent paper (Nature, 30 November 1989, pp. 543-545), Luck,
   Hillyard, Mangun and Gazzaniga report that split-brain patients are
   twice as good as normals on Triesman-type conjunctive feature visual
   search tasks when the stimulus array is distributed across both
   hemifields, but no better than normals when the array is restricted to
   one hemifield.  This suggests that commissurotomy permits a "splitting
   of attention" that is impossible with connected hemispheres, and that
   remains impossible within each hemisphere.


It seems to be fairly obvious that attention is impossible without
inhibition, and that attention can be interpreted to be the relative
lack of it in a subset of neurons.  If you adopt this view, then the
results of the paper mentioned by kube can be easily explained: One
hemisphere inhibits the other.  If the connections between them are
cut, then each may act independently -- thus doubling the apparent
capacity for attention of the brain as a whole.  However, I imagine
that a commissurotomy also has some UNdesirable effects. . . .

				Thomas H. Hildebrandt
				North Carolina State