Soviet neuropsychologist Sokolov's notions of tonic and phasic orienting responses and of defense responses are examined for relevance to individual information processing. The phasic orienting response provides an index to attention and to information demands generated by the cerebral cortex. The sum of orienting responses elicted by a message would then become the information-demand value of the message. The tonic orienting response appears to be an equivalent to individual capacity to attend at any moment. The defense response is a potential indicator of information processing overload. (Author/AA)