The Transfer of Information between Sense-Modalities: A Neuropsychological Review

Abstract

This paper deals with a special case of the transmission of information within the normal brain: the exchange of information between sense-modalities. Two main kinds of relevant behaviour can be distinguished: (1) cross-modal matching or recognition; and (2) cross-modal transfer. The findings indicate that man can match across sense-modalities even in the absence of language as a mediator or bridge; that apes probably possess this ability; but monkeys probably do not (although insufficient experiments have been undertaken with both apes and monkeys). Specific learning apparently fails to transfer between sense-modalities in man and the monkey (when verbal mediation is precluded for man); and no relevant findings exist for apes. Curiously, some non-primates succeed where primates apparently fail, but the so-called specific “cross-modal transfer” of non-primate mammals should perhaps be regarded instead as wide stimulus generalisation. In contrast, general learning has so far been shown to transfer across sense-modalities only in man, but this claim must be qualified: apes have not yet been assessed; and non-primates may transfer a primitive form of general learning.

These experiments on intact animals (a) advance the classification of cognitive processes in behaviour; (b) taken with other lines of evidence, should help to establish meaningful groupings of different species of mammal; and (c) permit predictions to be made (independently of any other behavioural data) of the existence of different kinds of neural system in different species. For example, the behavioural evidence suggests that man and apes may have a higher-order cortical system for cross-modal matching and general transfer, but monkeys and non-primates may not have this system; on the other hand,non-primates may possess a lower-order sub-cortical system (which, if present, is functionally inhibited in man and most primates) for cross-modal stimulus generalisation.