ABSTRACT
Some aspects of human cognitive function appear to be “encapsulated” or modular. Encapsulation refers to the fact that only the output, and not internal workings, of these modules is open to interaction with other brain systems. Visual illusions are an example of encapsulation. For example, in the Muller-Lyer illusion, even though viewers have the conscious knowledge that the two lines are the same length, they cannot help but perceive them as being of different lengths. Thus, the processing within a module is not affected by information in other parts of the system, only its end product (the lines being of different length) is accessible. Although there is evidence that the adult mind contains such encapsulated modules, there is very little evidence that they are innate. Rather, encapsulation of particular aspects of information processing might be a consequence, rather than a generator, of postnatal development (see also Johnson, 2000; KarmiloffSmith, 1992; Patterson et al., 1999).
