Levels indeed! A response to Broadbent.

Although Broadbent concedes that we are probably correct in supposing that memory representations are distributed, he argues that psychological evidence is irrelevant to our argument because our point is relevant only at what Marr (1982) has called the implementation ^ level of description and that psychological theory is only properly concerned with what Marr calls the computational level. We believe that Broadbent is wrong on both counts. First, our model is stated at a third level between the other two, Marr's representational and algorithmic level. Second, we believe that psychology is properly concerned with all three of these levels and that the information processing approach to psychology has been primarily concerned with the same level that we are, namely, the algorithmic level. Thus, our model is a competitor of the logogen model and other models of human information processing. We discuss these and other aspects of the question of levels, concluding that distributed models may ultimately provide more compelling accounts of a number of aspects of cognitive processes than other, competing algorithmic accounts.