The abstraction of arbitrary categories

Bransford and Franks (1971) showed that people retain the ideas expressed in linguistic input, rather than retaining the individual sentences. The extent to which this phenomenon reflects organizational' processes based on co-occurrence information was investigated by using Bransford and Franks' procedure but substituting arbitrarily chosen groups of words for sentences. The subjects gave higher recognition ratings to large new groups (analogous to complex sentences) than to small new groups (analogous to simpler ones), so long as the size of the group was in the range normally presented. They also showed the same ordering for old groups; but they rated old groups higher than new groups within each group size. Hierarchical recognition response structure can be established without an ideational basis, and it does not require complete absence from memory of original input items.