Order error in immediate recall of sequences

The only attempts to account for order errors in serial recall, have been informational analyses leading to models involving separate storage for item and order information. The present study begins by showing that there is a high degree of association between order and item errors. Items which acoustically confuse with each other are likely to transpose in recall. This result suggests that apparent order error could arise from two or more independent item errors substituting for each other. Taking into account the demonstrated association between acoustic similarity of items and liability to confuse in recall, the chance that two independent item errors will form a transposition is much increased beyond the pure chance level. This chance is even further increased because (a) acoustic confusions in recall reciprocate, and (b) when sequences are such that repetition of items does not occur, when Ss have made one mistake, they are more willing to make a wrong report on a later item than to be led into a repetition. It is concluded that memory models do not necessarily need a mechanism which could transpose the order of items in storage. A simpler model is suggested in which items are fixed in the input order, encoded only according to properties of individual items. There is in addition a response availability store from which item substitutions are drawn. The size of this store is independent of vocabulary size, is relatively small, and consists primarily of recent responses only. Thus even when sequence items are drawn from a very large vocabulary, this modified mutual substitution model would still be adequate to account for differences between the order in which items enter and leave a memory store.