Immediate Recall of Numbers Containing a Familiar Prefix or Postfix

Ss studied and then attempted to reproduce, from memory, each 8-digit number in one of 2 types of series. In the “prefix” type, the last 4 digits of each number were selected at random while the first 4 digits were selected from just 2 familiar 4-digit prefix sequences. In the “postfix” type, this order was reversed so that one of these two familiar sequences always followed the 4 random digits. A predicted finding (with potential implications for schemes for man-machine communication) was that, in comparison with the prefix type of series, numbers from the postfix type resulted in decreases of 20% in time scores and 50% in errors. Also, errors in which Ss substituted one entire prefix or postfix for the other indicated that these 4-digit sequences were handled as coherent wholes.