EFFECTS OF WORD-FREQUENCY AND AGE OF ACQUISITION ON SHORT-TERM-MEMORYSPAN

The experiments reported examine the effects of two highly related var iables, word frequency and age of acquisition, on short-term memory sp an. Short-term memory span and speech rate were measured for sets of w ords which independently manipulated frequency and age of acquisition. It was found that frequency had a considerable effect on short-term m emory span, which was not mediated by speech rate differences-although frequency did affect speech rate in one experiment. For age of acquis ition, this situation was reversed; there was a small but significant effect of age of acquisition on speech rate, but no effect on memory s pan. This occurred despite results confirming that the stimuli used in the experiments produce an effect of age of acquisition on word namin g. The results are discussed in terms of a two-component view of perfo rmance on short-term memory tasks.