The present research is aimed at understanding the processes involved in short-term memory and how they interact with age. Specifically, word length effects were examined under forward serial recall, backward serial recall, and item recognition tasks, with performance being interpreted within an item-order theoretical framework. The interaction of age, word length, and direction of recall was examined in two experiments, the first of which confirmed that the word length was present with forward recall and absent with backward recall. In addition, age effects were stronger in backward recall than in forward recall. In the second experiment, an item-order trade-off methodology was utilized with backward recall. When order memory was required, there was no word length effect and strong age effects. When memory was tested via an item recognition test, there was a reverse word length effect and no age effect. While word length effects can be interpreted within the item-order framework, age effects cannot.Keywords Short-term memory . Word length . Foward recall . Backward recall . Aging Immediate forward serial recall of short lists of words is influenced by the length of the to-be-remembered words, such that lists of short words are better recalled in order than lists of long words (Baddeley, Thomson, & Buchanan, 1975). The word length effect has been seen as one of the benchmark phenomena of short-term recall that models of short-term memory must account for. However, almost all theory development has occurred in the context of forward serial recall, and very little attention has been devoted to explaining performance on backward recall, and where it has been addressed (Page & Norris, 1998), it has been assumed that the same structures and processes that underpin forward recall also support backward recall. Recently, this assumption has proved to be untenable in that many of the benchmark effects of forward recall, including the word length effect, are eliminated or severely attenuated in backward recall (Bireta, Fry, Jalbert, Neath, Surprenant, Tehan, & Tolan, 2010). Thus, one of the aims of the present experiments was to understand why the word length effect differs for backward and forward recall.The second aim of the present study had to do with understanding age differences in short-term memory performance. Again, most of the focus in aging effects in short-term memory has concentrated upon forward serial recall, with very little research being conducted using backward recall. If forward and backward recall are not supported by the same mechanisms and processes, aging effects may well differ for forward and backward recall. At the very least, examining backward recall will provide additional empirical evidence with which to explore agerelated influences on short-term memory.
Word length in forward and backward serial recallIn exploring word length effects, it appears that two forms of the effect need to be considered: the time-based effect and the syllable-based effect. The time-based effect refers to...