BRINLEY PLOTS, EXPLAINED VARIANCE, AND THE ANALYSIS OF AGE-DIFFERENCES IN RESPONSE LATENCIES

Critics of Brinley plot analyses (e.g., Fisk, Fisher, & Rogers, 1992; Perfect, 1994) claim: (a) that lack of overlap between latencies on di fferent tasks inflates r(2) values; (b) that Brinley plots mask task-s pecific age differences; and (c) that measurement error in young adult s' latencies precludes the use of regression techniques with Brinley p lot data. We dispute these claims. We show that lack of overlap does n ot inflate r(2) and that the possible presence of task specific effect s in Brinley plot data may be evaluated using standard regression tech niques. These techniques are illustrated using data from the Fisk and Rogers (1991) study of visual and memory search. Analysis of their dat a reveals significant differences between the lexical and nonlexical d omains, but not between types of search. Finally, the effect of measur ement error on Brinley plot analyses is shown to be small and, if take n into account, leads to increased support for general cognitive slowi ng.