Ironic effects of repetition: Measuring age-related differences in memory.

Four experiments examined ironic effects of repetition, effects opposite to those desired (cf. D. M. Wegner, 1994). For an exclusion task, participants were to respond "yes" to words heard earlier but "no" to words that were read earlier. Results from young adults given adequate time to respond showed that false alarms to earlier-read words decreased with their repetition. An opposite, ironic effect of repetition was found for elderly adults--false alarms to earlier-read words increased with repetition. Younger adults forced to respond quickly or to perform a secondary task while reading words showed the same ironic effect of repetition as did elderly adults. The process-dissociation procedure (L. L. Jacoby, 1991, 1998) was used to show that factors that produce ironic effects do so by reducing recollection while leaving effects of repetition on familiarity unchanged.