意向保持间隔对时间性前瞻记忆的影响

The Effects of Duration of Retention Intervals on Timebased Prospective Memory

通过两个实验来探讨意向保持间隔对时间性前瞻记忆的影响。实验一通过嵌入前瞻目标的背景任务来操纵保持间隔,实验二通过在背景任务之前加入不同时长的填充任务来改变意向保持间隔。结果发现,(1)背景任务中的保持间隔越长,前瞻记忆成绩越差;(2)背景任务中的保持间隔和填充任务的时长对前瞻记忆的影响存在交互作用。成绩最好的为15min-2min组,最差的为15min-15min组。结果表明,背景任务和填充任务阶段对于个体保持前瞻意向可能有不同的功能。

The duration of the delay between forming new information in memory and the moment that information is to be extracted is an importantfactor that influences memory performance. Recently, a small but increasing number of studies have examined the effect of the delay between intentionformation and retrieval on prospective memory （PM） performance. These studies have found that the effect of delay on PM is complicated. However,most of the studies are related to event-based PM. We know little about the influence of delay on time-based PM. The present study explored the effectof retention intervals on time-based PM with two experiments. In Experiment I, the duration of ongoing task prior to the presentation of the first PM goal was manipulated. Participants were told to press theA key every 2 min or 8 min or 15 min when they were performing the task. The participants in the control condition only performed the ongoing taskfor about 7 min. There were three PM responses in the PM conditions. In Experiment 2, participants were required to perform the filler task before theongoing task in which PM goals were embedded. The duration of filler task was 2 min or 15 min. The duration between the onset of ongoing task andthe first PM goal was also 2 min or 15 min. The experiment conformed to a 2（filler task duration 2 min vs. 15 min）x2（ongoing task interval： 2 minvs. 15 min） between-subjects design. For example, the subjects should perform a 2-min filler task, and then perform the ongoing task. They needed topress the A key every 15 min when they started the ongoing task. There were two PM responses. The results showed that in Experiment 1, the PM performance in the 15-min delay condition was significantly lower than the other twoconditions. The reaction time （RT） of the ongoing task in the 2-rain delay condition was longer than the other conditions. The accurate rate of theongoing task in the control group was higher than that in the other groups. However, when the retention interval was defined by both the filler taskduration and the ongoing task duration in Experiment 2, the PM performances were different. The interaction effect between the filler task duration andthe ongoing task interval was significant. The subsequent analysis revealed that in the long filler task conditions, the PM performance with the 2-minongoing task interval was better than in the 15-rain delay condition. In short filler task conditions, there was no significant difference between the 2-minand the 15-min ongoing task delay conditions. For the RTs of the ongoing task, the ANOVA revealed a main effect of ongoing task interval. The RTsfor the short ongoing task interval were longer compared to those of the long ongoing task interval. For the accurate rate of ongoing task, the maineffect of the filler task duration, the ongoing task interval, and their interaction was not significant. The present study suggests that the duration of filler tasks vs. ongoing tasks is an important factor to consider in evaluating the impact of delaysbetween intention formation and intention retrieval. The delay of filler task and ongoing task may have different effects on intention maintaining intime-based PM. A filler task more or less alleviates the negative influence of long ongoing task delay on PM. Participants may use different strategiesto maintain PM goal. However, many other factors will affect the intention retrieval in time-based PM; for example, the number and feature of fillertasks. Future research may consider these issues.