Background:
The present study examines prospective memory, which is the ability to remember to do something in the future. The authors point out that there are two types of prospective memory. The first, event-based intentions, occur when an environmental cue causes one to remember a previous intention. A person who has to remember to complete an activity at a specific time is using time-based intentions. Most studies focus more with event-based intentions. The studies that do examine time-based intentions are mainly comparing performance on time-based tasks to event-based tasks. One reason given for performance differences is that the environment doesn’t give good retrieval cues for time-based intentions. There is only one theory explaining the success of time-based intentions which is Miller et. al.’s (1960) theory called test-wait-test-exit (TWTE). The theory states that people go through a cycle of checking if the correct amount of time has passed and if not continue what they were doing and test again later or stop the cycle and perform the time-based task. The main problem with this theory is that it doesn’t explain the cognitive processes leading up the time-checking behavior. It also doesn’t explain the differences between pulses (i.e. intentions to perform an activity at a specific time) and steps (i.e. intentions that can be completed within a large window of time). Pulses tend to be completed more often than steps. The goal of the present study is to further explain time-based intentions. The authors hypothesize that either 1) the occurrence of an expected context may cue the intention which in turn causes time-checking or 2) entering the expected context explicitly cues recollection of the intention and that in turn causes time-checking.
Experiment 1:
METHOD: Participants were randomly assigned into one of four conditions. In the two experimental conditions, the participant was told to remember to press a key between the 6 and 7-minute mark of elapsed time from the beginning of the experiment. The participants could check a clock by pressing the z key, which showed the elapsed time. There were three phases (pleasantness ratings, demographic questions, and syllabi counting), and participants were told to expect the 6-7 minute mark to be in the third phase. In one of the conditions, the 6-7 mark occurred in the predicted phase, and in the other condition the 6-7 minute mark occurred during the first phase (fig. 1 p.349). There were also two conditions the same as above, but the experimenter didn’t suggest when the prospective memory task should occur.
RESULTS: The two comparison conditions were statistically equivalent in participants’ ability for prospective memory. Also, the number of clock checks didn’t differ significantly. Time based prospective memory was significantly different among the conditions. They context correct condition had significantly more correct responses than the control condition. Furthermore, the wrong context condition had significantly worse correct responses than the control condition. This shows that associating time-based intention with a future context improves performance when the expected context is correct. When the context is not correct then it is detrimental. There was not a significant difference in the number of clock checks between the conditions. But, there was a difference of when people checked the clock. In the short phase first, people did it more earlier on while in the long phase first it was not check until immediately before the time if they made the time at all. This shows that when an expected context occurs earlier than expected that people haven’t adequately monitored the passage of time and miss the task.
Experiment 2:
METHOD: All of the procedures were similar to the long-first context of experiment one. The changes are reminder conditions of 1 minute into the experiment and 5 minutes into the experiment and the control of no reminders. Researches predict that the reminder will increase prospective memory. Reminders have never been tested with time based intentions, and too many reminders have shown to be detrimental to prospective memory because of people habituating them.
RESULTS: The poor performance of the miscued context was reproduced from experiment 1 (no reminder). However, reminders significantly increase performance on prospective memory. Although there was better performance when the reminder was at five minutes, the two conditions didn’t differ significantly. The fact that there was a reminder was more important than the location of the reminder. Participants also checked the clock more often in the reminder conditions when compared to the no reminder condition. The reminder still did not increase the performance to the experiment one condition of correct context’s level.
Experiment 3:
METHOD: The authors in this experiment wanted to see if adding an event-based intention increased the time-based intentions performance. The methods were similar to experiment 2 except that instead of a reminder, participants and to press / for a specific word either presented at 1 min or 5 minutes. There is evidence that people think of other intentions once a particular intention is completed.
RESULTS: Performance for the event-based intention was better 1 minute into the experiment than 5 minutes into it. The outcome was that time-based performance was not increased by also having an event intention. Contrarily, time-based performance was significantly decreased by the event-based intention only in the 5-minute condition, but was nominally lower in the 1-minute condition. The number of clock checks was not statistically different. There was increased clock checking in the appropriate phase (phase 3) over phase 1 (when the time intention was) however, at this time it was too late. But the dual tasked seemed to cause participants to rely more on the context rather than time checking.
General Discussion:
When a time-based intention is associated with a context, prospective memory was more correct when the context as the correct time rather then it wasn’t. There were deleterious consequences for when the time based task was out of context. Reminders helped to perform the task at the correct time, but still less than when the task was in the correct context. The study also shows why implementation intentions (i.e. intentions with specific plans for completion) are more successful than other intentions. Finally, this study shows the importance of how future expectations affect our intention completions.
Important Legal
Disclaimer: The preceding are articles we read together in the Lampinen Lab
Fall 2005 false memory reading group. By clicking on the button next to the
article you can see the summary of that article. The summary was prepared by
the student presenting that article and it is of course the case that the views
expressed in the summary do not necessarily represent the views of the reading
group as a whole, Dr. Lampinen, the Lampinen Lab, Hugo's, the University of
Arkansas, the Razorback Football or Basketball teams (although we're not sure
about cross country), people living down the street from us, Bob Dylan, Jack
Fate, our extended families, or anyone else for that matter except for the
student who wrote the summary (and they don't necessarily believe what they
wrote either).