The Characteristics And Processing Mechanism Of The Practice Effect On Time-Based Prospective Memory

Prospective memory refers to the ability to remember to perform planned events or activities.According to the nature of cue,prospective memory can be divided to event-based prospective memory and time-based prospective memory.The event-based prospective memory needs to be executed when specific external cues appear.However,the time-based prospective memory does not have explicit external cues and it needs to be executed at a specific time.In our daily life,prospective memory tasks are very common and occupy more than half of our memory.In view of the importance of prospective memory,how to improve prospective memory performance has been a hot topic in the field of prospective memory.Repetitive behavior training is usually a simple and effective way to improve cognitive performance.In the present study,the phenomenon of improving the performance of specific prospective memory tasks through repeated prospective memory training is called the practice effect on prospective memory.In our daily life,this phenomenon is also very common.To perform a specific prospective memory task day by day corresponds to the habit formation.Forming a stable prospective memory habit usually allows us to perform this task well.At present,a large number of studies had confirmed the existence of the practice effect on event-based prospective memory.However,only four studies had focused on the practice effect on time-based prospective memory.Three of them had big flaws due to the virtual week paradigm.The cues of the repeated time-based prospective memory tasks they set up in this paradigm were presented in text on the grid.Such time-based prospective memory tasks were more like event-based prospective memory tasks in essence.Another study used both cognitive processing training and coding strategy training,so there was no way to distinguish which way worked.Therefore,from the existing studies,we were not yet sure whether the practice effect on time-based prospective memory existed.The purpose of Study 1 was to preliminary test the existence of the practice effect on time-based prospective memory.The temporal information processing involved in time-based prospective memory was mainly time estimation.The time estimation training was limited by attention load,so the present study speculated that the practice effect on time-based prospective memory was also easily affected by attention.There were many ways to manipulate attention.The first method was to change the difficulty of background tasks,which could indirectly manipulate individuals’ attention input in time-based prospective memory tasks.The second method was to directly manipulate attention resources available to the individuals on time-based prospective memory by increasing the delay time after the background tasks.The first two methods mainly manipulated the attention resources available to individuals.However,even if individuals had sufficient available attention resources,when there were effective cues,they would tend to use external cues to actively reduce attention input in temporal information processing,which might also affect the practice effect on time-based prospective memory.Therefore,the third way was to manipulate attention by whether to set a reminder or not.Experiment 1 preliminary explored whether the practice effect on time-based prospective memory could be produced under the easy background tasks.The background task was 1-back task.The results of this experiment revealed that,compared with the control group,the experimental group had better prospective memory performance,which indicated that the practice effect on time-based prospective memory existed under easy background task.Experiment 2 further explored whether the practice effect on time-based prospective memory existed under difficult background task(2-back task).The results showed that there was no difference between the experimental group and the control group,indicating that the difficult background task interfered with the practice effect on time-based prospective memory.Experiment 3 explored on the basis of Experiment 2 whether increasing the delay time could eliminate the interference of difficult background task on the practice effect.The background task still used the 2-back task,the difference was that Experiment 3 added the delay time of 500 milliseconds after each 2-back task.The results showed that the prospective memory performance of the experimental group was significantly better than that of the control group,indicating that the practice effect on time-based prospective memory also produced under the difficult background task with delay.Experiment 4 explored whether external reminders affected the practice effect on time-based prospective memory.The results showed that the prospective memory performance of no reminder group was better than that of the reminder group and the control group,while there was no difference between the reminder group and the control group,which indicated that external reminders interfered with the practice effect on time-based prospective memory.The results of Study 1 indicated that the practice effect on time-based prospective memory could be produced only when individuals paid enough attention to the time-based prospective memory task.The purpose of Study 2 was to explore the processing mechanism of the practice effect on time-based prospective memory from the changes of time estimation ability and attention.Experiment 5 explored the changes of individuals’ attention and time estimation ability when the practice effect on time-based prospective memory was produced.The results showed that compared with the control group,the experimental group had better prospective memory performance,better time estimation performance and smaller time difference.It revealed that when the practice effect was produced,individuals’ time estimation ability and the effectiveness of attention were improved.Experiment 6 further verified whether time estimation played a key role in the practice effect on time-based prospective memory.In this experiment,time estimation training was used to replace the original prospective memory training in the training stage.The results also showed that compared with control group,the experiment group had better prospective memory performance.They also had better time estimation performance and smaller time difference.It was consistent with the results of Experiment 5,indicating that time estimation did play a key role in the practice effect on time-based prospective memory.Memory training usually improved individuals’ level of automatic processing in memory tasks and reduced their attention consumption.However,the results of several experiments in this study were not consistent.Considering that this might be due to external interference in some experiments,Experiment 7 created a more ideal experimental environment to further explore whether the individuals trained in time-based prospective memory could save attention resources,and if so,whether it could reach the level of automatic processing.The results showed that compared with the control group,experimental group had less time monitoring times and better performance in background tasks,which indicated that the time-based prospective memory task did have a significant reduction in attention consumption after training.In addition,compared with the baseline group,the experimental group had worse background task performance,which indicated that the time-based prospective memory task could not achieve the degree of automatic processing even after training.The purpose of Experiment 3 was to explore the transferability and specificity of the practice effect on time-based prospective memory,whose essence was to explore its scope of action.Transferability referred to the phenomenon that training effect could transfer from training stimulus or training condition to other stimulus or condition,while specificity was the opposite.According to the characteristics of prospective memory,this study mainly explored the transferability and specificity from two aspects:(1)whether it could transfer between different background tasks;(2)whether it could transfer between prospective memory tasks with different time intervals.In view of the fact that the practice effect on time-based prospective memory was easily influenced by attention,it should be explored separately whether it could transfer from easy background task to difficult background task and whether it could transfer from difficult background task to easy background task.Experiment 8 explored whether the practice effect on time-based prospective memory could transfer from easy background task to difficult background task.The results showed that there was no difference between the experimental group and the control group in the measurement of transfer performance,indicating that the transfer from easy to difficult could not produce,showing specificity.Experiment 9 explored whether the practice effect on time-based prospective memory could transfer from difficult background task to easy background task.The results showed that the prospective memory performance of experimental group was significantly better than that of the control group at the stage of measuring the transfer performance,indicating that the transfer from difficult background task to easy background task could produce,showing the transferability.The results of Experiment 8 and Experiment 9 showed that the transferability of the practice effect on time-based prospective memory was also affected by attention.Experiment 10 explored whether the training effect could transfer from the short time interval(1 minute)to long time interval(3 minute).The results showed that there was no difference between the control group and the experimental group at the stage of measuring the transfer performance,indicating that the training effect of time-based prospective memory could transfer between different time intervals,showing specificity.In Experiment 8 and Experiment 10,the time difference between the experimental group and the control group was no difference.But in Experiment 9,the time difference between the control group and the experimental group was significantly smaller.It indirectly suggested that time estimation also played a role in the transferability of the practice effect on time-based prospective memory.Through these studies above,three conclusions could be drawn:(1)the practice effect on time-based prospective memory was affected by attention;(2)time estimation played a key role in the practice effect on time-based prospective memory;(3)the practice effect on time-based prospective memory could only transfer from difficult background task to easy background task.This study was the first to explore the practice effect on time-based prospective memory in a real sense,and it also had a certain contribution to the theoretical significance and application value.In theory,this study further enriched the dynamic attention theory.Dynamic attention theory only emphasized that rhythmic stimulus structure could promote individuals’ the attention efficiency in temporal information processing,thus improving the performance of time task.This study also found that previous experience could also improve the effectiveness of attention,and the main reason for the improvement of attention efficiency was the improvement of time estimation ability.The findings of this study further improve the applicability of the dynamic attention theory in the interpretation of time-based prospective memory.In term of application value,this study found that the practice effect of time-based prospective memory and its transferability were affected by attention.This could guide normal people and special groups(for example,Alzheimer’s disease group)to be in a loose environment in the process of forming a time-based prospective memory habit,which would more easily form a stable habit and improve their quality of life.