Prospective memory: A new construct?

It seems that prospective memory has been given new life, at least according to what I've been reading. Briefly, prospective memory, as coined by Meacham (1975) refers to the ability to remember something that a person plans to do in the future, such as picking up some beer on the way home from work. Alan Baddeley also said that research on prospective memory was picking up in his book, The Psychology of Memory, in 1976. I wanted to know if it was just me noticing it more and more in my literature reviews or if there was an actual trend. The following describes a new method for investigating social trends in cognitive psychology and cognitive science, and what I found on the use of the common theoretical memory constructs, namely semantic, episodic, and prospective memory.

If I had to take a guess at what is going on sociologically in cognitive psychology and cognitive science, I would say that investigating semantic memory is getting pretty old. As I understand it, semantic memory is an ungrounded, abstract, amodal symbol network. With research in embodied cognition growing in popularity it seems that research on semantic memory might be leveling off. Secondly, episodic memory has been more accepted over the last decade as a construct that is at least grounded in experience. I would expect the number of publications, conferences, chapters, and books to increase over that time. Third, I think that the concept of prospective memory has been gaining in popularity as shown by the greater quantity of literature. Lastly, it seems that authors are no longer pitting episodic memory against semantic memory in their publications, but may be talking about the similarity between episodic and prospective memory. My own work shows that remembering an episode in the past is a similar process to thinking about a similar event planned for the future. I predict that if there had been a rise in publications on episodic memory that a similar increase in work on prospective memory would be found.

Methods
I used the database PsycINFO to collect search results for the keywords semantic, episodic, and prospective memory from 1994-2006 limiting results to the area of the social sciences. I stopped at 1994 because there are only 44 results for prospective memory prior to 1994 (PsycINFO goes back to 1984).

Results
PsycINFO breaks down the results to journal articles, peer reviewed journal articles, conferences, chapters/essays, books, dissertations, book reviews, reports, and other. In order to get a general measure of what keyword is getting the most press I used the total number of results in my line graph (Graph 1). As shown in Graph 1, the number of results increases sharply for episodic memory since 1994, surpassing semantic memory after 1999. Also as predicted semantic memory seems to have leveled off since 2003. Prospective memory seems to be more visible in the literature in the last few years and the slope between 2005-2006 looks similar to that of episodic memory.

Graph 1


Discussion
These results show the growing number of publications and related press given to episodic memory and prospective memory since 2004 compared to the leveling off of work on semantic memory. It is not clear from these data that authors are investigating the similarity between episodic and prospective memory, but it is curious that the slopes resemble one another so closely.

General Discussion
The data presented here show that the trend in cognitive psychology and cognitive science is to write up research in terms of episodic memory and increasingly so for prospective memory. Published research and related press on semantic memory, while still higher in number than prospective memory, has leveled off since 2004.

Google trends could also be used to explore what people are searching for and it even breaks searches down by country and city. Psychological constructs, however, are not searched for enough to get a trend using this method. Further researchers may be able to automate the process of mining PsycINFO, Google trends, or other databases to look for trends in the way that people write about, search for, and maybe even talk about key terms. Through these methods it is possible to find out where research is going.

One of the limitations with this method, as with most qualitative research, is that these preliminary findings do not explain why there is a trend, only that one exists. Alan Baddeley, Martin Conway, and John Aggleton published a book on episodic memory in 2002, and that could have been the impetus for the sharp increase in related research. However, even if it generated a lot of research, an experiment would have to be done to support a causal link.