How often do we think about past experiences? How often do we imagine future events? Do the frequencies of these thoughts change as we age? For example, as the pool of retrievable past experiences may be larger in an older compared with a younger individual, does an older adult, on average, spend more time reminiscing his or her past? Likewise, does a younger adult typically spend more time planning future experiences? In a recent paper, published in Psychology and Aging, Gardner and Ascoli (2015) (PDF, 225KB) asked these questions and more.
The researchers used a naturalistic technique called experience sampling to identify and probe thoughts from participants (ranging in age from 18 to 75 years old) as they went about their daily activities. Specifically, each participant was prompted at random moments during his or her day via a cell phone, receiving, on average, approximately 220 cell-phone prompts over the course of 19 days.
Each time a prompt was received, participants were asked to introspect and document if at that moment they were either remembering a past experience (termed autobiographical memory: AM) or thinking about a future event (termed prospective memory: PM). Thus, for each participant, the likelihood of engaging in AM or PM at any given moment could be estimated. In addition to documenting the occurrence of AM and PM, the participant also estimated the duration of the thought up to the point of the prompt. From these probability and duration data, the researchers estimated the total number of memories experienced in a typical waking hour or other given time period.
About 10% of prompts interrupted an AM, and this probability did not differ between younger and older individuals. Strikingly, however, the age of the subject was positively correlated with the likelihood of experiencing PM; while younger subjects were just as likely to engage in PM as they were to engage in AM, older adults were more than twice as likely to report PMs. Moreover, as the durations of AMs and PMs did not change across age groups, the total number of PMs experienced per unit time was significantly greater in older compared with younger individuals.
Overall, these findings point to an age-related shift in the temporality of thought for personal experiences. Older adults more frequently engage in thought directed toward their personal future.
Moreover, AM and PM occurrences were positively correlated; on average, those individuals who were more likely to experience AM were also more likely to experience PM, and this relationship was strongest among younger adults. These findings suggest that typically some individuals experience high rates of thoughts pertaining to both past and future experiences, while others experience fewer thoughts pertaining to experiences from either temporal period.
Citation:
Gardner, R. S., & Ascoli, G. A. (2015). The Natural Frequency of Human Prospective Memory Increases With Age. Psychology and Aging, 30(2), 209–219.http://dx.doi.org/10.1037/a0038876
Note: This article is in the Developmental Psychology topic area. View more articles in the Developmental Psychology topic area.