Remembering the past and imagining the future: Selective effects of an episodic specificity induction on detail generation

Abstract

According to the constructive episodic simulation hypothesis, remembering past experiences and imagining future experiences both rely heavily on episodic memory. However, recent research indicates that nonepisodic processes such as descriptive ability also influence memory and imagination. We recently found that an episodic specificity induction—brief training in recollecting details of past experiences—enhanced detail generation on memory and imagination tasks but not a picture description task and thereby concluded that the induction can dissociate episodic processes involved in remembering the past and imagining the future from those nonepisodic processes involved in description. To evaluate the generality of our previous findings and to examine the role of generative search in producing those findings, we modified our paradigm so that word cues replaced picture cues, and a word comparison task that requires generation of sentences and word definitions replaced picture description. Young adult participants received either a specificity induction or one of two control inductions before completing the memory, imagination, and word comparison tasks. Replicating and extending our previous work, we found that the specificity induction increased detail generation in memory and imagination without having an effect on word comparison. The induction's selective effect on memory and imagination stemmed from an increase in internal (i.e., on-topic and episodic) details and had no effect on external (e.g., off-topic or semantic) details. The results point to the efficacy of the specificity induction for isolating episodic processes involved in remembering the past and imagining the future even when a nonepisodic task requires generative search.

Keywords:

• Episodic specificity induction
• Episodic memory
• Future thinking
• Word comparison
• Detail generation

Notes

¹It should be noted that in Addis et al. (2009) participants took less time to construct a word comparison than to construct a remembered or imagined event, whereas here we found that participants took more time to construct a word comparison. We do not think this difference is important because participants overall did not significantly differ in times to construct for the episodic event tasks. Moreover, recent evidence from Hach, Tippett, and Addis (2014) with young adults shows the same pattern as that found in the current study, with time to construct longer for word comparison than for the episodic event tasks (which do not differ from each other).

²We also examined how long participants spent generating a description in response to each cue, as well as word count. We found that participants spent significantly longer describing, F(1, 31) = 4.96, MSE = 6.99, p = .033, , and used more words on memory trials, F(1, 31) = 6.65, MSE = 39.76, p = .015, , when they had received the specificity induction than when they had received the control induction. We did not find significant differences in timing or word count on the imagination trials or word comparison trials as a function of induction (Fs ≤ 2.03, MSEs ≥ 5.17, ps ≥ .17, ). Thus, it seems unlikely that the differences in timing and word count on memory trials are critical to the specificity induction effect because we observed the same detail boost from the specificity induction on the imagination task, where timing and word count did not differ. Moreover, it is not unreasonable to expect that the specificity induction could help participants generate richer and more detailed events on a later task than they otherwise would, which could be reflected in timing and/or word count differences. We have also observed the same specificity induction benefit on memory and imagination tasks when time is held constant across conditions (i.e., Madore et al., 2014; Madore & Schacter, 2014) rather than self-paced.