Thought probes during prospective memory encoding: Evidence for perfunctory processes.

For nearly 50 years, psychologists have studied prospective memory, or the ability to execute delayed intentions. Yet, there remains a gap in understanding as to whether initial encoding of the intention must be elaborative and strategic, or whether some components of successful encoding can occur in a perfunctory, transient manner. In eight studies (N = 680), we instructed participants to remember to press the Q key if they saw words representing fruits (cue) during an ongoing lexical decision task. They then typed what they were thinking and responded whether they encoded fruits as a general category, as specific exemplars, or hardly thought about it at all. Consistent with the perfunctory view, participants often reported mind wandering (42.9%) and hardly thinking about the prospective memory task (22.5%). Even though participants were given a general category cue, many participants generated specific category exemplars (34.5%). Bayesian analyses of encoding durations indicated that specific exemplars came to mind in a perfunctory manner rather than via strategic, elaborative mechanisms. Few participants correctly guessed the research hypotheses and changing from fruit category cues to initial-letter cues eliminated reports of specific exemplar generation, thereby arguing against demand characteristics in the thought probe procedure. In a final experiment, encoding duration was unrelated to prospective memory performance; however, specific-exemplar encoders outperformed general-category encoders with no ongoing task monitoring costs. Our findings reveal substantial variability in intention encoding, and demonstrate that some components of prospective memory encoding can be done "in passing.

Frequency of responses to yes/no and encoding bias questions across experiments.

<p>Frequency of responses to yes/no and encoding bias questions across experiments.</p

Response times on correct, non-target ongoing task trials in Experiment 8 (means ± standard deviations).

<p>Response times on correct, non-target ongoing task trials in Experiment 8 (means ± standard deviations).</p

Encoding thought probe data collapsed across Experiments 1–8.

<p>The figures depict the aggregate (A) free response data, (B) generation of specific exemplars, and (C) bias toward different encoding strategies.</p

Depiction of the encoding thought probe procedure.

<p>In Experiments 1–2, the target category was animals. This figure was adapted with permission [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198646#pone.0198646.ref024" target="_blank">24</a>].</p

Encoding duration data (in seconds) across Experiments 3–8.

<p>Encoding duration data were not collected in Experiments 1–2. Positive correlations indicate that longer encoding durations were associated with more specific exemplar generation and more mind wandering.</p

Ongoing task accuracy in Experiment 8 (proportion correct means ± standard deviations).

<p>Ongoing task accuracy in Experiment 8 (proportion correct means ± standard deviations).</p

Prospective memory performance in Experiment 8 as a function of specific exemplar encoding.

<p>Error bars reflect standard errors and ** indicates <i>p</i> < .01.</p

Free response data classification as on-task (task-related) or off-task (task unrelated) across experiments.

<p>On-task responses were further classified as mentioning the ongoing task (context), prospective memory response key, or cue words. The on-task specification numbers will not sum to 100% due to some participants providing only miscellaneous responses (e.g., “this experiment”) and others listing multiple components (e.g., response key and cue words).</p

A summary of the research questions and main results/interpretations across eight studies/experiments of prospective memory encoding.

<p>The reader is directed to the methods and results section of each study for research details and inferential statistics.</p