When we must forget: the effect of cognitive load on prospective memory commission errors

ABSTRACT

Recent studies consistently show that prospective memory (PM) intentions are not always deactivated when no-longer needed and might be erroneously performed upon encountering the once relevant cue – termed PM commission errors. However, empirical evidence on the potential mechanisms that might lead to this kind of memory failure remains mostly unexplored. This study aimed to investigate the influence of the ongoing task demands on PM deactivation of non-performed intentions. Younger adults, except for those in the no-PM condition, were asked to perform a PM task and were then told that the intention was finished. Later, they perform a lexical decision task with some trials containing (irrelevant) PM cues while simultaneously carrying out a counting recall task with two levels of difficulty. The results showed a higher risk of PM commission errors under moderate cognitive load (74%) as compared to the no-load condition (40%). Results also show that commission error risk did not increase in the high-load (54%) compared with the moderate-load condition. Furthermore, comparisons of the ongoign task performance between the no-PM condition and the other conditions with a PM task requirement support that commission errors might arise from a spontaneous PM retrieval. The implications of these findings are discussed within the dual-mechanisms account.

KEYWORDS:

• Prospective memory
• unfulfilled intentions
• commission errors
• ongoing task load

Acknowledgments

We thank Ana Paula Soares for providing us the lexical decision database; and Paul Verhaeghen for his helpful comments on an earlier version of the article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Finding

This work was supported by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia, FCT) [grant numbers BD/123421/2016, BPD/91347/2012] and the Portuguese Ministry of Science, Technology and Higher Education, through the State Budget [UID/PSI/01662/2019].

ORCID

Patrícia Matos http://orcid.org/0000-0002-2622-2205

Flávia H. Santos http://orcid.org/0000-0003-2592-9038

Pedro B. Albuquerque http://orcid.org/0000-0002-5874-4497

Notes

1 This criterion has been used in previous studies (e.g., Scullin & Bugg, 2013; Bugg et al., 2013; Bugg et al., 2016) since the primary goal of PM research is to identify whether a participant will ever repeat a PM response after they have been instructed that the PM task is finished.

2 Previous work has found that younger adults make commission errors when there is a salient background, contextual overlap between the active- and the finished-PM phase (Scullin et al., 2012), and no PM cues appear during the active-PM phase. Thus, we followed these laboratory parameters to avoid floor effects.

3 Participants were only included if they recall the target words and target key, as well as the instruction that the PM task was finished (either spontaneously or if they recall the episodic event after a prompt). Importantly, participants were not significantly more likely to make a commission error if they recall the cancelled instructions spontaneously (n = 71) or with a prompt (n = 34), χ² = 2.68, p = .10, φ = .16. Thus, participants who only recall the instruction that the PM task was finished when given a prompt did not raise the risk of making commission errors. Moreover, when excluding those participants (n = 34), we still observe the group effect, χ² = 11.96, p = .003, φ = .41.