Repeated failures to obtain selective directed forgetting in lab and online samples and variations in stimuli

ABSTRACT

Previous research has produced mixed findings as to whether it is possible to selectively forget a subset of items while maintaining access to the remaining items from the same episode, using a modified version of the list-method directed forgetting (LMDF) paradigm. The present study includes six attempts to obtain the selective directed forgetting (SDF) effect with the aim of exploring its underlying mechanisms. However, despite variations in the stimuli and samples, which included both lab and online participants, we failed to obtain SDF across five experiments. In one of the experiments, we observed what appeared to be an SDF effect; however, the unexpected baseline differences across the conditions make the interpretation of this result equivocal. In contrast, standard directed forgetting effect was obtained when an LMDF condition was included in the design. An evaluation of the previous literature in combination with the present study raises questions about the reliability of the SDF phenomenon.

KEYWORDS:

• Selective directed forgetting
• inhibition
• context-change

Acknowledgements

The authors thank Teresa Bajo, Carmen Aguirre, and Carlos Gomez-Ariza for helpful discussions and input on the instructions. They are also grateful to Todd Berkenpas, Stephanie Coghill, Kristin Johnson, Divya Polson, Priyanka Rao, Mariel Reyes, Nathan Davis, and Marisa Allen for their assistance with data collection and coding.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. The pattern of results remained unaffected when items were counted as correct regardless of the list with which they were recalled.

2. See Appendix for the wording of the warning instruction.

3. The colour–word pair presentation format of the items is more similar to the stimuli used in most of the previous SDF studies (e.g., Delaney et al., 2009) which consisted of sentences about different characters engaging in various actions (e.g., Tom ate a sandwich, Alex watched TV).

4. A similar concern was also present in Delaney et al.’s (2009) study, where the recall of Tom sentences (TBF items in the SDF condition) was higher than the recall of Alex sentences (TBR items in SDF condition) in the R condition for no apparent reason, and could have given rise to the apparent SDF effect.

5. The only difference between Experiment 6 and Delaney et al. (2009) study was the length of the distractor interval between the two lists (60 vs. 90 s respectively). However, this is unlikely to have affected the results, especially given Storm et al.’s (2013) findings showing no SDF effects with or without the distractor interval.

6. Even though the standard DF was not the focus of the investigation, it is noteworthy to mention that Experiments 2–4 were conducted on Mturk and to the best of our knowledge, they were the first online experiments to demonstrate the standard LMDF.