Abstract. Research consistently shows that task switching slows down performance on switch compared to repeat trials, but the consequences on memory are less clear. In the present study, we investigated the impact of task switching on subsequent memory performance. Participants had to switch between two semantic classification tasks. In Experiment 1, the stimuli were univalent; in Experiment 2, the stimuli were bivalent (relevant for both tasks). The aim was to disentangle the conflicts triggered by task switching and bivalency. In both experiments, recognition memory for switch and repeat stimuli was tested subsequently. During encoding, task switching produced switch costs. Critically, subsequent memory was lower for switch compared to repeat stimuli in both experiments, and this effect was increased in Experiment 2 with bivalent material. We suggest that the requirement to switch tasks hurts the encoding of task-relevant information and thus impairs subsequent memory performance.

The impact of cognitive control demands on long-term memory is mixed, with some conflicts leading to better, others leading to worse subsequent memory. The current study was designed to investigate how different types of cognitive control demands modulate the effects on memory. At study, participants had to switch between two classification tasks and later, free recall performance was assessed. The stimuli consisted of two interleaved words, one word had to be categorized and the other word had to be ignored. In four experiments, the congruency between target and ignored words was manipulated by changing the distractor category. This allowed us to investigate the impact of different types of conflict (i.e., task switching, perceptual load, response-category conflict, stimulus-category conflict). The results revealed that task switching impaired memory in all experiments. In Experiment 1, higher perceptual load also impaired memory. Experiments 2–4 showed that the co-activation of two words which required different responses (i.e., response-category conflict) enhanced memory performance but only when the conflict stimuli were presented in pure blocks. Overall, memory performance seems to depend on attentional policies. Withdrawing attention from target encoding results in lower memory performance. In contrast, focusing attention on the target results in enhanced memory performance.

Perceptual fluency, that is, the ease with which people perceive information, has diverse effects on cognition and learning. For example, when judging the truth of plausible but incorrect information, easy-to-read statements are incorrectly judged as true while difficult to read statements are not. As we better remember information that is consistent with pre-existing schemata (i.e., schema congruency), statements judged as true should be remembered better, which would suggest that fluency boosts memory. Another line of research suggests that learning information from hard-to-read statements enhances subsequent memory compared to easy-to-read statements (i.e., desirable difficulties). In the present study, we tested these possibilities in two experiments with student participants. In the study phase, they read plausible statements that were either easy or difficult to read and judged their truth. To assess the sustainability of learning, the test phase in which we tested recognition memory for these statements was delayed for 24 h. In Experiment 1, we manipulated fluency by presenting the statements in colors that made them easy or difficult to read. In Experiment 2, we manipulated fluency by presenting the statements in font types that made them easy or difficult to read. Moreover, in Experiment 2, memory was tested either immediately or after a 24 h delay. In both experiments, the results showed a consistent effect of schema congruency, but perceptual fluency did not affect sustainable learning. However, in the immediate test of Experiment 2, perceptual fluency enhanced memory for schema-incongruent materials. Thus, perceptual fluency can boost initial memory for schema-incongruent memory most likely due to short-lived perceptual traces, which are cropped during consolidation, but does not boost sustainable learning. We discuss these results in relation to research on the role of desirable difficulties for student learning, to effects of cognitive conflict on subsequent memory, and more generally in how to design learning methods and environments in a sustainable way.

Precognition describes the ability to anticipate information about a future event before this event occurs. The goal of our study was to test the occurrence of precognition by trying to replicate three experiments of the most central study in the field (Bem, 2011, Journal of Personality and Social Psychology). In this study, Bem time-reversed well-established psychological effects so that a “causal” stimulus appeared after the participants gave their response. We conducted two priming experiments and a free recall experiment in the backward “precognition” version and, as a control manipulation, in the classic forward version. More than 2000 participants participated via the Internet; thus, our study had high statistical power. The results showed no precognition effects at all. We further conducted exploratory post hoc analyses on different variables and questionnaire items and found some significant effects. Further studies should validate these potentially interesting findings by using theory-driven hypotheses, preregistrations, and confirmatory data analyses.

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