Optimistic amnesia: how online and offline processing shape belief updating and memory biases in immediate and long-term optimism biases

Abstract

When people are confronted with feedback that counters their prior beliefs, they preferentially rely on desirable rather than undesirable feedback in belief updating, i.e. an optimism bias. In two pre-registered EEG studies employing an adverse life event probability estimation task, we investigated the neurocognitive processes that support the formation and the change of optimism biases in immediate and 24 h delayed tests. We found that optimistic belief updating biases not only emerged immediately but also became significantly larger after 24 h, suggesting an active role of valence-dependent offline consolidation processes in the change of optimism biases. Participants also showed optimistic memory biases: they were less accurate in remembering undesirable than desirable feedback probabilities, with inferior memories of undesirable feedback associated with lower belief updating in the delayed test. Examining event-related brain potentials (ERPs) revealed that desirability of feedback biased initial encoding: desirable feedback elicited larger P300s than undesirable feedback, with larger P300 amplitudes predicting both higher belief updating and memory accuracies. These results suggest that desirability of feedback could bias both online and offline memory-related processes such as encoding and consolidation, with both processes contributing to the formation and change of optimism biases.

Keywords: P300; belief updating; motivated cognition; offline processing; optimism bias.

Fig. 1.

A trial flow in the life event probability estimation task across two conditions. Each trial began with a 0.5 s fixation on the center of the screen, followed by a life event presented for 2 s. Participants were given 8 s to estimate the probability (E1) of them experiencing the specific event at least once in the future. Feedback probability of the same event happening to people of the same gender/age/socio-cultural background was then presented for 2 s, during which participants’ ERPs were analyzed. Following an inter-stimulus interval varying randomly between 0.4 and 0.6 s, participants were instructed to give an estimation of the same event for a second time (E2) within 8 s. (A) Desirable condition. (B) Undesirable condition.

Fig. 2.

Predicted values of belief updating and memory errors. (A). Participants showed significant optimistic belief updating, which became larger after a 24 h delay. (B). Participants showed worse memories (higher memory errors) for undesirable than desirable feedback, i.e. an optimistic amnesia effect. Error bars indicate 95% confidence intervals (CIs).

Fig. 3.

FRN over the frontocentral electrodes. (A). Grand averaged ERPs over the frontocentral cluster (Fz, FCz, F1/2 and FC1/2). There were no significant FRN differences between desirable and undesirable conditions. (B). The topography of mean amplitudes of undesirable–desirable ERP difference waves between 200 and 400 ms.

Fig. 4.

Grand averaged P300 (300–800 ms) and LPP (800–1600 ms) over the parietal electrodes. (A) left-parietal cluster (P1/3, CP1/3), (B) midline cluster (Cz/Pz) and (C) right-parietal cluster (P2/4, CP2/4). Desirable feedback elicited significantly higher P300s than undesirable feedback across left-/right-parietal and midline clusters. The topography of the mean amplitude of desirable–undesirable difference waves for (D) P300 and (E) LPP.

Fig. 5.

Single-trial P300 and LPP predicted belief updating in both desirable and undesirable conditions. Enhanced (A) P300s and (B) LPPs over the left-parietal cluster predicted higher immediate belief updating. (C) Enhanced LPPs over the right-parietal cluster predicted higher delayed belief updating. The shaded areas represent 95% CIs. For visualization purposes, predictions from ERPs are plotted separately for both desirable and undesirable conditions.

Fig. 6.

Single-trial P300s/LPPs predicted immediate memory errors. (A), (D) Enhanced left-parietal P300/LPP amplitudes predicted reduced immediate memory errors only to undesirable feedback. (B), (E) While midline P300 effects were not significant, enhanced midline LPP amplitudes significantly predicted reduced immediate memory errors in both desirable and undesirable feedback. (C), (F) Enhanced right-parietal P300/LPP amplitudes predicted reduced immediate memory errors to both desirable and undesirable feedback. Shaded areas represent 95% CIs.