The limited reach of surprise: Evidence against effects of surprise on memory for preceding elements of an event

Abstract

When reflecting on the past, some of our strongest memories are for experiences that took us by surprise. Extensive research has backed this intuition that we are more likely to remember surprising moments than mundane ones. But what about the moments leading up to the surprise? Are we more likely to remember those as well? While surprise is a well-established modulator of memory, it is unknown whether memory for the entire event will be enhanced, or only for the surprising occurrence itself. We developed a novel paradigm utilising stop-motion films, depicting of a sequence of narrative events, in which specific occurrences could be replaced with surprising ones, while keeping the rest of the film unaltered. Using this design, we tested whether surprise exerts retroactive effects on memory, and specifically whether any potential effect would be confined to elements in the same event as the surprising occurrence. In a large cohort of participants (n = 340), we found strong evidence that surprise did not retroactively modulate memory, neither when participants were tested immediately after study nor when they were tested 24 hours later. We suggest two possible accounts for these findings: (1) that the components of an event are encoded as independent episodic elements (not as a cohesive unit), or (2) that surprise segments experience, sectioning off the preceding elements as a separate event.

Acoustic features drive event segmentation in speech.

“…Furthermore, whereas in previous experiments participants were explicitly asked to adopt an associative binding strategy (Clewett et al, 2020;DuBrow & Davachi, 2016;Heusser et al, 2018), here we allowed them to adopt any mnemonic strategy (or none at all) as they saw fit. While the importance of goal-state and prediction in event segmentation is well-established in past literature (Antony et al, 2021;Ben-Yakov et al, 2021;Reynolds et al, 2007;Rouhani et al, 2019;Zwaan et al, 1995), the fact that the memory boost for within-event and boundary comparisons persisted despite these changes in task design suggests that event segmentation might be a more automatic process than previously argued, at least in the auditory domain. In other words, the lack of an explicit integration task suggest that participants may not need to engage in a conscious binding process for segmentation effects to arise.…”

Long-term, multi-event surprise enhances autobiographical memory

“…Therefore, this concern has been partially addressed for momentary surprise in laboratory settings, but future studies could examine whether surprise plays a role by probing a broader swath of autobiographical memories 64,65 . Another promising future direction follows laboratory findings that surprise boosts surrounding memories in some paradigms 24,128,129 , whereas in others it has no effect 3,87 . Therefore, future studies could examine memory effects for information before or after surprising events, such as plays, games, or seasons before or after the chosen memories.…”

Novel immersive virtual reality experiences do not produce retroactive memory benefits for unrelated material

“…Nonetheless, there is also recent study that did find evidence for behavioural tagging in high-school students (e.g., Ramirez Butavand et al, 2020 ), plus a further study that used familiar and novel Minecraft environments and found a retroactive effect, but only for attention deficit hyperactivity disorder patients and not for typically developing children/adolescents ( Baumann et al, 2020 ). Another study failed to find an effect of surprising actions within video clips on memory for other actions that happened before ( Ben-Yakov et al, 2021 ); though surprise and novelty might function somewhat differently in their effects on memory ( Quent et al, 2021 ). While the evidence in animal studies is more consistent, it is worth noting that the proactive effect of VR on human memory reported by Schomaker and colleagues ( Schomaker et al, 2014 ; Schomaker & Wittmann, 2021 ) is unlikely to represent the behavioural tagging-like processes seen in animal experiments, because the latter is assumed to take time to influence memory consolidation, whereas Schomaker and colleagues tested memory immediately after the VR experience.…”