Counterfactual imagination impairs memory for true actions: EEG and behavioural evidence.

Imagined events can be misremembered as experienced, leading to memory distortions. However, less is known regarding how imagining counterfactual versions of past events can impair existing memories. We addressed this issue, and used EEG to investigate the neurocognitive processes involved when retrieving memories of true events that are associated with a competing imagined event. Participants first performed simple actions with everyday objects (e.g., rolling dice). A week later, they were shown pictures of some of the objects and either imagined the same action they had originally performed, or imagined a counterfactual action (e.g., stacking the dice). Subsequent tests showed that memory for performed actions was reduced after counterfactual imagination when compared to both veridical imagination and a baseline condition that had not been imagined at all, providing novel evidence that counterfactual imagination impairs true memories beyond simple forgetting over time. ERPs and EEG oscillations showed evidence of separate processes associated with memory retrieval versus post-retrieval processes that were recruited to support recall of memories that were challenging to access. The findings show that counterfactual imagination can cause impairments to sensorimotor-rich event memories, and provide new evidence regarding the neurocognitive mechanisms that are recruited when people need to distinguish memories of imagined versus true events.

Imagining a false alibi impairs concealed memory detection with the autobiographical Implicit Association Test.

Imagining counterfactual versions of past events can distort memory. In 3 experiments, we examined whether imagining a false alibi for a mock crime would make suspects appear less guilty in a concealed memory detection test, the autobiographical Implicit Association Test (aIAT), which aims to determine which of 2 autobiographical events are true. First, "guilty" participants completed a mock crime, whereas "innocent" participants completed an innocent act. Next, some of the guilty participants were asked to imagine a false alibi that corresponded to the innocent act. Finally, all groups completed the aIAT. Across experiments, we varied the type of aIAT used and also compared the effectiveness of the false alibi countermeasure when only imagined once, versus when it was repeatedly imagined over a week-long period. The aIAT accurately detected the mock crime as true for guilty participants without a false alibi, but was consistently less able to detect the mock crime as true for guilty participants who had imagined a false alibi. The findings suggest that if guilty suspects fabricate an alibi, this may create a memory for the alibi that appears to be true based on the aIAT, which is problematic for its real-life applications in concealed memory detection. (PsycInfo Database Record (c) 2020 APA, all rights reserved).