Evaluating heart rate variability as a predictor of the influence of lying on memory.

Previous research suggests self-provided misinformation (lying) impairs memory for the truth, whereby more incorrect details are remembered compared to being truthful. The cognitive control processes evoked by inhibiting retrieval of truthful information may come at the expense of retaining that information in memory. Because lying requires quick adaptability to the situation, heart rate variability (HRV), reflecting cognitive control processes, is a useful metric of these cognitive demands. The present experiment extends previous research (Paige et al., 2019) and had participants complete a questionnaire orally in front of a panel while electrocardiography (ECG) data was collected. Participants were instructed to tell the truth for half of the questions and lie for the other half. For a subset of the questions, participants were instructed to elaborate on their response. After a delay, participants completed the same questionnaire on the computer, responding truthfully to all items. Results revealed that correct memory was lower for items participants previously lied about compared to truthful items. Although prior work suggests increased HRV is associated with increased cognitive control, HRV did not predict memory for truth or lie items. These findings are consistent with past literature showing that lying impairs memory for veridical information compared to truth-telling.

Age differences in the relationship between cortisol and emotional memory.

Research has shown that remembering emotional information can occur at the expense of surrounding neutral background information; this emotional memory trade-off occurs similarly in both younger and older adults. We investigated how levels of cortisol, a hormone that acts on the central nervous system, impact emotional memory with age. Younger and older adult participants incidentally encoded emotional (positive, negative, or neutral) items placed on neutral backgrounds and later completed recognition tests for both the items and the backgrounds. Cortisol was measured at multiple time points to assess basal cortisol. Results are reported for prelearning levels, as findings were comparable across time points. Results revealed that higher levels of cortisol predicted a lower memory trade-off effect for older adults compared to younger adults and that this age difference in the role of cortisol tended to be strongest for memory for negative items (rather than for backgrounds or neutral items). No such interaction emerged for the positive trade-off effect. These results suggest that cortisol levels play a different role in supporting emotional memory across the life span, with lower levels of cortisol potentially more adaptive for memory for negative emotional information and higher levels indicating potential impairment with age. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Influence of age on the effects of lying on memory.

False memories are elicited from exposure to misleading information. It is possible that self-provided misinformation, or lying, has similar effects. We hypothesized that lying impairs memory for younger adults, as increased cognitive control, necessary to inhibit a truthful response, comes at the expense of retaining veridical information in memory. Because older adults show deficits in cognitive control, we hypothesized their memory is unaffected by lying. In the present study, participants made truthful and deceptive responses on a computer while EEG data were recorded. We investigated medial frontal negativity (MFN), an ERP component associated with deception and cognitive control, which may be differentially generated across age groups due to differences in cognitive control. Unexpectedly, results revealed that older adults showed reduced accurate memory for items to which they previously lied compared to younger adults. There were no age differences in correct memory for truth items. We did not find the expected MFN effect, however results revealed long-lasting negative slow waves (NSW) to lie items across age in the pre-response period and following the response cue, suggesting the role of working memory processes in deception. These findings demonstrate that lying is another source of misinformation and influences memory differently across the lifespan.

Cultural specialization of visual cortex.

A growing body of evidence suggests culture influences how individuals perceive the world around them. This study investigates whether these cultural differences extend to a simple object viewing task and visual cortex by examining voxel pattern representations with multi-voxel pattern analysis (MVPA). During functional magnetic resonance imaging scanning, 20 East Asian and 20 American participants viewed photos of everyday items, equated for familiarity and conceptual agreement across cultures. Whole brain searchlight mapping with non-parametric statistical evaluation tested whether these stimuli evoked multi-voxel patterns that were distinct between cultural groups. We found that participants' cultural identities were successfully predicted from stimuli representations in visual cortex Brodmann areas 18 and 19. This result demonstrates culturally specialized visual cortex during a basic perceptual task ubiquitous to everyday life.

Cross-cultural differences in the neural correlates of specific and general recognition.

Research suggests that culture influences how people perceive the world, which extends to memory specificity, or how much perceptual detail is remembered. The present study investigated cross-cultural differences (Americans vs East Asians) at the time of encoding in the neural correlates of specific versus general memory formation. Participants encoded photos of everyday items in the scanner and 48 h later completed a surprise recognition test. The recognition test consisted of same (i.e., previously seen in scanner), similar (i.e., same name, different features), or new photos (i.e., items not previously seen in scanner). For Americans compared to East Asians, we predicted greater activation in the hippocampus and right fusiform for specific memory at recognition, as these regions were implicated previously in encoding perceptual details. Results revealed that East Asians activated the left fusiform and left hippocampus more than Americans for specific versus general memory. Follow-up analyses ruled out alternative explanations of retrieval difficulty and familiarity for this pattern of cross-cultural differences at encoding. Results overall suggest that culture should be considered as another individual difference that affects memory specificity and modulates neural regions underlying these processes.

Influence of encoding instructions and response bias on cross-cultural differences in specific recognition.

Prior cross-cultural research has reported cultural variations in memory. One study revealed that Americans remembered images with more perceptual detail than East Asians (Millar et al. in Cult Brain 1(2-4):138-157, 2013). However, in a later study, this expected pattern was not replicated, possibly due to differences in encoding instructions (Paige et al. in Cortex 91:250-261, 2017). The present study sought to examine when cultural variation in memory-related decisions occur and the role of instructions. American and East Asian participants viewed images of objects while making a Purchase decision or an Approach decision and later completed a surprise recognition test. Results revealed Americans had higher hit rates for specific memory, regardless of instruction type, and a less stringent response criterion relative to East Asians. Additionally, a pattern emerged where the Approach decision enhanced hit rates for specific memory relative to the Purchase decision only when administered first; this pattern did not differ across cultures. Results suggest encoding instructions do not magnify cross-cultural differences in memory. Ultimately, cross-cultural differences in response bias, rather than memory sensitivity per se, may account for findings of cultural differences in memory specificity.

Age differences in hippocampal activation during gist-based false recognition.

Age-related increases in reliance on gist-based processes can cause increased false recognition. Understanding the neural basis for this increase helps to elucidate a mechanism underlying this vulnerability in memory. We assessed age differences in gist-based false memory by increasing image set size at encoding, thereby increasing the rate of false alarms. False alarms during a recognition test elicited increased hippocampal activity for older adults as compared to younger adults for the small set sizes, whereas the age groups had similar hippocampal activation for items associated with larger set sizes. Interestingly, younger adults had stronger connectivity between the hippocampus and posterior temporal regions relative to older adults during false alarms for items associated with large versus small set sizes. With increased gist, younger adults might rely more on additional processes (e.g., semantic associations) during recognition than older adults. Parametric modulation revealed that younger adults had increased anterior cingulate activity than older adults with decreasing set size, perhaps indicating difficulty in using monitoring processes in error-prone situations.