Diversity of daily activities is associated with greater hippocampal volume.

Greater engagement in a range of daily activities is associated with better cognitive functioning (Lee et al., Lee et al., 2020). The hippocampus, a subcortical brain structure implicated in learning, memory, spatial navigation and other aspects of cognitive functioning, may be structurally sensitive to exposure to and engagement with novel experiences and environments. The present study tested whether greater activity diversity, defined as the range of common daily activities engaged in and the proportion of time spent in each, is associated with larger hippocampal volume. Greater diversity of activities, as measured using daily diaries across an 8-day period, was related to greater hippocampal volume averaged across the left and right hemispheres, even when adjusting for estimated intracranial volume, total activity time, sociodemographic factors, and self-reported physical health. These findings are broadly consistent with nonhuman animal studies, demonstrating a link between enriched environments and structural changes to the hippocampus. Future longitudinal and experimental work can elucidate causal and directional relationships between diversity of daily activities and hippocampal volume.

Emotional context effects on memory accuracy for neutral information.

Despite decades of study, it remains unclear how emotional contexts influence memory for non-emotional information. In two studies, we previously found memory accuracy for neutral information encoded in an emotional context differed by valence. Specifically, neutral images encoded in a negative context were remembered with similar accuracy as those encoded in a non-emotional context, and neutral images encoded in a positive context were remembered with less accuracy than a non-emotional context. This Registered Report contains a third study to replicate our original results and allow for direct comparison between the negative and positive encoding conditions. People in the positive condition showed decreased memory accuracy, but this effect was very small in size and only significant when compared to the neutral condition. Given the lack of difference between negative and neutral conditions, effects of emotion on memory are not only a function of emotional arousal. At the same time, given the nonsignificant, small difference between positive and negative conditions, effects of emotion on memory are also not solely attributable to valence. This series of studies represents a step towards re-examining the tenet that emotion enhances memory unless the experience elicits sufficiently high arousal levels such that memory is impaired.

Rich and Balanced Experiences of Daily Emotions Are Associated With Activity Diversity Across Adulthood.

OBJECTIVES: Studies demonstrate the association between diverse emotions and health. However, we know little about how these emotions are related to activities in daily life. This study examined whether the diversity of daily activities ("activity diversity") is associated with the diversity of both positive and negative daily emotions ("emodiversity") in adulthood. We also examined if these associations differed by age. METHOD: 2 separate samples of participants from the Midlife in the United States Study II (M2: 2004-2009, n = 2,012, Mage = 56 years) and Refresher (MR: 2012-2016, n = 779, Mage = 47 years) provided activity and emotion data for 8 consecutive days. Using Shannon's entropy, we constructed activity diversity and emodiversity (positive, negative) scores. Analyses adjusted for sociodemographic and health characteristics, total activity time, mean positive/negative emotions, and number of days with positive/negative emotion data. RESULTS: Greater activity diversity was associated with greater positive emodiversity and greater negative emodiversity in both samples. In the M2 sample, the association between activity diversity and positive emodiversity was stronger among relatively younger adults, such that the positive association among those aged 33-44 years was greater than that observed among those aged 68-84 years. Results held after adjusting for time spent in each of the activities or when using different emodiversity metrics (Gini or Simpson coefficients). DISCUSSION: Broad and even participation of daily activities may provide more opportunities to experience rich and balanced emotions. Findings suggest that the association between activity diversity and emodiversity exists across adulthood, underscoring the value of including information about daily activities when examining emotional experiences across the life span.

Emodiversity, health, and well-being in the Midlife in the United States (MIDUS) daily diary study.

Emodiversity, or the variety and relative abundance of emotions experienced, provides a metric that can be used to understand emotional experience and its relation to well-being above and beyond average levels of positive and negative affect. Past research has found that more diverse emotional experiences, both positive and negative, are related to better mental and physical health outcomes. The present research aimed to test the relationship between positive and negative emodiversity across the span of 8 days with measures of health and well-being using 2 samples of the Midlife in the United States study (http://midus.wisc.edu/). Participants (N = 2,788) reported emotional states (14 negative, 13 positive) once each day for 8 days. Emodiversity scores were computed for each day using an adaptation of Shannon's biodiversity index and averaged across the days. All models included average affect and demographic covariates. Greater positive emodiversity was associated with fewer symptoms of depression and anxiety and fewer physical health symptoms but was not related to eudaimonic well-being nor cognitive functioning. In contrast to previous research, greater negative emodiversity was related to more symptoms of depression and anxiety and more physical health symptoms. Greater negative emodiversity was only associated with one positive outcome: better executive functioning. These findings illustrate inconsistencies across studies in whether negative emodiversity is associated with better or worse outcomes and raise further questions about how the construct of emodiversity can be better refined. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Modifying the Trier Social Stress Test to Induce Positive Affect.

Studies comparing the effects of positive and negative affect on psychological outcomes are limited by differences in the situations that evoke these states and in the resulting levels of arousal. In the present research, we adapted the speech portion of the Trier Social Stress Test (TSST) to create conditions with similar situational features that induce either positive, negative, or neutral affective states (N = 301). Pre-post emotion ratings showed that negative affect increased in the negative condition but decreased in the positive and neutral conditions. Positive affect increased in the positive condition, remained unchanged in the neutral condition, and decreased in the negative condition. Participants' post-speech ratings of their positive and negative emotions differed significantly between the positive and negative conditions, which has not been accomplished in previous attempts to create a non-stressful positive TSST. Importantly, participants in the positive and negative conditions did not differ in self-reported levels of arousal and showed similar changes in mean arterial pressure across the speech period, although heart rate was relatively higher during the speech for participants in the negative compared to positive and neutral conditions. Findings demonstrate the effectiveness of a modified TSST for inducing positive affect with similar levels of emotional arousal to the traditional negative TSST. Supplementary Information: The online version contains supplementary material available at 10.1007/s42761-021-00074-6.