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Research Spotlights: July 2022

High levels of optimism is linked with longevity in women across racial and ethnic groups

There is increasing evidence for the association of positive psychological factors to reduced risk of morbidity and mortality. Even though optimism has been linked with improved health outcomes, such as exceptional longevity, most studies were performed in non-diverse, primarily white populations. Recently published research supported by NIA investigated the association of optimism to longevity across racial and ethnic groups and if lifestyle choices were a mediating factor.

In order to investigate this association, researchers leveraged the Women’s Health Initiative study, which includes a diverse racial and ethnic population of American postmenopausal women aged 50-79 (N = 159,255). The demographics and medical history of the women were reported through questionnaires. Women were excluded from the analysis if they died within 2 years (matched to National Death Index) of follow-up to mitigate concerns that health status affected optimism levels. Using this data, the researchers created a composite measure of healthy lifestyle based on diet quality, physical activity, smoking status, alcohol consumption, and body mass index. Scores were summed to create an overall lifestyle score ranging from 0 “least healthy” to 5 “most healthy.” The 6-item Life Orientation Test Revised was used to assess optimism baseline by choosing from a range of 1= “strongly disagree” or 5= “strongly agree” on positively and negatively worded statements, such that higher scores reflected higher levels of optimism.

The results from this longitudinal study indicated that higher levels of optimism were associated with lengthier longevity, with no distinction by race or ethnicity. The life expectancy of women in 2018 was 81.2 years and optimism was correlated with an average increase in lifespan by 4.4 years. In prior studies, exercise has been shown to add 0.4 to 4.2 years of life; therefore, the effect of optimism may be comparable to that of exercise on the lifespan. Lifestyle factors only had a modest contribution (24%) to these associations and varied across racial and ethnic groups differed. This variance may be due to the extent the different groups have access and opportunities to participate in healthy behaviors (e.g., availability of healthy food or a place to exercise).

The study findings had some limitations including that study participants, for the most part, achieved higher education levels than the average US population. The definition of longevity of survival to age 90 or older was from recent literature, and a high percentage (53%) of participants were able to attain it, signifying these women were also healthier than the average US population. Additionally, racial and ethnic categories were not broken down into more detailed groups (e.g., Hispanic Black women or non-Hispanic Black women). In summary, this study indicates that optimism is an important factor for promoting health and longevity in diverse populations.

Koga HK, Trudel-Fitzgerald C, Lee LO, James P, Kroenke C, Garcia L, Shadyab AH, Salmoirago-Blotcher E, Manson JE, Grodstein F, Kubzansky LD. Optimism, lifestyle, and longevity in a racially diverse cohort of women. J Am Geriatr Soc. 2022 Jun 8. doi: 10.1111/jgs.17897. Epub ahead of print. PMID: 35674052.

Working memory training: recent research shows that 'near transfer' predicts 'far transfer' of training effects

Working memory (WM) has been linked to IQ, aging, and mental health functioning. The effectiveness of training to improve a person's working memory in order to improve performance on untrained/unrelated tasks is still unclear. A recent publication funded by the NIA and NIMH aimed to address question by testing the hypothesis that far transfer may depend on near transfer. Near transfer refers to being skilled at similar tasks as to what the person was trained on, for instance if the person was good at crossword puzzles, they may also be good at other word games. An example of far transfer in this instance would be if the skills obtained by training on crosswords resulted in better focus in daily living activities.

In these studies, the researchers used the N-back task, a commonly used task for WM training which is an updating task and has been positively correlated to Matrix Reasoning (far transfer). Matrix Reasoning measures visual processing and abstract, spatial perception. N-back training has been shown to improve performance on other untrained N-back tasks (near transfer); however, if this effect extends to performance other unrelated tasks such as Matrix reasoning (far transfer) remains unknown. The researchers hypothesized that N-back training groups would improve on Matrix Reasoning (far transfer) compared with no-contact control groups, and furthermore that this effect would be mediated by post-test performance on an untrained N-back task (near transfer).

The researchers conducted three randomized control trials (n = 460) to examine, understand, and replicate their findings. The training tasks consisted of two 20-minute training sessions for ten days. The WM training studies confirmed the hypothesis that N-back training improves performance on untrained N-back tasks and leads to transfer to Matrix Reasoning (far transfer) resulting in a significant mediation effect and intervention effect. Key findings from the study show that updating and executive attention are strongly related with Matrix Reasoning performance. Additionally, this study provides a replication of the finding that transfer to Matrix Reasoning is dependent on the extent to which individuals show near transfer. Secondly, only the N-back task mediated transfer to Matrix Reasoning. Third, N-back training led to small yet significant improvements in a WM composite consisting of sequencing and span-based tasks.

In summary, this study demonstrated that people who show near transfer are more likely to show far transfer. More research is needed to fully understand the underlying mechanisms of WM training, especially from a more personalized, precision medicine approach to help determine for whom and when WM training interventions are most effective.

Pahor A, Seitz AR, Jaeggi SM. Near transfer to an unrelated N-back task mediates the effect of N-back working memory training on matrix reasoning. Nat Hum Behav. 2022 Jun 20. doi: 10.1038/s41562-022-01384-w. Epub ahead of print. PMID: 35726054.

A recent study in college men indicates that aggressive behaviors towards rival groups may be associated with increased activity in the brain's reward network

People across the world associate themselves with various groups, whether it be based on religious, political, athletics, or other personal interests. With the formation of these groups there is the risk of becoming in conflict with rival groups. There has been previous research investigating the psychological and socio-ecological determinants of intergroup aggression, however the neuroscience underlaying this phenomenon is incomplete. A recent study supported by the NIAAA, NCATS, and others sought to examine the neural correlates of aggression directed at outgroup (versus ingroup) targets.

In this study, researchers recruited healthy young male participants who were current or former students from the same university (n = 35). The participants completed an adapted version of the Taylor Aggression Paradigm against either a student from their university or from what they were told was a rival university. While the participants underwent functional MRI, they completed the aggression task against both an ingroup and an outgroup opponent during which their opponents repeatedly provoked them at varying levels and then participants could retaliate. Briefly, the task involved the participants repeatedly competing against an opponent to see who could press a button faster when a prompt appeared. In reality, there was no other person and participants completed the task against a computer program. The motivational component of the task involved participants being punished if they lost a round of competition by receiving an aversive noise blast through a pair of headphones at the volume their fictitious opponent set for them. Conversely, if participants won the round of competition, they were told their fictitious opponent received the same punishment at the volume that participants previously set for them, and the participant heard nothing. Participants were then socially included and then excluded by two outgroup members and then completed the same aggression task against the same two opponents.

The researchers found that prior to and after outgroup exclusion, aggression toward outgroup members was positively associated with activity in the ventral striatum while making decisions about how aggressive to be toward their outgroup opponent. Aggression toward outgroup members was also associated with greater post-exclusion activity in the rostral and dorsal medial prefrontal cortex during provocation from their outgroup opponent. These alterations in brain activity patterns indicate that frontostriatal mechanisms in the brain may play a significant role in motivating aggression toward outgroup members. In summary, these findings suggest that acting aggressively/harming outgroup members may be rewarding and associated with experiences of positive emotions, thus providing a psychological reinforcement mechanism for human intergroup conflict. While several previous studies focused on the influence of negative emotional states, such as anger and fear, for motivating aggressive behaviors, this study points to a potential role for positive emotions in motivating intergroup aggression. Additional studies are needed to replicate and confirm these findings in a larger, more diverse sample population; however, these findings may be the first steps towards the better understanding of intergroup aggressive behavior and for development of potential interventions for group-based violence.

Lasko EN, Dagher AC, West SJ, Chester DS. Neural mechanisms of intergroup exclusion and retaliatory aggression. Soc Neurosci. 2022 Jun 14:1-13. doi: 10.1080/17470919.2022.2086617. Epub ahead of print. PMID: 35658812.