Research roundup: Healthy aging and the positivity effect
Identifying the regulatory mechanisms behind positivity bias in older adults.
According to the U.S. Census, the number of Americans over the age of 65 is expected to double from 46 million to more than 98 million by 2060, resulting in a cohort that represent 24% of the general population (2015). While most empirical research has focused on age-related decline, disability, and mortality, few focus on the promotion of healthy aging.
One aspect essential to healthy aging is emotional wellness. The positivity effect, an attentional preference for positive information as well as avoidance of negative information, is an established pattern found in older adults (Mather & Carstensen, 2005). However, because there is continued debate about the actual mechanisms involved in this processing bias, guidance on specific practical implications has been limited.
The following studies examine the distinct mechanisms proposed in current theories as the driving cause behind the positivity effect in older adults. Two such theories include the socioemotional selectivity theory (SST; Carstensen, Isaacowitz & Charles, 1999), that suggests adults consciously emphasize goals of well-being and emotional stability through controlled cognitive strategies in attention, and the dynamic integration theory (DIT; Labouvie-Vief, 2003), which suggests that older adults’ ability to process affective information can be compromised as age-related limitations in cognitive resources may cause older adults to have difficulties in managing the cognitive-affective complexity.
A better understanding of why the positivity effect occurs could give clinicians more accurate strategies and techniques in promoting emotional well-being in older adults.
In addition to reviewing the following research summaries, psychologists are encouraged to explore the literature more completely to determine what may be useful to them in practice.
Gronchi, G., Righi, S., Pierguidi, L., Giovannelli, F., Murasecco, I., & Viggiano, M.P. (2018). Automatic and controlled attentional orienting in the elderly: A dual-process view of the positivity effect. Acta Psychologica, 185, 229–234.
As described above, current theories predict that the positivity effect seen in older adults depends on either controlled attentional processes as described in the socioemotional selectivity theory (SST), meaning that the relative importance of goals for an older adult becomes more significant as their perception of their future time left shrinks, or on an automatic gating selection mechanism as outlined in the dynamic integration theory (DIT), whereby automatic processes in attention “gate” out negative emotional stimuli.
In this study, researchers from the University of Florence, Italy, attempt to compare the SST and the DIT, by determining if the positivity effect is driven by controlled top-down processes that require conscious attention (SST) or if it is observable as an early avoidance of negative stimuli (DIT).
Two dot-probe tasks (with the duration of the stimuli lasting 100 ms and 500 ms, respectively) were employed to compare the attentional bias of 35 young (20–30 years old), and 35 older (70–89 years old) healthy adults. The stimuli used were expressive faces displaying neutral, disgusted, fearful, and happy expressions obtained by the International Affective Pictures Systems. Each dot-probe task consisted of one block of practice stimuli followed by eight randomized experimental blocks, each containing 24 emotional-neutral face pairs and four neutral-neutral face pairs.
Compared to young people, older adults allocated more attention to happy faces in the short duration stimuli, suggesting an automatic processing bias towards positive emotional stimuli in support of the DIT. The results also showed that older adults avoided fearful and disgusted faces over neutral faces in the long stimuli duration supporting the SST.
Taken together, the findings suggest that the positivity effect is driven by two different processes: an automatic attention bias toward positive stimuli and a controlled mechanism that diverts attention away from negative stimuli. Aging may produce adaptive changes not only in the voluntary components of attention, but also in the automatic mechanism to increase emotional well-being overall.
Ziaei, M., Samrani, G., & Persson, J. (2017). Age-related alterations in functional connectivity patterns during working memory encoding of emotional items. Neuropsychologia, 94, 1–12.
Researchers from the University of Queensland, Australia, sought to provide further support for the positivity effect in aging with neuroimaging studies. The frontoparietal network (which is engaged in directing attention to, and processing of, relevant stimuli) and the amygdala network (which is automatically activated when the amount of cognitive control required for encoding of stimuli becomes too effortful) could potentially serve as the neurological mechanisms of the SST and DIT, respectively.
This study investigates the impact of aging on functional brain network connectivity between the prefrontal cortex (PFC), a major component of the frontoparietal network, and amygdala and the rest of the brain during working memory encoding of emotional items.
Thirteen younger adults aged 23–26 years and 13 older adults aged 64–74 completed preliminary measures including the color-word Stroop, a complex short-term memory test (operation span task), and the Emotion Regulation Questionnaire. Older adults also completed the Mini-Mental State Examination. The participants then performed an emotional working memory task under functional MRI where they were asked to attend to emotional targets and ignore irrelevant distractors.
Connectivity patterns in the PFC showed that younger adults recruited one network for encoding of both positive and negative emotional targets and that this network contributed to younger adults’ higher memory accuracy. Older adults, on the other hand, engaged two distinct networks for encoding of positive and negative targets: a fronto-parietal network during encoding negative emotion and distinct frontal regions for encoding positive emotions.
The positivity bias as defined by the SST may stem from this fronto-parietal cognitive control network. Looking to the amygdala, network engagement was seen for encoding of both positive and negative items in older adults, but only for negative items among younger adults. Activation in the amygdala network was associated with higher memory performance and faster response times in older adults.
This result contradicts the DIT postulation that the positivity effect stems from a decline in cognitive functioning over the lifespan. If automatic “gating” of negative stimuli as described in the DIT contributes to the positivity effect, it is not because of an age-related decline in amygdala performance. For the behavioral findings, enhanced memory performance was observed during instructed attention compared to passive viewing in both age groups.
Since the PFC was associated with greater improvements in memory of emotional stimuli, these findings indicate the superiority of the SST over the DIT as an explanation of the positivity effect.
Murphy, S.E, O’Donoghue, M.C., Blackwell, S.E., Nobre, A.C., Browning, M., & Holmes, E.A. (2017). Increased rostral anterior cingulate activity following positive mental imagery training in healthy older adults. Social Cognitive and Affective Neuroscience, 12(12), 1950–1958.
Increasing the vividness of positive prospective mental imagery may be especially beneficial for older adults, particularly those affected by late-life depression. Previous research has confirmed that imagining future events can increase motivation, effort, and goal-directed behavior in older adults consistent with the socioemotional selectivity theory (SST; Mather & Carstensen 2005).
There is also an established positive link between optimism for the future and physical and mental health outcomes in older adult populations, making positive mental images an interest in cognitive training (Steptoe, Dockray & Wardle, 2009). This could serve to address issues like late-life depression, which is associated with a reduced ability to form vivid mental images of positive future events and reduced recall of such images. The ventromedial prefrontal cortex (vmPFC) and adjacent rostral anterior cingulate cortex (rACC) have been shown to play a key role in the simulation of future positive affective episodes, and depression in older adults.
In this study, psychologists at the University of Oxford targeted these brain areas when observing the effects of positive imagery training during the imagination of novel, ambiguous scenarios vs closely matched control training.
75 participants without dementia aged 60–80 received four weeks of either “positive imagery” or control training.
The positive imagery training consisted of six auditory trials, where participants were asked to imagine themselves in a described scenario. The outcome of each scenario was initially ambiguous, but all descriptions resolved positively. There were also six visual sessions, where participants were asked to generate an imagined image that incorporated ambiguous pictures of everyday scenes with words that resolved the scene in a positive way.
In the control training, participants were required to simply process verbal aspects of the stimuli. After completing the training, participants underwent a functional magnetic resonance imaging scan. During scanning, they completed an Ambiguous Sentences Task, which required them to form and rate the pleasantness of mental images in response to cues describing ambiguous social events. All scenes were “disambiguated,” asking the participant to reimagine the scene after the initial scenario was resolved positively or negatively.
Results demonstrated that the activity in the rACC and vmPFC had a strong relationship with the degree of pleasantness participants reported from their ambiguous scenarios. Then, after positive imagery training, researchers found increased activity in the rACC compared to those in the control training group.
This study illustrates that rACC activity during positive imagery can be changed by cognitive training. Practically speaking, this means that positive mental imagery cognitive training creates structural changes in the brain that influences a person’s affective quality of an experience.
The association between prospective mental imagery and positive affect provides further support for the positivity bias in older adults, highlighting the role of the rACC in that process. Positive imagery training to promote rACC activity may serve as an affective cognitive intervention to address well-being in healthy aging through mediating factors like positivity and optimism.
Taken together, these studies suggest that older adults have an age-related ability to alter their cognition and affect because of a shift in future time perspective and attentional controls as described by the Socioemotional Selectivity Theory. Literature suggests this positivity bias can be seen in corresponding changes in brain activation. Most importantly to clinicians, this effect can be incited or strengthened through cognitive training.
As the number of older adults rises, clinicians may see an increase in older patients with needs unique to that group. Psychologists who work with older adults may want to be aware of the specific mechanisms that inhibit or reinforce older adults’ emotional, social, and physical well-being.
Older adults experience depression and other psychopathology, but the cognitive structure of that experience may be different than that of younger adults. While intervention is important, a potentially more effective strategy to address these issues is prevention through reinforcing the strengths inherent in older adults.
Clinicians may wish to incorporate positive future mental imagery into already established therapeutic techniques, such as cognitive bias modification training, to promote general well-being in addition to addressing specific mental health issues.
Emerging research suggests that meditation mindfulness may be an effective at-home strategy for practicing positive prospective mental imagery. Clinicians may want to suggest that their older patients incorporate daily meditation into their personal lives. Building habits of positive prospective mental imagery may promote some of those same neurological and emotional benefits in the literature discussed above.
For example, early studies have found that even short-term meditation courses showed improved reactivity in the amygdala and connectivity in the ventromedial prefrontal cortex, the areas of the brain implicated in successful emotion regulation (Kral et al., 2018).
The growing age of our nation’s population emphasizes a growing need for geropsychologists. Clinicians working with older adults may want to familiarize themselves with the APA Guidelines for Psychological Practice with Older Adults (2013) (PDF, 270KB).
The APA Office on Aging has extensive resources for those working with older adults, as well for students and the general public.