Posts Tagged ‘The Cognitive Upside of Aging’

The Happiness U-Curve

March 16, 2017

This post is based on a section with the same subtitle in “The Cognitive Upside of Aging” an article by Alexandra Michel in the February 2017 “Observer”, a publication of the Association of Psychological Science (APS).

Despite all the negative components of aging, researchers consistently find a happiness paradox:  As the body declines, happiness tends to increase.  Across the lifespan this “Positivity effect” follows a U-shaped pattern:  happiness starts out high in late adolescence, bottoms out in middle age, and reaches a second zenith in old age.

A 2011 Gallup analysis of 500,000 phone interviews found that “a septuagenarian is far more likely than someone in their 30s to have high emotional health.  This happiness advantage held true even after controlling for demographic factors, including gender, race, education, marital status, employment, and regional location.

This happiness U-shape appears across the world.  Economists Andrew Oswald and David G. Blanchfower documented this pattern in more than 500,000 people living in more than 70 different countries.  Their analysis concluded that from Azerbaijan to Zimbabwe, people around the world tend to be happiest in their old age regardless of their nationality.

Oswald says, “Only in their 50s do most people emerge from the low period.  But encouragingly, by the time you are 70, if you are still physically fit then on average you are as happy and mentally healthy as a 20 year old.  Perhaps realizing that such feelings are completely normal in midlife might even help individuals survive this phase better.”

This universality of happiness U-curve implies the aging may play a positive role in the brain.  A team of Australian researchers led by Leanne Williams, who is now at the Stanford University School of Medicine, argues that a combination of neurological changes and life experiences account for this phenomenon.  Using functional magnetic resonance imaging (fMRI) to monitor emotional processing as people of various ages viewed photographs of different facial expressions, the researchers found that older people were more emotionally stable and less reactive to negative emotional stimuli than younger people.

Contrary to the ubiquitous negative stereotypes of declining memory and cognitive integrity, Williams and colleagues found emotional well-being may increase with normal aging.  Their study included 242 individuals (122 males and 120 females) divided up into four major age categories:  12-19 years, 20-29 years, 30-49 years, and 50-79 years.  Participants were assessed in the scanner for the neural activation evoked by emotions of threat and happiness depicted in facial expressions.  After being shown a photograph of a face, participants had to select the best option for identifying the emotion being displayed in the photograph.  They also rated on a 1-to-5 scale, the intensity of the emotion being displayed.
Rather than showing an inevitable decline across all functions, the images displayed a linear increase in emotional stability with age, meaning that people in their 70s ultimately experience better emotional well-being than most people in their 20s.

The fMRI results suggest that as we age, the way our brains process emotional stimuli  changes in ways that favor emotional stability.  The brain scans indicated that the medial prefrontal cortex (mPFC), which is a brain area involved in the governance of emotional functions, processed stimuli differently across the lifespan, contributing to better emotional stability for older adults.  As we age, the mPFC areas become increasingly active while processing negative emotions compared with positive ones, suggesting that older people were comparatively better at controlling negative emotions.

This article ends as follows: “Ultimately Williams and colleagues argue that as we age this combination of neural processing, as well as an accumulation of life experience, provides older adults with the neural tools to take life in stride—a capability their younger counterparts will just have to wait for.”

Finding Focus

March 15, 2017

This post is based on a section with the same subtitle in “The Cognitive Upside of Aging” is an article by Alexandra Michel in the February 2017 Observer, and publication of the Association for Psychological Science (APS).  This study  used data collected from and was published in “Psychological Science.”  It found another unexpected boom for aging brains:  Sustained attention tends to improve over time, peaking in the mid-40s.

This study was led by Francesca C. Fortenbaugh, Joseph DeGutis, and Michael S. Esterman of the Boston Attention and Learning Laboratory at the VA Boston Healthcare System.  This study tested sustained attention across 10,430 adults using a specialized task for identifying individual differences in people’s ability to focus on a single task over 4 minutes.  DeGutis said in a statement, “While younger adults may excel in the speed and flexibility of information processing, adults approaching their middle-years may have the greatest capacity to remain focused.  One current hypothesis  is that compared to younger adults, adults in their mid-years mind-wander less, leading to better sustained attention performance.  This sample was larger than all previous efforts to model changes in sustained-attention performance during development, aging, or across the life span combined, which allows us to more precisely model transition periods in performance across the life span using segmented linear regression”

Sustained attention underlies several important cognitive processes, including learning, perception, and memory.  Lapses in attention can lead to serious problems ranging from difficulty at work to an increased risk of car accidents.  Measuring attention across individuals is itself a challenge; attention fluctuates, sometimes dramatically, from moment to moment.

The researchers used a new tool they developed:  the gradual-onset continuos performance task (gradCPT).  Participants were shown serious of grayscale photographs go 10 city scenes and 10 mountain scenes.  One photograph gradually transitioned into the next every 800 milliseconds, so that as one image faded, a new image steadily took its place.

There were 5,027 male and 5,403 female participants between  10 and 70 years old who completed the gradCPT on between March and September of 2014.  The participants were told to press the space bar whenever they saw a city scene, but to withhold a response when the image was a mountain scene.  Here the goal was to create a task that required frequent responses from participants while having a relatively low cognitive demand.  Identifying the differences between the two scenes was easy, but carefully attending to the transitions repeatedly became challenging over time.

By analyzing mean reaction time, reaction time variability, hits, misses, discrimination ability, and criterion (a measure of strategy or willingness to respond in the case of uncertainty), the researchers were able to tease apart the changes in unsustained attention across the lifespan.  From the ages 10 through 16, gains in both reaction times and discrimination ability were extremely large.  After age 16, gains in these skills were much smaller until they peaked around age 43.

A factor analysis of the results suggests than people also begin to use different cognitive strategies as they age.  Younger individuals demonstrated faster reaction times (due to either super information-processing speed or more liberal response strategy), whereas older individuals showed a slower, more cautious strategy and evidence they made more adjustments after a mistake.