Losing our minds in middle age

When negative stress affects our well-being, we sometimes feel like we are losing our minds...

But when in the lifespan does this really happen? When do we lose our brains?

Until age two we experience rapid growth of brain cells, or neurons. Around that age, rarely used neurons and unneeded connections between neurons (synapses) are reduced. Past research by Hedman, van Haren, Schnack, Kahn, and Hulshoff (2012) suggests that childhood is a time of brain growth, with more neurons being produced. Starting around age thirteen and continuing through adolescence we see brain volume loss as pruning reoccurs so that our brains can be more efficient. Most of young adulthood sees little change in brain volume, but starting at age 35, MRI scans demonstrate a yearly loss of about 0.2% of brain volume. This loss accelerates in older age: in our sixties this increases to a loss of about 0.5% of brain volume every year; this acceleration is often given as one of many explanations for other normal declines associated with aging.

To examine in detail the brain volume loss during the transition to midlife, Guo, Isohanni, Miettunen, Jääskeläinen, Kiviniemi, Nikklinen, Remes, Huhtaniska, Veijola, Jones, and Murray (2016) examined MRI scans of 43 men and 23 women as they aged from their 30s (33-35 years) to their 40s (42-44 years). The participants in this longitudinal study were part of the Northern Finland 1966 Birth Cohort so they should have had similar experiences in their lives as they grew up at the same time. The researchers' goals were to measure overall brain volume at both ages, to identify the locations of any loss as observed in the second MRI performed when the participants were in their 40s, and to clarify any sex differences that emerged.

Total brain volume decline was higher than predicted by past research: on average men lost 3.21% and women lost 4.03%. This sex difference was very small but it reached statistical significance, meaning that the difference was unlikely to be due to chance.

The location of loss also showed a sex difference. After taking into account percentage of total brain loss, Guo et al. found that men lost most of their neurons in the midline areas (specifically: bilateral precentral gyri; bilateral paracingulate gyri; and bilateral supplementary motor cortices). Most of these areas relate to motor skills and one may be involved in decoding certain emotions.

Women's loss was more spread out with most of it occurring in the outer brain (specifically: bilateral frontal parietal; temporal lobe; occipital cortex; cerebellum). These areas relate to language, motor skills, sensory interpretation, vision and visual memories, and emotion association.

Guo et al. did not make guesses beyond a quick mention of hormones as to what caused the sex differences in overall brain loss or the sex differences in loss locations. They also speculated that these differences may translate into differences in midlife men's and women's health or behavior, yet they did not offer any examples.

That leaves us all free to speculate. One bit of demographic information that caught my eye was that the researchers coded participants on "parental leave" as working full-time, because it meant that the participants usually worked full-time but were absent from that work to take care of a newborn child. This made me think about other research related to brain volume and parenting. For example, when women are pregnant their brain volumes can shrink an average 4% and not return to normal volume until about six months after birth. First, that makes the 4.03% decline found in Guo et al.'s female participants sound less ominous: this sort of decline is a normal experience for many women in young adulthood. Second, although most Finnish women in the 1980s usually started having babies at age 29, is it possible that some of the 23 women in this study gave birth just before the second MRI scan? Or is the location of brain loss during pregnancy similar to the location of women's brain loss in the transition to middle age?

Starting in the 80s, Finland offered parental leave to fathers as well as mothers. So it is possible that some of the male participants may have also identified themselves as being on parental leave. However, we know that fathers and mothers often take on different roles in parenting. For example, women are more likely to report that they get up to feed or care for babies in the middle of the night; mothers report more sleep loss than fathers even as children grow older. Poor sleep is associated with brain volume loss in the frontal, temporal, and parietal lobes. Different parental roles and related sleep loss may contribute to women's additional 1% of brain loss; brain volume loss related to poor sleep and brain volume loss related to women's transition to midlife are located in similar areas.

In the end we do not know what is causing these declines or sex differences, and even if we did, at this point we cannot know if these are related to any changes in men's and women's behavior or health as they age. The one thing you can know for sure is that if you are middle aged, pregnant, a new mother, or are sleep-deprived, you ARE losing your mind.

FURTHER READING:

The Guo et al. (2016) article can be accessed online or through your local college library.

Loss of brain cells does not always relate to loss of cognitive functioning. Read an APA Monitor on Psychology article by Melissa Phillips on the strengths of the middle-aged mind.

Childhood trauma can also reduce brain volume. Read a report on trauma's effects on brain development from the Child Welfare Information Gateway (U.S. Dept. of Health and Human Services).

BONUS:

Watch a video from Brown University on Synaptic Pruning:

Revenge of the preteen nerds

Many people get an education because they want good careers that earn good money. Being studious may not make you cool but it should set you up to meet that goal; students who party instead of studying may not be so successful:

This quotation is actually from Bill Gates, even if Actual Advice Mallard seems to be stating it here. Did Bill Gates get it right? Are today's nerdy kids likely to be well-employed and financially stable as adults?

Spengler, Brunner, Damian, Lüdtke, Martin, and Roberts (2015) examined data from a large-scale, longitudinal study done in Luxembourg, a small country in Europe. In 1968 the MAGRIP study collected data on Luxembourgish youngsters around age 12. This included measures of the children's IQs, their parents' levels of wealth and education (SES), ratings from teachers on how studious the children appeared to be, and self-reports about feelings of inferiority, being a responsible student, defying their parents' rules, and talking back to their parents.

In 2008, the second wave of MAGRIP followed up with 745 of these same individuals when they were in their 40s. At that time the participants were asked about their educational attainment (years of education after elementary school), their current or most recent jobs, and their yearly incomes. In their analysis, Spengler et al. wanted to know what traits at age 12 were associated with greater educational attainment, occupational success (as measured by prestige and social class), and higher incomes in middle age.

In line with past research, the participants who had higher IQs and higher SES families when they were 12 attained higher amounts of education by middle age. However, even when those two variables were accounted for, three other attributes predicted educational attainment: feeling that you are not as good as others; studiousness; talking back to parents and not always following the rules. Two of these are not surprising: self-reported feelings inferiority at age 12 were related to lower levels of education by one's 40s; while teachers' higher ratings of studiousness at age 12 predicted higher levels of education by middle age. Interestingly, reporting at age 12 that you talk back to and do not always obey your parents was also related to higher educational attainment in adulthood.

Likewise, more occupational success in middle age was predicted by having a higher IQ and coming from a higher SES family at age 12. Even when those two variables were held steady, seeing yourself as a responsible student at age 12 predicted occupational success in your 40s. Higher teacher ratings of studiousness during childhood also predicted occupational success, however this relationship played out through the amount of education that the participants experienced. Spengler et al. clarified that being seen as studious by your teachers in childhood suggests that you have traits that might lead you to choose more years of and more challenging levels of education. In fact, educational attainment was the best predictor of occupational success.

The analysis revealed an unexpected finding related to personal income. The participants who at age 12 admitted that they talked back to their parents and did not always follow their rules were more likely to have higher incomes during their 40s! This was true even when childhood IQ, family SES, and lifetime educational attainment were taken into account. Spengler et al. caution us that this finding needs to be replicated in future research - so this is not a green light for preteens around the globe to sass back at their parents. They also offer two explanations: these individuals may be more likely to argue to get higher wages; it is also possible that these individuals broke the rules as adults to get this higher income.

I would add that it is also possible that they were raised by good, Authoritative parents. These parents express love to their children and raise them with the correct amount of fair discipline; they are also willing to discuss household rules with their children, conversations which may start off with "talking back." Authoritative parents want their kids to be able to reason about their behavior choices instead of simply showing obedience to authority. So, it would stand to reason that their children may not always follow even their own rules to the letter. Authoritative parenting also prepares children for white collar jobs that require independent decision making and less emphasis on following orders; these jobs may also offer higher levels of pay.

Another possibility that I can imagine is that some of these individuals are Gifted. In general, higher IQs are related to higher incomes and Gifted children have IQs that are at least twice as different as we would expect from an average child. Parents of Gifted children often joke about them being "little lawyers," because they can be argumentative even with adults in authority. So Spengler et al.'s surprising finding may simply reflect a variable that is related to unusually high intelligence.

The authors admit that the predictive powers of pre-teen Luxembourgish children's behavior in 1968 may not generalize: it may be that educational attainment, occupational success, and income level are predicted by different traits today and these traits may vary from culture to culture. On the other hand, the Spengler et al. analysis demonstrated that personal factors like being a responsible student, coming across to teachers as being studious, and how you relate to people in positions of authority can predict achievement beyond their relationships with general intelligence and social class. In that case, being a studious (and perhaps argumentative) nerd may be enough: you don't have to be a genius like Bill Gates or have a wealthy parent like Bill Gates to become an adult with a good job and a good income.

Further Reading:

The Spengler et al. (2015) article can be accessed through your local college library.

Clinical Psychologist Kelly Flanagan blogged for The Huffington Post about why he thinks "...Every Kid Should Talk Back to Their Parents."

Serious students may have a good chance of landing a job found in U.S. News and World Report's list of "The 100 Best Jobs" of 2015.

BONUS: Watch an amusing promotional video titled "Is it true what they say about... Luxembourg?" made by the Luxembourg National Tourism Board. Spoiler Alert: no volcanoes; yes happy dogs.

When I'm 64

As a serious college student I remember feeling old before my time compared to some of my classmates who would blow off studying to socialize. Now as a middle-aged professor I don't "feel" as old as many of my peers (even though my daughter reminds me all of the time that I am "very old"). Apparently my experience is shared by Yoko Ono:

Chronological age, or how many years old you are, is just one way to think about aging. You can also consider: Biological age - how healthy you are; Social age - the habits you have and the roles that you take on; and Psychological age - how well you reason and think.

A recent study highlights how people's perceptions of their Biological and Social ages can influence their Subjective ages - or how old they feel. Stephan, Demulier, and Terracciano (2012) asked more than 1,000 French adults ages 18-91 to rate their physical health, to complete a version of the Big Five personality inventory, and to report their subjective ages.

The results support the idea that how old we feel is based on more than how old we are. These effects varied depending on the ages of the participants. The authors did not state the ranges of the age groups, but we would usually assume that their young adults were ages 18-39, middle-aged adults were 40-59, and older adults were 60-91.

A strong relationship between chronological age, health, and subjective age emerged. Middle aged and older adult participants who rated themselves as being in good health were more likely to say that they felt younger than they actually were. Stephan et al. clarify that on average, these middle aged adults felt 2 years younger and these older adults felt four years younger. These results support the importance of considering a person's Biological age.

When the authors controlled for health and demographic factors a relationship between chronological age, certain Big Five traits, and subjective age appeared. Because our personality traits often relate to our behaviors and activities, these results support the importance of assessing a person's Social age. For example, young adults who were high in Conscientiousness felt older than they really were. Conscientiousness implies being responsible and organized. Motivated and reliable young adults might feel like they are older than their peers because these are not characteristics that Western culture often associates with that age.

Middle aged and older adults who were high in Openness to Experience, and older adults who were high in Extraversion felt younger than they were. Openness to Experience has to do with engaging in diverse interests and being open to new ideas; Extraversion is associated with being out-going and dynamic. Both are traits that Western culture does not associate with middle and older age, so people with these traits are likely to feel younger than they really are as they age.

These results explain the experience that Yoko Ono and I share. When I was a young adult, my conscientious behavior did not match with my stereotype about my age: so I felt older. Now as a middle aged person who has broad interests and loves creativity, my self-perception again runs contrary to the stereotype about my age: so I feel younger. In some decades, I can predict that I will continue to feel younger because I am relatively high in Extraversion.

This research also raises a question about Western stereotypes about age. What does it mean that we view young adults as irresponsible, middle-agers and seniors as stuck in their ways, and senior citizens as being unsociable? If we can imagine a time that these negative assumptions are no longer part of our culture, it would have implications for subjective age. Instead of feeling older or younger than our chronological age we would simply be that old and recognize that at all ages individuals can differ on Big Five traits.

Further Reading:

A pre-publication version of the Stephan et al. (2012) article can be read here thanks to the National Institute of Health. The Psychology and Aging article can be accessed through your local college library.

A blog post from the AARP about research done by Rippon and Steptoe (2015): "Feeling Old vs Being Old." More support for Biological age!

Know an Extraverted senior? The social networking site Meet Up has groups around the world for outgoing older people who want to socialize!