The Biology of Fear

I want to point to a good open source review article in Current Biology on the brain correlates of fear, by Ralph Adolphs. You might find the summary graphics useful. The summary:

Each of us has felt afraid, and we can all recognize fear in many animal species. Yet there is no consensus in the scientific study of fear. Some argue that ‘fear’ is a psychological construct rather than something discoverable through scientific investigation. Others argue that the term ‘fear’ cannot properly be applied to animals because we cannot know whether they feel afraid. Studies in rodents show that there are highly specific brain circuits for fear, whereas findings from human neuroimaging seem to make the opposite claim. Here, I review the field and urge three approaches that could reconcile the debates. For one, we need a broadly comparative approach that would identify core components of fear conserved across phylogeny. This also pushes us towards the second point of emphasis: an ecological theory of fear that is essentially functional. Finally, we should aim even to incorporate the conscious experience of being afraid, reinvigorating the study of feelings across species.

You are going to die...

The "Opinionator" online commentary feature of the New York Times has another engaging contribution in its "Anxiety" series, from Tim Kreider, author of collections of essays and cartoons. He starts with a visit to a posh retirement community his mother has decided to enter, which she describes as "like a college dorm, except the boys aren't as good-looking." In spite of her enthusiasm, he feels sadness, which he then realizes is mainly selfish, because the family home he grew up in is being sold, the familiar phone number lost. Some clips of sections that struck me:

Plenty of people before me have lamented the way that we in industrialized countries regard our elderly as unproductive workers or obsolete products, and lock them away in institutions instead of taking them into our own homes out of devotion and duty...what I wonder about is what it's doing to the rest of us...I think we also segregate the elderly from the rest of society because we're afraid of them, as if age might be contagious. Which, it turns out, it is.

Segregating the old and the sick enables a fantasy, as baseless as the fantasy of capitalism's endless expansion, of youth and health as eternal, in which old age can seem to be an inexplicably bad lifestyle choice...So that when through absolutely no fault of your own your eyesight begins to blur and you can no longer eat whatever you want without consequence and the hangovers start lasting for days, you feel somehow ripped off, lied to. Aging feels grotesquely unfair. As if there ought to be someone to sue.

Because of all the stories we've absorbed, we vaguely imagine that our lives will take the shape of a narrative - the classic Aristotelian ramp diagram of gradual rising action (struggle and setbacks), climax (happy marriage, professional success), and a brief, cozy denoument (kicking back with family and friends, remembering the good times on a porch someplace pretty). But life is not shaped like a story; it's an elongate and flattened bell curve, with an attenuated, anticlimactic decline as long as its beginning. Friends have described seeing their parents lose their faculties one by one, in more or less the reverse order that their young children are acquiring them.

On the desire for life extension therapies:

I am all for raging against the dying of the light, and if they ever develop DNA rejuvenation or some other longevity technique I will personally claw, throttle and gouge my way through Warren Buffett, Rupert Murdoch and any number of other decrepit billionaires in order to be first in line.

But we don't have a choice. You are older at this moment than you've ever been before, and it's the youngest you're ever going to get. The mortality rate is holding at a scandalous 100 percent. Pretending death can be indefinitely evaded with hot yoga or a gluten-free diet or antioxidants or just by refusing to look is craven denial.

Thoughts as material objects - impact on evaluations

It's hard to get rid of unwanted thoughts. What about just throwing them in the garbage like unwanted objects? In some conditions might we discard our thoughts as easily as we dispose of objects? If Mr. Descartes was right (straw man, I know), a thought cannot literally be thrown into the garbage, because it does not have a material or physical nature. If a component of our cognition is taken to be a physical object, we should be able to discard it. Briñol et al. make some observations relevant to these points. Their experiments involved subjects writing down positive and negative thoughts about their bodies. First, their abstract:

In Western dualistic culture, it is assumed that thoughts cannot be treated as material objects; however, language is replete with metaphorical analogies suggesting otherwise. In the research reported here, we examined whether objectifying thoughts can influence whether the thoughts are used in subsequent evaluations. In a firstexperiment participants wrote about what they either liked or disliked about their bodies. Then, the paper on which they wrote their thoughts was either ripped up and tossed in the trash or kept and checked for errors. When participants physically discarded a representation of their thoughts, they mentally discarded them as well, using them less in forming judgments than did participants who retained a representation of their thoughts. A second experiment replicated this finding and also showed that people relied on their thoughts more when they physically kept them in a safe place—putting their thoughts in their pockets—than when they discarded them. A final study revealed that these effects were stronger when the action was performed physically rather than merely imagined.

Now, a bit more detail on the first experiment:

The experiment was presented as a study on body image. All participants received written instructions asking them to complete several tasks. As part of the first task, each participant was randomly assigned to generate and write down either positive or negative thoughts about his or her own body during a 3-min period. In the positive-thoughts condition, participants were told to list as many positive thoughts about their bodies as they could; in the negative-thoughts condition, participants were told to list as many negative thoughts about their bodies as they could (e.g., Killeya & Johnson, 1998). Examination of the thoughts listed indicated that all participants followed the instructions.

After listing his or her thoughts, each participant was randomly assigned to either the thought-disposal or the control condition. All participants were asked to look back at the thoughts they wrote. In the thought-disposal condition, participants were asked to contemplate their thoughts and then throw them into the trash can located in the room, because their thoughts did not have to remain with them. In the control condition, participants were asked to contemplate their thoughts and to check for any grammar or spelling errors they could find.

The dependent variable in our analysis was participants’ attitudes toward their bodies. Participants were told that they should record these attitudes because their self-image might have influenced their previous responses. Attitudes were assessed using three 9-point semantic-differential scales (e.g., bad-good, unattractive-attractive, like-dislike). Ratings were highly intercorrelated (α = .88), so we averaged them (after reverse scoring as appropriate) to create a composite attitude index. Higher values on this index indicated more favorable attitudes.

From their discussion:

Consistent with our hypothesis that a thought-disposal treatment can influence judgments by invalidating people’s thoughts, results showed that the attitudes of participants who physically threw their thoughts away showed less impact of the thought-direction induction than did the attitudes of participants who physically retained their thoughts....It is important to note that because the treatment was induced after thoughts were already generated, it could not affect the valence or the number of participants’ thoughts. Rather, the treatment decreased the strength of the influence that participants’ thoughts had on their attitudes.

What we should fear...

Gary Marcus does a review of some answers to the annual question of John Brockman's edge.org, "What *should* we be worried about?" On the question of whether we are psychologically and politically constituted to worry about what we most need to worry about, Marcus suggests:

that there is good reason to think that we are not inclined that way, both because of an inherent cognitive bias that makes us focus on immediate concerns (like getting our dishwasher fixed) to the diminishment of our attention to long-term issues (like getting enough exercise to maintain our cardiovascular fitness) and because of a chronic bias toward optimism known as a “just-world fallacy” (the comforting but unrealistic idea that moral actions will invariably lead to just rewards).

A theme throughout the collection is what Stanford psychologist Brian Knutson calls “metaworry”. His metaworry is that:

...actual threats [to our species] are changing much more rapidly than they have in the ancestral past. Humans have created much of this environment with our mechanisms, computers, and algorithms that induce rapid, “disruptive,” and even global change. Both financial and environmental examples easily spring to mind.… Our worry engines [may] not retune their direction to focus on these rapidly changing threats fast enough to take preventative action.

Brain correlates of developing intuition.

An interesting open access study from Wan et al.:

The superior capability of cognitive experts largely depends on automatic, quick information processing, which is often referred to as intuition. Intuition develops following extensive long-term training. There are many cognitive models on intuition development, but its neural basis is not known. Here we trained novices for 15 weeks to learn a simple board game and measured their brain activities in early and end phases of the training while they quickly generated the best next-move to a given board pattern. We found that the activation in the head of caudate nucleus developed over the course of training, in parallel to the development of the capability to quickly generate the best next-move, and the magnitude of the caudate activity was correlated with the subject's performance. In contrast, cortical activations, which already appeared in the early phase of training, did not further change. Thus, neural activation in the caudate head, but not those in cortical areas, tracked the development of capability to quickly generate the best next-move, indicating that circuitries including the caudate head may automate cognitive computations.

A few pictures showing location of the caudate head (pointed to by to line in right figure):

How procrastination gets things done...

John Tierney writes a delightful piece on not getting some things done. He notes several authors' comments on procrastination:

The key to productivity, John Perry argues in “The Art of Procrastination,” is to make more commitments — but to be methodical about it...At the top of your to-do list, put a couple of daunting, if not impossible, tasks that are vaguely important-sounding (but really aren’t) and seem to have deadlines (but really don’t). Then, farther down the list, include some doable tasks that really matter.,,“Doing these tasks becomes a way of not doing the things higher up on the list,” Dr. Perry writes. “With this sort of appropriate task structure, the procrastinator becomes a useful citizen. Indeed, the procrastinator can even acquire, as I have, a reputation for getting a lot done.”

Robert Benchley:

“The secret of my incredible energy and efficiency in getting work done is a simple one,” he wrote. “The psychological principle is this: anyone can do any amount of work, provided it isn’t the work he is supposed to be doing at that moment.”

Piers Steel ("The Procrastination Equation", 2011):

For most of us, procrastination can be beaten down, but not entirely beaten…My best trick is to play my projects off against each other, procrastinating on one by working on another….We are willing to pursue any vile task as long as it allows us to avoid something worse.

Procrastinators rarely sit around absolutely idle. The author Raymond Chandler forced himself to write detective stories by setting aside 4 hours each day with two rules:

a) You don’t have to write.

b) You can’t do anything else.

Another rule from Perry:

Never do today any task that may disappear by tomorrow.

Hedonic adaptation - where did the warm glow go?

Obtaining something we want follows a very stereotyped course, as noted in Oscar Wilde's famous aphorism: "There are only two tragedies in life: one is not getting what one wants, and the other is getting it." Or, consider the scene from the musical "Stop the World, I want to get off." in which the character at the climax of a song are entwined in a happy summation...the music stops...the characters keep holding their position, and keep holding....and keep holding...begin to wobble just a bit...wobble a bit more...and finally fall apart.

Why is the warm glow on attaining some we desire sustained? Why is happily-ever-after so rare? The issue, in terms of relationships, is addressed in Jane Brody recent review of writing and studies on keeping love alive in relationships. The happiness boost that occurs with marriage lasts only about two years, after which people revert to their former levels of happiness - or unhappiness, and infatuation and passion have even shorter life spans. The phenomenon is dubbed "hedonic adaptation" by psychologists - things that thrill us tend to be short-lived. (The reaction of many brain circuits to repeated stimulation is to decrease their reactivity or output, an example being the mesolimbic dopamine system, whose role in the brain reward system is controversial.)

 Lyubomirsky's new book "The Myth of Happiness" deals with this situation and notes techniques, backed by recent research, that help relationships evolve into companionate love, composed more of deep affection, connection and liking (I just downloaded a test sample from Amazon to my iPad to check it out). Barbara L. Fredrickson, author of the forthcoming "Love 2.0" specifies that a flourishing relationship needs three times as many positive emotions as negative ones.

The advice on relationships all seems to boil down to "practice a bit more kindness and gratitude".   I have to say, that when I've been able to budge my curmudgeonly nature enough to actually do this for brief periods of time, it has worked wonders!

How environments talk to genes.

The January issue of Nature Neuroscience has some fascinating articles on gene-environment interactions. Vassoler et al. report that in rats paternal cocaine use causes a heritable increase in cortical brain-derived neurotrophic factor (Bdnf) gene expression, which then confers a cocaine-resistant phenotype in male, but not female, progeny (The sins of the father are forgiven!):

We delineated a heritable phenotype resulting from the self-administration of cocaine in rats. We observed delayed acquisition and reduced maintenance of cocaine self-administration in male, but not female, offspring of sires that self-administered cocaine. Brain-derived neurotrophic factor (Bdnf) mRNA and BDNF protein were increased in the medial prefrontal cortex (mPFC), and there was an increased association of acetylated histone H3 with Bdnf promoters in only the male offspring of cocaine-experienced sires. Administration of a BDNF receptor antagonist (the TrkB receptor antagonist ANA-12) reversed the diminished cocaine self-administration in male cocaine-sired rats. In addition, the association of acetylated histone H3 with Bdnf promoters was increased in the sperm of sires that self-administered cocaine. Collectively, these findings indicate that voluntary paternal ingestion of cocaine results in epigenetic reprogramming of the germline, having profound effects on mPFC gene expression and resistance to cocaine reinforcement in male offspring.

And, Klengel et al. find a molecular mechanism in the case of post-traumatic stress disorder: demethylation of a glucocorticoid response element in the stress response regulator FKBP5 that depends on both the risk allele and childhood trauma. Here is the jargon:

Although the fact that genetic predisposition and environmental exposures interact to shape development and function of the human brain and, ultimately, the risk of psychiatric disorders has drawn wide interest, the corresponding molecular mechanisms have not yet been elucidated. We found that a functional polymorphism altering chromatin interaction between the transcription start site and long-range enhancers in the FK506 binding protein 5 (FKBP5) gene, an important regulator of the stress hormone system, increased the risk of developing stress-related psychiatric disorders in adulthood by allele-specific, childhood trauma–dependent DNA demethylation in functional glucocorticoid response elements of FKBP5. This demethylation was linked to increased stress-dependent gene transcription followed by a long-term dysregulation of the stress hormone system and a global effect on the function of immune cells and brain areas associated with stress regulation. This identification of molecular mechanisms of genotype-directed long-term environmental reactivity will be useful for designing more effective treatment strategies for stress-related disorders.

Our brains change operating modes during an eyeblink.

Nakano et al. suggest that an eye blink briefly gives our attentional network a rest, as activity shifts to the default network:

It remains unknown why we generate spontaneous eyeblinks every few seconds, more often than necessary for ocular lubrication. Because eyeblinks tend to occur at implicit breakpoints while viewing videos, we hypothesized that eyeblinks are actively involved in the release of attention. We show that while viewing videos, cortical activity momentarily decreases in the dorsal attention network after blink onset but increases in the default-mode network implicated in internal processing. In contrast, physical blackouts of the video do not elicit such reciprocal changes in brain networks. The results suggest that eyeblinks are actively involved in the process of attentional disengagement during a cognitive behavior by momentarily activating the default-mode network while deactivating the dorsal attention network.

Why mental arithmetic counts.

Price et al. show that brain activation during single digit arithmetic predicts high school math scores:

Do individual differences in the brain mechanisms for arithmetic underlie variability in high school mathematical competence? Using functional magnetic resonance imaging, we correlated brain responses to single digit calculation with standard scores on the Preliminary Scholastic Aptitude Test (PSAT) math subtest in high school seniors. PSAT math scores, while controlling for PSAT Critical Reading scores, correlated positively with calculation activation in the left supramarginal gyrus and bilateral anterior cingulate cortex, brain regions known to be engaged during arithmetic fact retrieval. At the same time, greater activation in the right intraparietal sulcus during calculation, a region established to be involved in numerical quantity processing, was related to lower PSAT math scores. These data reveal that the relative engagement of brain mechanisms associated with procedural versus memory-based calculation of single-digit arithmetic problems is related to high school level mathematical competence, highlighting the fundamental role that mental arithmetic fluency plays in the acquisition of higher-level mathematical competence.

Lifelong bilingualism enhances cognitive control in aging.

This work by Gold et al. makes me wish I had maintained the proficiency in German that I had in my college years:

Recent behavioral data have shown that lifelong bilingualism can maintain youthful cognitive control abilities in aging. Here, we provide the first direct evidence of a neural basis for the bilingual cognitive control boost in aging. Two experiments were conducted, using a perceptual task-switching paradigm, including a total of 110 participants. In Experiment 1, older adult bilinguals showed better perceptual switching performance than their monolingual peers. In Experiment 2, younger and older adult monolinguals and bilinguals completed the same perceptual task-switching experiment while functional magnetic resonance imaging (fMRI) was performed. Typical age-related performance reductions and fMRI activation increases were observed. However, like younger adults, bilingual older adults outperformed their monolingual peers while displaying decreased activation in left lateral frontal cortex and cingulate cortex. Critically, this attenuation of age-related over-recruitment associated with bilingualism was directly correlated with better task-switching performance. In addition, the lower blood oxygenation level-dependent response in frontal regions accounted for 82% of the variance in the bilingual task-switching reaction time advantage. These results suggest that lifelong bilingualism offsets age-related declines in the neural efficiency for cognitive control processes.

A great New Yorker Cover

I can't resist passing on the cover of the most recent issue of The New Yorker:

Mindfulness neuroscience

The journal Social Cognitive and Affective Neuroscience has released an issue devoted to studies of brain correlates of different kinds of meditation. One article, on compassion or loving-kindness meditation, is open access. For me, the crucial article is the last one, written by a senior guru of the brain imaging field, Michael Posner, and his colleague Yi-Yuan Tang, outlining theoretical and methodological issues in the field. They note that reviews of the field have:

..summarized four components of how mindfulness meditation may work: (i) attention regulation, (ii) body awareness, (iii) emotion regulation (including reappraisal, exposure, extinction and reconsolidation) and (iv) change in perspective on the self. The authors indicate that mindfulness practice comprises a process of enhanced self-regulation that can be differentiated into distinct but interrelated components. While these components are a start, future empirical work should identify additional components of mindfulness and establish to what extent the components involve distinct mechanisms.

Many studies have difficulties with appropriate control and comparison subjects:

Different control and comparison groups have been used in mindfulness research, such as waiting lists, active control groups and interventions designed to match the non-specific effects of mindfulness practices, such as trainer’s confidence, expectancy effects and group support... Ideally, participants would be randomly assigned to condition, and the conditions would be matched with the many non-specific factors that have been found to produce beneficial change... Random assignment allows the changes observed in mindfulness research to be reasonably attributed to the active ingredient of mindfulness practice per se rather than to pre-existing differences in the experimental and control groups. Therefore, moving the field will require the use of rigorous comparison conditions to which participants are randomly assigned.

In long-term studies, an active control is not possible. In studies of long-term practitioners such as monks with many thousands of hours of practice, it is challenging to find even a matched control group. We don’t know how the monks differed before meditation practice and other factors including the environment and low stress, which differ from any ‘matched’ control group.

Other issues are that the various studies employ different mindfulness techniques, stages of practice, or duration of training. (Motivated readers can request a copy of his article from me.)

The power of concentration

I've been meaning to pass on this review by Konnikova on the salutary effects of mindfulness and concentration. It pulls together a number of observations that I have noted in previous MindBlog posts. Here are a few clips:

...mindfulness is less about spirituality and more about concentration: the ability to quiet your mind, focus your attention on the present, and dismiss any distractions that come your way...In 2011, researchers from the University of Wisconsin demonstrated that daily meditation-like thought could shift frontal brain activity toward a pattern that is associated with what cognitive scientists call positive, approach-oriented emotional states — states that make us more likely to engage the world rather than to withdraw from it...

An exercise in mindfulness can also help with that plague of modern existence: multitasking...researchers led by a team from the University of Washington examined the effects of meditation training on multitasking in a real-world setting. They asked a group of human resources professionals to engage in the type of simultaneous planning they did habitually... After the multitasking free-for-all, participants were divided into three groups: one was assigned to an eight-week meditation course (two hours of instruction, weekly); another group didn’t take the course at first, but took it later; and the last group took an eight-week course in body relaxation. Everyone was put through a second round of frenzy...The only participants to show improvement were those who had received the mindfulness training.Not only did they report fewer negative emotions at the end of the assignment, but their ability to concentrate improved significantly. They could stay on task longer and they switched between tasks less frequently.

In recent years, mindfulness has been shown to improve connectivity inside our brain’s attentional networks, as well as between attentional and medial frontal regions — changes that save us from distraction. Mindfulness, in other words, helps our attention networks communicate better and with fewer interruptions than they otherwise would...In 2006, a team of psychologists demonstrated that the neural activation patterns of older adults (specifically, activation in the prefrontal cortex), began to resemble those of much younger subjects after just five one-hour training sessions on a task of attentional control. Their brains became more efficient at coordinating multiple tasks — and the benefit transferred to untrained activities, suggesting that it was symptomatic of general improvement.

Similar changes have been observed in the default network (the brain’s resting-state activity). In 2012, researchers from Ohio State University demonstrated that older adults who scored higher on mindfulness scales had increased connectivity in their default networks, specifically in two of the brain’s major information processing hubs. And while we already know that this kind of increased connectivity is a very good thing, there’s more to these particular results. The precise areas that show increased connectivity with mindfulness are also known to be pathophysiological sites of Alzheimer’s disease.

Self affirmation enhances responsiveness to errors.

Legault et al. note brain responses that correlate with augmented attention and emotional receptivity to performance errors caused by enhanced self affirmation. The experiments used the usual group of undergraduate psychology students, who were split into two groups given writing exercises designed to either enhance or undermine self-affirmation. Both groups then performed a simple go, no-go exercise, with errors getting negative feedback. EEG recordings were made during this exercise. Here is their summary extract:

Self-affirmation produces large effects: Even a simple reminder of one’s core values reduces defensiveness against threatening information. But how, exactly, does self-affirmation work? We explored this question by examining the impact of self-affirmation on neurophysiological responses to threatening events. We hypothesized that because self-affirmation increases openness to threat and enhances approachability of unfavorable feedback, it should augment attention and emotional receptivity to performance errors. We further hypothesized that this augmentation could be assessed directly, at the level of the brain. We measured self-affirmed and nonaffirmed participants’ electrophysiological responses to making errors on a task. As we anticipated, self-affirmation elicited greater error responsiveness than did nonaffirmation, as indexed by the error-related negativity, a neural signal of error monitoring. Self-affirmed participants also performed better on the task than did nonaffirmed participants. We offer novel brain evidence that self-affirmation increases openness to threat and discuss the role of error detection in the link between self-affirmation and performance.

Music and movement: shared dynamic structure in universal expressions of emotion

Sievers et al. do a fascinating analysis. They designed an ingenious computer program that used slider bars to adjust a music player or a bouncing ball with varying rate, jitter (regularity of rate), direction, step size, and dissonance/visual spikiness. Participants were instructed to take as much time as needed to set the sliders in the program to express five emotions: “angry,” “happy,” “peaceful,” “sad,” and “scared.” One set of participants was instructed to move sliders to express the emotion with the moving ball, then other set told to move the sliders to use music to express the emotion. U.S. college students were one experimental group, the other was a culturally isolated Kreug ethnic minority in northern Cambodia with music formally dissimilar to Western music: no system of vertical pitch relations equivalent to Western tonal harmony, constructed using different scales and tunings, and performed on morphologically dissimilar instruments. Here is the authors' summary abstract:

Music moves us. Its kinetic power is the foundation of human behaviors as diverse as dance, romance, lullabies, and the military march. Despite its significance, the music-movement relationship is poorly understood. We present an empirical method for testing whether music and movement share a common structure that affords equivalent and universal emotional expressions. Our method uses a computer program that can generate matching examples of music and movement from a single set of features: rate, jitter (regularity of rate), direction, step size, and dissonance/visual spikiness. We applied our method in two experiments, one in the United States and another in an isolated tribal village in Cambodia. These experiments revealed three things: (i) each emotion was represented by a unique combination of features, (ii) each combination expressed the same emotion in both music and movement, and (iii) this common structure between music and movement was evident within and across cultures.

The End of History Illusion.

The Jan 4 issue of Science has an interested article by Quoidbach et al. on our perception of how much we changed in the past decade and how much we expect to change in the next. Here is some context from their introduction:

At every stage of life, people make decisions that profoundly influence the lives of the people they will become—and when they finally become those people, they aren’t always thrilled about it. Young adults pay to remove the tattoos that teenagers paid to get, middle-aged adults rush to divorce the people whom young adults rushed to marry, and older adults visit health spas to lose what middle-aged adults visited restaurants to gain. Why do people so often make decisions that their future selves regret? One possibility is that people have a fundamental misconception about their future selves. Time is a powerful force that transforms people’s preferences, reshapes their values, and alters their personalities, and we suspect that people generally underestimate the magnitude of those changes. In other words, people may believe that who they are today is pretty much who they will be tomorrow, despite the fact that it isn’t who they were yesterday. In the studies we describe here, we showed that people expect to change little in the future, despite knowing that they have changed a lot in the past, and that this tendency bedevils their decision-making. We call this tendency to underestimate the magnitude of future change the “end of history illusion.”

And here is their summary and discussion:

Across six studies of more than 19,000 participants, we found consistent evidence to indicate that people underestimate how much they will change in the future, and that doing so can lead to suboptimal decisions. Although these data cannot tell us what causes the end of history illusion, two possibilities seem likely. First, most people believe that their personalities are attractive, their values admirable, and their preferences wise (10); and having reached that exalted state, they may be reluctant to entertain the possibility of change. People also like to believe that they know themselves well (11), and the possibility of future change may threaten that belief. In short, people are motivated to think well of themselves and to feel secure in that understanding, and the end of history illusion may help them accomplish these goals.

Second, there is at least one important difference between the cognitive processes that allow people to look forward and backward in time (12). Prospection is a constructive process, retrospection is a reconstructive process, and constructing new things is typically more difficult than reconstructing old ones (13, 14). The reason this matters is that people often draw inferences from the ease with which they can remember or imagine (15, 16). If people find it difficult to imagine the ways in which their traits, values, or preferences will change in the future, they may assume that such changes are unlikely. In short, people may confuse the difficulty of imagining personal change with the unlikelihood of change itself.

Although the magnitude of this end of history illusion in some of our studies was greater for younger people than for older people, it was nonetheless evident at every stage of adult life that we could analyze. Both teenagers and grandparents seem to believe that the pace of personal change has slowed to a crawl and that they have recently become the people they will remain. History, it seems, is always ending today.

Surprise! Satisfied old folks live longer.

Contra a popular assumption that feisty, grumpy old farts are likely to live longer than sweet docile passive ones, Judith Graham reviews recent work by Becca Levy, an associate professor of epidemiology and psychology at Yale University that suggests the opposite - basically that older people become what they think, what their age stereotypes are. Some edited clips:

She looked at a a database of 660 adults age 50 and older in Oxford, Ohio, who were followed for a period of 23 years, from 1975 to 1998, and reported in The Journal of Personal and Social Psychology in 2002 that those with positive age stereotypes lived 7.5 years longer than those with negative stereotypes. She also did a series of laboratory experiments with older people, exposing them subliminally to negative or positive stereotypes by flashing words associated with aging on a computer screen too fast for them to process consciously. Then these seniors were asked to perform a task. Those exposed to negative words such as "decrepit" had poorer handwriting, slower walking speeds, higher levels of cardiovascular stress and a greater willingness to reject hypothetical medical interventions that could prolong their lives. Those primed with positive words such as "wisdom" did much better.

Levy established that people with positive age stereotypes were more likely to eat a balanced diet, exercise, limit their alcohol consumption, stop smoking and get regular physical exams, and that they had a higher level of physical functioning over time. Results were controlled for other factors like illness, gender, race and socioeconomic status…In these papers, Dr. Levy hypothesized that positive age stereotypes are associated with a greater sense of control and that this enhanced seniors' sense of self efficacy -- their ability to remain captains of their own ship, as it were.

Human evolution: endurance running made our brains larger and smarter.

Gretchen Reynolds reviews work suggesting that our advanced cleverness and big brains may have come not from the need to think but becoming endurance athletes, able to bring down swifter prey through sheer doggedness, jogging and plodding along behind them until the animals dropped. It turns out our larger brain size with respect to body size is also shown to some extent by species like dogs and rats that have a high innate endurance capacity, presumably evolved over millennia. it is also seen in mice and rats systematically bred to be marathon runners. After multiple generations, these animals begin to develop innately higher levels of tissue growth and health promoters, including the protein brain-derived neurotrophic factor, or BDNF. These substances are important for endurance performance. They also are known to drive brain growth. Such observations have led Raichlen and Polk to suggest that physical activity may have helped to make early humans smarter:

The hunting and gathering lifestyle adopted by human ancestors around 2 Ma required a large increase in aerobic activity. High levels of physical activity altered the shape of the human body, enabling access to new food resources (e.g. animal protein) in a changing environment. Recent experimental work provides strong evidence that both acute bouts of exercise and long-term exercise training increase the size of brain components and improve cognitive performance in humans and other taxa. However, to date, researchers have not explored the possibility that the increases in aerobic capacity and physical activity that occurred during human evolution directly influenced the human brain. Here, we hypothesize that proximate mechanisms linking physical activity and neurobiology in living species may help to explain changes in brain size and cognitive function during human evolution. We review evidence that selection acting on endurance increased baseline neurotrophin and growth factor signalling (compounds responsible for both brain growth and for metabolic regulation during exercise) in some mammals, which in turn led to increased overall brain growth and development. This hypothesis suggests that a significant portion of human neurobiology evolved due to selection acting on features unrelated to cognitive performance.

Why are older people more susceptible to fraud?

From Castle et al: a succinct set of observations. Their data is quite compelling.

Older adults are disproportionately vulnerable to fraud, and federal agencies have speculated that excessive trust explains their greater vulnerability. Two studies, one behavioral and one using neuroimaging methodology, identified age differences in trust and their neural underpinnings. Older and younger adults rated faces high in trust cues similarly, but older adults perceived faces with cues to untrustworthiness to be significantly more trustworthy and approachable than younger adults. This age-related pattern was mirrored in neural activation to cues of trustworthiness. Whereas younger adults showed greater anterior insula activation to untrustworthy versus trustworthy faces, older adults showed muted activation of the anterior insula to untrustworthy faces. The insula has been shown to support interoceptive awareness that forms the basis of “gut feelings,” which represent expected risk and predict risk-avoidant behavior. Thus, a diminished “gut” response to cues of untrustworthiness may partially underlie older adults’ vulnerability to fraud.