Enhance your working intelligence with simple exercises...

Bakalar points to an interesting study by Jaeggi et al. showing that fluid intelligence (the kind of mental ability that allows us to solve new problems without having any relevant previous experience) can be enhanced by simple working memory training. It turns out that carefully structured training of the kind of memory that allows memorization of a telephone number just long enough to dial it enhances performance on standard tests of fluid intelligence. This suggests that fluid intelligence and working memory depend on the same brain circuitry.

Fairness activates brain reward circuitry.

Some interesting observations from Tabibnia et al. They:

...examined self-reported happiness and neural responses to fair and unfair offers while controlling for monetary payoff. Compared with unfair offers of equal monetary value, fair offers led to higher happiness ratings and activation in several reward regions of the brain. Furthermore, the tendency to accept unfair proposals was associated with increased activity in right ventrolateral prefrontal cortex, a region involved in emotion regulation, and with decreased activity in the anterior insula, which has been implicated in negative affect. This work provides evidence that fairness is hedonically valued and that tolerating unfair treatment for material gain involves a pattern of activation resembling suppression of negative affect.

Figure legend - Ventromedial prefrontal cortex (VMPFC), ventral striatum, and amygdala activation associated with fairness preference. The illustration (a) shows the location of clusters with significantly greater activation in response to fair compared with unfair offers.



Figure legend - Brain activation associated with the tendency to accept unfair offers. The illustrations show the location of areas in (a) left anterior insula and (c) right ventrolateral prefrontal cortex (right VLPFC) whose activation predicted this tendency.

More on language and perception...

Christine Kenneally writes a nice summary of current work on how language can nudge our perception. One interesting result demonstrates that labeling different categories enhances one's ability to discriminate between them. She discusses the work of Boroditsky mentioned in my Feb. 22 post, and work showing that in giving us symbols for spatial patterns, spatial language helps us carve up the world in specific ways. It appears that the ability to count is necessary to deal with large, specific numbers. And the only way to count past a certain point is with language.

The secret life of emotions.

Another demonstration that we can be nudged by unconscious emotional stimuli - that both global and specific emotional responses can be induced without awareness. From the discussion of an article with the title of this post from Ruys and Stapel, whose results show:

...that specific emotions can be elicited without conscious awareness of their cause...disgusting pictures (presented for 120 msec, not perceived) increased cognitive accessibility of disgust words and feelings of disgust. Similarly, fearful pictures increased cognitive accessibility of fear words and feelings of fear. When exposure to the priming stimuli was super-quick (40 msec), global mood, rather than a specific emotion, was evoked. These findings... empirically demonstrate (a) that specific emotions can be evoked without conscious awareness of their cause, (b) that unconscious exposure to emotion-eliciting pictures can evoke the specific corresponding emotion and does not evoke other emotions of similar valence, and (c) that unconscious emotion induction develops from elicitation of global affect to elicitation of specific emotions.

For a calm start to your week... some Debussy

Here is a second version (posted April 23, 2007) of the Debussy Reverie I initially put on YouTube Aug 29, 2006). I'm amazed that the first version has had ~90,000 viewings, and the second (made in response to comments on the first version) has had ~8,000.

A longevity-o-meter

Check out the "Vitality Compass" at the Blue Zones Community website. The results of a 2-3 minute quiz are based on a complex, 106-page algorithm developed by Dr. Robert Kane, a physician and a professor at the University of Minnesota School of Public Health. Here is my result (I'm 66 years old). Blue zone years refer to the number of years one has gained or lost given one's current behaviors.:

If you haven't OD'ed on the internet already....

Have a look at this site, which points to "20 websites that can change your life." (with 2 more added by feedback from viewers). Engaging a number of them (especially twitter) would appear to destroy any remnants of time or privacy that your life might contain.

Brain network disruption during aging.

Most work on brain changes with aging has focused on individual regions, especially those in the frontal lobe, which may shrink or lose activity even in the absence of disease. Andrews-Hanna et al. offer an important paper showing how long range interactions between brain regions are compromised with aging. The work looked at neural activity during a task in two large-scale networks that span the brain: the default network, used when we’re worrying, thinking of the past and future, or imagining people in our lives; and the attention network, used when we’re focusing on a specific task, such as word processing or math problems. The brain regions making up these systems were in sync in young people, but much less so, or not at all, in people over 60.

Figure - the younger brain, below, shows more synchronized activity than the older brain, above.

Brain imaging can predict the mistakes you are about to make.

From Fountain's review of work by Eichele et al.:

...brain patterns start to change about 30 seconds before an error is committed... changes were seen in two brain networks. One, called the default mode region, is normally active when a person is relaxed and at rest. When a person is doing something, like playing the game, this region becomes deactivated...researchers found that in the time leading up to an error, the region became active again — the subject was heading toward a relaxed state...Another network in the right frontal lobe gradually became less active, the researchers found. This is an area in the brain thought to be related to cognitive control, Dr. Eichele said, to keeping “on task.”

...it might be possible someday to develop a warning system — perhaps by monitoring the brain’s electrical activity, which is more practical — that could be used by people doing monotonous or repetitive tasks. Such a system would alert users when they are heading for a harmful or costly, not to mention mindless, mistake.

Positive psychology - a new organization

Some of you might wish to check out the website of the new International Positive Psychology Association (IPPA). It's board includes Martin Seligman, Mihaly Csikszentmihalyi, Tal Ben-Shahar, etc. The organization seeks to promote the science and practice of positive psychology and to facilitate communication and collaboration among researchers and practitioners around the world. A first world congress is planned for June 2009 in Philadelphia.

An antidepressant enhances brain plasticity

The title of the article by Vetencourt et al. is "The Antidepressant Fluoxetine Restores Plasticity in the Adult Visual Cortex. " [Fluoxetine hydrochloride, i.e. Prozac, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class.] Here is their abstract:

We investigated whether fluoxetine, a widely prescribed medication for treatment of depression, restores neuronal plasticity in the adult visual system of the rat. We found that chronic administration of fluoxetine reinstates ocular dominance plasticity in adulthood and promotes the recovery of visual functions in adult amblyopic animals, as tested electrophysiologically and behaviorally. These effects were accompanied by reduced intracortical inhibition and increased expression of brain-derived neurotrophic factor in the visual cortex. Cortical administration of diazepam prevented the effects induced by fluoxetine, indicating that the reduction of intracortical inhibition promotes visual cortical plasticity in the adult. Our results suggest a potential clinical application for fluoxetine in amblyopia as well as new mechanisms for the therapeutic effects of antidepressants and for the pathophysiology of mood disorders.

Space versus body based number representation

Here is a fascinating bit of work from Brozzoli et al. showing how our touch perception can reveal the dominance of spatial over digital representation of numbers.

We learn counting on our fingers, and the digital representation of numbers we develop is still present in adulthood. Such an anatomy–magnitude association establishes tight functional correspondences between fingers and numbers. However, it has long been known that small-to-large magnitude information is arranged left-to-right along a mental number line. Here, we investigated touch perception to disambiguate whether number representation is embodied on the hand ("1" = thumb; "5" = little finger) or disembodied in the extrapersonal space ("1" = left; "5" = right). We directly contrasted these number representations in two experiments using a single centrally located effector (the foot) and a simple postural manipulation of the hand (palm-up vs. palm-down). We show that visual presentation of a number ("1" or "5") shifts attention cross-modally, modulating the detection of tactile stimuli delivered on the little finger or thumb. With the hand resting palm-down, subjects perform better when reporting tactile stimuli delivered to the little finger after presentation of number "5" than number "1." Crucially, this pattern reverses (better performance after number "1" than "5") when the hand is in a palm-up posture, in which the position of the fingers in external space, but not their relative anatomical position, is reversed. The human brain can thus use either space- or body-based representation of numbers, but in case of competition, the former dominates the latter, showing the stronger role played by the mental number line organization.

Testosterone predicts financial profitability

..at least on a stock trading floor in London. Dan Mitchell summarizes the work of Coats and Herbert, published in PNAS. Men with elevated levels of testosterone, the hormone associated with aggression, made more money. When the markets were more volatile, the men showed higher levels of the stress hormone cortisol. There is the minor question of which is cause and which is effect....

Mine is longer than yours....

The last game of the baby boomers: Who wins is not who has the most toys, but who lives longest. Check out this great New Yorker article by Michael Kinsley. And, by the way, you might refer back to my May 2, 2007 post on Gawande's excellent article on aging.

Stirring Dull roots with spring rain... at Twin Valley

I'm back in Madison, WI., at the old stone schoolhouse on Twin Valley road.

A mouse model for PTSD suggests a therapy

Pibiri et al. have performed experiments on mice that model the emotional hyper-reactivity (including enhanced contextual fear and impaired contextual fear extinction) that is observed in human post traumatic stress disorder (PTSD) patients. They suggest that activation of neuronal steroid synthesis might be useful in PTSD therapy. The edited abstract:

Mice subjected to social isolation (3–4 weeks) exhibit enhanced contextual fear responses and impaired fear extinction. These responses are time-related to a decrease of ... allopregnanolone (Allo) levels in selected neurons of the medial prefrontal cortex, hippocampus, and basolateral amygdala...In socially isolated mice, S-norfluoxetine, in doses that increase brain Allo levels but fail to inhibit serotonin reuptake, greatly attenuates enhanced contextual fear response. The drug SKF decreases corticolimbic Allo levels and enhances the contextual fear response in group housed mice... A recent clinical study reported that cerebrospinal fluid Allo levels also are down-regulated in human PTSD patients and correlate negatively with PTSD symptoms and negative mood. Thus, protracted social isolation of mice combined with tests of fear conditioning may be a suitable model to study emotional behavioral components associated with neurochemical alterations relating to PTSD. Importantly, selective brain steroidogenic stimulants such as S-norfluoxetine, which rapidly increase corticolimbic Allo levels, normalize the exaggerated contextual fear responses resulting from social isolation, suggesting that selective activation of neurosteroidogenesis may be useful in PTSD therapy.

8-month-old infants use intuitive statistics..

Here is a fascinating result from Xu and Garcia, a demonstration that our brains begin to employ statistics at a very young age. Here are some (slightly edited) clips from their paper:

One hallmark of human learning is that human learners are able to make inductive inferences given a small amount of data. Our hunter–gatherer ancestors may have tasted a few berries on a tree and then decided that all berries from the same kind of tree are edible. They may have encountered a few friendly people from a neighboring tribe and made the inference that people in that tribe are likely to be friendly in general. Once such generalizations are made, the inferences may go in the other direction as well. This type of statistical inference (going from samples to populations, and from populations to samples) is present in virtually every domain of learning, be it foraging, social interaction, visual perception, word learning, or causal reasoning . Inductive learning in general requires some understanding of intuitive statistics, perhaps a simpler version of what scientists do in laboratory experiments or field studies.

Xu and Garcia performed six experiments investigating whether 8-month-old infants are "intuitive statisticians." Their results show that, given a sample, the infants are able to make inferences about the population from which the sample had been drawn. Conversely, given information about the entire population of relatively small size, the infants are able to make predictions about the sample...This ability to make inferences based on samples or information about the population develops early and in the absence of schooling or explicit teaching. Human infants may be rational learners from very early in development.

Here is one of the experiments, which asked whether 8-month-old infants could use the information in a sample to make inferences about a larger population:

...8-month-old infants watched some events unfold on a puppet stage. Each infant was first given a set of six ping-pong balls in a small container to play with for a few seconds; half of the ping-pong balls were red, half were white. Then the infant was shown four familiarization trials. On each trial, a large box was brought onto the stage. The experimenter opened the front panel of the box and drew the infant's attention to the box. The box contained either mostly red ping-pong balls and a few white ping-pong balls or mostly white ping-pong balls and a few red ping-pong balls. The experimenter showed the infants these two displays alternately; thus the infants were equally familiarized with each display. Then the test trials began (see Fig. 1 for a schematic representation of the test events). On each test trial, the same box was brought onto the stage, its content not known to the infants. The experimenter shook the box for a few seconds, closed her eyes, reached into the top opening, and pulled out a ping-pong ball. She then placed it into a transparent sample display container next to the large box. A total of five ping-pong balls were drawn from the box, one at a time. In half of the test trials, a sample of four red and one white ping-pong balls were drawn. In the other half of the test trials, a sample of one red and four white ping-pong balls were drawn. After the five ping-pong balls were placed in the sample display container, the experimenter opened the front panel of the box to reveal its content. The infant's looking time was recorded. The experimenter then cleared the stage and started the next test trial until a total of eight test trials were completed. Only one outcome display was shown for each infant, either the mostly white or the mostly red one. On alternate test trials, the infants were shown the two samples (four red and one white or one red and four white). For an infant who saw the mostly red outcome display when the box was opened, the four red and one white sample was more probable and therefore expected, whereas the four white and one red ball sample was much less probable and therefore unexpected,{dagger} assuming each set was a random sample from the box. For an infant who saw the mostly white outcome display, the converse was true.


Figure - Schematic representation of the test events (Images 1, 3, and 5) The experimenter shook the box for a few seconds, closed her eyes, reached into the top opening, and pulled out a ping-pong ball. (Images 2, 4, and 6) She then placed the ball into a transparent sample display container next to the large box. Test outcomes are shown at the bottom.

The infants looked reliably longer at the unexpected outcome (M = 9.9s) than the expected outcome (M = 7.5 s). It appears that infants were able to predict the content of the box from which the samples had been drawn.

Even brief stress can zap your brain...

Well...to be sure, we're talking about rat brains, but the message is probably there for us as well. An interesting (and sobering) piece of work from Sapolsky's laboratory shows that a single dose of corticosterone, i.e. an increase in its levels of the sort that would be induced by temporary stress, is sufficient to induce the hyper-growth of nerve cell dendrites in the basolateral amygdala and heighten anxiety behaviors. Here is the complete abstract, followed by a figure from the paper:

Stress is known to induce dendritic hypertrophy in the basolateral amygdala (BLA) and to enhance anxiety. Stress also leads to secretion of glucocorticoids (GC), and the BLA has a high concentration of glucocorticoid receptors. This raises the possibility that stress-induced elevation in GC secretion might directly affect amygdaloid neurons. To address the possible effects of GC on neurons of amygdala and on anxiety, we used rats treated either acutely with a single dose or chronically with 10 daily doses of high physiological levels of corticosterone (the rat-specific glucocorticoid). Behavior and morphological changes in neurons of BLA were measured 12 days after the initiation of treatment in both groups. A single acute dose of corticosterone was sufficient to induce dendritic hypertrophy in the BLA and heightened anxiety, as measured on an elevated plus maze. Moreover, this form of dendritic hypertrophy after acute treatment was of a magnitude similar to that caused by chronic treatment. Thus, plasticity of BLA neurons is sufficiently sensitive so as to be saturated by a single day of stress. The effects of corticosterone were specific to anxiety, as neither acute nor chronic treatment caused any change in conditioned fear or in general locomotor activity in these animals.

Figure - Representative camera lucida drawing of neurons from animals treated either acutely (A) or chronically (B) with CORT (Right) compared with their respective vehicle-treated controls (i.e. injection without the hormone) (Left).

What do you see and not see?

Here is an update of a well known demonstration that I have used in my lectures (and in my "I-Illusion" web-lecture at dericbownds.net) - on what happens when you focus your attention.

Money makes us happy...

In the Business section of the NY Times, Leonhardt points to a recent article by Betsey Stevenson and Justin Wolfers that disagrees with a classic paper published by Richard Easterlin in 1974, in which he argued that economic growth didn’t necessarily lead to more satisfaction. The prevailing idea as been that once a basic level of subsistence has been reached people care more about how much they make with respect to those around them than they do about their absolute level of income. An 'aspiration treadmill' makes people continuously dissatisfied (You own an iPod, now you want an iPod touch). Better public opinion data has been obtained over the past 34 years, and the bottom line is that income does matter, money indeed tends to bring happiness, even if it doesn’t guarantee it.

If anything...absolute income seems to matter more than relative income. In the United States, about 90 percent of people in households making at least $250,000 a year called themselves “very happy” in a recent Gallup Poll. In households with income below $30,000, only 42 percent of people gave that answer. But the international polling data suggests that the under-$30,000 crowd might not be happier if they lived in a poorer country.

Here is a summary graphic from Leonhardt's article (click to enlarge):