Listening to Resveratrol

David Kent writes a well balanced article in American Scientist on issues of human longevity. A graphic and some text on the consequences of lifespan-prolonging therapies on population growth and demographic structure:

In the past century, disease-specific medicine reduced mortality at all ages, including the economically productive years between one's 20s and 60s. Historical trends show an increasing "rectangularization" of mortality rates over the past century, meaning that most people survive to an advanced age, at which point there is a precipitous increase in the number of deaths (green curves). Such data have led some researchers to theorize that the human lifespan is reaching an "ideal" length, beyond which substantial extension is not possible. However, discoveries about the basic mechanisms of aging may permit life expectancy to extend beyond this theoretical limit (red curves).


The rectangularization of the mortality curve implies that life-prolonging therapies will add years only at the end of life. Unless there is a shift in the retirement age, 21st-century medical innovation will have an even more dramatic effect on the dependency ratio (a measure of the portion of a population composed of those either too old or too young to work). Maintaining retirement as a widespread option at around 65, already an economic stretch, undoubtedly will become untenable. The price of longer life will almost certainly be a longer work life.

Chinese kids are ahead even before elementary school...

More sobering data from Siegler and Mu on occidental versus oriental child development. The superior mathematical knowledge of East Asian preschoolers is not limited to skills that are taught directly by parents or in school but is more general.

Kindergartners in China showed greater numerical knowledge than their age peers in the United States, not only when tested with arithmetic problems, which Chinese parents present to their children more often than U.S. parents do, but also when tested with number-line estimation problems, which were novel to the children in both countries. The Chinese kindergartners' number-line estimates were comparable to those of U.S. children 1 to 2 years more advanced in school. Individual differences in arithmetic and number-line-estimation performance were positively correlated within each country. These results indicate that performance differences between Chinese and U.S. children on both practiced and unpracticed mathematical tasks are substantial even before the children begin elementary school.

Watching the testosterone crash in anxious men who lose a contest.

This work from Maner et al. makes a rather blunt point:

Although theory suggests a link between social anxiety and social dominance, direct empirical evidence for this link is limited. The present experiment tested the hypothesis that socially anxious individuals, particularly men, would respond to a social-dominance threat by exhibiting decrements in their testosterone levels, an endocrinological change that typically reflects pronounced social submission in humans and other animals. Participants were randomly assigned to either win or lose a rigged face-to-face competition with a confederate. Although no zero-order relationship between social anxiety and level of testosterone was observed, testosterone levels showed a pronounced drop among socially anxious men who lost the competition. No significant changes were observed in nonanxious men or in women. This research provides novel insight into the nature and consequences of social anxiety, and also illustrates the utility of integrating social psychological theory with endocrinological approaches to psychological science.


Figure: Change in testosterone level as a function of experimental condition (losers vs. winners) and social anxiety (1 SD above the mean vs. 1 SD below the mean). Results are presented separately for men and women. Change scores were standardized within each gender.

La gazza ladra passes the mirror test - a crow with a self!

The Eurasian magpie belongs to the same bird family that includes the crows, ravens, and jays. de Waal writes a fascinating review of recent work by Prior et al. that demonstrates that magpies recognize themselves in a mirror - a test that persists as the gold standard of self-identity or 'personhood.' The experiments actually had better controls than many of those done with apes and human children...

...which generally fail to include “sham” marks. A sham mark is applied in the same way as a visible mark, and supposed to feel and smell the same, but cannot be visibly detected. In the magpie study, this was done by placing a black mark onto the magpies' black throat feathers.

Placed on the same black throat feathers, the visible mark—a tiny colored sticker—stood out, but only in a mirror. Put in front of a mirror, the magpies kept scratching with their foot until the mark was gone, whereas they left the sham mark alone. They also didn't do the same amount of frantic scratching if there was no mirror to see themselves in. Evidently, their self-preening was guided by visual feedback from the mirror.

de Waal also discusses work with other species and the “co-emergence hypothesis,” according to which the capacities for mirror self recognition and perspective-taking appear in tandem during both evolution and development.

Speaking of crows, Nijhuis writes a brief piece on work showing that crows recognize individual human faces.

Neural correlates of consciousness

I just came across this succinct and informative site in Scholarpedia curated by Christof Koch and Florian Mormann at Cal. Tech. It has some useful instructional graphics.


Midline structures in the brainstem and thalamus necessary to regulate the level of brain arousal. Small, bilateral lesions in many of these nuclei cause a global loss of consciousness. (From Koch, 2004, The Quest for Consciousness: A Neurobiological Approach. Roberts, Denver, CO.)

When a referee sees red...

It has been shown that wearing red sports attire has a positive impact on one's outcome in combat sports such as tae kwon do or wrestling. One speculation has been that this is due to an evolutionary or cultural association of the color red with dominance and aggression, with this association triggering a psychological effects (dominance/submission) in the competitors. Hagemann et al. offer evidence that perceptual bias in the referee is the more likely explanation, by showing that when tae kwon do referees watch videos of matches in which the competitors wear either read or blue protective gear:

The competitor wearing red protective gear was awarded an average of 13% (0.94 points) more points than the competitor wearing blue protective gear. The number of points awarded increased for a blue competitor who was digitally transformed into a red competitor, and decreased for a red competitor who was digitally transformed into a blue competitor.

Culture shapes how we look at faces.

Studies of eye movements have persistently revealed a systematic triangular sequence of fixations over the eye and the mouth, with dominance to the eyes, suggesting that the presence of a face triggers a universal, biologically-determined information extraction pattern. However, the literature is based on observations with adults from Western cultures only. Blais et al. have monitored the eye movements of Western Caucasian and East Asian observers while they learned, recognized, and categorized by race Western Caucasian and East Asian faces. Western Caucasian observers reproduced a scattered triangular pattern of fixations for faces of both races and across tasks. Contrary to intuition, East Asian observers focused more on the central region of the face. The work suggests that face processing does not rise from a universal sequence of perceptual events, but rather that the strategy employed to extract visual information from faces differs across cultures.

Sleep preferentially enhances our emotional memories

Interesting observations from Payne et al. Sleep can preserve our memory of negative objects seen and then forgotten during the day, but not the background in which they originally appeared :

Central aspects of emotional experiences are often well remembered at the expense of background details. Previous studies of such memory trade-offs have focused on memory after brief delays, but little is known about how these components of emotional memories change over time. We investigated the evolution of memory for negative scenes across 30 min, 12 daytime hours spent awake, and 12 nighttime hours including sleep. After 30 min, negative objects were well remembered at the expense of information about their backgrounds. Time spent awake led to forgetting of the entire negative scene, with memories of objects and their backgrounds decaying at similar rates. Sleep, in contrast, led to a preservation of memories of negative objects, but not their backgrounds, a result suggesting that the two components undergo differential processing during sleep. Memory for a negative scene develops differentially across time delays containing sleep and wake, with sleep selectively consolidating those aspects of memory that are of greatest value to the organism.

Our body language of pride and shame is innate

Tracy and Matsumoto have performed an interesting cross cultural study of nonverbal displays of pride and shame in sighted, blind, and congenitally blind individuals:

The research examined whether the recognizable nonverbal expressions associated with pride and shame may be biologically innate behavioral responses to success and failure. Specifically, we tested whether sighted, blind, and congenitally blind individuals across cultures spontaneously display pride and shame behaviors in response to the same success and failure situations—victory and defeat at the Olympic or Paralympic Games. Results showed that sighted, blind, and congenitally blind individuals from >30 nations displayed the behaviors associated with the prototypical pride expression in response to success. Sighted, blind, and congenitally blind individuals from most cultures also displayed behaviors associated with shame in response to failure. However, culture moderated the shame response among sighted athletes: it was less pronounced among individuals from highly individualistic, self-expression-valuing cultures, primarily in North America and West Eurasia. Given that congenitally blind individuals across cultures showed the shame response to failure, findings overall are consistent with the suggestion that the behavioral expressions associated with both shame and pride are likely to be innate, but the shame display may be intentionally inhibited by some sighted individuals in accordance with cultural norms.


Mean levels of pride and shame nonverbal behaviors spontaneously displayed in response to match wins and losses by congenitally blind athletes.

MindBlog strikes it rich...

Here is the result of the little box of Google adds that I let run in the left column of this blog starting a little over a year ago. They send you a check after your cut of the revenue from clicks on the advertisements reaches $100. I guess I had better not quit my day job (being a retired professor).

Subjective/Objective - applying real-time fMRI

R. Christopher deCharms offers an interesting review article on exploring the mind-body interface with neuroimaging. Here is the abstract, followed by one figure. The PDF is here.

For centuries people have aspired to understand and control the functions of the mind and brain. It has now become possible to image the functioning of the human brain in real time using functional MRI (fMRI), and thereby to access both sides of the mind–brain interface — subjective experience (that is, one's mind) and objective observations (that is, external, quantitative measurements of one's brain activity) — simultaneously. Developments in neuroimaging are now being translated into many new potential practical applications, including the reading of brain states, brain–computer interfaces, communicating with locked-in patients, lie detection, and learning control over brain activation to modulate cognition or even treat disease.


a) Descartes used introspection as a way to perceive the mechanisms of the mind. This approach to observing the mind–brain interface is what people were limited to in the absence of technology. b) Today, using real-time functional MRI, it is possible to measure the level of activation from approx216 brain locations per second. Here, measured activation levels are represented as colours that have been overlaid onto a three-dimensional rendered set of anatomical brain images. c) Information from individual spatial points can be segregated into multiple anatomically defined three-dimensional regions of interest. Here the activation levels (represented as colours) of three brain regions are rendered on a translucent 'glass brain' view. d) Activation in these regions can either be plotted second-by-second in real time or can be presented to subjects in more abstract forms, such as this virtual-reality video display of a beach bonfire, in which each of the three elements of the flickering fire corresponds to activation in a particular brain region. Brain activation can control arbitrarily complex elements of computer-generated scenarios.

Predictability determines whether our attention fades away.

A universal feature of our sensory systems (vision, audition, touch, etc.) is that they adapt, or habituate, to a repeated stimulus - their reporting grows weaker. The common view is that this decrement in response is due largely to automatic processes in sensory neurons. Doing fMRI measurements of cortical responses to photographs of sequentially displayed faces, Summerfield et al. find evidence of a further 'top-down' mechanism for repetition suppression:

By manipulating the likelihood of stimulus repetition, we found that repetition suppression in the human brain was reduced when stimulus repetitions were improbable (and thus, unexpected). Our data suggest that repetition suppression reflects a relative reduction in top-down perceptual 'prediction error' when processing an expected, compared with an unexpected, stimulus.

Vasopressin receptor genes of philandering men

Wow, this little item went from online publications by Proc. Nat. Acad. Sci. yesterday straight to the NBC evening news I watched last night. We were bound eventually to find out that what's true for randy male prairie voles is also true for human males. Walum et al:

Pair-bonding has been suggested to be a critical factor in the evolutionary development of the social brain. The brain neuropeptide arginine vasopressin (AVP) exerts an important influence on pair-bonding behavior in voles. There is a strong association between a polymorphic repeat sequence in the 5′ flanking region of the gene (avpr1a) encoding one of the AVP receptor subtypes (V1aR), and proneness for monogamous behavior in males of this species. It is not yet known whether similar mechanisms are important also for human pair-bonding. Here, we report an association between one of the human AVPR1A repeat polymorphisms (RS3) and traits reflecting pair-bonding behavior in men, including partner bonding, perceived marital problems, and marital status, and show that the RS3 genotype of the males also affects marital quality as perceived by their spouses. These results suggest an association between a single gene and pair-bonding behavior in humans, and indicate that the well characterized influence of AVP on pair-bonding in voles may be of relevance also for humans.

We can use our visual cortex for touch

Merabet et al. perform the fascinating experiment of simply blindfolding normal subject for five days, during which intensive tactile training is carried out that improves the subjects' ability to read Braille characters. fMRI measurements reveal an increase in visual cortex responses to tactile stimulation during this period, suggesting that a non-visual input to the visual cortex is being unmasked.

...This increase in signal was no longer present 24 hours after blindfold removal. Finally, reversible disruption of occipital cortex function on the fifth day (by repetitive transcranial magnetic stimulation; rTMS) impaired Braille character recognition ability in the blindfold group but not in non-blindfolded controls. This disruptive effect was no longer evident once the blindfold had been removed for 24 hours.

Overall, our findings suggest that sudden and complete visual deprivation in normally sighted individuals can lead to profound, but rapidly reversible, neuroplastic changes by which the occipital cortex becomes engaged in processing of non-visual information. The speed and dynamic nature of the observed changes suggests that normally inhibited or masked functions in the sighted are revealed by visual loss. The unmasking of pre-existing connections and shifts in connectivity represent rapid, early plastic changes, which presumably can lead, if sustained and reinforced, to slower developing, but more permanent structural changes, such as the establishment of new neural connections in the blind.

Updating our memory requires its original context.

Here is some fascinating work by Hupbach et. al. A clip from a Science Magazine summary:

Recent research has shown that reactivating apparently stable memories can render them fragile and open to modification and to another round of stabilization in a process called reconsolidation. Hupbach et al. explored the conditions leading to the updating of episodic memory. They found that memory plasticity at reactivation provides a mechanism for updating memories, and that the latter are determined by the spatial context; that is, the "where" of episodic memory. Only when the memory was reactivated in the same context as when it was learned could new learning be incorporated into the existing store of knowledge; if reactivated in a new context, no updating occurred.

The abstract of the work:

Understanding the dynamics of memory change is one of the current challenges facing cognitive neuroscience. Recent animal work on memory reconsolidation shows that memories can be altered long after acquisition. When reactivated, memories can be modified and require a restabilization (reconsolidation) process. We recently extended this finding to human episodic memory by showing that memory reactivation mediates the incorporation of new information into existing memory. Here we show that the spatial context plays a unique role for this type of memory updating: Being in the same spatial context during original and new learning is both necessary and sufficient for the incorporation of new information into existing episodic memories. Memories are automatically reactivated when subjects return to an original learning context, where updating by incorporating new contents can occur. However, when in a novel context, updating of existing memories does not occur, and a new episodic memory is created instead.

The neural correlates of desire...

Kawabata and Zeki show that categorizing any stimulus according to its desirability activates three different brain areas: the superior orbito-frontal, the mid-cingulate, and the anterior cingulate cortices. The article has the usual pretty fMRI pictures. (Now - if we could just get a fix on the areas active in desire's satiation and avoid all the fuss of real life by just stimulating them directly!)

Predicting the choices of undecided voters - the unseen mind

Not to much of a surprise, but voters who declare themselves to be undecided may be fooling themselves, and are actually unconsciously biased towards one of the choices presented. As Wilson and Bar-Anan point out in their review of the work of Galdi et al.

Social psychologists have discovered an adaptive unconscious that allows people to size up the world extremely quickly, make decisions, and set goals--all while their conscious minds are otherwise occupied. The human mind operates largely out of view of its owners, possibly because that's the way it evolved to work initially, and because that's the way it works best, under many circumstances. Without such an efficient, powerful, and fast means of understanding and acting on the world, it would be difficult to survive. We would be stuck pondering every little decision, such as whether to put our left or right foot forward first, as the world sped by (2-7). But as a result, we are often strangers to ourselves, unable to observe directly the workings of our own minds.

Confabulation. As in this drawing by Saul Steinberg, people construct images of themselves. In real life, people do not realize that their self-knowledge is a construction, and fail to recognize that they possess a vast adaptive unconscious that operates out of their conscious awareness.

Here is the abstract of Galdi et al. that supports this picture using computer-based measures that assess implicit attitudes and traits:

Common wisdom holds that choice decisions are based on conscious deliberations of the available information about choice options. On the basis of recent insights about unconscious influences on information processing, we tested whether automatic mental associations of undecided individuals bias future choices in a manner such that these choices reflect the evaluations implied by earlier automatic associations. With the use of a computer-based, speeded categorization task to assess automatic mental associations (i.e., associations that are activated unintentionally, difficult to control, and not necessarily endorsed at a conscious level) and self-report measures to assess consciously endorsed beliefs and choice preferences, automatic associations of undecided participants predicted changes in consciously reported beliefs and future choices over a period of 1 week. Conversely, for decided participants, consciously reported beliefs predicted changes in automatic associations and future choices over the same period. These results indicate that decision-makers sometimes have already made up their mind at an unconscious level, even when they consciously indicate that they are still undecided.

A 'training of the conscious by the unconscious' is suggested by the observation that the conscious beliefs of the decided voters, which, at the first question period, showed no correlation with their automatic or implicit preferences, did, in fact, predict their implicit preferences during the second session. This suggests that the interaction between unconscious and conscious cognition is a two-way street.

Update on my "Biology of Mind" book - an ebook version

I had an email exchange yesterday with Michiel, in the Netherlands, who has now formatted the web version of my Biology of Mind book as a Sony-formatted file and also as raw HTML for conversion to whatever format you prefer. These are now posted at the mobileread site. (Here is the HTML version which you can simply download, un-zip, and drag into your web browser's window.) In the process, Michiel cleaned up some background noise in the illustrations, and I have placed his improved figures in my website's version of the book. I am most grateful to him for what was a rather major effort.

Ability to use symbols appeared 35 million years ago?

Humans are sometimes said to be distinguished as "The Symbolic Species." A Research Highlights note in Nature point to the work of Addessi et al., who show that capuchin monkeys, who diverged from the human lineage ~35 million years ago, can be trained to use and assign value to tokens (symbols) for different items of food.

...Elsa Addessi of the CNR, Italy's national research council, and her colleagues trained five monkeys to associate a particular token — such as a green chip, black plastic tube or a brass hook — with one of three specific types of food. They then gave the monkeys a series of choices, each time between different amounts of two food items or between two types of token...The value the monkeys assigned to a token was very similar to the value they gave to the food it represented, which suggests that the animals weighed up both real and symbolic options in an equivalent manner.

Cultural evolution in the laboratory

Kirby et al. offer experimental validation for the idea that cultural transmission can lead to the appearance of design without a designer. The abstract is below, and the experimental design best appreciated by examining the paper here:

We introduce an experimental paradigm for studying the cumulative cultural evolution of language. In doing so we provide the first experimental validation for the idea that cultural transmission can lead to the appearance of design without a designer. Our experiments involve the iterated learning of artificial languages by human participants. We show that languages transmitted culturally evolve in such a way as to maximize their own transmissibility: over time, the languages in our experiments become easier to learn and increasingly structured. Furthermore, this structure emerges purely as a consequence of the transmission of language over generations, without any intentional design on the part of individual language learners. Previous computational and mathematical models suggest that iterated learning provides an explanation for the structure of human language and link particular aspects of linguistic structure with particular constraints acting on language during its transmission. The experimental work presented here shows that the predictions of these models, and models of cultural evolution more generally, can be tested in the laboratory.