The five "most popular" consciousness papers for August 2007

I pass on the report from the ASSC (Assoc. for Sci. Study of Cons.) of the papers most downloaded from their eprint archives in August:

1. Mashour, George A. (2007) Inverse Zombies, Anesthesia Awareness, and the
Hard Problem of Unconsciousness. In: 11th Annual Meeting of the ASSC, Las
Vegas.
(936 downloads from 21 countries). http://eprints.assc.caltech.edu/294/
2. Windt, Jennifer Michelle and Metzinger, Thomas (2006) The philosophy of
dreaming and self-consciousness: What happens to the experiential subject
during the dream state? In: The new science of dreaming (928 downloads from
19 countries). http://eprints.assc.caltech.edu/200/
3. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge handbook
of consciousness. CUP (801 downloads from 18 countries)
http://eprints.assc.caltech.edu/175/
4. Rosenthal, David (2007) Consciousness and its function. In: 11th annual
meeting of the Association for the Scientific Study of Consciousness, 22-25
June 2007, Las Vegas, USA. (741 downloads from 19 countries).
http://eprints.assc.caltech.edu/293/
5. Rosen, Alan and Rosen, David B. (2006) The Design of a
Sensation-generating Mechanism in the Brain: A first step towards a
quantitative definition of consciousness. Consciousness and Cognition,
CONCOG-06-00174 (596 downloads from 18 countries).
http://eprints.assc.caltech.edu/195/

Mind Over Manual

This is the title of an Op-Ed piece in the 9/13/2007 NY Times by Sally Satel which describes the difficulties and issues faced by the forthcoming revision (due in 2012) of the Diagnostic and Statistical Manual of Mental Disorders (PDF here). It faces issue such as the 40-fold jump in diagnosis of childhood bipolar disorder from 1994 to 2003. Some clips from the article:

We still don’t know how much of this increase represents long-overdue care of mentally ill youth and how much comes from facile labeling of youngsters who are merely irritable and moody...Part of the confusion stems from the lack of a discrete definition of juvenile bipolar illness in the diagnostic manual. But there is a deeper problem: despite the great progress being made in neuroscience, we still don’t have a clear picture of the brain mechanisms underlying bipolar illness — or most other mental illnesses... many patients meet several diagnostic definitions at once. Roughly half of adults with clinical depression, for example, also have symptoms that fit the definition of an anxiety disorder...the link between diagnosis and treatment is relatively weak. Antidepressants like Prozac help treat not only depression but also panic disorder, obsessive-compulsive disorder, bulimia and social phobia. This explains why clinicians often treat by symptom rather than diagnosis. Paranoia, for example, is treated with an antipsychotic drug whether it occurs in the context of schizophrenia, bipolar illness or methamphetamine use.

An updated manual..is unlikely to transform treatment substantially — after all, revising diagnoses is still just another way to describe mental conditions we don’t fully understand. But these refinements may well stimulate valuable new inquiry, enabling swifter progress in understanding the mechanisms of disease, better deployment of treatments we have and more efficient discovery of new ones.

Walking the Walk

A new study of human locomotion shows a pattern of changes in independent neural controllers for left and right legs. Here is the abstract from Choi and Bastian and a summary figure from the review by Miall.

Human walking is remarkably adaptable on short and long timescales. We can immediately transition between directions and gait patterns, and we can adaptively learn accurate calibrations for different walking contexts. Here we studied the degree to which different motor patterns can adapt independently. We used a split-belt treadmill to adapt the right and left legs to different speeds and in different directions (forward versus backward). To our surprise, adults could easily walk with their legs moving in opposite directions. Analysis of aftereffects showed that walking adaptations are stored independently for each leg and do not transfer across directions. Thus, there are separate functional networks controlling forward and backward walking in humans, and the circuits controlling the right and left legs can be trained individually. Such training could provide a new therapeutic approach for correcting various walking asymmetries.

Four neural systems are postulated, controlling forward (FW) and backward (BW) walking in left and right legs.
(a) In forward split-belt training, indicated by the dashed box, the right belt is faster than the left, inducing relative changes in the left and right forward-walking circuits (dotted circles). When walking on the tied-belt was tested after adaptation, an aftereffect was seen in forward walking, but not in backward walking. (b,c) In hybrid adaptive walking (b, diagonal dashed box), the left leg is on the slow backward belt and the right leg on the fast forward belt. This induced changes that were evident as aftereffects in both forward and backward walking, and that were compatible with this model of four functionally separate controllers, but were incompatible with a model (c, arrows) in which functional connections between these controllers are modified by learning.

Roles of parietal and prefrontal cortex in working memory

Champod and Petrides distinguish monitoring and manipulation tasks carried out by working memory and demonstrate different brain correlates. Their abstract, and a figure:

Numerous functional neuroimaging studies reported increased activity in the middorsolateral prefrontal cortex (MDLFC) and the posterior parietal cortex (PPC) during the performance of working memory tasks. However, the role of the PPC in working memory is not understood and, although there is strong evidence that the MDLFC is involved in the monitoring of information in working memory, it is also often stated that it is involved in the manipulation of such information. This event-related functional magnetic resonance imaging study compared brain activity during the performance of working memory trials in which either monitoring or manipulation of information was required. The results show that the PPC is centrally involved in manipulation processes, whereas activation of the MDLFC is related to the monitoring of the information that is being manipulated. This study provides dissociation of activation in these two regions and, thus, succeeds in further specifying their relative contribution to working memory.

Figure: Activity in the manipulation minus monitoring and in the monitoring minus manipulation comparisons. Cortical surface renderings in standard stereotaxic space of a subject's brain are shown on the left. (a) Increased activity in the left IPS obtained from the manipulation minus monitoring comparison. The vertical blue line on the left hemisphere cortical surface rendering indicates the anteroposterior level of the coronal section illustrated on the right. (b) Increased activity in the right MDLFC obtained from the monitoring minus manipulation comparison. The vertical green line on the right hemisphere cortical surface rendering indicates the anteroposterior level of the coronal section illustrated on the right side. CS, central sulcus; PoCS, postcentral sulcus; PCS, precentral sulcus; SFS, superior frontal sulcus; IFS, inferior frontal sulcus; MFS, middle frontal sulcus.

The obsession with inhibiting aging...

Coming upon the website of the Methuselah Foundation and the Methuselah Mouse prize begins to bring out the curmudgeon in me. I'm fine with prolonging vitality thought better understanding of the chemistry of aging (check out BrainReady.com, and previous lists of anti-aging sites I've put on the blog, check blog category "aging"), but fantasies about immortality strike me a pure hubris. Contra Dylan Thomas, I think we bloody ought to go gently into that good night, once we've done a good turn here....

Daytime sleep consolidates motor memory

Here is the abstract from Korman et al. :

Two behavioral phenomena characterize human motor memory consolidation: diminishing susceptibility to interference by a subsequent experience and the emergence of delayed, offline gains in performance. A recent model proposes that the sleep-independent reduction in interference is followed by the sleep-dependent expression of offline gains. Here, using the finger-opposition sequence–learning task, we show that an interference experienced at 2 h, but not 8 h, following the initial training prevented the expression of delayed gains at 24 h post-training. However, a 90-min nap, immediately post-training, markedly reduced the susceptibility to interference, with robust delayed gains expressed overnight, despite interference at 2 h post-training. With no interference, a nap resulted in much earlier expression of delayed gains, within 8 h post-training. These results suggest that the evolution of robustness to interference and the evolution of delayed gains can coincide immediately post-training and that both effects reflect sleep-sensitive processes.

And here is a graphic summarizing the results from the review by Diekelmann and Born:

Two ways of consolidating memory of finger tapping skill.
(a) Evolution of finger-to-thumb tapping skill under three experimental key conditions. From top to bottom: after training a specific sequence (Sequence A) in the morning and a first retest 8 h later, a distinct gain in performance developed at the second retest following overnight sleep (purple). Interference by training on a different sequence (Sequence B) 2 h after training of Sequence A completely abolished any sleep-dependent overnight gain developing between the first and second retest (blue). This overnight gain was restored when subjects napped for 90 min between training of Sequence A and interference training on Sequence B (green). (b) Model of skill memory consolidation. Representations of finger tapping skill are encoded in a temporary store. Stabilization (resistance to interference) of the representation can be achieved either through time-dependent synaptic consolidation (dark green) in the temporary buffer or through sleep-dependent system consolidation (red) that leads to a redistribution of the representation to different neuronal networks for long-term storage. Memory enhancement (delayed gains in performance) requires sleep-dependent system consolidation.

Fly brains/Human brains - similarities in sleep induction

Some membrane signaling pathways important in initiating sleep appeared in a common ancestor of humans and insects! Here is the abstract from Foltenyi et al. (the pathways are complicated, but you can get the over all idea):

Epidermal growth factor receptor (EGFR) signaling in the mammalian hypothalamus is important in the circadian regulation of activity. We have examined the role of this pathway in the regulation of sleep in Drosophila melanogaster. Our results demonstrate that rhomboid (Rho)- and Star-mediated [ed. note - these are proteases] activation of EGFR and ERK signaling increases sleep in a dose-dependent manner, and that blockade of rhomboid (rho) expression in the nervous system decreases sleep. The requirement of rho for sleep localized to the pars intercerebralis, a part of the fly brain that is developmentally and functionally analogous to the hypothalamus in vertebrates. These results suggest that sleep and its regulation by EGFR signaling may be ancestral to insects and mammals.

And a graphic from the review by Colwell:

Proposed role of extracellular signal–regulated kinase (ERK) in the regulation of sleep in Drosophila.
(a) Rho-mediated activation of ERK signaling increases sleep duration. During the night, Rho activation in the pars intercerebralis (PI) leads to the production and secretion of an EGFR ligand. The resulting phosphorylation of EGFR activates ERK in the tritocerebrum (TriC). Although the final targets of this signaling pathway are not known, the phosphorylated ERK seems to stay in the processes of the TriC neurons and may well regulate electrical activity and synaptic transmission in these neurons. (b) During wakefulness, Rho signaling in the PI is proposed to be downregulated, resulting in basal levels of ERK signaling. Inhibition of Rho expression in PI neurons results in decreased sleep levels, with short, fragmented sleep bouts. This observation suggests that these mutant flies have an increased need for sleep but are unable to stay asleep (making them a fly model of insomnia).

This week's music - Rachmaninoff Trio Elegiaque no. 1

Sonny Enslen (cello), Daphne Tsao (violin) and I are doing a final rehearsal of this Rachmaninoff Elegy before performing it for a local music group.

Do you have absolute pitch?

Curious that I came across this article, just after a post on Pavoratti's High C. From Athos et al.

Absolute pitch (AP) is the rare ability to identify the pitch of a tone without the aid of a reference tone. Understanding both the nature and genesis of AP can provide insights into neuroplasticity in the auditory system. We explored factors that may influence the accuracy of pitch perception in AP subjects both during the development of the trait and in later age. We used a Web-based survey and a pitch-labeling test to collect perceptual data from 2,213 individuals, 981 (44%) of whom proved to have extraordinary pitch-naming ability. The bimodal distribution in pitch-naming ability signifies AP as a distinct perceptual trait, with possible implications for its genetic basis. The wealth of these data has allowed us to uncover unsuspected note-naming irregularities suggestive of a "perceptual magnet" centered at the note "A." In addition, we document a gradual decline in pitch-naming accuracy with age, characterized by a perceptual shift in the "sharp" direction. These findings speak both to the process of acquisition of AP and to its stability.

From a commentary by Drayna in the same issue of PNAS:

Absolute pitch is an especially tantalizing trait for genetic analysis. It has an onset early in life, it occurs equally in males and females, it is highly heritable, it is rare in the population, and it appears to be nonsyndromic, that is, unassociated with other conditions. All of these features bode well for the prospects of gene finding. However, unlike most inherited neurological conditions for which affected individuals present themselves to a medical specialist, AP individuals and families have not been easily ascertained. The demonstration by Athos et al. that a web site can be an effective tool for identifying, testing, and recruiting AP subjects is an important development. The identification of the genetic variation that leads to AP is likely to tell us much about a part of the auditory system that is currently obscure, and the results of Athos et al. are indeed encouraging in this quest.

Pavarotti's high C

I'm an opera buff, and can be reduced to a puddle by beautiful singing. Thus I pass on some clips from an essay by Daniel Wakin (PDF here) on the passing of Luciano Pavarotti, regarded as the king of the High C's:

His voice, especially earlier in his career, was remarkable across its range. But that little note, an octave above middle C on the piano, played a role in projecting Mr. Pavarotti’s fame around the world. That is no surprise. The tenor high C has a long and noble tradition, and a healthy dose of mystique...Tenor high C’s are scattered throughout the opera literature. Sometimes tenors transpose the aria down slightly or drop an octave, other times they fake it and edge into falsetto voice, where it is easier to sing. Just as often, they hit it, and hold it, and that moment is one of the most exciting in an opera house. It is moments like those when opera, in addition to the aesthetic joys and emotional satisfactions, can seem like a spectator sport or a circus high-wire act. They’re times when opera audiences cheer or jeer.

But the high C has a more visceral, spine-tingling lure...“The reason it’s so exciting to people is, it’s based on the human cry,” said Maitland Peters, chairman of the voice department at the Manhattan School of Music. “It’s instinctual. It’s like a baby. You’re pulled into it.” When a tenor sings a ringing high C, it seems, “there’s nothing in his way,” Mr. Peters said...The pitch, in itself, has a satisfying quality. The key of C major, after all, is a stable, cheerful, happy key, the one with no sharps or flats.

Sigmund Freud revising his views on religion...

Mark Edmundson offers an essay in the NY Times of 9/9/2007 (PDF here)on the legacy of Freud's last days that I found fascinating. Without renouncing his atheism, Freud describes in a controversial book on Moses what he sees as some useful consequences of the Jewish faith. Here are some clips from the essay:

About two-thirds of the way into the volume, he makes a point that is simple and rather profound — the sort of point that Freud at his best excels in making. Judaism’s distinction as a faith, he says, comes from its commitment to belief in an invisible God, and from this commitment, many consequential things follow. Freud argues that taking God into the mind enriches the individual immeasurably. The ability to believe in an internal, invisible God vastly improves people’s capacity for abstraction. “The prohibition against making an image of God — the compulsion to worship a God whom one cannot see,” he says, meant that in Judaism “a sensory perception was given second place to what may be called an abstract idea — a triumph of intellectuality over sensuality.”

Freud speculates that one of the strongest human desires is to encounter God — or the gods — directly. We want to see our deities and to know them. Part of the appeal of Greek religion lay in the fact that it offered adherents direct, and often gorgeous, renderings of the immortals — and also, perhaps, the possibility of meeting them on earth. With its panoply of saints, Christianity restored visual intensity to religion; it took a step back from Judaism in the direction of the pagan faiths. And that, Freud says, is one of the reasons it prospered.

If people can worship what is not there, they can also reflect on what is not there, or on what is presented to them in symbolic and not immediate terms. So the mental labor of monotheism prepared the Jews — as it would eventually prepare others in the West — to achieve distinction in law, in mathematics, in science and in literary art. It gave them an advantage in all activities that involved making an abstract model of experience, in words or numbers or lines, and working with the abstraction to achieve control over nature or to bring humane order to life. Freud calls this internalizing process an “advance in intellectuality,” and he credits it directly to religion.

Freud’s argument suggests that belief in an unseen God may prepare the ground not only for science and literature and law but also for intense introspection. Someone who can contemplate an invisible God, Freud implies, is in a strong position to take seriously the invisible, but perhaps determining, dynamics of inner life. He is in a better position to know himself. To live well, the modern individual must learn to understand himself in all his singularity. He must be able to pause and consider his own character, his desires, his inhibitions and values, his inner contradictions. And Judaism, with its commitment to one unseen God, opens the way for doing so. It gives us the gift of inwardness.

It seems to me that the same points could be made about Buddhism and other eastern religions.

Mind-Set matters: More on contruals and the placebo effect altering physiology and perfomance

I am grateful to a blog reader for pointing out an article that adds to one of the threads in this blog, how brief interventions with a small amount of information can alter performance in striking ways. Two previous posts have mentioned how such information can alter math related gender differences and racial achievement gaps. Here is more on how, by altering the stories we tell ourselves, we can fundamentally change our physiology and our performace: Crum and Langer report in Psychological Science (PDF here) that the relationship between exercise and health can be altered by offering a bit of information that changes how exercise is regarded. Here is their abstract:

In a study testing whether the relationship between exercise and health is moderated by one's mind-set, 84 female room attendants working in seven different hotels were measured on physiological health variables affected by exercise. Those in the informed condition were told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Surgeon General's recommendations for an active lifestyle. Examples of how their work was exercise were provided. Subjects in the control group were not given this information. Although actual behavior did not change, 4 weeks after the intervention, the informed group perceived themselves to be getting significantly more exercise than before. As a result, compared with the control group, they showed a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index. These results support the hypothesis that exercise affects health in part or in whole via the placebo effect.

A study like this makes you wonder how much of the benefit of physical education regimes like yoga, pilates, etc.- versus just being active - are due to such a placebo effect.

Want to avoid snakes?..Heat your tail.

Prey species have evolved a number of tricks to avoid or deceive predators, involving movement, visual, sound, or smell cues. Now infrared cues get added to the list. Rundus et al. have found that California ground squirrels have evolved a clever trick to deceive snakes, who use infrared (heat) detectors in sizing up their potential prey. The squirrel heats its tail as it shakes it, thus giving off the amount of heat expected from a larger animal and making the snake think that it is larger than it really is. Because larger squirrels are more likely to directly attack snakes, the snake thus is more cautious and less likely to strike.

Neurocognitive correlates of liberalism and conservatism

David Amodio (who got his Ph.D. here at Wisconsin in 2003) is now at NYU, and with a group of collaborators reports on neuronal correlates of political stance (PDF here). Here is their abstract, followed by a bit of text and a figure:

Political scientists and psychologists have noted that, on average, conservatives show more structured and persistent cognitive styles, whereas liberals are more responsive to informational complexity, ambiguity and novelty. We tested the hypothesis that these profiles relate to differences in general neurocognitive functioning using event-related potentials, and found that greater liberalism was associated with stronger conflict-related anterior cingulate activity, suggesting greater neurocognitive sensitivity to cues for altering a habitual response pattern.

In our study, conflict-related ACC activity was indexed by two ERP components. ERPs are scalp-recorded voltage changes reflecting the concerted firing of neurons in response to a psychological event. The response-locked error-related negativity (ERN), which peaks at approximately 50 ms following an incorrect behavioral response, reflects conflict between a habitual tendency (for example, the Go response) and an alternative response (for example, to inhibit behavior in response to a No-Go stimulus. We also examined the No-Go N2 component, which is believed to reflect conflict-monitoring activity associated with the successful inhibition of the prepotent Go response on No-Go trials7. Relationships between political orientation and these neurocognitive indices were examined using correlation analyses (two-tailed).



Figure 1. The relation between political orientation and a neurocognitive index of conflict monitoring.
(a) Political liberalism was associated with larger No-Go error-related negativity (ERN) amplitudes, as indicated by more negative scores, suggesting greater neurocognitive sensitivity to response conflict. (b) ERP waveforms corresponding to No-Go errors, with the waveform for correct Go responses subtracted, are shown for both liberal and conservative participants (response made at 0 ms; ERN peaked at 44 ms postresponse), with the inset showing the voltage map of the scalp distribution of the ERN. (c) Source localization indicates a dorsal anterior cingulate generator for the ERN, computed at peak amplitude (red line in panel b).

In memoriam - Alex the Parrot

Sad news, reported in the Sept. 11 NY Times. Alex the talking parrot passed away of natural causes last week at the age of 31. I have heard Irene Pepperberg (former wife of a vision colleague of mine) give talks about Alex over a 25 year period. Irene taught Alex to learn scores of words, which he could put into categories, and to count small numbers of items, as well as recognize colors and shapes. His cognitive and language skills appeared to be about as competent as those in trained primates, and like them, he showed no evidence of having the recursive logic capabilities required for grammar and working with digital numbers.

Here is a brief video of Alex performing in his prime:

The Blakeslees on the body's own mind...

"The Body Has a Mind of Its Own" is the title of a book being released today, September 11, by Sandra Blakeslee (N.Y.Times Science writer) and her son Matthew Blakeslee (also a science writer, making him the fourth generation of science writers in the family line!). Its subject is the maps that our brain makes of our internal and external worlds, including our feelings, emotions, and sense of self... and how plastic they can be. Much of the work they describe has been the subject of posts on this MindBlog. I enjoyed reading the book, and would highly recommend it. It crams an amazing amount of material into a small space. It is easy to read and engaging.

Here is one of the figures from the book, illustrating how our brain cells adapt to tool use, incorporating the tool into our body image.

How our brain changes when we (or monkeys, as in the figure) use a hand tool to extend our reach. Legend. a) Before learning to use a rake (left) or while passively holding the rake (right) without the intention of using it as a tool, the monkey's hand-centered visual-tacile receptive fields stay confined to the hand's immediate vicinity. But while the monkey is actively wielding the rake (center), the cells' visual receptive fields expand along its length. (Visual or tactile input to the shaded area causes a hand-centered cell in the parietal lobe to fire.) b). The visual-tacile receptive field expansion of one of the monkey's shoulder-centered neurons.

These positive points having been made, I felt during my reading like I was looking over the authors' shoulders as they were writing, and I kept wanting to suggest that the presentation be tightened up with more bottom lines brought up front. Many times I had the "Ah Ha!, why didn't they tell me THIS is where they were going" experience. With one study after another thrown onto the page I found myself loosing the thread. When I did find an interesting nugget I had not be aware of, I was frustrated by the fact that there is no bibliography or list of references provided. It would be very useful for the authors to provide such references on a website associated with the book.

There are many excellent summaries and quotable passages in the book. I like the ending paragraphs, which follow a discussion of the neural correlates of our sense of self, and how distortions in our sense of ownership can occur. A few clips:

So, is the self ultimately "just" an illusion?...According to the neuroscience of body maps - and incidentally, the majority of Eastern religions - in many respects, yes...A key point is that your mind feels like a seamless whole when "all your faculties" are working. But if your body mandala were to go on the fritz in one of a hundred ways, whether through damage to one map or several, or through a severing of between-map connections, you might suddenly experience extra arms, a phantom leg...hemineglect (where half the universe winks out of your awareness), alien hand syndrome, and all manner of delusions and misperceptions. Case studies of brain damage like these are one of the biggest philosophical, not to mention logical, arguments against the idea of a uniatry psychic core. When certain parts of the brain break, certain parts of the mind break; the illusion is spoiled, and the underlying multifariousness of the psyche is exposed......The illusion of the self is that self is a kernel, rather than a distributed, emergent system....Localizations of psychic functions are better said to exist in loops of information processing, or circuits, rather than specific points...the...psychic self...is an orchestra without a conductor or a fixed score, but whose players are so good at collaborative improv that wonderful music keeps flowing out of it. Just as the orchestra has no score and no conductor, the mind has no kernel, no "little man" sitting at the center of the fray directing the action. But it is teeming with noncentral "little men," the brain's motley team of homunculi, who form the backbone of the whole production. And you, thankfully, have the irreducible illusion of being the conductor of yours life's music in all its complexity, emotional nuace, crescendo and diminuendo - the ballad that is the you-ness of you."

This week's music: Beethoven violin/piano sonata no. 3

Daphne Tsao (violin) and I are doing a final rehearsal before playing this piece for two amateur musical performance groups in Madison, Wisconsin: Carnaval and Allegro. This is Beethoven sonata no. 3 for violin and piano, the first movement.

The smell of an alpha male....

Pheromones influence sexual behavior and reproduction in rodents. Mak et al report that:

...the pheromones of dominant (but not subordinate) males stimulate neuronal production in both the olfactory bulb and hippocampus of female mice, which are independently mediated by prolactin and luteinizing hormone, respectively. Neurogenesis induced by dominant-male pheromones correlates with a female preference for dominant males over subordinate males, whereas blocking neurogenesis with the mitotic inhibitor cytosine arabinoside eliminated this preference. These results suggest that male pheromones are involved in regulating neurogenesis in both the olfactory bulb and hippocampus, which may be important for female reproductive success.

I keep wondering if we won't be finding evidence for a version of this effect (perhaps more subtle) in humans... would the cheerleader, like the female rat in the box below, be more likely to hang out with the star quarterback if she had smelled his sweaty jersey a day earlier??

An illustration from the summary review by DiRocco and Xia:

Figure legend: Dominant male pheromones stimulate neurogenesis in females.
(a) Female mice exposed to dominant male pheromones spent more time sniffing the dominant male, whereas females exposed to subordinate male pheromones did not show any preference. (b) Exposing female mice to pheromones from dominant males led to increased neurogenesis in the subventricular zone (SVZ) and dentate gyrus (DG). Pheromones signal the main olfactory epithelium (MOE)–main olfactory bulb (MOB) axis, which relays the signal to the hypothalamus (HYP)–pituitary (PIT) axis, leading to the release of luteinizing hormone (LH) and prolactin (PRL). LH appeared to stimulate neurogenesis in the dentate gyrus of the hippocampus, whereas prolactin induced neurogenesis in the SVZ and MOB. It is hypothesized that pheromone-induced neurogenesis may underlie female mating preference for the dominant male. NC, nasal cavity; RMS, rostral migratory stream; green circles, newborn neurons.

Mistakes were made...Cognitive Dissonance Theory

William Swann reviews the book by Tavris and Aronson "Mistakes Were Made (But Not By Me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts." On cognitive dissonance theory:

..the authors' version is that people's brains are wired to find consistency between what they do and their positive images of themselves. Presumably this is why people engage in a wide array of mental gymnastics to salvage their self-esteem rather than own up to their mistakes. The typical outcome is that people twist the truth to make it seem kinder or more flattering than it actually is. In extreme cases, they may engage in distortion and denial of objective reality...dissonance theory can explain many laboratory findings and elements of many naturally occurring phenomena. For example, the authors maintain that when ordinary people blithely agreed to administer dangerously strong electric shocks to hapless learners in Stanley Milgram's classic experiments, the subjects' penchant for self-justification ("the experimenter told me to continue") was a key contributor to their complicity. Similarly, in instances in which prosecutors have refused to back down when DNA evidence has revealed that a defendant was wrongfully sentenced for a crime, Tavris and Aronson attribute theprosecutors' refusal to admit error to pernicious self-justification processes. The authors also maintain that most champions of the repressed-memory movement, when confronted with information suggesting that the "memories" of alleged victims are false, simply dismiss the evidence as being a form of backlash against child victims and incest survivors...As the book's title suggests, one of the topics touched on is contemporary politics. Tavris and Aronson mention in the endnotes that many U.S. presidents have used the phrase "mistakes were made," including Bill Clinton, Ronald Reagan and Richard Nixon. Although Alberto Gonzales's use of the phrase a few months ago ("I acknowledge that mistakes were made here") occurred too recently to make it into the book, the authors do discuss some of the self-justifications and self-deceptions of the current administration. For example, they characterize George W. Bush as "the poster boy for 'tenacious clinging to a discredited belief.'"

The evil that men do - The Lucifer Effect

Robert Levine reviews the recent book "The Lucifer Effect: Understanding How Good People Turn Evil," by Philip Zimbardo, the man who did the famous Stanford Prison Experiment that has become a cornerstone of social psychology (PDF of review here).

The 1971 Stanford Prison Experiment, in which subjects (ordinary college-age men) were assigned to play the role of a prisoner or guard, demonstrated that situations may be more powerful than personality traits in affecting behavior. Subjects playing the role of guards in the Stanford Prison Experiment were quickly transformed into abusers. This scene eerily evokes the photos taken decades later by the guards at Abu Ghraib prison in Iraq.

A clip from the review:

What, Zimbardo asks, leads ordinary people to do bad things, things they never would have imagined doing? Most evildoing, it becomes depressingly clear, is driven by rather ordinary social-psychological reactions. Zimbardo offers an extensive list and discussion of the toxic situational forces and normal psychological reactions to them that tend to activate the Lucifer effect. He provides a detailed, intelligent and workable program for resisting unwanted social influence, highlighting dangers and offering tangible prescriptions for neutralizing negative effects. There are, for example, mini-tutorials on how to distinguish between just and unjust authorities, on being careful not to sacrifice one's freedom for the illusion of security, and on learning to recognize when, where and how to stand up to unjust systems.

The final chapter is a gem. Here Zimbardo seamlessly demonstrates how the same social psychology that may exploit our worst instincts can be reconstrued to cultivate the best in ourselves. Altruism, like evil, is readily responsive to situational forces, and Zimbardo suggests strategies for tapping into these potentialities. He also presents a provocative, multidimensional taxonomy of heroism that I hope will stimulate long-overdue research and education in this area.