Hearing with both your skin and your ears

Gick and Derrick offer a fascinating example of cross modal sensory perception, demonstrating 'aero-tactile' integration in speech perception:

...we show that perceivers integrate naturalistic tactile information during auditory speech perception without previous training. Drawing on the observation that some speech sounds produce tiny bursts of aspiration (such as English 'p'), we applied slight, inaudible air puffs on participants' skin at one of two locations: the right hand or the neck. Syllables heard simultaneously with cutaneous air puffs were more likely to be heard as aspirated (for example, causing participants to mishear 'b' as 'p'). These results demonstrate that perceivers integrate event-relevant tactile information in auditory perception in much the same way as they do visual information.

The syllables included “pa” and “ta,” which produce a brief puff from the mouth when spoken, and “da” and “ba,” which do not produce puffs. When listeners heard “da” or “ba” while a puff of air was blown onto their skin, they perceived the sound as “ta” or “pa.” It seems likely that this integration of different sensory cues is innate, for subjects were completely unaware that they were doing it.

Buttress self esteem - reduce aggression

Here is a fascinating study from Thomaes et al. They conducted a randomized field trial in the Netherlands to assess the efficacy of a brief affirmation exercise designed to buttress self-esteem. Before the intervention, aggressive behavior was prevalent among the individuals who scored high on the narcissism scale and low on self-esteem. Afterward, acts of aggression decreased even though the individual levels of self-esteem (both high and low) were unchanged. Here is the abstract:

Narcissistic individuals are prone to become aggressive when their egos are threatened. We report a randomized field experiment that tested whether a social-psychological intervention designed to lessen the impact of ego threat reduces narcissistic aggression. A sample of 405 young adolescents (mean age = 13.9 years) were randomly assigned to complete either a short self-affirmation writing assignment (which allowed them to reflect on their personally important values) or a control writing assignment. We expected that the self-affirmation would temporarily attenuate the ego-protective motivations that normally drive narcissists' aggression. As expected, the self-affirmation writing assignment reduced narcissistic aggression for a period of a school week, that is, for a period up to 400 times the duration of the intervention itself. These results provide the first empirical demonstration that buttressing self-esteem (as opposed to boosting self-esteem) can be effective at reducing aggression in at-risk youth.

How's Your Gaydar?

From the random samples section of the Nov. 27 issue of Science:

Can you guess a woman's sexual orientation just from her face? Surprisingly, your guess would be better than flipping a coin....Psychologist Nicholas Rule of Tufts University in Medford, Massachusetts, and colleagues asked 21 college students the same question about 192 photos—cropped to eliminate hair and ears—of gay and straight women from dating Web sites. The undergraduates guessed right 64% of the time and scored better than chance—53%—even when they saw only the women's eyes, the researchers report this month in the Journal of Experimental Social Psychology. In 2008, Rule reported similar results with male faces.

The process appears to be unconscious, Rule says. Subjects were more accurate when told to make snap judgments than when they pondered their decisions. Rule believes subtle differences in facial muscles caused by habitual expressions may be the clue. Previous work has shown that homosexuals tend to adopt facial expressions more typical of the opposite sex. The results show that we know much more about others from snippets of information than we realize, says psychologist David Kenny of the University of Connecticut, Storrs.

Here is the abstract from Rule et al.

Whereas previous work has shown that male sexual orientation can be accurately and rapidly perceived from the human face and its individual features, no study has examined the judgment of female sexual orientation. To fill this gap, the current work examined the accuracy, speed, and automaticity of judgments of female sexual orientation from the face and from facial features. Study 1 showed that female sexual orientation could be accurately judged from the face and from just eyes without brows and limited to the outer canthi. Study 2 then examined the speed and efficiency of these judgments, showing that judgments of the faces following very brief, near subliminal (40 ms) exposures were significantly better than chance guessing. Finally, Study 3 tested the automaticity of judgments of female sexual orientation by examining the effects of deliberation on accuracy. Participants who made snap judgments of female sexual orientation were significantly more accurate than participants who made thoughtful and deliberated judgments. These data therefore evidence a robust, reliable, and automatic capacity for extracting information about female sexual orientation from nonverbal cues in the face.

Dietary specialization: man-eating lions

I thought this fascinating bit of work was a hoot. Two famous man-eating lions in the Tsavo region of Kenya were identified and shot in 1989, and these guys analyzed their diet from studies of the isotopes in their bones:

Cooperation is the cornerstone of lion social behavior. In a notorious case, a coalition of two adult male lions from Tsavo, southern Kenya, cooperatively killed dozens of railway workers in 1898. The “man-eaters of Tsavo” have since become the subject of numerous popular accounts, including three Hollywood films. Yet the full extent of the lions' man-eating behavior is unknown; estimates range widely from 28 to 135 victims. Here we use stable isotope ratios to quantify increasing dietary specialization on novel prey during a time of food limitation. For one lion, the δ¹³C and δ¹⁵N values of bone collagen and hair keratin (which reflect dietary inputs over years and months, respectively) reveal isotopic changes that are consistent with a progressive dietary specialization on humans. These findings not only support the hypothesis that prey scarcity drives individual dietary specialization, but also demonstrate that sustained dietary individuality can exist within a cooperative framework. The intensity of human predation (up to 30% reliance during the final months of 1898) is also associated with severe craniodental infirmities, which may have further promoted the inclusion of unconventional prey under perturbed environmental conditions.



The man-eaters of Tsavo and a Taita ancestral shrine. (A) Lieutenant Colonel J. H. Patterson and lion FMNH 23970 shot December 9, 1898 (16) (FMNH photo archives no. z93658, Field Museum of Natural History). (B) Articulated jaws of FMNH 23970 revealing a fractured lower right canine (and subsequent root-tip abscess), missing lower incisors, supererupted upper right incisors, and rotation and malocclusion of the upper right canine. Cranial asymmetry of 23970 occurred after injury and before death. (C) Lion FMNH 23969 shot December 29, 1898. (D) Articulated jaws of FMNH 23969, revealing a fractured upper left carnassial with a double pulp exposure. (E) A Taita ancestral shrine photographed in 1929 by L. S. B. Leakey. Such a shrine results from the unusual funerary practices of the Taita; after approximately 1 year of burial in a seated position, skulls are exhumed, severed, and enshrined in ancestral caves or rock shelters.

Facial plus vocal emotion - watching the brain's enhanced response

From Hagan et al:

An influential neural model of face perception suggests that the posterior superior temporal sulcus (STS) is sensitive to those aspects of faces that produce transient visual changes, including facial expression. Other researchers note that recognition of expression involves multiple sensory modalities and suggest that the STS also may respond to crossmodal facial signals that change transiently. Indeed, many studies of audiovisual (AV) speech perception show STS involvement in AV speech integration. Here we examine whether these findings extend to AV emotion. We used magnetoencephalography to measure the neural responses of participants as they viewed and heard emotionally congruent fear and minimally congruent neutral face and voice stimuli. We demonstrate significant supra-additive responses (i.e., where AV > [unimodal auditory + unimodal visual]) in the posterior STS within the first 250 ms for emotionally congruent AV stimuli. These findings show a role for the STS in processing crossmodal emotive signals.

Dieting, compulsive eating, and brain stress.

An interesting piece from Cottone et al:

Dieting to control body weight involves cycles of deprivation from palatable food that can promote compulsive eating. The present study shows that rats withdrawn from intermittent access to palatable food exhibit overeating of palatable food upon renewed access and an affective withdrawal-like state characterized by corticotropin-releasing factor-1 (CRF1) receptor antagonist-reversible behaviors, including hypophagia, motivational deficits to obtain less palatable food, and anxiogenic-like behavior. Withdrawal was accompanied by increased CRF expression and CRF1 electrophysiological responsiveness in the central nucleus of the amygdala. We propose that recruitment of anti-reward extrahypothalamic CRF-CRF1 systems during withdrawal from palatable food, analogous to abstinence from abused drugs, may promote compulsive selection of palatable food, undereating of healthier alternatives, and a negative emotional state when intake of palatable food is prevented.

Neural architecture of music-evoked autobiographical memories

Interesting work (open access article) from Janata:

The medial prefrontal cortex (MPFC) is regarded as a region of the brain that supports self-referential processes, including the integration of sensory information with self-knowledge and the retrieval of autobiographical information. I used functional magnetic resonance imaging and a novel procedure for eliciting autobiographical memories with excerpts of popular music dating to one's extended childhood to test the hypothesis that music and autobiographical memories are integrated in the MPFC. Dorsal regions of the MPFC (Brodmann area 8/9) were shown to respond parametrically to the degree of autobiographical salience experienced over the course of individual 30 s excerpts. Moreover, the dorsal MPFC also responded on a second, faster timescale corresponding to the signature movements of the musical excerpts through tonal space. These results suggest that the dorsal MPFC associates music and memories when we experience emotionally salient episodic memories that are triggered by familiar songs from our personal past. MPFC acted in concert with lateral prefrontal and posterior cortices both in terms of tonality tracking and overall responsiveness to familiar and autobiographically salient songs. These findings extend the results of previous autobiographical memory research by demonstrating the spontaneous activation of an autobiographical memory network in a naturalistic task with low retrieval demands.

Neural correlates of detecting wrong notes in advance.

I'm always fascinating by studies on the brains of pianists (like myself). This from Ruiz et al:

Music performance is an extremely rapid process with low incidence of errors even at the fast rates of production required. This is possible only due to the fast functioning of the self-monitoring system. Surprisingly, no specific data about error monitoring have been published in the music domain. Consequently, the present study investigated the electrophysiological correlates of executive control mechanisms, in particular error detection, during piano performance. Our target was to extend the previous research efforts on understanding of the human action-monitoring system by selecting a highly skilled multimodal task. Pianists had to retrieve memorized music pieces at a fast tempo in the presence or absence of auditory feedback. Our main interest was to study the interplay between auditory and sensorimotor information in the processes triggered by an erroneous action, considering only wrong pitches as errors. We found that around 70 ms prior to errors a negative component is elicited in the event-related potentials and is generated by the anterior cingulate cortex. Interestingly, this component was independent of the auditory feedback. However, the auditory information did modulate the processing of the errors after their execution, as reflected in a larger error positivity (Pe). Our data are interpreted within the context of feedforward models and the auditory–motor coupling.

Nutrition, brain aging, and neurodegeneration

Joseph et al. offer a review of recent work showing that dietary changes favoring berry fruit, nut, fish oil, and curcumin intake, as well as and caloric restriction mimetics (such as resveratrol) may provide beneficial effects in aging and prevent or delay the onset of neurodegenerative diseases such as Alzheimer disease. While many of the mechanisms for the beneficial effects of these nutritional interventions have yet to be discerned, it is clear that they involve decreases in oxidative/inflammatory stress signaling, increases in protective signaling, and may even involve hormetic effects to protect against the two major villains of aging, oxidative and inflammatory stressors. (Hormetic is a term used to describe generally-favorable biological responses to low exposures to toxins and other stressors.)

The fMRI of understanding others' regret.

Rizzolatti and colleagues carry the mirror neuron story to an even higher level in a study of regret:

Previous studies showed that the understanding of others' basic emotional experiences is based on a “resonant” mechanism, i.e., on the reactivation, in the observer's brain, of the cerebral areas associated with those experiences. The present study aimed to investigate whether the same neural mechanism is activated both when experiencing and attending complex, cognitively-generated, emotions. A gambling task and functional-Magnetic-Resonance-Imaging (fMRI) were used to test this hypothesis using regret, the negative cognitively-based emotion resulting from an unfavorable counterfactual comparison between the outcomes of chosen and discarded options. Do the same brain structures that mediate the experience of regret become active in the observation of situations eliciting regret in another individual? Here we show that observing the regretful outcomes of someone else's choices activates the same regions that are activated during a first-person experience of regret, i.e. the ventromedial prefrontal cortex, anterior cingulate cortex and hippocampus. These results extend the possible role of a mirror-like mechanism beyond basic emotions.

The religious wars

In a NYTimes OpEd piece appropriate to yesterday's Thanksgiving rituals Kristof notes a new crop of books on religion that that he feels are less combative and more thoughtful than extreme fundamentalist (The "Left Behind" novels) or atheist (Dawkins, Harris, Hitchens) efforts.

One of these is “The Evolution of God,” by Robert Wright, who explores how religions have changed — improved — over the millennia. He notes that God, as perceived by humans, has mellowed from the capricious warlord sometimes depicted in the Old Testament who periodically orders genocides...Karen Armstrong’s “The Case for God,” likewise doesn’t posit a Grandpa-in-the-Sky; rather, she sees God in terms of an ineffable presence that can be neither proven nor disproven in any rational sense. To Ms. Armstrong, faith belongs to the realm of life’s mysteries, beyond the world of reason, and people on both sides of the “God gap” make the mistake of interpreting religious traditions too literally...“The Faith Instinct,” by...Nicholas Wade, suggests a reason for the durability of faith: humans may be programmed for religious belief, because faith conferred evolutionary advantages in primitive times. That doesn’t go to the question of whether God exists, but it suggests that religion in some form may be with us for eons to come.

Openness versus conservatism - its cultural evolution

Acerbi et al. ask what might make different groups of people more liberal or conservative (or open minded versus having inflexible views), and develop a model which shows that cultural evolution can maintain openness to new information as well as effectiveness at cultural transmission. They consider how rules of cultural transmission can be modified by social learning. For example, individuals might learn from others whether or not to rely on social information. Their model predicts smaller societies to be more conservative, which agrees with the observation that traditional societies (whose very name implies conservatism) tend to be small. It is consistent with archaeological evidence showing that large cultural repertoires can be maintained only by large groups.

We present a model of cultural evolution in which an individual's propensity to engage in social learning is affected by social learning itself. We assume that individuals observe cultural traits displayed by others and decide whether to copy them based on their overall preference for the displayed traits. Preferences, too, can be transmitted between individuals. Our results show that such cultural dynamics tends to produce conservative individuals, i.e., individuals who are reluctant to copy new traits. Openness to new information, however, can be maintained when individuals need significant time to acquire the cultural traits that make them effective cultural models. We show that a gradual enculturation of young individuals by many models and a larger cultural repertoire to be acquired are favorable circumstances for the long-term maintenance of openness in individuals and groups. Our results agree with data about lifetime personality change, showing that openness to new information decreases with age. Our results show that cultural remodeling of cultural transmission is a powerful force in cultural evolution, i.e., that cultural evolution can change its own dynamics.

Deconstructing the Placebo

I want to point you to this great post at Neuroskeptic. Here is its ending text:

"The placebo effect" has become a vague catch-all term for anything that seems to happen to people when you give them a sugar pill. Of course, lots of things could happen. They could feel better just because of the passage of time. Or they could realize that they're supposed to feel better and say they feel better, even if they don't.

The "true" placebo effect refers to improvement (or worsening) of symptoms driven purely by the psychological expectation of such. But even this is something of a catch-all term. Many things could drive this improvement. Suppose you give someone a placebo pill that you claim will make them more intelligent, and they believe it.

Believing themselves to be smarter, they start doing smart things like crosswords, math puzzles, reading hard books (or even reading Neuroskeptic), etc. But the placebo itself was just a nudge in the right direction. Anything which provided that nudge would also have worked - and the nudge itself can't take all the credit.

The strongest meaning of the "placebo effect" is a direct effect of belief upon symptoms. You give someone a sugar pill or injection, and they immediately feel less pain, or whatever. But even this effect encompasses two kinds of things. It's one thing if the original symptoms have a "real" medical cause, like a broken leg. But it's another thing if the original symptoms are themselves partially or wholly driven by psychological factors, i.e. if they are "psychosomatic".

If a placebo treats a "psychosomatic" disease, then that's not because the placebo has some mysterious, mind-over-matter "placebo effect". All the mystery, rather, lies with the psychosomatic disease. But this is a crucial distinction.

People seem more willing to accept the mind-over-matter powers of "the placebo" than they are to accept the existence of psychosomatic illness. As if only doctors with sugar pills possess the power of suggestion. If a simple pill can convince someone that they are cured, surely the modern world in all its complexity could convince people that they're ill.

Watching our brains judge gain versus pain

Yet another lucidly presented bit of work from a collaboration involving Dolan's group at University College London:

The maxim "no pain, no gain" summarizes scenarios in which an action leading to reward also entails a cost. Although we know a substantial amount about how the brain represents pain and reward separately, we know little about how they are integrated during goal-directed behavior. Two theoretical models might account for the integration of reward and pain. An additive model specifies that the disutility of costs is summed linearly with the utility of benefits, whereas an interactive model suggests that cost and benefit utilities interact so that the sensitivity to benefits is attenuated as costs become increasingly aversive. Using a novel task that required integration of physical pain and monetary reward, we examined the mechanism underlying cost–benefit integration in humans. We provide evidence in support of an interactive model in behavioral choice. Using functional neuroimaging, we identify a neural signature for this interaction such that, when the consequences of actions embody a mixture of reward and pain, there is an attenuation of a predictive reward signal in both ventral anterior cingulate cortex and ventral striatum. We conclude that these regions subserve integration of action costs and benefits in humans, a finding that suggests a cross-species similarity in neural substrates that implement this function and illuminates mechanisms that underlie altered decision making under aversive conditions.

Curing musicians' dystonia.

Here is another bit on music or musicians. (I seem to be doing a fair number of postings in this area, maybe because I'm back into more hard core piano playing since returning to Fort Lauderdale...my hands are fatigued after 3 hours of Dvorak and Dohnanyi piano quintets yesterday.) Rosenkranz et al. show that an overly expanded spatial integration of proprioceptive input into the hand motor cortex that can cause deficiencies in hand motor controls (dystonia) can be reversed by proprioceptive training in pianists with musician's dystonia to the pattern seen in healthy pianists. (The training intervention requires the subject's attention to be focused for 15 min on random vibrations delivered to three hand muscles.):

Professional musicians are an excellent model of long-term motor learning effects on structure and function of the sensorimotor system. However, intensive motor skill training has been associated with task-specific deficiency in hand motor control, which has a higher prevalence among musicians (musician's dystonia) than in the general population. Using a transcranial magnetic stimulation paradigm, we previously found an expanded spatial integration of proprioceptive input into the hand motor cortex [sensorimotor organization (SMO)] in healthy musicians. In musician's dystonia, however, this expansion was even larger. Whereas motor skills of musicians are likely to be supported by a spatially expanded SMO, we hypothesized that in musician's dystonia this might have developed too far and now disrupts rather than assists task-specific motor control. If so, motor control should be regained by reversing the excessive reorganization in musician's dystonia. Here, we test this hypothesis and show that a 15 min intervention with proprioceptive input (proprioceptive training) restored SMO in pianists with musician's dystonia to the pattern seen in healthy pianists. Crucially, task-specific motor control improved significantly and objectively as measured with a MIDI (musical instrument digital interface) piano, and the amount of behavioral improvement was significantly correlated to the degree of sensorimotor reorganization. In healthy pianists and nonmusicians, the SMO and motor performance remained essentially unchanged. These findings suggest that the differentiation of SMO in the hand motor cortex and the degree of motor control of intensively practiced tasks are significantly linked and finely balanced. Proprioceptive training restored this balance in musician's dystonia to the behaviorally beneficial level of healthy musicians.

More on the trust and empathy hormone...

Natalie Angier does a summary of some recent studies on oxytocin, several of which I've already mentioned in MindBlog posts (enter oxytocin in the search box to list them). Of particular interest is recent work from Keltner's group showing that genetic differences in people’s responsiveness to the effects of oxytocin are linked to their ability to read faces, infer the emotions of others, feel distress at others’ hardship and even to identify with characters in a novel. Here is the abstract from the Keltner group:

Oxytocin, a peptide that functions as both a hormone and neurotransmitter, has broad influences on social and emotional processing throughout the body and the brain. In this study, we tested how a polymorphism (rs53576) of the oxytocin receptor relates to two key social processes related to oxytocin: empathy and stress reactivity. Compared with individuals homozygous for the G allele of rs53576 (GG), individuals with one or two copies of the A allele (AG/AA) exhibited lower behavioral and dispositional empathy, as measured by the “Reading the Mind in the Eyes” Test and an other-oriented empathy scale. Furthermore, AA/AG individuals displayed higher physiological and dispositional stress reactivity than GG individuals, as determined by heart rate response during a startle anticipation task and an affective reactivity scale. Our results provide evidence of how a naturally occurring genetic variation of the oxytocin receptor relates to both empathy and stress profiles.

Origins of empathetic yawning?

Interesting observations by Palagi et al:

Yawn contagion in humans has been proposed to be related to our capacity for empathy. It is presently unclear whether this capacity is uniquely human or shared with other primates, especially monkeys. Here, we show that in gelada baboons (Theropithecus gelada) yawning is contagious between individuals, especially those that are socially close, i.e., the contagiousness of yawning correlated with the level of grooming contact between individuals. This correlation persisted after controlling for the effect of spatial association. Thus, emotional proximity rather than spatial proximity best predicts yawn contagion. Adult females showed precise matching of different yawning types, which suggests a mirroring mechanism that activates shared representations. The present study also suggests that females have an enhanced sensitivity and emotional tuning toward companions. These findings are consistent with the view that contagious yawning reveals an emotional connection between individuals. This phenomenon, here demonstrated in monkeys, could be a building block for full-blown empathy.

Three different yawning displays performed by gelada baboons. Covered teeth yawning (left) uncovered teeth yawning (middle). and uncovered gums yawning (right).

Sounds during sleep aid memory

Rudoy et al. (PDF here) find that if, while asleep, people hear sounds that had earlier been associated with objects at specific spatial locations, upon waking they recalled these locations more accurately than other locations for which no reminder cues were provided. Consolidation thus operates during sleep with high specificity and is subject to systematic influences through simple auditory stimulation.

The Music Instinct

Steven Mithen (author of The Singing Neanderthals) does a summary of his ideas on the evolutionary basis of musicality in this open access article in the Annals of the New York Academy of Sciences.

Why does music pervade our lives and those of all known human beings living today and in the recent past? Why do we feel compelled to engage in musical activity, or at least simply enjoy listening to music even if we choose not to actively participate? I argue that this is because musicality—communication using variations in pitch, rhythm, dynamics and timbre, by a combination of the voice, body (as in dance), and material culture—was essential to the lives of our pre-linguistic hominin ancestors. As a consequence we have inherited a desire to engage with music, even if this has no adaptive benefit for us today as a species whose communication system is dominated by spoken language. In this article I provide a summary of the arguments to support this view.

Musicians are not as bothered by background noise.

From Parbery-Clark et al.:

Musicians have lifelong experience parsing melodies from background harmonies, which can be considered a process analogous to speech perception in noise. To investigate the effect of musical experience on the neural representation of speech-in-noise, we compared subcortical neurophysiological responses to speech in quiet and noise in a group of highly trained musicians and nonmusician controls. Musicians were found to have a more robust subcortical representation of the acoustic stimulus in the presence of noise. Specifically, musicians demonstrated faster neural timing, enhanced representation of speech harmonics, and less degraded response morphology in noise. Neural measures were associated with better behavioral performance on the Hearing in Noise Test (HINT) for which musicians outperformed the nonmusician controls. These findings suggest that musical experience limits the negative effects of competing background noise, thereby providing the first biological evidence for musicians' perceptual advantage for speech-in-noise.