The Thinker
The Right Side? Under Time Pressure, Approach Motivation Leads to Right-Oriented Bias
Marieke Roskes et al.
Psychological Science, November 2011, Pages 1403-1407
Abstract:
Approach motivation, a focus on achieving positive outcomes, is related to relative left-hemispheric brain activation, which translates to a variety of right-oriented behavioral biases. In two studies, we found that approach-motivated individuals display a right-oriented bias, but only when they are forced to act quickly. In a task in which they had to divide lines into two equal parts, approach-motivated individuals bisected the line at a point farther to the right than avoidance-motivated individuals did, but only when they worked under high time pressure. In our analysis of all Fédération Internationale de Football Association (FIFA) World Cup penalty shoot-outs, we found that goalkeepers were two times more likely to dive to the right than to the left when their team was behind, a situation that we conjecture induces approach motivation. Because penalty takers shot toward the two sides of the goal equally often, the goalkeepers' right-oriented bias was dysfunctional, allowing more goals to be scored. Directional biases may facilitate group coordination but prove maladaptive in individual settings and interpersonal competition.
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Kinga Morsanyi & Simon Handley
Journal of Experimental Psychology: Learning, Memory, and Cognition, forthcoming
Abstract:
When people evaluate syllogisms, their judgments of validity are often biased by the believability of the conclusions of the problems. Thus, it has been suggested that syllogistic reasoning performance is based on an interplay between a conscious and effortful evaluation of logicality and an intuitive appreciation of the believability of the conclusions (e.g., Evans, Newstead, Allen, & Pollard, 1994). However, logic effects in syllogistic reasoning emerge even when participants are unlikely to carry out a full logical analysis of the problems (e.g., Shynkaruk & Thompson, 2006). There is also evidence that people can implicitly detect the conflict between their beliefs and the validity of the problems, even if they are unable to consciously produce a logical response (e.g., De Neys, Moyens, & Vansteenwegen, 2010). In 4 experiments we demonstrate that people intuitively detect the logicality of syllogisms, and this effect emerges independently of participants' conscious mindset and their cognitive capacity. This logic effect is also unrelated to the superficial structure of the problems. Additionally, we provide evidence that the logicality of the syllogisms is detected through slight changes in participants' affective states. In fact, subliminal affective priming had an effect on participants' subjective evaluations of the problems. Finally, when participants misattributed their emotional reactions to background music, this significantly reduced the logic effect.
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James McCubbin et al.
Psychosomatic Medicine, November-December 2011, Pages 743-750
Objective: Persons with elevated blood pressure (BP) show dampened emotional responses to affect-laden stimuli. We sought to further examine cardiovascular-emotional dampening by examination of the relationship between resting hemodynamic measures and recognition of emotion in an African American community-based sample.
Methods: Participants were 106 African American men and women (55 women; mean age = 52.8 years), mainly low in socioeconomic status, and part of the Healthy Aging in Nationally Diverse Longitudinal Samples pilot study. Participants evaluated emotional expressions in faces and sentences using the Perception of Affect Test (PAT). Resting BP, total peripheral resistance (TPR), cardiac output, and heart rate were obtained continuously using a Portapres BP monitor.
Results: Total PAT scores were inversely related to systolic (r = -0.30) and diastolic (r = -0.24) BPs, TPR (r = -0.36), and age (r = -0.31; p values < .01) and were positively related to cardiac output (r = 0.27) and education (r = 0.38; p values < .01), as well as with mental state (r = 0.25) and body mass index (r = -0.20; p values < .05). Accuracy of emotion recognition on the PAT tasks remained inversely related to TPR and BP after adjustment for demographic variables, medication, mental state, and body mass index.
Conclusions: Elevated BP and TPR were associated with reduced perception of affect. TPR was the most consistent independent hemodynamic correlate of emotional dampening for the PAT scores. These results suggest potentially important links among central nervous system regulation of emotions, hemodynamic processes, and hypertension development.
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Saul Miller, Marjorie Prokosch & Jon Maner
Journal of Experimental Social Psychology, forthcoming
Abstract:
People in long-term romantic relationships possess relationship maintenance mechanisms designed to protect against the temptation of desirable relationship alternatives. The current research examined the link between relationship maintenance mechanisms and an index of neurologically based approach/avoidance motivation. Participants completed a line bisection task that yields measures of asymmetric activity in the right and left frontal cortices; such activity is thought to reflect people's level of approach/avoidance motivation. Compared to single participants, participants in committed relationships displayed relatively less left visual field bias on the line bisection task (indicative of greater left frontal cortical activation and greater cognitive avoidance motivation) in response to available, attractive opposite-sex targets. Decreased left visual field bias was particularly pronounced among individuals with moderate levels of relationship commitment - those expected to display the highest levels of relationship maintenance. These findings provide insight into perceptual, motivational, and neurological processes that may help people avoid tempting relationship alternatives.
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Cognitive Control and Individual Differences in Economic Ultimatum Decision-Making
Wim De Neys et al.
PLoS ONE, November 2011, e27107
Abstract:
Much publicity has been given to the fact that people's economic decisions often deviate from the rational predictions of standard economic models. In the classic ultimatum game, for example, most people turn down financial gains by rejecting unequal monetary splits. The present study points to neglected individual differences in this debate. After participants played the ultimatum game we tested for individual differences in cognitive control capacity of the most and least economic responders. The key finding was that people who were higher in cognitive control, as measured by behavioral (Go/No-Go performance) and neural (No-Go N2 amplitude) markers, did tend to behave more in line with the standard models and showed increased acceptance of unequal splits. Hence, the cognitively highest scoring decision-makers were more likely to maximize their monetary payoffs and adhere to the standard economic predictions. Findings question popular claims with respect to the rejection of standard economic models and the irrationality of human economic decision-making.
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Look over there! Unilateral gaze increases geographical memory of the 50 United States
Ruth Propper et al.
Brain and Cognition, forthcoming
Abstract:
Based on their specialized processing abilities, the left and right hemispheres of the brain may not contribute equally to recall of general world knowledge. US college students recalled the verbal names and spatial locations of the 50 US states while sustaining leftward or rightward unilateral gaze, a procedure that selectively activates the contralateral hemisphere. Compared to a no-unilateral gaze control, right gaze/left hemisphere activation resulted in better recall, demonstrating left hemisphere superiority in recall of general world knowledge and offering equivocal support for the hemispheric encoding asymmetry model of memory. Unilateral gaze - regardless of direction - improved recall of spatial, but not verbal, information. Future research could investigate the conditions under which unilateral gaze increases recall. Sustained unilateral gaze can be used as a simple, inexpensive, means for testing theories of hemispheric specialization of cognitive functions. Results support an overall deficit in US geographical knowledge in undergraduate college students.
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Leaning to the Left Makes the Eiffel Tower Seem Smaller: Posture-Modulated Thought
Anita Eerland, Tulio Guadalupe & Rolf Zwaan
Psychological Science, forthcoming
Abstract:
In two experiments, we investigated whether body posture influences people's estimates of quantities, heights, and percentages of entities in the world. According to an influential idea, people mentally represent numbers along a line with small numbers on the left and large numbers on the right. We hypothesized that surreptitiously making people lean to the right or left would affect their estimates. Participants answered estimation questions while standing on the WiiTM Balance Board. Posture was manipulated within subjects, so that participants answered some questions while they leaned slightly to the left, slightly to the right or while they stood upright. Crucially, participants were not aware of this manipulation. Subjects' estimates were significantly smaller when they leaned to the left than when they leaned to the right.
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Brain Biochemistry and Personality: A Magnetic Resonance Spectroscopy Study
Sephira Ryman et al.
PLoS ONE, November 2011, e26758
Abstract:
To investigate the biochemical correlates of normal personality we utilized proton magnetic resonance spectroscopy (1H-MRS). Our sample consisted of 60 subjects ranging in age from 18 to 32 (27 females). Personality was assessed with the NEO Five-Factor Inventory (NEO-FFI). We measured brain biochemistry within the precuneus, the cingulate cortex, and underlying white matter. We hypothesized that brain biochemistry within these regions would predict individual differences across major domains of personality functioning. Biochemical models were fit for all personality domains including Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Our findings involved differing concentrations of Choline (Cho), Creatine (Cre), and N-acetylaspartate (NAA) in regions both within (i.e., posterior cingulate cortex) and white matter underlying (i.e., precuneus) the Default Mode Network (DMN). These results add to an emerging literature regarding personality neuroscience, and implicate biochemical integrity within the default mode network as constraining major personality domains within normal human subjects.
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Energetics and the evolution of human brain size
Ana Navarrete, Carel van Schaik & Karin Isler
Nature, forthcoming
Abstract:
The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis1 explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.
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Does Personality Smell? Accuracy of Personality Assessments Based on Body Odour
Agnieszka Sorokowska, Piotr Sorokowski & Andrzej Szmajke
European Journal of Personality, forthcoming
Abstract:
People are able to assess some personality traits of others based on videotaped behaviour, short interaction or a photograph. In our study, we investigated the relationship between body odour and the Big Five personality dimensions and dominance. Sixty odour samples were assessed by 20 raters each. The main finding of the presented study is that for a few personality traits, the correlation between self-assessed personality of odour donors and judgments based on their body odour was above chance level. The correlations were strongest for extraversion (.36), neuroticism (.34) and dominance (.29). Further analyses showed that self-other agreement in assessments of neuroticism slightly differed between sexes and that the ratings of dominance were particularly accurate for assessments of the opposite sex.
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Serotonin Transporter Genotype (5-HTTLPR) Predicts Utilitarian Moral Judgments
Abigail Marsh et al.
PLoS ONE, October 2011, e25148
Background: The psychological and neurobiological processes underlying moral judgment have been the focus of extensive recent research. Here we show that serotonin transporter (5-HTTLPR) genotype predicts responses to moral dilemmas featuring foreseen harm to an innocent.
Methodology/Principal Findings: Participants in this study judged the acceptability of actions that would unintentionally or intentionally harm an innocent victim in order to save others' lives. An analysis of variance revealed a genotype × scenario interaction, F(2, 63) = 4.52, p = .02. Results showed that, relative to long allele homozygotes (LL), carriers of the short (S) allele showed particular reluctance to endorse utilitarian actions resulting in foreseen harm to an innocent individual. LL genotype participants rated perpetrating unintentional harm as more acceptable (M = 4.98, SEM = 0.20) than did SL genotype participants (M = 4.65, SEM = 0.20) or SS genotype participants (M = 4.29, SEM = 0.30). No group differences in moral judgments were observed in response to scenarios featuring intentional harm.
Conclusions/Significance: The results indicate that inherited variants in a genetic polymorphism that influences serotonin neurotransmission influence utilitarian moral judgments as well. This finding is interpreted in light of evidence that the S allele is associated with elevated emotional responsiveness.
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Prefrontal cortex glutamate and extraversion
Simone Grimm et al.
Social Cognitive and Affective Neuroscience, forthcoming
Abstract:
Extraversion is considered one of the core traits of personality. Low extraversion has been associated with increased vulnerability to affective and anxiety disorders. Brain imaging studies have linked extraversion, approach behaviour and the production of positive emotional states to the dorsolateral prefrontal cortex (DLPFC) and glutamatergic neurotransmission. However, the relationship between extraversion and glutamate in the DLPFC has not been investigated so far. In order to address this issue, absolute glutamate concentrations in the DLPFC and the visual cortex as a control region were measured by 3-Tesla proton magnetic resonance spectroscopy (1H-MRS) in 29 subjects with high and low extraversion. We found increased glutamate levels in the DLPFC of introverts as compared with extraverts. The increased glutamate concentration was specific for the DLPFC and negatively associated with state anxiety. Although preliminary, results indicate altered top-down control of DLPFC due to reduced glutamate concentration as a function of extraversion. Glutamate measurement with 1H-MRS may facilitate the understanding of biological underpinnings of personality traits and psychiatric diseases associated with dysfunctions in approach behaviour and the production of positive emotional states.
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Lisa Kramer & Mark Weber
Social Psychological and Personality Science, forthcoming
Abstract:
This study found that people who suffer from seasonal affective disorder (SAD) displayed financial risk aversion that varied across the seasons as a function of seasonally changing affect. The SAD-sufferers had significantly stronger preferences for safe choices during the winter than non-SAD-sufferers, and they did not differ from non-SAD-sufferers during the summer. The effect of SAD on risk aversion in the winter was mediated by depression.
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Theresa Dahm et al.
PLoS ONE, October 2011, e26351
Abstract:
Self-regulation depletion (SRD), or ego-depletion, refers to decrements in self-regulation performance immediately following a different self-regulation-demanding activity. There are now over a hundred studies reporting SRD across a broad range of tasks and conditions. However, most studies have used young student samples. Because prefrontal brain regions thought to subserve self-regulation do not fully mature until 25 years of age, it is possible that SRD effects are confined to younger populations and are attenuated or disappear in older samples. We investigated this using the Stroop color task as an SRD induction and an autobiographical memory task as the outcome measure. We found that younger participants (<25 years) were susceptible to depletion effects, but found no support for such effects in an older group (40-65 years). This suggests that the widely-reported phenomenon of SRD has important developmental boundary conditions casting doubt on claims that it represents a general feature of human cognition.
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Verbal and non-verbal intelligence changes in the teenage brain
Sue Ramsden et al.
Nature, 3 November 2011, Pages 113-116
Abstract:
Intelligence quotient (IQ) is a standardized measure of human intellectual capacity that takes into account a wide range of cognitive skills. IQ is generally considered to be stable across the lifespan, with scores at one time point used to predict educational achievement and employment prospects in later years. Neuroimaging allows us to test whether unexpected longitudinal fluctuations in measured IQ are related to brain development. Here we show that verbal and non-verbal IQ can rise or fall in the teenage years, with these changes in performance validated by their close correlation with changes in local brain structure. A combination of structural and functional imaging showed that verbal IQ changed with grey matter in a region that was activated by speech, whereas non-verbal IQ changed with grey matter in a region that was activated by finger movements. By using longitudinal assessments of the same individuals, we obviated the many sources of variation in brain structure that confound cross-sectional studies. This allowed us to dissociate neural markers for the two types of IQ and to show that general verbal and non-verbal abilities are closely linked to the sensorimotor skills involved in learning. More generally, our results emphasize the possibility that an individual's intellectual capacity relative to their peers can decrease or increase in the teenage years. This would be encouraging to those whose intellectual potential may improve, and would be a warning that early achievers may not maintain their potential.
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Clancy Blair et al.
Child Development, forthcoming
Abstract:
In a predominantly low-income population-based longitudinal sample of 1,292 children followed from birth, higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years. Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ. The effect of positive parenting on executive functions was partially mediated through cortisol. Typical or resting level of cortisol was increased in African American relative to White participants. In combination with positive and negative parenting and household risk, cortisol mediated effects of income-to-need, maternal education, and African American ethnicity on child cognitive ability.
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Individual Differences in Impulsivity Predict Anticipatory Eye Movements
Laetitia Cirilli et al.
PLoS ONE, October 2011, e26699
Abstract:
Impulsivity is the tendency to act without forethought. It is a personality trait commonly used in the diagnosis of many psychiatric diseases. In clinical practice, impulsivity is estimated using written questionnaires. However, answers to questions might be subject to personal biases and misinterpretations. In order to alleviate this problem, eye movements could be used to study differences in decision processes related to impulsivity. Therefore, we investigated correlations between impulsivity scores obtained with a questionnaire in healthy subjects and characteristics of their anticipatory eye movements in a simple smooth pursuit task. Healthy subjects were asked to answer the UPPS questionnaire (Urgency Premeditation Perseverance and Sensation seeking Impulsive Behavior scale), which distinguishes four independent dimensions of impulsivity: Urgency, lack of Premeditation, lack of Perseverance, and Sensation seeking. The same subjects took part in an oculomotor task that consisted of pursuing a target that moved in a predictable direction. This task reliably evoked anticipatory saccades and smooth eye movements. We found that eye movement characteristics such as latency and velocity were significantly correlated with UPPS scores. The specific correlations between distinct UPPS factors and oculomotor anticipation parameters support the validity of the UPPS construct and corroborate neurobiological explanations for impulsivity. We suggest that the oculomotor approach of impulsivity put forth in the present study could help bridge the gap between psychiatry and physiology.
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Transformation of stimulus value signals into motor commands during simple choice
Todd Hare et al.
Proceedings of the National Academy of Sciences, 1 November 2011, Pages 18120-18125
Abstract:
Decision-making can be broken down into several component processes: assigning values to stimuli under consideration, selecting an option by comparing those values, and initiating motor responses to obtain the reward. Although much is known about the neural encoding of stimulus values and motor commands, little is known about the mechanisms through which stimulus values are compared, and the resulting decision is transmitted to motor systems. We investigated this process using human fMRI in a task where choices were indicated using the left or right hand. We found evidence consistent with the hypothesis that value signals are computed in the ventral medial prefrontal cortex, they are passed to regions of dorsomedial prefrontal cortex and intraparietal sulcus, implementing a comparison process, and the output of the comparator regions modulates activity in motor cortex to implement the choice. These results describe the network through which stimulus values are transformed into actions during a simple choice task.
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Tracking Decision Makers under Uncertainty
Amos Arieli, Yaniv Ben-Ami & Ariel Rubinstein
American Economic Journal: Microeconomics, November 2011, Pages 68-76
Abstract:
Eye tracking is used to investigate the procedures that participants employ in choosing between two lotteries. Eye movement patterns in problems where the deliberation process is clearly identified are used to substantiate an interpretation of the results. The data provide little support for the hypothesis that decision makers rely exclusively upon an expected utility type of calculation. Instead eye patterns indicate that decision makers often compare prizes and probabilities separately. This is particularly true when the multiplication of sums and probabilities is laborious to compute.