Magnitude of cerebral asymmetry at rest: covariation with baseline cardiovascular activity

The cerebral regulation of cardiovascular functioning varies along both a lateral and a longitudinal axis. The parasympathetic and sympathetic nervous systems are lateralized to the left and right cerebral hemispheres, respectively. Further, the frontal lobes are known to be inhibitory in nature, whereas the temporal lobes are excitatory. However, no systematic investigation has been conducted to determine the nature and strength of the relationship between the left and right frontal and temporal lobes in regulating cardiovascular activity. The present investigation sought to examine these relationships by testing the hypothesis that negative correlations would be found between baseline heart rate and blood pressure and asymmetry of alpha magnitude across the frontal lobes. Further, positive correlations were hypothesized to exist across the temporal lobes. A total of 20 women were asked to relax with their eyes closed while heart rate and blood pressure as well as quantitative electroencephalography data were obtained. The results indicated that, as hypothesized, significant negative correlations existed across the frontal lobes and significant positive correlations existed across the temporal lobes. The results provide further support for a division of responsibility between the left and right frontal and temporal lobes in the regulation of heart rate and blood pressure.     

The exponential learning equation as a function of successful trials results in sigmoid performance

While the exponential learning equation, indicating a gradually diminishing improvement, is one of the standard equations to describe learning, a sigmoid behavior with initially increasing then decreasing improvement has also been suggested. Here we show that the sigmoid behavior is mathematically derived from the standard exponential equation when the independent variable of the equation is restricted to the successful trials alone. It is suggested that for tasks promoting success-based learning, performance is better described by the derived sigmoid curve.     

Rate, Probability and Matching: Comments on ��The Identities Hidden in the Matching Laws, and Their Uses�� by David Thorne

David Thorne's (2010) article, “The Identities Hidden In The Matching Laws, And Their Uses” performs a valuable service in pointing out alternative expressions of matching. However, some identities tend to obscure rather than illuminate empirical relationships. Three such problematic instances are discussed: interresponse time as a function of interval and ratio schedule parameters; probability equality as implying rate matching; the apparent simplicity of probabilistic functions, as opposed to response rate functions, of reinforcement rate.     

Possible influence of electrostatics in molecular bonding at supported metal nanoparticles

A mechanism is proposed for interaction between gas molecules and supported metal nanoparticles. Hot electrons that are formed via electron–hole pair excitations caused by exothermic reactions on the particles, enter into the insulating support, thereby leaving a positive charge that is distributed over the volume of the nanoparticle. The lifetime of the charge depends on the size of the metal particle and on the electronic and dielectric properties of the support, and may be too short for equilibrium to be established between the particle and its surroundings on the time scale of the chemical reaction. The electrostatic potential of the particle depends on its size, and therefore the position of the d-density of states of the particle, and thus the interaction with adsorbed molecules may be tuned by changing particle size. Thus, catalytic activity and selectivity may be affected for chemical reactions.     

Revisiting the rise and fall of false recall: Presentation rate effects depend on retention interval

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease—a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)—contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.     

Framing the Ultimatum Game: Gender differences and autonomic responses

The present study aimed at investigating whether the way offers are framed in the Ultimatum Game (UG) affects behavioral and autonomic responses in men and women. The “I give you” and “I take” expressions were used as gain and loss frames, respectively. Skin conductance and heart rate were recorded as indices of autonomic activation in response to unfair, mid‐value, and fair offers. Acceptance rates were higher in men than in women under the gain frame. Moreover, men showed higher acceptance rates under the gain than under the loss frame with mid‐value offers, whereas women's choices were not affected by frame. On the physiological level, men produced differential autonomic response patterns during decision‐making when offers were presented under gain and loss framing. The “I take” frame, by acting as a loss frame, elicited in men the characteristic defensive response pattern that is evoked by aversive stimulation, in which increases in skin conductance are coupled with increases in heart rate. On the other hand, the “I give you” frame, by acting as a gain frame, elicited in men increases in skin conductance associated with prevailing heart rate deceleratory responses, reflecting a state of enhanced attention and orienting. In contrast, women's autonomic reactivity was not affected by frame, consistent with behavioral results. Phasic changes in heart rate were crucial in revealing differential functional significance of skin conductance responses under different frames in men, thus questioning the assumption that this autonomic measure can be used as an index of negative emotional arousal in the UG.     

The Effect of Attentional Control and Heart-Period Variability on Negative Affect and Trait Anxiety

In this study, the author examines the effect of attentional control and heart-period variability on measures of negative affect and trait anxiety in undergraduate students. Baseline heart rate was recorded from 119 participants within a laboratory setting. Spectral analysis was used on the heart-rate data to isolate the parasympathetic contribution to the cardiac pattern. Participants completed measures of negative affect, attentional control, and trait anxiety following the recording of heart rate. Regression analysis indicated that high negative affect, low attentional control, and reduced parasympathetic tone were significant predictors of high trait anxiety. Subsequent regression analysis pointed toward the interaction of attentional control and parasympathetic tone in influencing self-rated measures of negative affect. Results highlight the importance of attentional control and parasympathetic tone as regulatory mechanisms related to self-rated estimates of negative affect and trait anxiety.     

Effects of Accelerated Reading Rate on Processing Words' Syntactic Functions by Normal and Dyslexic Readers: Event Related Potentials Evidence

In the present study, the authors examined differences in brain activity, as measured by amplitudes and latencies of event related potentials (ERP) components, in Hebrew-speaking adult dyslexic and normal readers when processing sentence components with different grammatical functions. Participants were 20 dyslexic and 20 normally reading male college students aged 18–27 years. The authors examined the processing of normal word strings in word–by-word reading of sentences having subject-verb-object (SVO) syntactic structure in self- and fast-paced conditions. Data revealed that in both reading conditions, the N100 and P300 ERP components were sensitive to internal processes such as recognition of words' grammatical functions. However, the results revealed that fast-paced reading rate might affect this process, as was reflected in the systematic changes of amplitudes and latencies of both ERP components. In accelerated reading, a significant decrease of latencies and increase of amplitudes in dyslexics were shown. It was also found that influence of fast-paced reading rate was realized in the full usage of the word-order strategy in sentence processing. In turn, this fact confirmed the hypothesis concerning a syntactic processing “weakness” in dyslexia.     

Sex differences in the effects of disinhibition,perceived peer drinking,and delay discounting on drinking among Japanese college students

Disinhibition, perceived peer drinking, and delay discounting are considered significant predictors of drinking in young adults. This study examined whether perceived peer drinking and delay discounting mediate the association between disinhibition and drinking for young men and women. In this study, 258 Japanese college students (109 men and 149 women, mean age 19.17 (SD = 1.20) years old) completed a self-administered questionnaire that included four measures—the disinhibition subscale of the Sensation Seeking Scale for Japanese Adolescents, the proportion of friends who drink as an index of perceived peer drinking behaviors, the Monetary Choice Questionnaire, and participants’ own drinking behavior. In the multiple mediator models analyzed using structural equation modeling, for both sexes, perceived peer drinking had the largest direct effect on participants’ drinking, followed by disinhibition and delay discounting. However, the results of mediation analyses indicated that perceived peer drinking mediated the association between disinhibition and drinking for only women. The results of this study imply that it is important to consider sex differences in the association between personality traits and peer influence to develop programs aiming to reduce drinking among young adults in Japan.     

Energy,Complexity, and Strategies of Evolution: As Illustrated by Maya Indians of Guatemala

Using free energy rate density (Φ_m) I differentiate two evolutionary strategies common to cosmic, biological, and cultural systems: the horizontal when energy increases proportional to mass, with no increase in complexity; and the vertical when it increases disproportionately to the mass and complexity increases. The vertical process is a continuing increase in complexity such that the system becomes vulnerable to collapse when energy sources fail. This is illustrated by a comparison of four Mayan Indian groups in Guatemala.