Interpersonal and intrapersonal variance of exponent of power function observed in grip strength task.

For grip strength there is a power function with an exponent of 1.7 between the subjective magnitude and the actual force exerted by a subject, but large variabilities among and within individuals were found. We focused on these variabilities and investigated the relationship between them by conducting a ratio production procedure requiring trials of maximum effort and half of maximum effort. For 30 adults we conducted four measurement trials, two on the same day, and the remaining two trials on a day or two later. The mean value of the exponent, the standard deviation, and the coefficient of variation of the four trials for each subject were calculated. The mean value of the exponent of the power function for all subjects was 1.6. This value approximated the value of 1.7 reported by Stevens and Mack. The values ranged from .50 to 5.39. The correlation between subjects' mean exponent value and standard deviation was .90, and the correlation between the mean value of the exponent and the coefficient of variation was .50. There was a close relationship between interpersonal and intrapersonal variance.     

Offender and crime characteristics of female serial arsonists in Japan

This study of Japanese female serial arsonists examined their crimes and background characteristics. The data were a sample from the national police register containing arson cases resulting in charges in Japan between 1982 and 2005. Serial arsonists were 6% of the arson offenders and 12% of these were female, resulting in 83 female serial arsonist data sets. The mean age was 37.6 years and 43% were unemployed. Nearly half were married. Only 28% had a documented history of mental problems and 22% had a prior arrest, usually for theft (19%). Female serial arsonists are characterised by going to a place near their home with a lighter and setting fire directly to combustible materials. Non‐metric multidimensional scaling was used to analyse 33 variables related to the offences. The arsons could be differentiated in terms of either expressive or instrumental sources of action. Expressive arsons were opportunistic and impulsive acts, motivated by emotional distress. The fires were mostly set close to home. Expressive arsons were characteristic of 66% of the females. Instrumental arsons were often motivated by revenge and involved planned and goal‐directed behaviours. They were committed by 13% of the females. Instrumental arsonists tended to travel further from home. Copyright © 2007 John Wiley & Sons, Ltd.     

Self-referential processing of negative stimuli within the ventral anterior cingulate gyrus and right amygdala

Neural activity associated with self-referential processing of emotional stimuli was investigated using whole brain functional magnetic resonance imaging (fMRI). Fifteen healthy subjects underwent fMRI scanning while making judgments about positive and negative trait words in four conditions (self-reference, other-reference, semantic processing, and letter processing). Significant activity was observed in the right ventral anterior cingulate gyrus and the right amygdala in the negative-word/self-reference condition, and in the left amygdala in the positive-word/self-reference condition. Compared with the semantic-processing condition, the self-reference conditions showed significantly more activity in the medial prefrontal and temporal gyri, posterior cingulate gyrus, and precuneus. These results suggest that the medial prefrontal gyrus, posterior cingulate gyrus, and precuneus are associated with a self-referential processing, and the ventral anterior cingulate gyrus is involved in self-referential processing of negative emotional stimuli. The results also suggest that the amygdala is associated with self-referential processing of both positive and negative emotional stimuli.     

Long-lasting effects of subliminal affective priming from facial expressions

Unconscious processing of stimuli with emotional content can bias affective judgments. Is this subliminal affective priming merely a transient phenomenon manifested in fleeting perceptual changes, or are long-lasting effects also induced? To address this question, we investigated memory for surprise faces 24 h after they had been shown with 30-ms fearful, happy, or neutral faces. Surprise faces subliminally primed by happy faces were initially rated as more positive, and were later remembered better, than those primed by fearful or neutral faces. Participants likely to have processed primes supraliminally did not respond differentially as a function of expression. These results converge with findings showing memory advantages with happy expressions, though here the expressions were displayed on the face of a different person, perceived subliminally, and not present at test. We conclude that behavioral biases induced by masked emotional expressions are not ephemeral, but rather can last at least 24 h.     

Individual differences in language lateralisation,schizotypy and the remote-associate task

We tested the hypothesis that the level of reduced laterality in language is correlated with the degrees of schizotypal personality in healthy individuals and with their performance in the remote-associate task (RAT). A total of 53 healthy participants completed a schizotypal personality measure of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE; a questionnaire measuring the level of psychotic proneness), a consonant–vowel–consonant (CVC; requiring the identification of letter trigrams presented tachistoscopically in the left/right visual fields or both), measuring reduced language laterality and a remote-associate task (RAT; requiring to report a word, weakly associated with three cue words). Analysis revealed correlations between CVC and O-LIFE, as well as between CVC and RAT performance. The results suggest that reduced language lateralisation (reduced hemispheric integration) may play a role in schizophrenic language disorganization, as reflected in highly schizotypal individuals, and that hemispheric integration plays a role in the remote-associate task.     

Choice between Single-Response and Multichoice Tasks in Humans

The Psychological Record - The present study examined choice in humans between a single-response task and a task with multiple alternatives (i.e., a multichoice task). The alternatives provided...     

Rapid volitional control of apparent motion during percept generation

How rapidly can one voluntarily influence percept generation? The time course of voluntary visual–spatial attention is well studied, but the time course of intentional control over percept generation is relatively unknown. We investigated the latter question using “one-shot” apparent motion. When a vertical or horizontal pair of squares is replaced by its 90º-rotated version, the bottom-up signal is ambiguous. From this ambiguous signal, it is known that people can intentionally generate a percept of rotation in a desired direction (clockwise or counterclockwise). To determine the time course of this intentional control, we instructed participants to voluntarily induce rotation in a precued direction (clockwise rotation when a high-pitched tone was heard, and counterclockwise rotation when a low-pitched tone was heard), and then to report the direction of rotation that was actually perceived. We varied the delay between the instructional cue and the rotated frame (cue-lead time) from 0 to 1,067 ms. Intentional control became more effective with longer cue-lead times (asymptotically effective at 533 ms). Notably, intentional control was reliable even with a zero cue-lead time; control experiments ruled out response bias and the development of an auditory–visual association as explanations. This demonstrates that people can interpret an auditory cue and intentionally generate a desired motion percept surprisingly rapidly, entirely within the subjectively instantaneous moment in which the visual system constructs a percept of apparent motion.     

Human Group Choice in Loss Minimization and Gain Maximization Games

The Psychological Record - College students participated as a group in a point-loss minimization game as well as in a point-gain maximization game. The rule of the maximization game was similar to...     

Thermal expansion of icosahedral Al-Pd-Mn and decagonal Al-Cu-Co quasicrystals

Thermal expansion measurements have been performed by X-ray diffractometry on icosahedral Al-Pd-Mn (i-(Al-Pd-Mn)) in the temperature range between 10 and 700K and on decagonal Al-Cu-Co (d-(Al-Cu-Co)) in the range between 100 and 750K. The linear thermal expansion coefficient alpha(T) of i-(Al-Pd-Mn) is about half of that for the pure aluminium phase at room temperature and does not show a negative thermal expansion at low temperatures. The degree of anisotropy in the thermal expansion of d-(Al-Cu-Co) is small; the ratio of the average alpha between the tenfold periodic direction and a quasiperiodic direction perpendicular to it is 0:93 +/- 0:05. The Gruneisen parameter gamma(T) has been evaluated from the measured alpha(T). gamma for d-(Al-CuCo) is almost isotropic, similar to alpha. The gamma values for the two phases lie in the range between 1.5 and 1.8, which are comparable with those for conventional metallic crystals. They are almost constant over the temperature range studied.