Stability in force-production tasks

Exerting a force on a mechanical system can induce mechanical instability. To overcome that instability, humans may take advantage of their upper limb mechanical impedance (e.g., hand stiffness). The authors investigated what stiffness is required to maintain static stability and how humans can achieve that stiffness in the context of the task of pushing on a pivoting stick. Results showed that the stiffness required is in the range of measured human upper limb stiffness. To avoid an ill-posed problem, one can better express the requirements for stability as a simple geometrical criterion related to the curvature of the potential energy field at the hand. A planar model of the upper limb revealed that individuals can use both hand rotational and translational stiffness to stabilize a stick. Although hand rotational stiffness does not participate in producing the axial force on the stick, it can significantly contribute to achieving a limb stiffness appropriate for maintaining static stability. Hand rotational stiffness can be important for the design of hand tools, because humans can increase it only by augmenting grip force, a biomechanical factor associated with cumulative trauma injuries of the upper extremities.     

Generation of speech continua through monaural fusion

A procedure based on monaural fusion has been developed to construct acoustic continua between natural speech sounds, to be used in studies of speech perception. Two speech stimuli of similar temporal structure and different spectral composition are precisely aligned in time and presented simultaneously to the listener. By mixing both stimulus components in varying intensity ratios, a transition from one component to the other can be achieved. Such stimulus continua have several advantages over the synthetic continua commonly used in studies of categorical perception and related phenomena: They are based on real speech stimuli; the endpoint stimuli are unambiguous; and the stimuli are characterized by a well-defined physical variable, the relative intensity of the two components.     

A goal-striving life event and the onset of hypomanic and depressive episodes and symptoms: perspective from the behavioral approach system (BAS) dysregulation theory

On the basis of the behavioral approach system (BAS) dysregulation theory of bipolar disorder, this study examined the relation between occurrence of a BAS activation-relevant life event--goal striving--and onset of hypomanic and depressive episodes and symptoms. In particular, the authors examined the relation between preparing for and completing final exams (a goal-striving event) and onset of bipolar spectrum episodes and symptoms in college students with bipolar II disorder or cyclothymia (i.e., "soft" bipolar spectrum conditions). One hundred fifty-nine individuals with either a bipolar spectrum disorder (n=68) or no major affective psychopathology (controls; n=91) were further classified on the basis of whether they were college students (i.e., completed final exams). Consistent with the BAS dysregulation theory, preparing for and completing final exams was associated with an increase in hypomanic but not depressive episodes and symptoms in individuals with a soft bipolar spectrum diagnosis. Furthermore, self-reported BAS sensitivity moderated the presence of certain hypomanic symptoms during final exams.     

Acute inhibition of calcineurin restores associative learning and memory in Tg2576 APP transgenic mice

Misfolded amyloid beta peptide (Abeta) is a pathological hallmark of Alzheimer's disease (AD), a neurodegenerative illness characterized by cognitive deficits and neuronal loss. Transgenic mouse models of Abeta over-production indicate that Abeta-induced cognitive deficits occur in the absence of overt neuronal death, suggesting that while extensive neuronal death may be associated with later stages of the human disease, subtle physiological changes may underlie initial cognitive deficits. Therefore, identifying signaling elements involved in those Abeta-induced cognitive impairments that occur prior to loss of neurons may reveal new potential pharmacological targets. Here, we report that the enzymatic activity of calcineurin, a key protein phosphatase involved in phosphorylation-dependent kinase activity crucial for synaptic plasticity and memory function, is upregulated in the CNS of the Tg2576 animal model for Abeta over-production. Furthermore, acute treatment of Tg2576 mice with the calcineurin inhibitor FK506 (10mg/kg i.p.) improves memory function. These results indicate that calcineurin may mediate some of the cognitive effects of excess Abeta such that inhibition of calcineurin shall be further explored as a potential treatment to reverse cognitive impairments in AD.     

Parents' child‐rearing values and beliefs in the United States and Russia: the impact of culture and social class

Parents' values for their children and their beliefs about appropriate child‐rearing practices contribute to the ways in which they try to shape their children's development. This paper examines the values and beliefs of 71 parents (37 mothers and 34 fathers) from two cities in the United States and Russia. Half of the families were middle class (determined by education and occupation criteria) and half were working class. The results revealed no cross‐societal differences in value for self‐direction in the children; perhaps reflecting the recent economic and ideological changes in Russia. In contrast, significant social class differences, for both mothers and fathers, were found in child‐rearing values and beliefs. Middle class parents in both societies were more likely to value self‐direction and believe that children should have freedom in and around the home, whereas working class parents were more likely to believe that children should be expected to conform to rules. The results of this study underscore the role of within‐society heterogeneity, as a function of social class, in parents' values and beliefs about child‐rearing.     

The 30‐Sec Sale: Using Thin‐Slice Judgments to Evaluate Sales Effectiveness

A successful sale depends on a customer's perception of the salesperson's personality, motivations, trustworthiness, and affect. Person perception research has shown that consistent and accurate assessments of these traits can be made based on very brief observations, or “thin slices.” Thus, examining impressions based on thin slices offers an effective approach to study how perceptions of salespeople translate into real‐world results, such as sales performance and customer satisfaction. The literature on the accuracy of thin‐slice judgments is briefly reviewed. Then, 2 studies are presented that investigated the predictive validity of judgments of salespeople based on thin slices of the vocal channel. Participants rated 20‐sec audio clips extracted from interviews with a sample of sales managers, on variables gauging interpersonal skills, task‐related skills, and anxiety. Results supported the hypothesis that observability of the rated variable is a key determinant in the criterion validity of thin‐slice judgments. Implications for the use of thin‐slice judgments in salesperson selection and customer satisfaction are discussed.     

Methamphetamine abuse and impairment of social functioning: a review of the underlying neurophysiological causes and behavioral implications

The highly addictive drug methamphetamine has been associated with impairments in social cognitions as evidenced by changes in users' behaviors. Physiological changes in brain structure and functioning, particularly in the frontal lobe, have also been identified. The authors propose a biopsychosocial approach to understanding the effects of methamphetamine addiction by relating the physiological effects of the drug to the behaviors and social cognitions of its users, through the application of the theory of mind paradigm. Although onset of methamphetamine use has been linked to the desire for socialization, chronic use has been associated with an increase in depression, aggressiveness, and social isolation, behaviors that also implicate involvement of the frontal lobe. The reviewed literature provides strong circumstantial evidence that social-cognitive functioning is significantly impacted by methamphetamine use and that the social isolation, depression, and aggressiveness associated with chronic use is due to more than just the social withdrawal associated with addiction. Treatment considerations for methamphetamine must therefore consider the role of social cognition, and pharmacological responses must address the documented impact of the drug on frontal lobe functioning.     

Personality factors related to quantitative estimation skill: confirmation and extension

The relationships of two measures of quantitative estimation skill, computational estimation and numerosity estimation, were examined with the 16 PF Global Factors corresponding to the Big Five personality dimensions in a sample of 80 college students. Correlations of Computational Estimation with the 16 PF scores confirmed findings from a previous study which used the NEO-Five Factor Inventory as a measure of the Big Five, specifically showing that Computational Estimation correlated significantly with the 16 PF's Independence factor. Numerosity Estimation did not correlate significantly with any of the 16 PF Global Factors or with any of the ability measures (Computational Estimation, SAT Verbal, SAT Mathematics, and self-rated mathematics ability) used in the study.     

Sense, nonsense, and the use of personality measures

Criticize measurement-based personality research by recounting a well-known limitation: indices of relationship are often inflated because of the similarity of content across measures of presumably different constructs. In this paper we endorse the major contention of Nicholls et al. that measurement-based research may be conducted thoughtlessly, and we extend their thinking by pointing out an important underlying issue—the problem of defining what constitutes a “syndrome.” In contrast to them, however, we argue that the problems in measurement they cite do not entail the consequences they foresee and, in addition, have limited application.