Context-dependent alarm responses in wild vervet monkeys

Animal Cognition - The alarm calls of nonhuman primates are occasionally cited as functionally equivalent to lexical word meaning in human language. Recently, however, it has become increasingly...     

Can we predict non-response in developmental tasks? Assessing the longitudinal relation between toddlers' non-response and early academic skills

To date, virtually no studies have examined toddlers' non-response in developmental tasks. This study investigates data from 3667 toddlers to address (1) whether two aspects of non-response (completion and engagement) are separable, (2) how stable these aspects are from ages two to three, (3) how non-response relates to background characteristics, and (4) whether non-response at ages two and three predicts early academic skills at age six. Structural equation modelling shows that completion and engagement are separable constructs, relatively stable across age, and related to several background characteristics. Especially engagement predicts later academic performance. Results show that non-response in behavioural tasks in toddlers is not random, increasing the likelihood of sampling bias and lack of generalizability in developmental studies.     

Stolen elections: How conspiracy beliefs during the 2020 American presidential elections changed over time

Conspiracy beliefs have been studied mostly through cross-sectional designs. We conducted a five-wave longitudinal study (N = 376; two waves before and three waves after the 2020 American presidential elections) to examine if the election results influenced specific conspiracy beliefs and conspiracy mentality, and whether effects differ between election winners (i.e., Biden voters) versus losers (i.e., Trump voters) at the individual level. Results revealed that conspiracy mentality kept unchanged over 2 months, providing first evidence that this indeed is a relatively stable trait. Specific conspiracy beliefs (outgroup and ingroup conspiracy beliefs) did change over time, however. In terms of group-level change, outgroup conspiracy beliefs decreased over time for Biden voters but increased for Trump voters. Ingroup conspiracy beliefs decreased over time across all voters, although those of Trump voters decreased faster. These findings illuminate how specific conspiracy beliefs are, and conspiracy mentality is not, influenced by an election event.     

Developing the social identity theory of leadership: Leader agency in leader group prototypicality

The social identity theory of leadership is a unique perspective in leadership research in capturing how responses to leadership are informed by how the leader is perceived through the lens of the group identity shared by leaders and followers. I review the theory in broad strokes to make the case that a particularly valuable future development of the theory is to complement the theory's emphasis on group member (follower) perceptions of leader group prototypicality, the extent to which the leader is perceived to embody the group identity, with theory and evidence speaking to leader agency in influencing such perceptions.     

RELATIONS BETWEEN PREDICTION- AND ESTIMATION-RESPONSES IN CUE-PROBABILITY LEARNING AND TRANSFER

B auer M arianne Relations between prediction- and estimation-responses in cue-probability learning and transfer. Scand. J. Psychol ., 1972, 13 , 198–207. —Comparisons were made between prediction- and estimation-responses, preceded by training with different types of responding and when task probabilities were shifted. The main results were: ( a ) differential effects of procedure of learning and shift in task structure on predictions and estimates support the hypothesis of two different processes, ( b ) estimates as indicators of probability learning reflect traits assumed to characterize the perception process, viz. sensitivity to shifts in probabilities, and robustness against influence from procedure of learning, and ( c ) prediction-responses were affected in the direction of more extreme responses by simultaneous estimation, which result strengthens the supposition that probability estimates are insufficient as indicators of the complete perception process in a prediction task.     

PSYCHOPHYSIOLOGICAL REACTIONS TO TWO DIFFERENT PLACEBO TREATMENTS

Reactions to a placebo introduced either as a depressant or as a stimulant drug were examined in 16 healthy female subjects. Comparisons between pre- and post-placebo measurements showed that the two treatments produced marked effects in opposite directions: (1) the 'depressant' placebo produced a statistically significant decrease in pulse rate, blood pressure, objective and subjective reaction speed, as well as significant effects on subjective mood in the expected directions, and (2) the 'stimulant' placebo produced opposite and significant changes in all variables. The subjective reactions were, on the whole, more pronounced than the effects on performance and physiological functions.     

AUTONOMIC INDICES OF HABITUATION TO COMPLEX AND SIMPLE STIMULI

Skin conductance and heart rate were continuously recorded in 8 subjects repeatedly exposed to a perceptual-conflict test and to auditory signals. (1) Both complex and simple stimuli gave rise to a pronounced increase in skin conductance, the magnitude of response decreasing with number of repetitions. For both types of stimuli a linear relationship was obtained when GSR, measured as the change in log conductance, was plotted against the logarithm of the stimulus number. (2) Each presentation of the conflict test increased heart rate, magnitude of change decreasing approximately linearly with number of trials.     

SUBJECTIVE TIME AS AFFECTED BY GRAVITATIONAL STRESS

Subjective time as affected by positive radial acceleration in a human centrifuge was studied by a modification of the method of ratio production. Auditory signals (1–20 sec.) were used as stimuli. The results showed a marked change in subjective time during gravitational stress. Subjective time, as measured by the methods employed, was a positively accelerated function of objective time and the positive acceleration was enhanced during centrifugation. The demonstrated change in time experience was caused by a difference in retention of preceding time intervals, retention being impaired during centrifugation.     

THE INFLUENCE OF INTENSITY AND DURATION OF ELECTRICAL STIMULATION ON SUBJECTIVE VARIABLES

The unpleasantness and subjective duration of an A.C. current of 50 c/sec applied to two fingers was scaled by subjects using the method of magnitude estimation. Stimulation was varied with regard to both intensity and duration. It was found that (1) unpleasantness increased logarithmically with stimulus duration, (2) unpleasantness was a power function, with the exponent 1.5, of stimulus intensity, (3) subjective duration was essentially linearly related to stimulus duration, and (4) subjective duration increased logarithmically with intensity of stimulation.