A fast numerical algorithm for the estimation of diffusion model parameters

In this paper, we describe a new algorithmic approach for parameter estimation in Ratcliff's [(1978). A theory of memory retrieval. Psychological Review, 85 (2), 59-108] diffusion model. This problem, especially if inter-trial variabilities of parameters are included in the model, is computationally very expensive; the parameter estimation procedure often takes a long time even with today's high-speed computers. The algorithm described here makes the calculation of the cumulative distribution functions for predicted process durations computationally much less expensive. This improvement is achieved by solving the Kolmogorov backward equation numerically instead of employing the previously used closed form solution. Additionally, the algorithm can determine the optimum fit for one of the model parameters (the starting point z) directly, thereby reducing the dimension of the parameter search space by one. The resulting method is shown to be notably faster than the standard (closed-form solution) method for parameter estimation.     

Both predator and prey: emotional arousal in threat and reward

This research examined the psychophysiology of emotional arousal anticipatory to potentially aversive and highly pleasant outcomes. Human brain reactions (event-related potentials) and body reactions (heart rate, skin conductance, the probe startle reflex) were assessed along motivational gradients determined by apparent distance from sites of potential punishment or reward. A predator-prey survival context was simulated using cues that signaled possible money rewards or possible losses; the cues appeared to loom progressively closer to the viewer, until a final step when a rapid key response could ensure reward or avoid a punishing loss. The observed anticipatory response patterns of heightened vigilance and physiological mobilization are consistent with the view that the physiology of emotion is founded on action dispositions that evolved in mammals to facilitate survival by dealing with threats or capturing life-sustaining rewards.     

Stimulus frequency influences spontaneous perceptual reversals in ambiguous apparent motion

The temporal integration of continuous sensory information into a temporally extended percept becomes evident in spontaneous reversals of ambiguous apparent motion. To study the temporal relation of spontaneous percept reversals and temporal stimulus properties, we systematically varied presentation frequency in an ambiguous-apparent-motion paradigm. Moreover, we triggered percept reversals in a manner that was not consciously perceived by manipulating the duration of single frames. We found that the reversal rate depended on the stimulus frequency (with higher frequencies resulting in faster percept reversals) and that we could externally trigger perceptual reversals. Our findings support the idea that spontaneous reversals of ambiguous apparent motion are influenced by bottom-up effects at early processing levels. The paradigm allows for specific contrasts of spontaneous and externally triggered (but otherwise identical) perceptual reversals and, by this means, for further study of the underlying mechanisms.     

Perfectionism and performance in a new basketball training task: Does striving for perfection enhance or undermine performance?

ObjectivesIn the psychology of sport and exercise, the question of how perfectionism affects performance is highly debated. While some researchers have identified perfectionism as a hallmark quality of elite athletes, others see perfectionism as a maladaptive characteristic that undermines, rather than helps, athletic performance. Against this background, the purpose of the present study was to investigate how different aspects of perfectionism predict performance and performance increments.MethodA study was conducted with 122 undergraduate athletes to investigate how perfectionism during training affects performance and performance increments in a series of trials with a new basketball training task. Two aspects of perfectionism were examined: striving for perfection and negative reactions to imperfection.DesignThe design was a correlational prospective design.ResultsResults showed that striving for perfection during training predicted higher performance in the new task. In contrast, negative reactions to imperfection predicted lower performance when athletes attempted the task for the first time, once the positive influence of striving for perfection on task performance was partialled out. However, negative reactions to imperfection did not undermine performance in the consecutive trials. On the contrary, athletes with both high levels of striving for perfection and high levels of negative reactions to imperfection showed the greatest performance increments over the series of trials.ConclusionThe findings suggest that perfectionism is not necessarily a maladaptive characteristic that generally undermines sport performance. Instead, when learning a new training task, perfectionism may enhance performance and lead to performance increments over repeated trials.     

From relational equality to personal responsibility

Philosophical Studies - According to relational egalitarians, equality is not primarily about the distribution of some good but about people relating to one another as equals. However, compared...     

„Nanotechnologie“ als neue „Schlüsseltechnologie“?—Versuch eines historischen und systematischen Vergleichs mit anderen Technologien

Nanotechnology seems to be a new “key-discipline”, which should lead to basic changes in many areas of living and producing. This estimation is questioned by a comparison with established technologies, which reach from heat engines to biotechnology. In this line it is possible to come to a more realistically assessment of nanotechnology. “Technologies” in the narrower sense are understood as techniques based scientifically and integrated systematically into a network. The development of these technologies starts first in the early modern times. Before this background the established technologies are characterised looking at relevant questions and problems, the role of researchers and inventors, the importance of theoretical foundations, important applications and innovations, as well as the relevance of visions and then confronted with nanotechnology in its present state. It is accentuated that there are no explicit theories and no specific applications of nanotechnology and it seems to be only a kind of chemical technology.

Gamma oscillations distinguish true from false memories

ABSTRACT— To test whether distinct patterns of electrophysiological activity prior to a response can distinguish true from false memories, we analyzed intracranial electroencephalographic recordings while 52 patients undergoing treatment for epilepsy performed a verbal free-recall task. These analyses revealed that the same pattern of gamma-band (28–100 Hz) oscillatory activity that predicts successful memory formation at item encoding—increased gamma power in the hippocampus, prefrontal cortex, and left temporal lobe—reemerges at retrieval to distinguish correct from incorrect responses. The timing of these oscillatory effects suggests that self-cued memory retrieval begins in the hippocampus and then spreads to the cortex. Thus, retrieval of true, as compared with false, memories induces a distinct pattern of gamma oscillations, possibly reflecting recollection of contextual information associated with past experience.     

Staying in or moving away from structured activities: Explanations involving parents and peers

Adolescent participation in structured activities, meaning those with adult leaders, regular meetings, and skill-building activities, is related to good adjustment. Participation in unstructured, unsupervised, peer-oriented activities is related to poor adjustment. Structured activity participation is high in early adolescence and then declines, raising the question of why youths leave structured activities. The authors examined explanations involving parents and peers. They used longitudinal data from 861 youths (ages 13-17 years). Results showed that, compared with youths who stayed in structured activities, those who switched to hanging out on the streets were less likely to have peers in structured activities and had less positive feelings about the home context and more negative interactions with parents. In addition, delinquency predicted switching to hanging out in the streets and never joining structured activities in the first place. The results concerning parents support a theoretical explanation of how parents might unintentionally affect youths' leisure choices. Furthermore, the authors found some indications that positive feelings at home might protect youths who switch from structured activities to hanging out on the streets from increases in delinquency.     

Intentions and expectations in temporal binding

Recently, it has been shown that the perceived times of voluntary movements and their effects are perceived as shifted towards each other. This temporal binding phenomenon was explained by an integrated representation of movement and effect, facilitating operant learning and the experience of intentionality. Here, we investigated whether temporal binding depends on explicit intentional attributions. In Experiment 1, participants intended to either produce or avoid producing an effect (a tone) by the timing of their movements, with the ratio of success being fixed at 2:1. In Experiments 2 and 3, the influence of the action-effect contingency ratio on temporal binding was controlled for by removing the intentional attribution of the effect. The results indicate that temporal binding is a general associative mechanism that facilitates the learning of movement-effect contingencies. Beyond that, temporal binding is sensitive to explicit intentional attributions, which selectively enhance the link between an intentional movement and the effect a moving agent intends to produce.