Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle

Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. The risetime is a parametric characteristic of the eliciting stimulus frequently used to differentiate among psychophysiological reflexes. The aim of the present study was to examine the effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. 100 participants underwent a psychophysiological reactivity test to five presentations of an intense acoustic stimulus (105 dB white noise) under one of five risetime conditions: 0, 24, 48, 96, and 240 ms. Total energy of the stimulus was controlled by increasing the base duration of the stimulus (1000 ms) by one third of the risetime. Results showed that risetime significantly affected motor startle but not cardiac defense. Startle amplitude decreased linearly with increasing risetime after 24 ms. On the other hand, repetition of the stimulus significantly affected cardiac defense but not motor startle. These results question the traditional differentiation between startle and defense based on risetime.     

Human sensitivity to reinforcement: A comment on Kollins, Newland, and Critchfield's (1997) quantitative literature review

In a quantitative review of human operant experiments, Kollins, Newland, and Critchfield (1997) found that humans are less sensitive to reinforcement contingencies than nonhumans are. Human performances were not as consistent with the matching law, and they were more variable from subject to subject. Some of the variables correlated with reduced human sensitivity were surprising. These included collection of the data under more controlled conditions (laboratory rather than naturalistic settings), and inclusions of discriminative stimuli correlated with alternative sources of reinforcement. We discuss these unexpected findings in the light of criticisms that have been leveled against meta-analytic literature reviews (e.g., the wisdom of grouping studies with widely diverse methods), and we suggest ways of improving future analyses of the behavior-analytic literature.     

Heightened sexual arousal and physical aggression: An extension to females

In order to examine the effects of heightened sexual arousal upon aggression by females, subjects were first angered or not angered by a female confederate, next exposed to one of four types of stimuli (nonerotic scenes; pictures of seminude young males; pictures of nude males; pictures of couples engaged in various acts of lovemaking), and finally provided with an opportunity to aggress against the confederate by means of electric shock. In accordance with previous research conduced with males, it was hypothesized that exposure to mild erotic stimuli would inhibit subsequent aggression, while exposure to more arousing stimuli of this type would facilitate such behavior. Results offered support for both predictions. In addition, it was found that females responded with increased aggression to types of erotic stimuli previously found to inhibit such behavior by males.     

Socially mediated fear reduction in rodents: Distraction,communication, or mere presence?

Two studies investigated why the presence of conspecifics reduces open-field fear. In Experiment 1 rats paired with another experimentally naive rat were not less fearful than alone controls. However, rats paired with a partner who had been preexposed to the open field exhibited fewer fear responses than alone controls. Since preexposed companions appeared to initiate more social interactions than nonpreexposed companions, it was argued that the preexposure effect could be the result of preexposed companions distracting actor rats from threatening stimuli. Experiment 2 tested this explanation by pairing socially sated or socially deprived rats with a socially sated or socially deprived companion. In accord with a distraction hypothesis, pairing two socially deprived rats produced the greatest fear reduction effects and also led to more social interaction than pairing socially sated rats. Alternative explanations involving conditioning and communication are discussed.     

Desired control and felt control as mediators of stress in a dental setting

Control-related variables have clearly affected stress responses in previous research (Thompson, 1981). Prior work, however, has primarily emphasized the amount of control that subjects perceive they have. In the three studies reported here, we examined the added predictive utility of assessing subjects' desire for control. Data from all three studies indicate that subjects who have a high desire for control coupled with a low feeling of control are characterized by particularly high degrees of dental distress. These results were found both in settings where patients anticipated immediate dental treatment and where treatment was not imminent. In addition, the results indicate that this "at risk" group reported greater distress before and immediately after actual dental treatment. Furthermore, they remembered their dental treatment as being more aversive 1 week after treatment. The practical implications and theoretical significance of these data are considered.     

When does algorithmic decomposition help? commentary

Algorithmic decomposition is a way of extending thinking. It will help when thinking is otherwise poor, and it may hinder when thinking is otherwise adequate. It may help decision making more than it helps numerical estimation.     

Psychological Perspectives on Entrepreneurship: Cognitive and Social Factors in Entrepreneurs' Success

Why are some entrepreneurs so much more successful than others in starting new companies—ones that create wealth for their societies as well as themselves? Growing evidence suggests that the answer involves the influence of both cognitive and social factors. Successful entrepreneurs appear to think differently than other persons in several respects (e.g., they are less likely to engage in counterfactual thinking but more likely to show overconfidence in their judgments). Similarly, successful entrepreneurs appear to be higher in social competence —the ability to interact effectively with others (e.g., they are better at social perception and adapting to new social situations). These results suggest that the principles and findings of psychology can be invaluable to researchers in the field of entrepreneurship, providing important insights into the factors that influence entrepreneurs' success.     

The curious case of spacetime emergence

Philosophical Studies - Work in quantum gravity suggests that spacetime is not fundamental. Rather, spacetime emerges from an underlying, non-spatiotemporal reality. After clarifying the type of...     

Grounding at a distance

Philosophical Studies - What distinguishes causation from grounding? One suggestion is that causation, but not grounding, occurs over time. Recently, however, counterexamples to this simple...