Equating the brightness of brief visual stimuli of unequal durations

The brightness of brief displays whose durations do not exceed a critical period of integration is known to covary with stimulus duration (Bloch’s law). There are cases in which the interdependence of duration and brightness introduces an unwanted confounding that must be avoided. Three methods for equating the brightness of brief stimuli displayed under computer control are described and evaluated, and an example of the outcome obtained with the most efficient procedure is reported.     

Prenatal maternal stress: Differential effects upon male and female offspring responses to restraint stress as adults

Pregnant primiparous rats were subjected to four days of light restraint stress on postconception days 7 through 10, inclusive, coincident with the development of the fetal gastrointestinal system. Twenty male and twenty female offspring from prenatally stressed and nonstressed rats were then subjected to two hours of supine cold-restraint as adults. Eighty percent of nonprenatally stressed offspring developed gastric lesions, while 47.5% of offspring of prenatally stressed mothers displayed lesions. A significant sex-stress interaction was detected, indicating that male offspring from prenatally stressed mothers display less severe gastric lesions in response to restraint stress as adults than do male offspring from nonprenatally stressed mothers. Female offspring from both prenatal stress conditions showed similar levels of stress-induced lesions.     

Food anticipation and lever-directed activities in rats

Three experiments are described which elaborate some of the conditions under which rats will contact and manipulate a periodically presented retractable lever. Experiment 1 demonstrated that (i) initial manipulative oral and manual contact with the lever was facilitated if the rat had previous experience of food delivery in the experimental chamber; (ii) persistence in contacting the lever on successive presentations was a function of whether food continued to be presented in the experimental environment; and (iii) food satiation significantly reduced the tendency of the rat to contact the lever even though an expectancy of food had previously been established under conditions of food deprivation. Experiment 2 suggested that the tendency to approach and contact the lever was in part a function of the local moment-to-moment conditional probability of food delivery. Experiment 3 found that the probability of contacting the lever was higher during presentation of an auditory CS signaling a high rate of food delivery than during stimuli signaling no food at all. These results are interpreted as suggesting that the food-signaling aspects of an appetitive CS and that CS's ability to generate signal-directed behaviors are experimentall separable properties.     

Are curmudgeon personality scales resistant to response distortion?

Curmudgeon personality, which is assessed by having participants evaluate a heterogeneous set of attitude objects, provides an applied value beyond that of more established personality traits. Recent research, for instance, suggests that curmudgeon personality is distinct from the Five Factor Model personality traits and that it predicts unique variance in important criteria, such as job attitudes and well-being. In the current paper we contribute to this literature by testing an explanation of how curmudgeon personality is distinct from other traits—their potential resistance to response distortion. We estimated response distortion for scales of curmudgeon personality and FFM traits across two quasi-experimental studies. As expected, the score shifts between nonapplicant and applicant conditions were smaller for scales of curmudgeon personality compared to scales of emotional stability and conscientiousness. We argue that curmudgeon personality scales may be more resistant to response distortion than are measures of other traits because curmudgeon personality items are semi-implicit and lack an obvious desirable response. The resistance to response distortion should serve as a call to future researchers to test the criterion validity of curmudgeon personality in regard to performance criteria.