Defensive reactions of “wild-type” and “Domesticated” wild rats to approach and contact by a threat stimulus

Selective breeding of wild rats over many generations on the basis of low or high defensive threat and attack to human approach and contact has produced highly polarized “domesticated” and “wild-type” animals. Because the selection procedure selectively involves these two defense patterns, and these clearly differ in the two groups, it is of interest to determine if other, nonselected, defensive behaviors to threat stimuli also change. “Domesticated” and “wild-type” rats of the thirty-fifth generation were run in a fear defense test battery (F/DTB) to systematically evaluate defensive behaviors to a variety of present threat stimuli. “Domesticated” rats showed reduced avoidance and slower flight speed to an approaching experimenter, reduced jump/startle response to handelap and dorsal contact, less vocalization and boxing to vibrissae stimulation or to an anesthetized conspecific, and reduced defensiveness to an attempted pickup by the experimenter. These results indicate that selective bi-directional breeding for defensive threat and attack to human approach and contact produces group differences in a variety of defensive behaviors, and in defensiveness to stimuli other than those on which the selection was based. © 1994 Wiley-Liss, Inc.     

Getting older and living up to implicit followership theories: Implications for employee psychological health and job attitudes

Age discrimination at work is a widespread destructive phenomenon that often takes subtle forms. Based on negative stereotypes about older employees, we argue that older employees often experience that they are perceived as less ideal followers than younger employees. We propose that older and younger employees do not differ in what they assume their supervisors expect of an ideal follower (implicit followership theories, IFTs). Thus, we hypothesize that older employees perceive that they compare less favorably to their supervisors' IFTs than younger employees (i.e., worse IFT-fit). This should entail lower quality of the relationship between leader and follower (leader-member-exchange, LMX), which, in turn, should have detrimental effects on employees' health (i.e., burnout) and job attitudes (i.e., job satisfaction, turnover intentions, and identification). We tested our model in a field study with 379 employees. Results differed for ideal and counter-ideal follower attributes. Concerning counter-ideal follower attributes (e.g., being incompetent), age had the proposed negative effect on psychological health and job attitudes that mediated through IFT-fit and LMX. Concerning ideal follower attributes (e.g., thinking ahead), older employees expected their supervisors not only to think less of them than of their younger colleagues, but also expected them to have less demanding IFTs—contrary to our expectations. Employee age was negatively related to psychological health and job attitudes, mediated through lower perceived IFTs, worse perceived appraisal of the actual employee and their joint effects on LMX.     

Aging Affects the Ability to Process the Optic Flow Stimulations: A Functional Near-Infrared Spectrometry Study

Abstract

Optic flow (OF) has been utilized to investigate the sensory integration of visual stimuli during postural control. It is little known how the OF speed affects the aging brain during the sensory integration process of postural control. This study was to examine the effect of OF speeds on the brain activation using functional near-infrared spectroscopy (fNIRS) and postural sway between younger and older adults. Eleven healthy younger adults (5M/6F, age 22?±?1-year-old) and ten healthy older adults (4M/6F, age 71?±?5-year-old) participated in this study. A virtual reality headset was used to provide the OF stimulus at different speeds. A forceplate was used to record the center-of-pressure to compute the amplitude of postural sway (peak-to-peak). Compared with younger adults, older adults showed significantly increased activation in the OF speed of 10?m/s and decreased activation in the OF speed of 20?m/s in the left dorsolateral prefrontal cortex. Older adults also showed decreased activation in the left temporoparietal region (VEST) in the OF speed of 20?m/s. A significant difference in peak-to-peak was found between groups. Our results indicated that age might be associated with the ability to process fast OF stimulation.     

Religiosity and Excess Weight Among African-American Adolescents: The Jackson Heart KIDS Study

Recent studies suggest that religion and spirituality can yield health benefits for young African-Americans. We examined the relationship between religious practices, spirituality, and excess weight among African-American adolescents (N = 212) residing in the Deep South. Results from modified Poisson regression analysis indicate that adolescents who prayed daily had a lower prevalence of excess weight (PR 0.77 [95% CI 0.62–0.96]) than those who did not. This relationship was only significant for 12–15 year-old participants in age-stratified analysis. These findings suggest that preventive interventions offered to children and younger adolescents can have implications for weight status across the lifespan.

     

The Value of Perception

This paper develops a form of transcendental naïve realism. According to naïve realism, veridical perceptual experiences are essentially relational. According to transcendental naïve realism, the naïve realist theory of perception is not just one theory of perception amongst others, to be established as an inference to the best explanation and assessed on the basis of a cost-benefit analysis that weighs performance along a number of different dimensions: for instance, fidelity to appearances, simplicity, systematicity, fit with scientific theories, and so on. Rather, naïve realism enjoys a special status in debates in the philosophy of perception because it represents part of the transcendental project of explaining how it is possible that perceptual experience has the distinctive characteristics it does. One of the potentially most interesting prospects of adopting a transcendental attitude towards naïve realism is that it promises to make the naïve realist theory of perception, in some sense, immune to falsification. This paper develops a modest form of transcendental naïve realism modelled loosely on the account of the reactive attitudes provided by Strawson in ‘Freedom and Resentment’, and suggests one way of understanding the claim that naïve realism is immune to falsification.     

Predatory aggression in the mink (Mustela vison): Roles of serotonin and food satiation

5-Hydroxytrypotophan at a dose of 50 mg/kg intraperitoneally (i.p.) sharply increased neural serotonin (5-HT) levels in mink and considerably inhibited that animal's predatory attack on rats. Intraperitoneal injection of 5-HT (10 and 20 mg/kg) did not influence such rat-killing. Neural levels of 5-HT or 5-hydroxyindoleacetic acid (5-HIAA) and subsequent aggression by the predator did not change to any great degree after ingestion of a single meal. Abundance of natural mink food for 3 days was associated with an increased level of 5-HIAA in the lateral hypothalamus and the amygdala as well as with an increased latency to attack and to kill rats. 5-HT seems to represent an endogenous factor that inhibits predatory attack by the mink; this effect appears to function through increased metabolism of 5-HT in some brain regions, which is evident after abundant intake of tryptophan with the natural diet.     

The effects of gendered information in stories on preschool children’s development of gender stereotypes

Social-cognitive theory posits that children learn gender stereotypes through gendered information. The present study examined whether children learn new gender stereotypes from stories when unknown words are linked to a gendered protagonist or context information. In Experiment 1, 40 3- to 6-year-old preschoolers were read stories with either a gendered protagonist embedded within a non-gendered context, or a non-gendered protagonist embedded within a gendered context. In Experiment 2, the same sample of children were read stories with the protagonist and the context displaying congruent or incongruent gender information. Each story featured an unknown activity linked with the stereotypical content. Both experiments indicate that the children rated the activity according to both the gender of the context and of the protagonist; however, the effect of the latter was stronger. In addition, children showed higher interest in the unknown activity if the protagonist’s gender matched their own sex. Thus, gender information in stories influences how children perceive unknown words.     

The utility of ground rule instructions with younger and older adult witnesses

This study examined the effectiveness of ground rules—simple instructions outlining the communication expectations of an investigative interview—with 73 younger (age 18–40) and 57 older (age 60+) adults. Participants watched a film depicting an implied sexual assault and were interviewed after a brief delay. One third received no ground rules, one third received ground rules as statements, and one third received the statements along with practice examples. The interview contained questions that required participants to apply one of the rules. Those who received ground rules were asked their perceptions of the rules. Results demonstrated that practicing ground rules improved response quality to problematic recognition questions, younger adults showed more variability in responses to different ground rules than older adults, and most participants found ground rule instructions useful in investigative interviews. Results provide support for the use of ground rules in interviews with adult witnesses.     

Image-size disparity reduces difference detection in face matching

Face matching is the act of deciding whether two facial images depict the same person or different people. The real-world face-matching task of checking photo IDs typically occurs under conditions of image-size disparity: A small picture is compared with a life-size face. We examined the effect of image-size disparity on face-matching accuracy. In three experiments, subjects were presented with pairs of equivalently or disparately sized images that depicted the same person or different people. Subjects made same/different judgments and, in two experiments, also reported confidence. Difference detection was significantly poorer given disparate (versus equivalent) image size. Confidence was significantly higher when responses were correct versus incorrect. These findings held whether viewing and decision time was unlimited or limited. Our results raise the practical concern that image-size disparity may undermine difference detection in ID checking, while also indicating that people have some insight into the accuracy of their face-matching judgments.