Effects of Control on the Stress Reactions of Commuters1

The effects of morning, rush hour commuting were examined in a quasi-experimental field study involving government-employed commuters (single and carpool drivers). Commuting stress was measured as a response to variations in how difficult it was for commuters to move from home to work. The mediation of these effects by two sources of control in the commuting situation also were assessed. Control was operationalized as control over the internal environment of the car (single versus carpool driver) and choice over routes taken to get to work. Among commuters with a high impedance route, driving to work was associated with significant increases in systolic and diastolic blood pressure and decreases in behavioral performance. The stress of commuting under high impedance conditions was reduced for single drivers relative to carpoolers. Under similar conditions of high impedance, however, having the option to select more than one route to get to work seemed to be more stressful than having only one route. The practical implications of these results are discussed.     

Some parameters affecting the distributional properties of operant-level running in rats

Six adult female albino rats were subjected to operations known to increase the frequency of wheel-running. Operations included limited access to wheel, food deprivation, and protracted maintenance on a 24-hr feeding schedule. A distributional analysis of response duration, burst duration, and inter-burst interval showed that the increased frequency in all cases arose mainly from a shortening of the interval between successive bursts. Only short-term food deprivation produced any notable increase in burst length, and even here changes in both speed of the individual responses and in number of responses per burst were slight compared to changes in inter-burst interval.     

Distributional properties of operant-level locomotion in the rat

Four rats had continuous access to activity wheels first, then access for 1 hr per day, and, subsequently, continuous access. Limiting S's access to the wheel substantially increased the total frequency of running. A distributional analysis of response duration, burst duration, and interburst interval showed that the increased frequency arose almost entirely from a shortening of the interval between successive bursts. In contrast, speed of the individual response and number of responses per burst changed only negligibly. If S were running, the probability that it would either stop or continue did not differ appreciably for the conditions of continuous or limited access to the wheel. But if S were not running, the probability that it would start running was appreciably greater for limited than for continuous access.     

The role of socio-communicative rearing environments in the development of social and physical cognition in apes

The cultural intelligence hypothesis (CIH) claims that humans’ advanced cognition is a direct result of human culture and that children are uniquely specialized to absorb and utilize this cultural experience ( Tomasello, 2000 ). Comparative data demonstrating that 2.5‐year‐old human children outperform apes on measures of social cognition but not on measures of physical cognition support this claim ( Herrmann et al., 2007 ). However, the previous study failed to control for rearing when comparing these two species. Specifically, the human children were raised in a human culture whereas the apes were raised in standard sanctuary settings. To further explore the CIH, here we compared the performance on multiple measures of social and physical cognition in a group of standard reared apes raised in conditions typical of zoo and biomedical laboratory settings to that of apes reared in an enculturated socio‐communicatively rich environment. Overall, the enculturated apes significantly outperformed their standard reared counterparts on the cognitive tasks and this was particularly true for measures of communication. Furthermore, the performance of the enculturated apes was very similar to previously reported data from 2.5‐year‐old children. We conclude that apes who are reared in a human‐like socio‐communicatively rich environment develop superior communicative abilities compared to apes reared in standard laboratory settings, which supports some assumptions of the cultural intelligence hypothesis.     

Modeling growth in boys' aggressive behavior across elementary school: links to later criminal involvement, conduct disorder, and antisocial personality disorder

The present study used general growth mixture modeling to identify pathways of antisocial behavior development within an epidemiological sample of urban, primarily African American boys. Teacher-rated aggression, measured longitudinally from 1st to 7th grade, was used to define growth trajectories. Three high-risk trajectories (chronic high, moderate, and increasing aggression) and one low-risk trajectory (stable low aggression) were found. Boys with chronic high and increasing trajectories were at increased risk for conduct disorder, juvenile and adult arrest, and antisocial personality disorder. Concentration problems were highest among boys with a chronic high trajectory and also differentiated boys with increasing aggression from boys with stable low aggression. Peer rejection was highest among boys with chronic high aggression. Interventions with boys with distinct patterns of aggression are discussed.     

A company-based lottery to reduce the personal driving of employees

A company-based lottery was used to reduce the number of nonessential miles employees drove their personal cars each day and thereby save gasoline. Employees were divided into an experimental and a contrast group. The experimental design involved two conditions: (a) a baseline in which no consequences were attached to driving behavior, and (b) a month-long lottery in which the experimentals were rewarded for decreasing their percentage of average miles driven per day relative to their initial baseline average. The experimentals received an ABA order of conditions while the contrast group remained in baseline. The lottery condition consisted of four weekly lotteries and one grand drawing held at the end of the month. During the lottery condition, the experimentals reduced their average daily mileage by 11.6% relative to their initial baseline (7.85 miles per employee per day) while the contrast employees increased their average mileage by 21.2%. Both groups exceeded their initial baseline averages in the return to baseline. The study was almost cost-effective because the experimentals' gas savings ($75) was within $4 of the cost of motivating them to reduce their mileage ($79).     

How do generic statements impact performance? Evidence for entity beliefs

Generic statements about the abilities of children's social groups (e.g. ‘Girls/Boys are good at this game’) negatively impact children's performance – even if the statements are favorable towards children's own social groups. We explored the mechanism by which generic language impairs children's performance. Across three studies, our findings suggest that generic statements influence children's performance by creating an entity belief (i.e. a belief that a fixed ability determines performance). Children who were exposed to a generic statement about their social group's ability performed worse than children in control conditions. This effect hurt children's performance even when the person who made the generic statement was no longer present and a new person not privy to the statement replaced them. However, when children heard a generic statement paired with an effort explanation (i.e. ‘Girls/Boys are good at this game because they try really hard when they draw’) they performed better than children who heard the generic statement with no explanation (i.e. just ‘Girls/Boys are good at this game’) and children who heard the generic statement paired with a trait explanation (i.e. ‘Girls/Boys are good at this game because they are smart and really good at drawing’). This work uncovers when and how generic statements that refer to the ability of one's social group hinder performance, informing the development of practices to improve student motivation and learning.