Deprivation and satiation: The interrelations between food and wheel running

Two experiments were designed to assess whether depriving rats of food would increase the reinforcement effectiveness of wheel running (Experiment 1) and whether satiation for wheel running would decrease the reinforcement effectiveness of food (Experiment 2). In Experiment 1, a progressive-ratio schedule was used to measure the reinforcement effectiveness of wheel running when rats were deprived or not deprived of food. Completion of a fixed number of lever presses released a brake on a running wheel for 60 s, and the response requirement was systematically increased until the rat stopped pressing or until 8 hr had elapsed. The ratio value reached (and the total number of lever presses) was an inverted-U function of food deprivation (percentage body weight). In Experiment 2, when wheel running preceded test sessions, fewer food-reinforced lever presses were maintained by the progressive-ratio schedule, and responding occurred at a lower rate on a variable-interval schedule. An interpretation of these results is that deprivation or satiation with respect to one event (such as food) alters the reinforcement effectiveness of a different event (such as access to wheel running).     

Alternative fixed-ratio fixed-interval schedules of reinforcement

Five rats were trained under alternative fixed-ratio fixed-interval schedules, in which food reinforcement was provided for the completion of either a fixed-ratio or a fixed-interval requirement, whichever was met first. Overall response rate and running rate (the rate of responding after the postreinforcement pause) decreased for all subjects as the fixed-ratio value increased. As the proportion of reinforcements obtained from the fixed-ratio component increased and the alternative schedule approached a simple fixed ratio, overall response rate and running rate both increased; conversely, as the proportion of reinforcements obtained from the fixed-interval component increased and the alternative schedule approached a simple fixed interval, response rates decreased. Postreinforcement pause length increased linearly as the average time between reinforcements increased, regardless of the schedule parameters. A break-run pattern of responding was predominant at low- and medium-valued fixed ratios. All subjects displayed at least occasional positively accelerated responding within interreinforcement intervals at higher fixed-ratio values.     

Progressive-ratio schedules: effects of later schedule requirements on earlier performances

Four rats were studied with variants of a progressive-ratio schedule with a step size of 6 in which different terminal components followed completion of the 20th ratio: (a) a reversal of the progression, (b) a fixed-ratio 6 schedule, or (c) extinction. Responding in the progressive-ratio components of these schedules was compared to performances under conventional progressive-ratio baselines. Under baseline conditions, postreinforcement pauses increased exponentially as a function of increasing ratio size, whereas running rates showed modest declines. The procedure of linking the progressive-ratio schedule to the reversed progression or to the fixed-ratio component resulted in decreased pausing. Linking the progressive-ratio schedule to the extinction component had the opposite effect, that of producing weakened progressive-ratio performances as evidenced by increased pausing. Subjects whose responses were reinforced on half of the ratios also showed exponential increases; however, pauses were substantially shorter following ratios on which the reinforcer was omitted. The results suggested that progressive-ratio pausing reflects the influence of remote as well as local contingencies.     

Responding for sucrose and wheel-running reinforcement: effects of sucrose concentration and wheel-running reinforcer duration

Six male albino rats were placed in running wheels and exposed to a fixed-interval 30-s schedule of lever pressing that produced either a drop of sucrose solution or the opportunity to run for a fixed duration as reinforcers. Each reinforcer type was signaled by a different stimulus. In Experiment 1, the duration of running was held constant at 15 s while the concentration of sucrose solution was varied across values of 0, 2.5. 5, 10, and 15%. As concentration decreased, postreinforcement pause duration increased and local rates decreased in the presence of the stimulus signaling sucrose. Consequently, the difference between responding in the presence of stimuli signaling wheel-running and sucrose reinforcers diminished, and at 2.5%, response functions for the two reinforcers were similar. In Experiment 2, the concentration of sucrose solution was held constant at 15% while the duration of the opportunity to run was first varied across values of 15, 45, and 90 s then subsequently across values of 5, 10, and 15 s. As run duration increased, postreinforcement pause duration in the presence of the wheel-running stimulus increased and local rates increased then decreased. In summary, inhibitory aftereffects of previous reinforcers occurred when both sucrose concentration and run duration varied; changes in responding were attributable to changes in the excitatory value of the stimuli signaling the two reinforcers.     

Traffic safety climate attitudes of road users in Germany

This paper validates traffic safety climate attitudes based on a representative sample of road users of all travel modes. We use the German version of the Traffic Climate Scale (TCS) which was applied in a large-scale road safety survey in 2010. A total of 1680 people were surveyed. The sample is representative for socio-demographic characteristics and travel mode choice in Germany. Factor analysis reveals a three-factor structure of traffic safety climate with the factor ‘External affective demands’ describing emotional engagement in traffic, the factor ‘Internal requirements’ representing individual skills and abilities to successfully participate in traffic, and the factor ‘Functionality’ describing requirements for a functional traffic system. The less emotionally demanding and the more functional traffic is perceived to be, the safer people feel in traffic. External affective demands are consistently related to the perception of others’ driving/riding style but not to one’s own, whereas internal requirements are consistently related to one’s own driving/riding style but not to the perception of others. There is no relation between traffic safety climate and accidents or near accidents. Contrary to our expectations, a positive traffic safety climate is associated with more secondary tasks while driving and traffic violations. Behavioural control beliefs may mediate the traffic climate–traffic behaviour relationship. The results are discussed with reference to attitude research and the theory of planned behaviour in particular.     

Comparing elite male and female distance runner's experiences of disordered eating through narrative analysis

ObjectivesResearchers have called for additional forms of theorizing and qualitative methodologies to explore disordered eating in athletes. The current study used social constructionism and narrative analysis to compare and contrast the disordered eating experiences of one male and female athlete.DesignNarrative inquiry was combined with an in-depth case study approach to explore the narrative and gendered construction of disordered eating in one elite male (age 19) and female (age 34) distance runner. The personal and cultural narratives drawn upon to construct meanings around the body, food and running and how these framed experiences were of interest.MethodsA structural and performative narrative analysis was conducted on four in-depth interviews (i.e., both runners participated in two separate interviews).ResultsBoth runners drew upon a performance narrative to construct running experiences and self-identities as elite athletes. When elite athletic identity became threatened by moments of perceived failure (e.g., poor performance, injury), disordered eating thoughts and behaviors emerged for both runners. Gendered narratives around the body, food and running further differentiated specific meanings and the emotional impact of these experiences for each male and female athlete.ConclusionsThis study extends quantitative and qualitative explorations of disordered eating in distance runners by highlighting additional understandings of the complex social, cultural and gendered construction of these experiences.     

Contextual effects on activity profiles of domestic field hockey during competition and training

Game context is widely accepted to influence performance but most data available is ‘categorical’ and addresses performance rather than activity. This study assessed direct effects of opposition and team ranking in field hockey to establish influences on activity. One hundred and eight (n = 108) female field hockey players (age 16–39 years) participated, giving 186 competition and 48 training analyses. Team average distance (mean ± SD) observed in a mid-ranked team during competition ranged from 5949 ± 611 to 7719 ± 257 m demonstrating an opposition rank effect (Pearson’s r = .71; adjusted R² = .42). However, multiple linear regression analysis demonstrated a stronger relationship in lower ranked teams (Pearson’s r = .99; adjusted R² = .97 through 3–9). In contrast, no team rank effect was observed during randomly monitored competition where team average distance ranged from 5177 ± 444 to 7316 ± 241 m (Pearson’s r = .15 and adjusted R² = .12). In training, however, a team rank effect was observed in distance-related performance indicators where team average distance during small-sided games ranged from 5877 ± 188 to 3551 ± 193 m drill (per 70 min) with Pearson’s r = .95 and adjusted R² = .87. The presence of contextual effects has significant practical implications for team sports where the training load assumed from competition may be overestimated.     

Reinforcement value and substitutability of sucrose and wheel running: implications for activity anorexia

Choice between sucrose and wheel-running reinforcement was assessed in two experiments. In the first experiment, ten male Wistar rats were exposed to concurrent VI 30 s VI 30 s schedules of wheel-running and sucrose reinforcement. Sucrose concentration varied across concentrations of 2.5, 7.5, and 12.5%. As concentration increased, more behavior was allocated to sucrose and more reinforcements were obtained from that alternative. Allocation of behavior to wheel running decreased, but obtained wheel-running reinforcement did not change. Overall, the results suggested that food-deprived rats were sensitive to qualitative changes in food supply (sucrose concentration) while continuing to defend a level of physical activity (wheel running). In the second study, 15 female Long Evans rats were exposed to concurrent variable ratio schedules of sucrose and wheel-running, wheel-running and wheel-running, and sucrose and sucrose reinforcement. For each pair of reinforcers, substitutability was assessed by the effect of income-compensated price changes on consumption of the two reinforcers. Results showed that, as expected, sucrose substituted for sucrose and wheel running substituted for wheel running. Wheel running, however, did not substitute for sucrose; but sucrose partially substituted for wheel running. We address the implications of the interrelationships of sucrose and wheel running for an understanding of activity anorexia.     

Aggressive driving: the contribution of the drivers and the situation

Aggressive driving is defined in terms of the frustration–aggression model. In that context aggressive driving is a syndrome of frustration-driven behaviors, enabled by the driver's environment. These behaviors can either take the form of instrumental aggression—that allows the frustrated driver to move ahead at the cost of infringing on other road users’ rights (e.g., by weaving and running red lights)—or hostile aggression which is directed at the object of frustration (e.g., cursing other drivers). While these behaviors may be reflective of individual differences in aggression, it is argued that the exclusive focus on the characteristics of the aggressive drivers and how to control them is short-sighted. Instead, this paper proposes a multi-factor approach to the problem. Five studies conducted so far tend to support this approach, by showing that specific aggressive behaviors—such as honking and running red lights—are associated with cultural norms, actual and perceived delays in travel, and congestion. Ergonomics-oriented approaches that involve environmental modifications are proposed.