Effects of caffeine on persuasion and attitude change: The role of secondary tasks in manipulating systematic message processing

Two experiments are reported that examine the effects of caffeine consumption on attitude change by using different secondary tasks to manipulate message processing. The first experiment employed an orientating task whilst the second experiment employed a distracter task. In both experiments participants consumed an orange‐juice drink that either contained caffeine (3.5 mg/kg body weight) or did not contain caffeine (placebo) prior to reading a counter‐attitudinal communication. The results across both experiments were similar. When message processing was reduced or under high distraction, there was no attitude change irrespective of caffeine consumption. However, when message processing was enhanced or under low distraction, there was greater attitude change in the caffeine vs. placebo conditions. Furthermore, attitudes formed after caffeine consumption resisted counter‐persuasion (Experiment 1) and led to indirect attitude change (Experiment 2). The extent that participants engaged in message‐congruent thinking mediated the amount of attitude change. These results provide evidence that moderate amounts of caffeine increase systematic processing of the arguments in the message resulting in greater agreement. Copyright © 2006 John Wiley & Sons, Ltd.     

Metaphor,Religious Language,and Religious Experience

Is it possible to talk about God without either misrepresentation or failing to assert anything of significance? The article begins by reviewing how, in attempting to answer this question, traditional theories of religious language have failed to sidestep both potential pitfalls adequately. After arguing that recently developed theories of metaphor seem better able to shed light on the nature of religious language, it considers the claim that huge areas of our language and, consequently, of our experience are shaped by metaphors. Finally, it considers some of the more significant implications of this claim for our understanding of both religious language and religious experience.     

Adolescent development of motor imagery in a visually guided pointing task

The development of action representation during adolescence was investigated using a visually guided pointing motor task (VGPT) to test motor imagery. Forty adolescents (24 males; mean age 13.1 years) and 33 adults (15 males; mean age 27.5 years) were instructed to both execute and imagine hand movements from a starting point to a target of varying size. Reaction time (RT) was measured for both Execution (E) and Imagery (I) conditions. There is typically a close association between time taken to execute and image actions in adults because action execution and action simulation rely on overlapping neural circuitry. Further, representations of actions are governed by the same speed-accuracy trade-off as real actions, as expressed by Fitts’ Law. In the current study, performance on the VGPT in both adolescents and adults conformed to Fitts’ Law in E and I conditions. However, the strength of association between E and I significantly increased with age, reflecting a refinement in action representation between adolescence and adulthood.     

Gauging possibilities for action based on friction underfoot

Standing and walking generate information about friction underfoot. Five experiments examined whether walkers use such perceptual information for prospective control of locomotion. In particular, do walkers integrate information about friction underfoot with visual cues for sloping ground ahead to make adaptive locomotor decisions? Participants stood on low-, medium-, and high-friction surfaces on a flat platform and made perceptual judgments for possibilities for locomotion over upcoming slopes. Perceptual judgments did not match locomotor abilities: Participants tended to overestimate their abilities on low-friction slopes and underestimate on high-friction slopes (Experiments 1-4). Accuracy improved only for judgments made while participants were in direct contact with the slope (Experiment 5), highlighting the difficulty of incorporating information about friction underfoot into a plan for future actions.     

Resisting persuasion by illegitimate means: a metacognitive perspective on minority influence

The present research tests a new metacognitive perspective on resistance in minority influence situations. It is proposed that when people initially resist persuasive messages from sources in the numerical minority, they can lose attitude certainty if they perceive that they have based their attitudes on the source's minority status and also believe this is an illegitimate basis for resistance. In three studies, participants were presented with a message from a minority source. In Study 1, participants became less certain of their attitudes after resisting this message. In Study 2, this effect only emerged when participants were led to believe they had based their attitudes on the source's minority status and this was an illegitimate thing to do. In Study 3, this effect was shown to have implications for persuasion in response to a second message. The implications of these findings for classic minority influence effects are discussed.     

Recycling,evolution and the structure of human personality

Lower childhood cognitive ability may be a risk factor for greater cognitive decline in late life and progression to dementia. To assess variation in age-related cognitive change, it is helpful to have valid measures of cognitive ability from early life. Here, we examine the relation between childhood intelligence and cognitive change in later life in two samples, one born in 1921 and the other in 1936. All participants completed the same test of mental ability (one of the Moray House Test series) at age about 11 years, and were re-examined on Raven’s Progressive Matrices at age 77 (1921-born) or age 64 (1936-born). Where possible, the 1921 sample was re-tested at the age of about 80 years old and the 1936 sample re-tested at about 66 years. After taking into account various covariates, including sex, education and occupation, childhood intelligence was a significant predictor of cognitive change in later life. Results were in the direction that participants with lower childhood mental ability experienced relatively greater cognitive decline, whereas those of higher childhood mental ability showed improved performance. This result suggests that higher premorbid cognitive ability is protective of decline in later life.     

Is body checking in the eating disorders more closely related to diagnosis or to symptom presentation?

Body checking behaviours and cognitions are seen as underlying the core pathology of eating disorders-the over-evaluation of eating, shape and weight. While it has been demonstrated that levels of behaviours and cognitions differentiate eating-disordered women from non-eating-disordered women, little is known with regard to how these findings relate to diagnostic group. This study aimed to determine whether body checking cognitions and behaviours are best understood with regard to diagnostic category or symptom presentation. Eighty-four eating-disordered women (with diagnoses of anorexia nervosa, bulimia nervosa, binge eating disorder or other Eating Disorders Not Otherwise Specified) completed measures of body checking behaviours and cognitions and eating psychopathology. Results showed that different aspects of body checking were more closely associated with diagnosis and with symptom presentation. Anorexia nervosa and binge-eating-disorder patients had particularly low levels of body checking behaviours and some related cognitions. However, the belief that body checking allows one to be accurate in knowing one's weight was associated with binging and vomiting behaviours, rather than diagnosis. Future directions for research include understanding the links between body checking phenomena and neurological features. Clinical implications are discussed.     

Modeling dynamic resource utilization in populations with unique constraints: preadolescents with and without Down syndrome

In this study we used a damped inverted pendulum and spring with an escapement function model to compare the global levels of stiffness and forcing used by 12 preadolescents with Down syndrome (DS) and 12 with typical development (TD). Participants walked overground at their self-selected speed and on a treadmill at speeds slower and faster than overground. Children with DS, who are characterized as hypotonic with reduced capacity for producing muscle force, exhibited significantly higher levels of stiffness and forcing (angular impulse) when walking on the treadmill and higher forcing but not stiffness overground, than children with TD. Both groups adapted to imposed speed increases similarly by increasing their global stiffness and angular impulse. We propose children with DS increased stiffness in order to overcome their hypotonia and joint laxity, thus, optimizing on stability, rather than metabolic efficiency. Higher angular impulse values for children with DS may reflect higher energy cost associated with increasing stiffness and their inherent biomechanical and physiological characteristics that reduce efficiency. We conclude that the inverted pendulum and spring with escapement function model is a useful tool for uncovering solutions to movement problems-solutions that reflect the dynamic resources of the individual and ones that are discovered, rather than prescribed.     

Perception of scene layout from optical contact, shadows, and motion

Kersten et al (1997 Perception 26 171-192) found that the perceived motion of an object in a 3-D scene was determined by the motion of a shadow. In the present study, we compared the effect of a shadow to that of a second object on the ground in determining the perceived position in depth of a floating object in both dynamic and stationary scenes. Changing the second (lower) object from textured to dark increased the influence of the second object on the judged position of the first object. Giving the second object zero thickness had this effect only if it was also dark. Variations in the height of the floating object were important with a second object but not with a shadow, in motion scenes. With alternative shadows present, the position of the floating object was determined primarily by matching speeds, with matching sizes as a secondary factor. These results show some similarities but important differences between the effect of a second object and that of a shadow.     

Application of piecewise hierarchical linear growth modeling to the study of continuity in behavioral development of baboons (Papio hamadryas)

In behavioral science, developmental discontinuities are thought to arise when the association between an outcome measure and the underlying process changes over time. Sudden changes in behavior across time are often taken to indicate that a reorganization in the outcome-process relationship may have occurred. The authors proposed in this article the use of piecewise hierarchical linear growth modeling as a statistical methodology to search for discontinuities in behavioral development and illustrated its possibilities by applying 2-piece hierarchical linear models to the study of developmental trajectories of baboon (Papio hamadryas) mothers' behavior during their infants' 1st year of life. The authors provided empirical evidence that piecewise growth modeling can be used to determine whether abrupt changes in development trajectories are tied to changes in the underlying process.