Caffeine modulates attention network function

The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a flanker task designed to test Posner’s three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). Cognitive neuroscience of attention. New York, NY: Guilford Press]. In a placebo-controlled, double-blind study using a repeated-measures design, we found that the effects of caffeine on visual attention vary as a function of dose and the attention network under examination. Caffeine improved alerting and executive control function in a dose–response manner, asymptoting at 200 mg; this effect is congruent with caffeine’s adenosine-mediated effects on dopamine-rich areas of brain, and the involvement of these areas in alerting and the executive control of visual attention. Higher doses of caffeine also led to a marginally less efficient allocation of visual attention towards cued regions during task performance (i.e., orienting). Taken together, results of this study demonstrate that caffeine has differential effects on visual attention networks as a function of dose, and such effects have implications for hypothesized interactions of caffeine, adenosine and dopamine in brain areas mediating visual attention.     

Acute caffeine consumption enhances the executive control of visual attention in habitual consumers

Recent work suggests that a dose of 200–400 mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined the effects of four caffeine doses (0 mg, 100 mg, 200 mg, 400 mg) on low- and high-level visual attention in individuals with high consumption profiles (n = 36), in a double-blind study using a repeated measures design. Results from the Attention Network Test indicated that caffeine enhanced both vigilance and the executive control of visual attention, but only at the highest administered dose (400 mg). We demonstrate that in habitual consumers high doses of caffeine can produce beneficial changes in visual attention. These results carry implications for the theorized interactions between caffeine, adenosine and dopamine in brain regions mediating visual attention.     

Prior knowledge enhances the category dimensionality effect

A study of the combined influence of prior knowledge and stimulus dimensionality on category learning was conducted. Subjects learned category structures with the same number of necessary dimensions but with more or fewer additional, redundant dimensions and with either knowledge-related or knowledge-unrelated features. Minimal-learning models predict that all subjects, regardless of condition, either should learn the same number of dimensions or should respond more slowly to each dimension. Despite similar learning rates and response times, subjects learned more features in the high-dimensional than in the low-dimensional condition. Furthermore, prior knowledge interacted with dimensionality, increasing what was learned, especially in the high-dimensional case. A second experiment confirmed that the participants did, in fact, learn more features during the training phase, rather than simply inferring them at test. These effects can be explained by direct associations among features (representing prior knowledge), combined with feedback between features and the category label, as was shown by simulations of the knowledge resonance, or KRES, model of category learning.     

Acquired flavour preferences: contextual control of adaptation-level effects

This experiment investigated the role of context in the expression of conditioned flavour preferences. Rats were trained on a mixture of almond and sucrose and were then given intermixed exposures to almond in one context (Context A) and to sucrose in a second context (Context S). Finally, choice tests were given in both contexts, with one group given almond-versus-water tests and the other almond + sucrose-versus-sucrose tests. Preference for almond over water was greater in Context A than in Context S. Conversely, preference for almond + sucrose over sucrose was greater in Context S than in Context A. These results suggest that the perceived sweetness of a flavour depends on the context in which it is presented and confirm that expression of a flavour preference depends on the type of test employed.     

Randomized, controlled trial of Behavioral Family Systems Therapy for Diabetes: maintenance and generalization of effects on parent-adolescent communication

We report a randomized trial of a revised Behavioral Family Systems Therapy for Diabetes (BFST-D) intervention. Families of 104 adolescents with diabetes were randomized to standard care (SC) or to 6 months of an educational support group (ES) or BFST-D. Family communication and problem-solving skills were assessed at 0, 6, 12, and 18 months by independent rating of videotaped family problem-solving discussions. BFST-D improved individual communication of adolescents and mothers, but not fathers. BFST-D significantly improved quality of family interaction compared to SC (10 of 12 comparisons) and ES (6 of 12 comparisons). Changes in family communication were differentially associated with changes in glycemic control, adherence, and family conflict. BFST-D improved family communication and problem solving relative to SC and modestly relative to ES.     

On the relations between action planning, object identification, and motor representations of observed actions and objects

Recent evidence suggests that viewing a static prime object (a hand grasp), can activate action representations that affect the subsequent identification of graspable target objects. The present study explored whether stronger effects on target object identification would occur when the prime object (a hand grasp) was made more action-rich and dynamic. Of additional interest was whether this type of action prime would affect the generation of motor activity normally elicited by the target object. Three experiments demonstrated that grasp observation improved the identification of grasp-congruent target objects relative to grasp-incongruent target objects. We argue from this data that identifying a graspable object includes the processing of its action-related attributes. In addition, grasp observation was shown to influence the motor activity elicited by the target object, demonstrating interplay between action-based and object-based motor coding.     

The effects of choice on intrinsic motivation and related outcomes: a meta-analysis of research findings

A meta-analysis of 41 studies examined the effect of choice on intrinsic motivation and related outcomes in a variety of settings with both child and adult samples. Results indicated that providing choice enhanced intrinsic motivation, effort, task performance, and perceived competence, among other outcomes. Moderator tests revealed the effect of choice on intrinsic motivation was stronger (a) for instructionally irrelevant choices compared to choices made between activities, versions of a task, rewards, and instructionally relevant options, (b) when 2 to 4 successive choices were given, (c) when rewards were not given after the choice manipulation, (d) when participants given choice were compared to the most controlling forms of control groups, (e) for children compared to adults, (f) for designs that yoked choice and control conditions compared to matched designs in which choice was reduced or designs in which nonyoked, nonmatched controls were used, and (g) when the experiment was conducted in a laboratory embedded in a natural setting. Implications for future research and applications to real-world settings are discussed.     

New job market entrants' future work self,career adaptability and job search outcomes: Examining mediating and moderating models

Based on career construction theory and the model of proactive motivation, the current research examined the mediating and moderating models for the relations among future work self, career adaptability, job search self-efficacy and employment status. A survey study was conducted among Chinese university graduates (N = 270). The results showed that future work self (measured at wave 1) had positive effect on employment status (measured at wave 3), with this relationship partially mediated by career adaptability (measured at wave 1) and job search self-efficacy (measured at wave 2). In addition, the results further revealed that the positive effect of future work self on job search self-efficacy was stronger among the graduates who had a higher level of career adaptability. In support of the hypothesized moderated mediation model, for individuals with a higher level of career adaptability, the indirect effect of future work self on employment status through job search self-efficacy was stronger. These findings carry implications for research on job search behavior, career education and career counseling.