Activity of cGMP-dependent protein kinase (PKG) affects sucrose responsiveness and habituation in Drosophila melanogaster

The cGMP-dependent protein kinase (PKG) has many cellular functions in vertebrates and insects that affect complex behaviors such as locomotion and foraging. The foraging (for) gene encodes a PKG in Drosophila melanogaster. Here, we demonstrate a function for the for gene in sensory responsiveness and nonassociative learning. Larvae of the natural variant sitter (for(s)) show less locomotor activity during feeding and have a lower PKG activity than rover (for(R)) larvae. We used rover and sitter adult flies to test whether PKG activity affects (1) responsiveness to sucrose stimuli applied to the front tarsi, and (2) habituation of proboscis extension after repeated sucrose stimulation. To determine whether the differences observed resulted from variation in the for gene, we also tested for(s2), a sitter mutant produced on a rover genetic background. We found that rovers (for(R)) were more responsive to sucrose than sitters (for(s) and for(s2)) at 1-, 2-, and 3-wk old. This was true for both sexes. Differences in sucrose responsiveness between rovers and sitters were greater after 2 h of food deprivation than after 24 h. Of flies with similar sucrose responsiveness, for(R) rovers showed less habituation and generalization of habituation than for(s) and for(s2) sitters. These results show that the PKG encoded by for independently affects sensory responsiveness and habituation in Drosophila melanogaster.     

The ideomotor principle and motor sequence acquisition: Tone effects facilitate movement chunking

Participants practiced short sequences of key presses; sequence length and response-effect mapping were the independent variables. Contingent, distinct key-effect relations were contrasted with either contingent but uniform or no response effects. In Experiment 1, tone effects were relevant as response-specific stimuli and also as effects. The sequence length effect for the tones group was reduced. In Experiment 2, participants were informed about the sequences to be executed and then given varying amounts of preparation time before the start signal. A reduction in the sequence length effect was observed, and initiation times and mean interresponse time (IRTs) were generally reduced in the tone group. Preparation time could compensate for some but not all of the latency reducing influence of the tone effects. The results are discussed with reference to ideomotor approaches to motor control, i.e., the notion that actions are represented in sensory format.     

The need for self-control in achievement tests: Changes in students’ state self-control capacity and effort investment

In the present research, we investigated the relation between changes in students’ state self-control capacity and their motivational test-taking effort over the course of an achievement test. Thereby, we considered trait self-control as a major predictor of achievement-related behavior as a covariate. N?=?1840 apprentices repeatedly rated their state self-control capacity and the test-taking effort they invested while working on a 140-min achievement test in mathematics and science. Using growth curve analyses, our results revealed correlated decreases in state self-control capacity and the test-taking effort invested over the course of the test. Furthermore, we found that trait self-control helped to keep state self-control capacity and test-taking effort at a higher level over the course of the test. Our results support the assumption of the process model of self-control that waning self-control capacity is reflected in reduced motivational effort. Furthermore, our findings provide evidence that self-control might play a crucial role in students’ test-taking behavior in large-scale assessment studies. By modeling changes in state self-control capacity and effort investment while considering trait self-control, we provide an alternative approach for investigating self-control-dependent processes and the underlying mechanisms of self-control in achievement situations.     

Perfectionism in young musicians: Relations with motivation, effort, achievement, and distress

Many musicians experience anxiety and distress when performing, which has been related to perfectionism. Recent findings, however, show that only some facets of perfectionism are associated with anxiety and distress, whereas other facets are associated with positive characteristics and outcomes such as motivation and achievement. To investigate how different facets of perfectionism are related to motivation, effort, achievement, and distress in musicians, 146 young musicians completed measures of perfectionism (striving for perfection, negative reactions to imperfection, and perceived pressure to be perfect), intrinsic and extrinsic motivation, effort, achievement, and distress. Results showed that striving for perfection was associated with intrinsic motivation (intrinsic/identified reasons), higher effort, and higher achievement. Whereas perceived pressure from music teachers was also associated with intrinsic motivation (identified reasons only), negative reactions to imperfection were associated with extrinsic motivation and higher distress. The findings demonstrate that perfectionism in musicians has both positive and negative sides. While negative reactions to imperfection are clearly unhealthy, striving for perfection may be regarded as a healthy pursuit of excellence.     

Faces as objects of non-expertise: processing of thatcherised faces in congenital prosopagnosia

Congenital prosopagnosia (cPA) is a severe disorder in recognising familiar faces, a human characteristic that is presumably innate, without any macro-spatial brain anomalies. Following the idea that cPA is based on deficits of configural face processing, we used a speeded grotesqueness decision task with thatcherised faces, since the Thatcher illusion can serve as a test of configural disruption (Lewis and Johnston, 1997 Perception 26 225-227). The time needed to report the grotesqueness of a face in relation to orientation showed dissociate patterns between a group of fourteen people with cPA and a group of matched controls: whereas the RTs of controls followed a strong sigmoid function depending on rotation from the upright orientation, the RTs of people with cPA showed a much weaker sigmoid trend approaching a linear function. The latter result is interpreted as a diagnostic sign of impaired configural processing, being the primary cause of the absence of 'face expertise' in prosopagnosia.     

The concavity effect is a compound of local and global effects

Using a change detection paradigm, Barenholtz, Cohen, Feldman, and Singh (2003) found that changes in concave regions of a contour are more easily detected than changes in convex regions. In a series of three experiments, we investigated this concavity effect using the same paradigm. We observed the effect in wire-like stimuli as well as in silhouettes (Experiment 1) and in complex, smoothed images as opposed to angular polygons (Experiment 2). We also observed a systematic effect of the magnitude of the change (Experiment 1). Furthermore, we find that the effect cannot be attributed to either local or global processing effects, but rather to a combination of both "mere" concaveness and an effect due to changes in the perceived part structure of the stimulus object (Experiment 3). For our data analysis, we used a nonparametric bootstrap method, which greatly increases sensitivity (compared to more traditional analyses like ANOVA).