Asymptotically distribution-free (ADF) interval estimation of coefficient alpha

The point estimate of sample coefficient alpha may provide a misleading impression of the reliability of the test score. Because sample coefficient alpha is consistently biased downward, it is more likely to yield a misleading impression of poor reliability. The magnitude of the bias is greatest precisely when the variability of sample alpha is greatest (small population reliability and small sample size). Taking into account the variability of sample alpha with an interval estimator may lead to retaining reliable tests that would be otherwise rejected. Here, the authors performed simulation studies to investigate the behavior of asymptotically distribution-free (ADF) versus normal-theory interval estimators of coefficient alpha under varied conditions. Normal-theory intervals were found to be less accurate when item skewness >1 or excess kurtosis >1. For sample sizes over 100 observations, ADF intervals are preferable, regardless of item skewness and kurtosis. A formula for computing ADF confidence intervals for coefficient alpha for tests of any size is provided, along with its implementation as an SAS macro.     

Two modes of sensorimotor integration in intention-based and stimulus-based actions

Human actions may be driven endogenously (to produce desired environmental effects) or exogenously (to accommodate to environmental demands). There is a large body of evidence indicating that these two kinds of action are controlled by different neural substrates. However, only little is known about what happens—in functional terms—on these different “routes to action”. Ideomotor approaches claim that actions are selected with respect to their perceptual consequences. We report experiments that support the validity of the ideomotor principle and that, at the same time, show that it is subject to a far-reaching constraint: It holds for endogenously driven actions only! Our results suggest that the activity of the two “routes to action” is based on different types of learning: The activity of the system guiding stimulus-based actions is accompanied by stimulus-response (sensorimotor) learning, whereas the activity of the system controlling intention-based actions results in action-effect (ideomotor) learning.     

Instrument specificity in experienced musicians

Previous studies have shown that experienced pianists have acquired integrated action-effect (A-E) associations. In the present study, we were interested in how specific these associations are for the own instrument by investigating pianists and guitarists. A-E associations were examined by testing whether the perception of a “potential” action-effect has an influence on actions. Participants played chords on their instrument in response to visual stimuli, while they were presented task-irrelevant auditory distractors (congruent or incongruent) in varying instrument timbre. In Experiment 1, pianists exhibited an interference effect with timbres of their own instrument category (keyboard instruments: piano and organ). In Experiment 2 guitarists showed an interference effect only with guitar timbre. Thus, integrated A-E associations primarily seem to consist of a specific component on a sensory-motor level involving the own instrument. Additionally, categorical knowledge about how an instrument is played seems to be involved.     

Recognition and evaluation of emotional prosody in individuals with generalized social phobia: a pilot study

Studies using facial emotional expressions as stimuli partially support the assumption of biased processing of social signals in social phobia. This pilot study explored for the first time whether individuals with social phobia display a processing bias towards emotional prosody. Fifteen individuals with generalized social phobia and fifteen healthy controls (HC) matched for gender, age, and education completed a recognition test consisting of meaningless utterances spoken in a neutral, angry, sad, fearful, disgusted or happy tone of voice. Participants also evaluated the stimuli with regard to valence and arousal. While these ratings did not differ significantly between groups, analysis of the recognition test revealed enhanced identification of sad and fearful voices and decreased identification of happy voices in individuals with social phobia compared with HC. The two groups did not differ in their processing of neutral, disgust, and anger prosody.     

Improving postswitch performance in the dimensional change card-sorting task: the importance of the switch and of pretraining by redescribing the test cards

The dimensional change card-sorting task (DCCS) is used to assess the executive abilities of young children. Typically, 3-year-olds have difficulty in performing this task. However, the exact nature of this difficulty is still being debated. In the standard DCCS, children need to sort, for example, test cards with a blue flower or a red car into two boxes marked with the target cards. The 3-year-olds commonly have pronounced difficulty in switching from one sorting criterion (e.g., color) to another (e.g., shape). Here two experiments with 3-year-olds showed that making the transition between the sorting criteria more distinct improved performance significantly. This was achieved by taking away the target cards for a brief time period, asking a question irrelevant to the task, and pretraining the children by redescribing the test cards.     

And deplete us not into temptation: Automatic attitudes, dietary restraint, and self-regulatory resources as determinants of eating behavior

Linking contemporary models of self-regulation to recent research on automatic attitudes, the present study investigated the impact of automatic candy attitudes, dietary restraint standards, and self-regulation resources on eating behavior. Participants were assigned to either an emotion suppression task (low self-regulation resources) or an emotion flow task (high self-regulation resources), and were then given an opportunity to taste candies. When self-regulation resources were high, candy consumption was uniquely related to dietary restraint standards (but not automatic candy attitudes). In contrast, when self-regulation resources were low, candy consumption was primarily predicted by automatic candy attitudes, with dietary restraint standards showing a tendency for counterintentional effects. These results indicate that the behavioral impact of automatic attitudes and personal standards depends on available control resources. Implications for research on automatic attitudes and self-regulation are discussed.     

Neural substrates for episodic encoding and recognition of unfamiliar faces

Functional MRI was used to investigate brain activation in healthy volunteers during encoding of unfamiliar faces as well as during correct recognition of newly learned faces (CR) compared to correct identification of distractor faces (CF), missed alarms (not recognizing previously presented faces, MA), and false alarms (incorrectly recognizing newly presented faces, FA). Encoding was associated with frontal, occipital/fusiform, thalamic, and cerebellar activation. CR produced activation in frontal and cerebellar regions, whereas CF activated frontal and occipitotemporal regions as well as the thalamus. In contrast, MA was associated with frontal and thalamic activation, and FA with frontal activation. The CR minus CF comparison showed left lateral prefrontal and parietal activation, while no suprathreshold positive signal changes were detected when subtracting the other conditions (CR minus MA, CR minus FA, and vice versa). These results support the view that the successful episodic retrieval of newly learned faces is based on a dorsal visual stream mechanism.     

Activation of action rules in action observation

Visually perceiving an action may activate corresponding motor programs. This automatic motor activation can occur both for higher level (i.e., the goal of an action) and for lower level (i.e., the specific effector with which it is executed) aspects of an action. The authors used a tool-use action paradigm to experimentally dissociate priming effects for observing the target, the movement, or the target-to-movement mapping of a tool-use action. In 3 experiments, participants took turns in acting, observing the tool-use action of another person in trial n-1, and executing an action in trial n. Trial transitions from n-1 to n were manipulated in 4 conditions with (a) mapping repeated and movement and target changed, (b) target repeated and movement and mapping changed, (c) movement repeated and target and mapping changed, or (d) all components repeated. Results indicate priming effects for repeating the target-to-movement mapping (i.e., the action rule) of a tool-use action and suggest that a rather abstract action schema is activated during action observation.