The effect of the Müller-Lyer illusion on map reading.

One important reason for studying visual illusions is that they can influence real-world perception as people interact with human-made displays. Three experiments examined how the Müller-Lyer illusion affects distance judgments and decision-making in the complex graphical context of a map by having subjects estimate the lengths of road segment lines framed by inward-going or outward-going wings in actual maps, in control displays that had the map context removed, and in simulated maps. The experiments showed that (1) outward-going wings led to higher distance estimates than did inward-going wings to the same extent both with and without the map context, (2) decisions based on distances determined from maps were affected by Müller-Lyer elements in the maps, and (3) map readers' measurement behavior influenced the effect of the Müller-Lyer elements in maps. The discussion focuses on how certain display manipulations and task manipulations affect the Müller-Lyer illusion. In addition, the discussion addresses the instances in which using a map might be affected by misestimation due to Müller-Lyer elements.     

Development of procedures for rating posed emotional expressions across facial, prosodic, and lexical channels.

A number of rating systems are available to evaluate emotional communication in a single modality. The main purpose of this study was to develop procedures to train human raters to evaluate posed expressions of emotion across three different channels of communication, i.e., facial, prosodic/intonational, and lexical/verbal. These procedures were used to evaluate posed emotional expressions produced by individuals with unilateral brain lesions from stroke. Posers in this preliminary report were two right brain-damaged, two left brain-damaged, and two normal control right-handed adults who were matched on demographic and neurological factors. Eight emotional expressions, both positive and negative, were produced in three channels and rated for intensity, pleasantness, and category accuracy. 15 normal adults served as raters, five per channel. The rating procedures were comparable across channels, with analogous properties, and yielded substantial interrater agreement. In this small sample of posers, it was observed that the expressions of the right brain-damaged group were rated as the least accurate and those of the left brain-damaged group as the most intense. When patterns of individual performance across the channels were examined, performance was quiet consistent for the normal controls yet variable for the right brain-damaged persons. These observations are in keeping with the notion that patients with right hemisphere pathology have difficulty in emotional communication. In summary, these findings suggest that comparison of emotional expressions across multiple channels is feasible.     

Disgust sensitivity, trait anxiety and anxiety disorders symptoms in normal children.

There is evidence to suggest that disgust sensitivity plays a role in the development of small animal fears and phobias. Recently, Phillips, Senior, Fahy, and David (1998) [Phillips, M. L., Senior, C., Fahy, T., & David, A. S. (1998). Disgust: the forgotten emotion of psychiatry. British Journal of Psychiatry, 172, 373-375.] suggested that disgust sensitivity is also involved in various other anxiety-based symptoms (e.g. obsessive-compulsive complaints, social phobia). The present study sought to test this suggestion in a large sample of normal school children (N = 189). Children completed a measure of disgust sensitivity, the trait anxiety version of the Spielberger State-Trait Anxiety Inventory for Children and the Screen for Child Anxiety Related Emotional Disorders, an instrument that measures DSM-defined anxiety disorders symptoms. Disgust sensitivity was indeed found to be correlated with a broad range of anxiety disorders symptoms. However, results also indicated that these correlations were predominantly carried by trait anxiety. That is, when controlling for levels of trait anxiety, only specific phobia symptoms (including animal phobia, blood-injection-injury phobia and situational-environmental phobia) and separation anxiety disorder symptoms were significantly related to disgust sensitivity, although correlations were rather modest. Taken together, these findings cast doubts on the claim that disgust sensitivity is an unique and independent factor that contributes to a broad range of anxiety disorders.     

Dynamics of oralrespiratory coordination in full-term and preterm infants: I. Comparisons at 38-40 weeks postconceptional age

This study compares the coordination of pacifier sucking and breathing between healthy full-term, low risk preterm, and high risk preterm infants at 38–40 weeks postconceptional age. High and low risk preterm infants did not differ in overall score on a neurobehavioral examination (NAPI), but infants in the high risk group differed from the others in breathing frequency and in the coordination of breathing and sucking rhythms. For infants in the high risk group, sucking had less influence on respiratory frequency and patterns of coordination between the frequencies of sucking and breathing were simpler. Oral–respiratory coordination may be a useful marker of infants at risk for later speech problems.     

Reducing Knowledge of Results About Relative Versus Absolute Timing: Differential Effects on Learning

The purpose of the present experiment was to examine further earlier suggestions that a reduced relative frequency of knowledge of results (KR) can enhance the learning of generalized motor programs (GMPs) but at the same time degrade parameter learning, compared with giving KR after every trial (Wulf & Schmidt, 1989; Wulf, Schmidt, & Deubel, 1993). In contrast to these earlier studies, here KR was given separately for relative timing and absolute timing. Subjects practiced three movement patterns that required the same relative timing but different absolute movement times. KR was provided on 100% or 50% of the practice trials for relative timing or absolute timing, respectively. In retention and transfer tests, the groups that had had 50% KR about relative timing demonstrated more effective learning of the relative-timing structure, that is, GMP learning, than the groups that had had 100% KR about relative timing. The KR frequency had no effect on parameterization during retention; yet, when transfer to a task with a novel overall duration was required, the groups given 100% KR about absolute timing were more accurate in parameterization than the groups provided with 50% KR about absolute timing. Thus, the reduced relative KR frequency enhanced GMP learning but had no beneficial effect, or even a degrading effect, on parameter learning. The differential effects of a reduced KR frequency on the learning of relative timing and absolute timing also provide additional support for the dissociation of GMP and parameterization processes.     

Phase transitions and critical fluctuations in the visual coordination of rhythmic movements between people

By watching each other's lower oscillating leg, 2 seated Ss kept a common tempo and a particular phase relation of either 0 degrees (symmetric mode) or 180 degrees (alternate mode). This study investigated the differential stability of the 2 phase modes. In Experiment 1, in which Ss were instructed to remain in the initial phase mode, the alternate phase mode was found to be less stable as the frequency of oscillation increased. In addition, analysis of the nonsteady state cycles revealed evidence of a switching to the symmetric phase mode for the initial alternate phase mode trials. In Experiments 2 and 3, Ss were instructed to remain at a noninitial phase angle if it was found to be more comfortable. The transition observed between the 2 phase modes satisfies the criteria of a physical bifurcation--hysteresis, critical fluctuations, and divergence--and is consonant with previous findings on transitions in limb coordination within a person.     

Methodology for motor learning: a paradigm for kinematic feedback

Knowledge of results (KR)--information feedback about goal achievement--has been one of the most extensively examined variables in motor learning. In most natural movement learning situations, however, instructors more common]y provide augmented information regarding various kinematic or kinetic aspects of the movement pattern itself (sometimes termed knowledge of performance, KP). But despite the inherent interest in kinematic feedback, several factors reviewed here have operated to inhibit its study, the most important of which has been the lack of a suitable laboratory task and paradigm. The limitations of earlier paradigms have concerned (a) the use of overly simple motor behaviors, probably to minimize the problems in kinematic measurement, (b) the tendency for the environmental goal or the task to be isomorphic with the kinematic pattern, and (c) thc failure to use transfer or retention tests as measures of learning effects of the feedback manipulations. In this article, we describe our efforts to create a new paradigm for kinematic feedback, the rationale for its development, and the details of its operation. Finally, we provide evidence that the task and paradigm are sensitive to manipulations of kinematic feedback, providing some assurance that the paradigm can potentially answer future research questions about the role of kinematic feedback for learning.     

Deceleration requirements and the control of pointing movements

When a limb is moved from one position to a target object, the limb and the target frequently collide. Often, the goal of the movement is to strike the target with a particular magnitude of impact. For single-aiming movements, impact forces have been shown to increase systematically with both an increased movement amplitude and a decreased movement time, thus providing deceleration to the moving limb. Models of speed-accuracy trade-off, however, have neglected to account for the contribution of these impact forces in the control of accurate movements. The aim of this experiment was to examine the modifications in the control strategy as a function of the amount of impact force a subject is allowed to use in decelerating his or her limb. Results showed that the structure of the acceleration-time functions was dictated by the amount of impact force subjects were allowed to use in decelerating the limb. Movement endpoint variability decreased as more impact force was used. The experiment suggests that the impact with a target is an important contributor to the deceleration of the moving limb and a critical determinant of movement organization.     

Dynamical substructure of coordinated rhythmic movements.

A coordinated rhythmic movement pattern is a dynamical activity involving many hidden layers of rhythmic subtasks. To investigate this dynamical substructure, spectroscopic concepts and methods were applied to an interlimb rhythmic movement task requiring 1:1 frequency locking of two hand-held pendulums in 180 degrees phase relation. The pendulums could be of identical or very different dimensions, thereby providing different values of the ratio omega of uncoupled frequencies. Analyses focused on the power spectrum of continuous relative phase as a function of variation in omega. Predictions were derived from the theories of mode locking and fractal time. Experimental results were in agreement with theoretical expectations and were discussed in terms of the possible recruiting of rhythmic subtasks in the assembling of interlimb absolute coordination, the interdependence of these subtasks, and the general dynamical principles that relate coordinative processes occurring at different length and time scales.     

Expressive and receptive language skills of temperamentally shy preschoolers

Although shy children speak less in social situations, the extent to which their language skills fall behind those of their more outgoing peers remains unclear. We selected 22 temperamentally shy and 22 non‐shy children from a larger group of 400 4‐year‐old children who were prescreened for temperamental shyness by maternal report, using the Colorado Childhood Temperament Inventory (CCTI). We then compared the two groups on widely used measures that index expressive and receptive language skills. We found that, although the temperamentally shy children scored lower on both expressive and receptive language skills compared with their non‐shy counterparts, they were nonetheless performing at their age equivalency. The non‐shy children, however, were performing significantly above their age level on expressive and receptive language skills. These findings suggest that the development of normal language skills is not compromised in temperamentally shy preschoolers. Copyright © 2004 John Wiley & Sons, Ltd.