Changes in pinch force with bidirectional load forces

The forces used to grasp an object were measured while positive (push) and negative (pull) load forces were applied to the hand under varying frictional conditions. Subjects held between the tips of their thumb and index finger a manipulandum composed of two symmetrically mounted disks. The manipulandum was connected to the stage of an electromagnetic linear motor that generated load forces under computer control. In the first experiment, subjects held the position of the manipulandum constant while the motor generated forces in first the positive and then the negative direction. The motor force at which the manipulandum slipped from the fingers was measured in the second experiment. In both experiments, friction was varied by changing the surface (sandpaper, suede, or plastic) of the manipulandum disks. The pinch forces produced by subjects were linearly related to changes in motor force in both the positive and negative directions, with the slope of this relation varying as a function of the surface properties of the manipulandum. The modulation of pinch force with motor force was influenced, however, by the direction of the load force; higher forces were produced in response to negative load forces. Slip forces varied as a function of pinch force and surface texture; higher forces were associated with materials with lower coefficients of friction. These findings suggest that the friction between the skin and an object being grasped changes as a function of the direction of force that the object applies to the skin, possibly due to the anisotropic nature of glabrous skin, and that this mechanical property contributes to variations in pinch force.     

Sources of variability in perceptions of and responses to sexual harassment

Social exchange theory was used to explain sexual harassment interactions in terms of perceived or actual inequities in incurred costs or rewards between targets and perpetrators. A factorial experiment was conducted in which the effects of severity of harassment, target response, target gender, and rater gender on perceptions of harassment, perpetrator appropriateness and target appropriateness and suggested responses to harassment were examined. Ninety-four male and 116 female students from two eastern universities served as subjects. The sample was approximately 90% Caucasian and was composed of traditional (18–22-year-old) undergraduates. Results indicated that all independent variables affected perceptions of and responses to sexual harassment situations.     

Prosodic Effects in Minimal Attachment

This experiment explores the role of prosodic cues in resolving temporary morphosyntactic ambiguities in spoken language comprehension. Using a cross-modal naming task, we find that prosodic cues are as effective as overt lexical cues in controlling how the listener resolves attachment ambiguities. This suggests that prosodic factors can affect the early stages of parsing and interpretation.     

Differential thresholds for limb movement measured using adaptive techniques

Differential thresholds for limb movement were measured in 10 subjects, using the transformed up-down procedure. Subjects were required to indicate which of two random displacement perturbations delivered to their forearms had the larger standard deviation (SD). TheSD of the reference signal was fixed for each experimental condition at one of seven values ranging from 0.05 to 3.2 mm. TheSD of the other signal varied depending on the subject’s response. Using this procedure, the differential threshold for limb movement was calculated to be 8%, which is very similar to the thresholds estimated previously for changes in limb position (9%) and force (7%). The sensitivity of the human proprioceptive system to changes in limb displacement was much greater than anticipated, with subjects being able to resolve a 5-μm difference between two perturbations delivered to their arms.     

Exposure to community violence and social support as predictors of anxiety and social and emotional behavior among African American children

We examined the effects of exposure to violence and social support on self-reported state and trait anxiety and parental rated problem behaviors among school-aged African-American children in low and high violence areas. Ninety-seven (97) fourth through sixth graders and their parents were interviewed about exposure to community violence, social support, and state and trait anxiety. Results indicate that trait anxiety was correlated positively with exposure to violence and negatively with social support. State anxiety was correlated negatively with family social support. Problem behaviors were correlated negatively with family support and income. Hierarchial multiple regression analyses indicated that children's reports of their exposure to community violence continued to explain significant variability in trait anxiety, and problem behavior after controlling for both income and social support measures. Social support from peers, family and teachers played differential roles in predicting problem behaviors among children from high and lower violence areas. These findings suggest that in planning intervention programs for children exposed to violence, greater attention to empowering parents to support their children, to fostering peer group support, and to bolstering teacher support may be useful, but attention to the underlying socio-political causes of violence exposure is essential.     

Assessing the effectiveness of a multimedia-based lab for upper division psychology students

The efficacy of multimedia-based training in producing increased learning was evaluated. Two multimedia software packages were compared with live or videotaped lectures on the same material. Results differed by type of student (low or high initial knowledge) and type of program. Multimedia training programs may need to provide more aid to students with less initial knowledge in the training domain. In addition, the effects of multimedia may be subtle and therefore require rigorous evaluation.     

Internet and the support of psychology education

The Computers in Teaching Initiative (CTI) Centre for Psychology has been promoting the use of computers in psychology education for the last 5 years. The advent of the Internet and ubiquitous access to the World-Wide Web has the potential to revolutionize the way the teaching and learning of psychology can be supported. This paper describes how we are using the Web to support psychology education through information dissemination, through the provision of teaching resources, and through facilities for communication.     

USE OF ASSISTED READING TO INCREASE CORRECT READING RATES AND DECREASE ERROR RATES OF STUDENTS WITH LEARNING DISABILITIES

The effects of assisted reading on 3 elementary students with learning disabilities were evaluated using a multiple baseline design. Data were collected from the students' oral reading from their basal texts. The results indicated an increase in number of words read correctly as well as a decrease in the number of words read incorrectly when assisted reading was used in the classroom.