Menarche: A crossroads that previews developmental change

In recent years the developmental implications of menarche have garnered particular attention. Investigators have determined that this developmental event tends to affect three significant domains of the adolescent girl's function: psychological status, relationships with peers, and role in the family. This paper explores these issues and introduces a new technique, referred to as previewing, that may help the teenage girl acclimate to the status of sexual maturity. Derived from the early life interactions of caregiver and infant, previewing promotes representational skills and enhances self-esteem as the adolescent confronts developmental challenges.     

Development of the University of Pittsburgh Medical Center policy for the care of terminally ill patients who may become organ donors after death following the removal of life support

In the mid 1980s it was apparent that the need for organ donors exceeded those willing to donate. Some University of Pittsburgh Medical Center (UPMC) physicians initiated discussion of possible new organ donor categories including individuals pronounced dead by traditional cardiac criteria. However, they reached no conclusion and dropped the discussion. In the late 1980s and the early 1990s, four cases arose in which dying patients or their families requested organ donation following the elective removal of mechanical ventilation. Controversy surrounding these cases precipitated open discussion of the use of organ donors pronounced dead on the basis of cardiac criteria. Prolonged deliberations by many committees in the absence of precedent ultimately resulted in what is, to our knowledge, the country's first policy for organ donation following elective removal of life support. The policy is intricate and conservative. Care was taken to include as many interested parties as possible in an effort to achieve representative and broad based support. This paper describes the development of the UPMC policy on non-heart-beating organ donation.     

An X Windows tool for synthesizing face images from eigenvectors

An X Windows software tool for the construction of faces with a weighted combination of eigenvectors is described. The eigenvectors were extracted from an autoassociative matrix that comprised 100 face images. The program input consists of eigenvectors and sets of weights that describe individual faces and combines these to create face images. The tool creates a panel of buttons that permits the display of individual eigenvectors and the display of an average face as well. Facilities for on-line changes to the intensity of individual eigenvectors can be used to change the appearance of a face. Previously, O’Toole, Abdi, Deffenbacher, and Bartlett (1991) have shown that the intensity of certain individual eigenvectors contains reliable information for determining the sex and race of the face.     

Infant use of relative motion as information for form: Evidence for spatiotemporal integration of complex motion displays

Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age.     

The Horsley gantt medal address October 11, 1992

The concept of systemic quantization of behavior was used to study the interaction between dominant motivation and reinforcement on brain neurons. Feeding and escape were used as experimental models. Results showed that feeding and escape motivations are based on the mechanisms of ascending activating influences of lateral or ventromedial hypothalamic centers, respectively, on cortical neurons. Feeding and escape motivations evoked by electrical stimulation of hypothalamus, or the ones occurring naturally, modify the responses of single neurons of sensorimotor and insular cortex to sensory stimuli, to microiontophoretic application of neurotransmitters and neuropeptides, and especially to reinforcement. Dominant motivations are reflected in the burst-like activity and in a specific pattern of interpulse intervals of single units in various brain structures. Reinforcement transforms this activity into a regular pattern and also changes the neuronal responses of hypothalamic feeding and escape centers, to electrical stimulation and to microiontophoretic application of oligopeptides. Specific patterns of the unit responses to conditioned stimuli in the course of consecutive reinforcement was determined. After several instances of reinforcement, especially after repetitive reinforcement, the brain neurons influenced by the dominant motivation begin to produce specific protein molecules that are important for organization of an appropriate type of behavior. This process can be blocked by protein synthesis inhibitors.     

Role of eye and hand initial position in the directional coding of reaching

To investigate the nature of the frames of reference used to control an arm movement aimed at a visual target, we studied the accuracy of movements differing by the initial arm and eye positions. The results support the assumption that in darkness target location is internally represented in an egocentric frame of reference. Furthermore, when movements carried out with and without eye saccade are compared, it appears that foveating the target changes the reference used to generate the reaching arm movements, that is, the oculocentric reference is replaced by a head-trunk reference. An explanation for this phenomenon could be that a steady body-related landmark is needed to insure stable registering of the target location in the surrounding space, despite displacement of the body segments with respect to one another.     

Proximal and Distal Predictors of Homophobia: Framing the Multivariate Roots of Outgroup Rejection1

A proximal-distal theoretical framework was developed to examine the multivariate roots of homophobia. Using data from a sample of 288 undergraduates who had participated in a computer-assisted panel study over a three-year period, the effects on homophobia of distal and proximal family factors (e. g., parental education and family environment), distal and proximal individual factors (e. g., personality constructs and current beliefs), and proximal individual-situational factors (e. g., acquaintance with homosexuals) were tested in regression analyses. Both analyses employing sets of variables varying in proximity to the homophobic attitude and hierarchical regression employing variables contributing significantly in each set supported the proposed framework. All sets predicted significantly when regressed separately on homophobia; the sets containing the distal factors contributed most weakly, and the sets containing the proximal factors contributed most strongly. In hierarchical regression analysis, this pattern maintained such that the incremental increase in r² decreased with the addition of each more distal set, with the most distal factors failing to contribute significantly to the prediction. The importance of study findings for attitude change efforts is discussed.     

FIXED-INTERVAL PERFORMANCE AND SELF-CONTROL IN INFANTS

Twenty-six infants, 3 to 23 months old, were trained on fixed-interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch-sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six-phase self-control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5-s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self-controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed-interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self-controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed-interval schedule (classified as pause-sensitive subjects) or produced short pauses and higher steady response rates (classified as pause-insensitive subjects). All pause-sensitive subjects made self-controlled choices in the self-control condition, and all pause-insensitive subjects made impulsive ones.     

The use of partial temporal information in dating personal events

Memory & Cognition - The use of different types of partial temporal information is shown to affect dating accuracy and the distribution of errors in event dating. Several different types of...