Age-related differences in collision detection during deceleration

Observers were presented with displays simulating a 3-D environment with obstacles in the path of motion. During the trial, observer motion decelerated at a constant rate and was followed by a blackout prior to the end of the display. On some trials the rate of deceleration resulted in stopping before the collision, whereas on other trials the rate of deceleration resulted in a collision with the obstacles. The observer's task was to detect which trials simulated an impending collision. Proportion of collision judgments was greater for older as compared with younger observers when a collision was not simulated. Older observers showed less sensitivity to detect collisions than younger observers did, particularly at high speeds. The age-dependent results are discussed in terms of analyses based on tau and constant deceleration. The results suggest that increased accident rates for older drivers may be due to an inability to detect collisions at high speeds.     

Pain sensitivity and individual differences in self-reported sexual behavior

The relationship between sexual behavior and pain sensitivity was assessed in 27 heterosexual men and 20 heterosexual women. Sexual behavior measures included sexual motivation and ratings of subjective sexual arousal to and enjoyment of an auditory stimulus. Pain sensitivity measures were pain threshold and pain tolerance in a cold pressor task. Participants were tested after exposure to a neutral or a sexual audio stimulus. Exposure to the sexual stimulus increased pain sensitivity in women but not in men. However, sexual behavior measures were correlated with pain threshold for both men and women. Specifically, higher pain thresholds were associated with weaker sexual motivation, lower enjoyment potential for sexual interaction, and increased inhibition during intercourse. These results are consistent with findings in laboratory animals, suggesting that differences in sexual behavior may reflect differences in responsiveness to a variety of stimuli.     

Sulcal/gyral pattern morphology of the perisylvian language region in developmental dyslexia

Two systems for classification of morphology of the perisylvian cortical area have been suggested, that of Steinmetz et al. (1990) and that of Witelson and Kigar (1992). This study examines whether the variations in placement of these convolutions in the language cortex are related to diagnosis of dyslexia in a clinic-referred sample of 55 children ages 8 to 12 years. Additionally, the systems are compared to determine their relationship to neurolinguistic performance. In this study, the Steinmetz et al. (1990) system captured morphological distinctions which were relevant to performance on neurolinguistic measures, while Witelson and Kigar's (1992) system did not. Under neither system was morphology associated with diagnosis of dyslexia.     

Gamma-range oscillations in backward-masking functions and their putative neural correlates

Backward-masking functions have been hitherto categorized into two types, commonly named Type A and Type B. The analysis of a model of Retino-Cortical Dynamics produces the prediction that spatially localized stimuli should reveal an oscillatory metacontrast function. The predicted new type of metacontrast masking function was investigated in a psychophysical experiment. The results show oscillatory metacontrast functions with significant power in the gamma range (30-70 Hz). A marked decrease in the oscillations is observed when the spatial extent of the stimuli is increased. The theoretical basis of the study relates the oscillations found in the metacontrast function to gamma-range oscillations observed in scalp and intracerebral recordings. The qualitative agreement between the model and data provides support for this putative relationship.     

Longitudinal changes in the contribution of genetic and environmental influences to symptoms of depression in older male twins

Genetically informative longitudinal data on self-reported symptoms of depression allow for an investigation of the causes of stability and change in depression symptoms throughout adult life. In this report, the authors investigated the relative contribution of genetic and environmental influences to symptoms of depression in 83 monozygotic and 84 dizygotic male twin pairs from the National Heart, Lung, and Blood Institute (NHLBI) Twin Study. Participants first completed the Center for Epidemiologic Studies-Depression (CES-D) scale in 1985-1986 and again during 1995-1997. Mean age of twins at baseline was 63 years, range 59 to 70. From cross-sectional genetic analyses we estimated the heritability of CES-D to be 25% (95% confidence interval [CI], 11%-39%) at baseline and 55% (95% CI, 40%-71%) at follow-up. Fitting longitudinal genetic models to the two-wave data, we found that stability of symptoms over the 10-year follow-up was due primarily to continuity of genetic influences.     

Biparental failure in the childhood experiences of borderline patients

The purpose of this study was to assess the role of biparental abuse and neglect in the development of borderline personality disorder (BPD). A semistructured research interview was used to blindly assess the childhood experiences of biparental abuse and neglect reported by 358 borderline inpatients and 109 axis II controls. Eighty-four percent of borderline patients reported having experienced some type of biparental abuse or neglect before the age of 18; 55% reported a childhood history of biparental abuse; 77% reported a childhood history of biparental neglect. These experiences were also reported by a substantial percentage of Axis II controls (biparental abuse or neglect [61%], biparental abuse [31%], and biparental neglect [55%]). However, borderline patients were significantly more likely than axis II controls to report having been verbally, emotionally, and physically but not sexually abused by caretakers of both sexes. They were also significantly more likely than controls to report having caretakers of both sexes deny the validity of their thoughts and feelings, fail to provide them with needed protection, neglect their physical care, withdraw from them emotionally, and treat them inconsistently. It was also found that female borderlines who reported a previous history of neglect by a female caretaker and abuse by a male caretaker were at significantly higher risk for having been sexually abused by a noncaretaker. Taken together, the results of this study suggest that biparental failure may be a significant factor in the etiology of BPD. They also suggest that biparental failure may significantly increase a preborderline girl's risk of being sexually abused by someone other than her parents.     

Some Developmental Implications of Structural Aspects of Preschoolers' Relations with Classmates

To gain insight into children's peer relations and their developmental significance, it is important to know not only how many relations children have but also to consider the structure of these relations. To demonstrate this, we used a multiple-study design in which we applied social network analyses to sociometric ratings and nominations from 1,082 4- to 5-year-old children in 83 school classes. Results showed that isolation in the classroom was more strongly associated with the choices that were given than those that were received. Gender plus the negative behavioral characteristics, aggressiveness and rejection, were the most important cues for social clustering. The structure of positive choices reflected the formation of friendship networks, whereas negative choices tended to be given directly to individual “problem” children. Finally, structure indices tapped aspects of children's relations that were not reflected in the traditional two-dimensional classification system and provided additional explanatory power for predicting developmental outcomes.     

Demonstration of a socially transmitted flavor aversion in rats? Kuan and Colwill (1997) revisited

In each of three experiments that differed only in procedural detail, observer rats interacted with pairs of conspecific demonstrators, one fed a cocoa-flavored diet (Diet Coc) and the other a cinnamon-flavored diet (Diet Cin). Immediately after both members of a pair of demonstrators had been fed, and 5 min before they interacted with an observer or observers, one of the demonstrators was made ill by intraperitoneal injection with lithium chloride. After interacting with a pair of demonstrators for 15 min, each observer was allowed to choose between Diet Cin and Diet Coc for 22 h. In all three experiments, observer rats consumed as much Diet Cin after interacting simultaneously with both an ill demonstrator that had eaten Diet Cin and a healthy demonstrator that had eaten Diet Coc as after interacting simultaneously with both a healthy demonstrator that had eaten Diet Cin and an ill demonstrator that had eaten Diet Coc. These results raise questions about the generality of Kuan and Colwill’s (1997) demonstration of socially transmitted flavor aversions in Norway rats.     

Onset of obsessive-compulsive disorder: premorbid conditions and prodromal phase

This article focuses on the clinical onset of obsessive-compulsive disorder (OCD), specifically addressing the age of onset, gradual and acute onset, and whether there are some types of premorbid conditions or a prodromal phase that predispose individuals to the onset of OCD. Clinical and epidemiological studies have come to different conclusions regarding age at onset as well as regarding differences between the sexes. Data gleaned from research to date have demonstrated a relationship between OCD and obsessive-compulsive personality disorder (OCPD), although OCPD does not appear to be the more prevalent personality disorder among patients with OCD. Preliminary research has suggested that Axis I disorders may predispose individuals to OCD onset; however, the significance of this relationship remains to be clarified. Evidence of the association between OCD and subthreshold obsessive-compulsive syndrome suggests that these disorders lie on a continuum of severity, with some cases developing OCD while others do not.