Four triggering factors in loudness adaptation.

A factor analysis was used to determine whether induced loudness adaptation (Botte, Canevet, & Scharf, 1982; Scharf, 1983) and adaptation measured by Hood's (1950) classic Simultaneous Dichotic Loudness Balance technique (SDLB) would cluster on the same factors. The two phenomena did not cluster on the same factors; thus, induced adaptation cannot replace SDLB adaptation. Four independent factors that trigger auditory adaptation were identified in the factor analysis.     

Human visual evoked responses are related to heart rate.

The purpose of the present experiment was to determine the relation between changes in heart rate and averaged evoked potentials. Sixteen male subjects with variable heart rates received 50 flashes of light during fast heart beats, 50 during slow heart beats, and 50 during midrange heart rate level. Evoked responses were recorded from the scalp overlying the right and left occipital lobes. Heart rate, respiration, eye movements, and cephalic blood flow were also recorded. The results indicated that spontaneous changes in heart rate are related to changes in visual evoked responses and that this relation differs for the two cerebral hemispheres. Furthermore, cephalic pulse amplitude was largest following slow heart beats and smallest following fast heart beats, which suggests that changes in heart rate are related to changes in cerebrovascular as well as electrocortical activity. The results are discussed in terms of formulations derived from behavioral studies regarding the relation between cardiovascular activity and attentional processes.     

Racial differences in birth outcomes: the role of general, pregnancy, and racism stress.

OBJECTIVE: This study examined the role of psychosocial stress in racial differences in birth outcomes. DESIGN: Maternal health, sociodemographic factors, and 3 forms of stress (general stress, pregnancy stress, and perceived racism) were assessed prospectively in a sample of 51 African American and 73 non-Hispanic White pregnant women. MAIN OUTCOME MEASURES: The outcomes of interest were birth weight and gestational age at delivery. Only predictive models of birth weight were tested as the groups did not differ significantly in gestational age. RESULTS: Perceived racism and indicators of general stress were correlated with birth weight and tested in regression analyses. In the sample as a whole, lifetime and childhood indicators of perceived racism predicted birth weight and attenuated racial differences, independent of medical and sociodemographic control variables. Models within each race group showed that perceived racism was a significant predictor of birth weight in African Americans, but not in non-Hispanic Whites. CONCLUSIONS: These findings provide further evidence that racism may play an important role in birth outcome disparities, and they are among the first to indicate the significance of psychosocial factors that occur early in the life course for these specific health outcomes.     

Loudness adaptation: fact or artifact?

In the present study, the authors tested the hypothesis that contrast effects confound the Ipsilateral Comparison Paradigm (ICP). Bidirectional referents were used in which base tones of 50 or 70 dB alternated with referents of greater or lesser intensity in a 3.5-min listening period. The contrast hypothesis leads to the expectation that the bidirectional referents would produce opposing effects that should nullify time-based loudness changes in the common base tone. Contrary to that expectation, base-tone loudness declined significantly over time in the context of the bidirectional referents, and the loudness of the referents also declined significantly over time. Thus, the results of the study testified to the validity of the ICP as a contrast-free measure of broad-based loudness adaptation.     

Ipsilateral Loudness Adaptation Over Multiple Intensity Levels

Three mirror tracing experiments were conducted to investigate the connection between perception and motor behavior. In the first experiment, some subjects traced a hex-maze, other subjects traced a hex-maze after observing a model trace, others traced a hex-maze after reading instructions on mirror images, and others traced a hex-maze after having observed a model and heard the instructions. There were no significant differences between the groups' error scores, but their time scores differed significantly, although not always in the predicted direction. In Experiment 2, the subjects were to trace selected letters of the alphabet. Error scores for the second experiment did not differ much from those for the first experiment. In Experiment 3, the experimenter gave each subject commands for the correct directions of movement, using the subject's body as a frame of reference. There was little improvement in motor performance. These results suggest that the visual information presented in the mirror captured the subjects' attention and blocked their motor tracing program.     

Prenatal maternal anxiety and early childhood temperament

The consequences of exposure to prenatal maternal anxiety for the development of child temperament were examined in a sample of 120 healthy, 2-year-old children. Prenatal maternal state and pregnancy-specific anxiety (PSA) were measured five times during pregnancy, and maternal state anxiety was measured again at 2 years post partum. Child temperament was measured at 2 years using the Early Childhood Behavior Questionnaire. The relationship between the trajectory of maternal anxiety across gestation and negative affectivity was evaluated using hierarchical linear growth curve modeling. Higher maternal PSA between 13 and 17 weeks of gestation was associated with increased negative temperament in the children. This association could not be explained by postnatal maternal anxiety, demographic, or obstetric factors. Prenatal maternal state anxiety was not associated with child temperament. These findings demonstrate that PSA early in gestation has a distinctive influence on the developing fetus.     

Perceived partner support in pregnancy predicts lower maternal and infant distress

Maternal postpartum emotional distress is quite common and can pose significant risk to mothers and infants. The current study investigated mothers' relationships with their partners during pregnancy and tested the hypotheses that perception of prenatal partner support is a significant predictor of changes in maternal emotional distress from midpregnancy to postpartum, and contributes to maternal ratings of infant distress to novelty. Using a prospective longitudinal design, 272 adult pregnant women were interviewed regarding their partner support, relationship satisfaction, and interpersonal security (attachment style and willingness to seek out support), and they completed standardized measures of prenatal symptoms of depression and anxiety (distress). At 6 to 8 weeks' postpartum, mothers reported these symptoms again and completed measures of their infants' temperament. Structural equation modeling (SEM) was used to test direct and indirect contributions of partner support, relationship satisfaction, and interpersonal security to maternal and infant postpartum distress. Mothers who perceived stronger social support from their partners midpregnancy had lower emotional distress postpartum after controlling for their distress in early pregnancy, and their infants were reported to be less distressed in response to novelty. Partner support mediated the effects of mothers' interpersonal security and relationship satisfaction on maternal and infant outcomes. A high-quality, supportive partner relationship during pregnancy may contribute to improved maternal and infant well-being postpartum, indicating a potential role for partner relationships in mental health interventions, with possible benefits for infants as well.     

Perceived susceptibility and self-protective behavior: a field experiment to encourage home radon testing

Tested in a field experiment (N = 647) the hypothesis that perceptions of personal susceptibility are important in decisions to test one's home for radioactive radon gas. Experimental group subjects received a personal telephone call to tell them they lived in a high-risk area and a personal letter to reinforce the telephone message. After the intervention, experimental subjects were significantly more likely than minimal-treatment subjects to acknowledge the possibility of high radon levels in their homes. Perceptions of susceptibility and illness severity were significantly correlated with orders of radon test kits and with testing intentions. Nevertheless, there were no differences between groups in test orders or intentions. Results are discussed in terms of the difficulty of getting people to acknowledge susceptibility and the factors other than risk perceptions that influence self-protective behavior.