Catherine Weir

Auditory frequency sensitivity of

Two studies were performed where five sinusoids, 125 Hz, 250 Hz, 500 Hz, 2 kHz, and 4 kHz, were presented to babies up to 9 days old along with several no-signal trials. Although variability in responding was the key result, a flat curve was representative of the intensities required for motor responding 50% of the time across the frequencies studied. In the second experiment, fixed intensities were chosen for each signal frequency, so d’ values could be estimated. The d’s differed over frequency. Evidence is cited that responding in the auditory response cradle which was used here varies with acoustic parameters. Some reasons are suggested as to why the newborns exhibit such variability.

Auditory Frequency Sensitivity in the Neonate: A Signal Detection Analysis.

Abstract Using signal detectability theory, an analysis was performed on some auditory frequency sensitivity data obtained in 1968 by Hutt et al. on human neonates. The d′ -values over the frequencies from 70 Hz to 2kHz formed a significant cubic function. No state of arousal effects were found on sensitivity, as had been found in 1968. The β-values did not vary systematically with state, which suggests that levels of arousal should be studied separately. It is also suggested that the complex sensitivity found may provide a mechanism by which neonates may monitor their own vocalizations.

Lay Theories of Child Development

Abstract Over 200 respondents from a variety of backgrounds completed a 64-item questionnaire on which they estimated the age at which most normal, healthy children can complete a variety of tasks. These results were compared with the norms available from tests and textbooks. Overall, the respondents underestimated the age at which older children (9–15 years old) can successfully perform tasks and overestimated the age at which younger children (2–4 years old) can perform tasks. There were various significant correlates of these estimations, particularly gender, age, and whether the respondents had children of their own. Results are discussed in terms of the literature on lay theories of child development.

Are backward words special for older adults

Two experiments comparing older and young adults confirmed that Stroop interference from lists of incongruent color words was greater for older adults. Similar age effects were observed when the lists of words were presented in 2 unusual print orientations (upside-down; backward and upside-down). In contrast, no age effect was observed, when participants named colors on backward-word lists, as measured with a percentage interference score that corrected for individual differences in baseline (color patches) naming times. Reading speed failed to account for all the interference effects in these data.

A comparison of fixed-trial and infant-control habituation procedures with 6- to 13-month-old at-risk infants

Abstract Response decrement and recovery were compared using fixed-trial and infant-control habituation procedures. Infants who had experienced perinatal difficulties (e.g., respiratory distress, jaundice) were tested at 6 to 13 months of age. Post hoc rescoring of the fixed-trial data according to infant-control rules showed similar baseline responding and decrement scores for two procedures, although the infant-control group made more frequent and longer looks at the stimulus. A response to novelty was obtained only for the infant-control procedure. Risk severity did not emerge as a significant factor. The findings are discussed with reference to contingency effects operating in infant-control and procedure-specific sensitization. It was concluded that infant-control and fixed-trial habituation paradigms offer alternative procedural routes for studying representational competence in infancy.

Use of Behavioural Tests in Early Diagnosis of Hearing Loss

Behavioural tests for infant hearing loss are surveyed. Two automated tests for newborns are described. Early results of validity studies indicate that they are promising techniques. The results of research on 1 to 5 month olds is summarized. The reasons why clinical assessment at this age is not often attempted are discussed. Finally, distraction test methods and their validity are mentioned. The need for repeated testing for infant hearing loss and continued research into the reliability and validity of existing assessment techniques is emphasized.

Age differences in alcohol and cocaine expectancies and attitudes.

Positive and negative expectancies regarding the behavioral effects of alcohol and cocaine were assessed and used to predict attitudes toward their use across four age groups (5–7, 8–10, 11–14, and 18–25, N = 121). Regardless of gender and minority status, children and early adolescents appeared to overgeneralize their beliefs about alcohol to a less familiar drug, cocaine, perceiving the effects of the two drugs similarly. Only college students differentiated between drugs, perceiving cocaine as less likely than alcohol to produce drunkenness and more likely to have stimulant and elation/empowerment effects. With age and other expectancies controlled, expectancy of drunkenness was the best predictor of disapproval of alcohol use; attitudes toward cocaine use were unrelated to expectancies but became more negative with age. Drug prevention programs should rest on data regarding childrens preexisting beliefs about the consequences of drug use and should help them understand that different drugs (for example, stimulants and depressants) pose different dangers.

Developmental differences in understanding of balance scales in the United States and Zimbabwe.

Abstract This cross-cultural, developmental study of understanding of the physics of a balance scale involved 2 age groups (5- and 22-year-olds) in 2 countries (the United States and Zimbabwe). A factorial design was used. Each participant solved 6 types of balance scale problems, and the patterns of errors for these problem types were analyzed to determine which rules and concepts the participant used (e.g., whether number of weights was considered). As expected, on average, older participants were more accurate than younger participants, although significant age differences in the Zimbabwean sample were not found for problems solved by weight or distance cues. One finding differing from earlier research was that problems in which the beam balanced were more difficult for all participants. Generally, understanding of the physics of a balance scale appeared fairly similar in the 2 countries. Some cultural practices may account for the findings—in particular, the availability of preschool and age at time of academic specialization in higher education.This cross-cultural, developmental study of understanding of the physics of a balance scale involved 2 age groups (5- and 22-year-olds) in 2 countries (the United States and Zimbabwe). A factorial design was used. Each participant solved 6 types of balance scale problems, and the patterns of errors for these problem types were analyzed to determine which rules and concepts the participant used (e.g., whether number of weights was considered). As expected, on average, older participants were more accurate than younger participants, although significant age differences in the Zimbabwean sample were not found for problems solved by weight or distance cues. One finding differing from earlier research was that problems in which the beam balanced were more difficult for all participants. Generally, understanding of the physics of a balance scale appeared fairly similar in the 2 countries. Some cultural practices may account for the findings--in particular, the availability of preschool and age at time of academic specialization in higher education.

Heart Rate Reactivity during Contingency Learning in 5- to 10-Month-Old at-Risk and Non-Risk Babies.

The study investigated the dynamic relation between contingency learning and heart rate with risk and non-risk babies 5- to 10-months-old. Four groups were compared in a two contingency treatments (contingent, yoked) × two risk status design. Concurrent heart rate was monitored during three phases of a contingency learning task (baseline, contingency/stimulation, extinction) and analysis focused on phase transitions. Non-risk babies presented with contingent stimulation showed an immediate increase in cardiac rate associated with a subsequent response increase to the contingency. Risk infants presented with contingent stimulation showed delayed cardiac reactivity accompanied by a smaller response increase to the contingency. Yoked controls decreased responding in the contingent period with no significant changes in cardiac reactivity at phase transitions. The findings of the study are discussed in relation to individual differences in physiological regulation and to differential sensitization in a contingency learning task.

Validation of the Auditory Response Cradle with Sound and Tactile Stimuli

The usefulness of the auditory response cradle as a device to test perception of neonates was extended to include tactile as well as sound stimuli. Newborns received three types of trials: white noise, von Frey hair (heavy and light) or no stimulus (control) presentations. The motor and respiration response probabilities were calculated for each type of trial. There was roughly equivalent responding for auditory and tactile stimuli whilst the control response rate was significantly lower. The heavy von Frey hair was more likely to evoke a response than the light one. These results were taken as evidence that the auditory response cradle can be used to test neonatal perception in more than one modality.