Stimulus sequence and the exponent of the power function for loudness

In two experiments, 15 and 13 subjects estimated the loudness of 12 sound-pressure levels (38-104 dB; 6-dB intervals) of a 1000-Hz tone by the method of magnitude estimation with a modulus assigned to the first stimulus presented. The tone duration was 1 sec. and the interstimulus interval was 6 sec. The presentation order was systematically ascending-descending in one experiment and balanced-irregular in the other. The results indicate that (1) loudness is a power function of sound pressure with an exponent of 0.60 for the systematic order and 0.29 for the irregular order. (2) For both the irregular and systematic orders, a large step-size (12 or 18 dB) between the stimulus on Trial n and on Trial n-1 (or n-3) results in a slight assimilation effect. This also occurs for the small step-size (6 dB) in the irregular order. (3) The size of momentary exponents (based on two points, Trials n and n-1 or n-3) depends on the sound pressures of successive stimuli, whether the steps are positive or negative, and whether the stimuli have been presented in systematic or irregular order. For positive steps, the momentary exponent is lower for a soft tone (Trial n) than for a loud tone, whereas for negative steps the momentary exponent is lower for a loud tone than for a soft tone. These effects ar more pronounced when these stimuli are presented in an irregular order. A relative judgment model is offered for magnitude estimation. It assumes that subjects judge the loudness of a stimulus in terms of three reference markers: the minimum and maximum sound pressures as well as the sound pressure of the previous stimulus.     

Individual Differences in Early Executive Functions: A Longitudinal Study from 12 to 36 Months

It has been proposed that executive functions develop in a hierarchical fashion, such that early, simple abilities seen already during the first year of life become increasingly coordinated with development, thereby enabling the emergence of more complex abilities. Although this hierarchical model has received support from empirical studies comparing executive function task performance across age groups, necessary support from longitudinal studies taking an individual differences perspective on development is missing. In addition, the model stresses the importance of attention in executive function development, but we do not know in what way attention contributes to the continued development once the earliest forms of simple functions have emerged. Using a longitudinal design, the present study investigated the relations between individual differences in simpler forms of executive functions as well as sustained attention at age 12 months and more complex executive functions at 24 and 36 months. The results indicated partial support for the hierarchical model, with infant inhibition being predictive of working memory in toddlerhood. In addition, at 12 months, sustained attention contributed to the development of toddler executive functions via the simple executive functions. This suggests that by this age, sustained attention has become an integrated part of early, simple executive functions. Copyright © 2015 John Wiley & Sons, Ltd.     

Motor response inhibition and execution in the stop-signal task: development and relation to ADHD behaviors.

The main aim of this study was to investigate the developmental course of motor response inhibition and execution as measured by the stop-signal task in a population-based sample of 525 4- to 12-year-olds. A further aspiration of the study was to enhance the limited knowledge on how the various stop-signal measures relate to ADHD behaviors in a normal sample. We also wanted to contribute to the theoretical understanding of the various stop-signal measures by examining the relations between the stop-signal measures and performance on tasks reflecting other aspects of response inhibition and execution. Our results showed that the ability to inhibit as well as to execute a motor response as measured by the stop-signal task improved with age during childhood. Of specific interest are the findings suggesting that this task captures the development of motor response inhibition in the late preschool years (age 5 years). Both of the inhibition measures derived from the stop-signal task (i.e., SSRT and probability of inhibition) related significantly to teacher ratings of inattention as well as to performance on tasks tapping other aspects of inhibition. The data provided by this study have thus contributed to the scarce knowledge on early development of motor response inhibition, as well as suggested that the stop-signal task may be a valuable tool for capturing deficient motor response inhibition in ADHD behaviors in normal samples.     

Maternal sensitivity,infant temperament,and the development of early feeding problems

Early feeding problems, assessed in maternal reports about general problems and refusal behaviors, were investigated in a normal sample (n = 115) at the ages of 10 months and 2 years. In a longitudinal design, stability of feeding problems was studied. A model for development of nonorganic failure to thrive proposed by Chatoor (1989: Chatoor & Egan, 1983) was used as a guide in selection of potential antecedents to early feeding problems. The predictive value of parent-rated infant temperament and directly observed maternal sensitivity for explaining variance in feeding problems was explored. The results showed moderate stability for feeding problems. Feeding problems at both ages were predicted by interactions between infant temperament and maternal sensitivity. At 10 months feeding problems were marginally associated with an interaction between sensitivity and infant manageability (degree of negative emotionality); less sensitive mothers with less manageable infants reported more refusal behaviors. At the age of 2 years irregular infants were reported to have more problems if their mothers were less sensitive to their signals. The results are discussed in relation to studies of more severe feeding problems in infancy, and the Chatoor model was found to contribute to an understanding of the development of everyday infant feeding problems in a normal sample. © 1997 Michigan Association for Infant Mental Health     

Developmental change in the relation between executive functions and symptoms of ADHD and co‐occurring behaviour problems

In a sample of 92 children aged 6–13 years this study investigates the normal developmental change in the relation between executive functioning (EF) and the core behavioural symptoms associated with attention deficit hyperactivity disorder (ADHD) (hyperactivity/impulsivity and inattention) as well as symptoms often co‐occurring with childhood hyperactivity (conduct‐ and internalizing problems). EF was assessed by using multiple tests grouped through prior factor analysis, resulting in cognitive measures relating to disinhibition, speed/arousal, verbal working memory, non‐verbal working memory, and fluency. The results showed that although disinhibition was positively related to hyperactivity/impulsivity and inattention mainly for the youngest age group, there were no significant age effects for these relations. Instead, age effects were found for the relations between speed/arousal and inattention as well as for the relations between verbal working memory/fluency and inattention. In the oldest age group poor performance on these cognitive measures was associated with high ratings of inattention. For the total sample a relation was obtained between disinhibition and hyperactivity/impulsivity as well as between both working memory measures and internalizing problems. In conclusion, the results from this study suggest that poor inhibition is most clearly associated with ADHD symptoms for younger children, whereas poor functioning with regard to later developing and more complex executive functions such as working memory and fluency is associated with ADHD symptoms for older children. Copyright © 2006 John Wiley & Sons, Ltd.     

“Good mothering”: Maternal attitudes and mother-infant interaction

Two groups of mother-infant pairs, with infants aged 1 to 5 months, were recruited by child health nurses. One group (n = 10) of infants had rational difficulties, whereas the other group (n = 22) did not. The research team was blind to group membership. The mothers were interviewed about background variables, their cognitive-emotional orientation during pregnancy and early motherhood, their self-confidence as mothers, their satisfaction with support from their husbands, and living conditions. Mother-infant interaction was observed in à diaper change and à face-to-face situation. Comparisons between the two groups showed no differences with regard to background variables, while significant differences were obtained with regard to interview and observation data. The problem group reported less satisfaction with and focus on maternal role, less self-confidence as mothers, and less satisfaction with husband support and living conditions than the no-problem group. With regard to observation data, the no-problem group mothers and infants both showed higher levels of what was à priori regarded as desirable interactional behavior. Correlations between interview and observation data, calculated within the no-problem group, showed the same kind of connection between mothers' cognitive emotional orientation and interactional behavior as was indicated by the group comparisons.     

Early food refusal: Infant and family characteristics

This study compared infants who developed food refusal during the first year of life with a healthy control group concerning feeding, growth pattern, family situation, and infant behavioral characteristics. Infants with food refusal had a lower relative weight at inclusion in the study and at follow-up at the age of 2 years. Food refusal was also associated with weaning problems, parental reports of lower food consumption, a higher incidence of breast-feeding, a higher frequency of meals, psychosocial problems in the family, less positive perceptions of parenting, infant difficultness, and problematic behaviors. The findings have implications for identification and understanding of factors related to early food refusal.