A general model for the analysis of multilevel data

A general model is developed for the analysis of multivariate multilevel data structures. Special cases of the model include repeated measures designs, multiple matrix samples, multilevel latent variable models, multiple time series, and variance and covariance component models.We would like to acknowledge the helpful comments of Ruth Silver. We also wish to thank the referees for helping to clarify the paper. This work was partly carried out with research funds provided by the Economic and Social Research Council (U.K.).     

Self-selection biases in correlational studies based on questionnaires

It is commonly held that even where questionnaire response is poor, correlational studies are affected only by loss of degrees of freedom or precision. We show that this supposition is not true. If the decision to respond is correlated with a substantive variable of interest, then regression or analysis of variance methods based upon the questionnaire results may be adversely affected by self-selection bias. Moreover such bias may arise even where response is 100%. The problem in both cases arises where selection information is passed to the score indirectly via the disturbance or individual effects, rather than entirely via the observable explanatory variables. We suggest tests for the ensuing self-selection bias and possible ways of handling the ensuing problems of inference.The author would like to thank members of the Psychology Department at UWA for references on the illustrative example, namely the effects of sex-stereotyping on achievements in mathematics; thanks are also due to the anonymous reviewers whose comments resulted in material improvements to the paper.     

Type A behaviour in pre-school children: Interrater reliability, stability over six months and subcomponents

Type A behaviour was measured in 250 boys and 245 girls (ages 3-7) using a Swedish version of Matthews' Youth Test for Health (MYTH). In addition, speech and voice characteristics (speed, loudness, response latency) were measured. Each child was independently rated by two play group leaders and measurements were repeated after a six month interval. Interrater reliability (first session) was 0.76 for both sexes and did not change with the age of the child. Boys obtained significantly (p less than 0.0001) higher scores than girls. Correlations over the six month period were 0.64 and 0.60 (p less than 0.001) for the two possible combinations of different raters and slightly higher (0.75 and 0.68, p less than 0.001) when the same rater was used. Two components of Type A behaviour were identified from a factor analysis of the data: impatience and competitiveness, and they accounted for 57% of the total variance. As for the total scale, boys obtained significantly higher scores than girls on both subscales. Scores on the competitiveness scale increased systematically with age. Speech and voice characteristics correlated significantly with Type A scores (total Type A behaviour: r = 0.50, using different raters, and 0.71, using the same raters, p less than 0.001) and, once again, boys obtained significantly (p less than 0.001) higher scores than girls. The results are in close agreement with the American findings from the original scale. It was concluded that the scale provides a reliable and valid instrument for measuring Type A or Type A-like behaviours in pre-school children.     

Facial reactions to auditory stimuli: Sex differences

This study explored whether males and females differ in facial muscle activity when exposed to tone stimuli with different intensity. Males and females were repeatedly exposed to 95 dB and 75 dB 1000 Hz tones while their facial electromyographic (EMG) activity from corrugator and zygomatic muscle regions were measured. Skin conductance responses were also measured. It was found that 95 dB but not 75 dB tones evoked increased corrugator activity. This effect differed significantly between males and females. Thus, it was only females that reacted with a significant increased corrugator response to the high intensity tone. While facial responses differed between the sexes, the skin conductance response patterns did not. Consistent with previous research it is concluded that females are more facially expressive than are males.     

Normal values for Type A behaviour patterns in Danish men and women and in potential high-risk groups

The Jenkins Activity Survey (JAS) was administered to a normal population of randomly selected Danish adults, to patients consulting a cardiologist, and to physicians in order to compare those groups in terms of their coronary-prone (Type A) behaviour patterns. The standard procedure of rating the JAS was used in order to obtain scores for each of the four subscales: Type A (time urgency and ambitiousness), Factor S (speed and impatience) Factor H (hard-driving and competitive) and Factor J (job involvement). Gender differences were observed in the normal population for each of the four subscale scores, and age-related differences were obtained for Factor J. Elevated scores for Factor S were obtained by physicians and by people in the population who had a cardiovascular disorder. Physicians had also elevated scores for Factor J, whereas their Factor H scores tended to be reduced. No reliable differences in JAS subscale scores were observed between four groups of heart patients (i.e. angina pectoris, arterial hypertension, atrial fibrillation and atherosclerosis), although there was a tendency for Factor J to be elevated in atherosclerosis. The findings provide normal values for JAS scores in Danish men and women, and suggest that some facets of coronary-prone behaviour may be enhanced in Danish high-risk groups.     

Familial similarity in Type A behaviour and physiological measurements as related to sex

Thirty-one families with pre-school children were examined with regard to Type A behaviour and cardiovascular and neuroendocrine measurements. Type A scores (MYTH) of the children from the ages of three to six were positively correlated with independent Type A measurements (Jenkins Activity Survey, Bortner Type A scale) of the parents (significant for fathers but not for mothers). The children's resting systolic blood pressures were significantly correlated with maternal and paternal values, while no significant familial aggregation was found for diastolic blood pressure, heart rate, catecholamine or cortisol excretion. The children's systolic and diastolic blood pressures and adrenaline excretion were significantly correlated between ages three and six. The results are consistent with the assumption that genetic as well as environmental factors contribute to the development of Type A behaviour. No significant association was found between Type A scores and physiological measurements during routine activities in the children or the adults.     

Patterns of mother-infant interaction and attachment: A cluster-analytic approach

This study examined stability and change in patterns of mother-infant interaction between 5 and 10 months and their relation to attachment security at 18 months. Cluster analysis was used to identify patterns of dyadic interaction. There was significant, but not substantial, stability in cluster membership from 5 to 10 months. For females, being in the most optimal cluster at 5 months related to subsequent attachment security, regardless of the 10-month pattern of interaction. For males, who were significantly more likely to be insecure than females, insecure attachment was predicted by negative change from 5 to 10 months (moving from a more optimal to a less optimal cluster).     

大学生场依存性─－独立性认知方式分析

对二十一个学科专业１５２６名大学生的场依存性─－独立性认知方式进行调查所获得的新近常模资料表明：大学生场依存性─－独立性个体差异的群体分布是正态性的,其总体平均水平以《认知方式图形测验》成绩作指标为１３．７（ｓ为４．６）。在此基础上,对文献所报道的影响场依存性─－独立性发展水平的两个因素作了进一步的研究分析,发现,大学生场依存性─－独立性的性别差异非常接近显著水平;专业分化是不依赖于性别因素而导致大学生场依存性─－独立性水平显著不同的主要因素．     

Attentiveness of mothers and fathers to their baby's cries

Thirty-two mother-father-infant triads participated in a study to examine whether parents' responsiveness to their own infant's distress was affected by the infant's birth order and gender. After separating from their 10- to 11-month-old baby, one parent from each family (16 mothers and 16 fathers) was selected to hear cries that were attributed to the child. Consistent with previous findings regarding physiological reactions to crying and observations of caretaking behavior, first-time parents gave quicker and more frequent attention to their infants than did multiporous parents. Speedy intervention was related to the amount of caretaking responsibilities that parents reported they assumed and to the age at which parents believed that their infant first recognized them. The results demonstrate the importance of caretaking for promoting parental sensitivity to infant signals.