Discovery algorithms for hierarchical relations

Two algorithms based on a latent class model are presented for discovering hierarchical relations that exist among a set ofK dichotomous items. The two algorithms, stepwise forward selection and backward elimination, incorporate statistical criteria for selecting (or deleting) 0–1 response pattern vectors to form the subset of the total possible 2 ^k vectors that uniquely describe the hierarchy. The performances of the algorithms are compared, using computer-constructed data, with those of three competing deterministic approaches based on ordering theory and the calculation of Phi/Phi-max coefficients. The discovery algorithms are also demonstrated on real data sets investigated in the literature.     

Role of Secondary Stressors in the Parental Death–Child Distress Relation

This study examined the psychological consequences and secondary stressors associated with death of a parent. The sample (N = 116) consisted of 26 youths who had lost a parent to homicide, 45 youths who had lost a parent to natural death, and 45 nonbereaved youths. Youngsters completed face-to-face interviews, while their guardians completed measures assessing the children's functioning. Results based on both child and guardian reports indicated that parental death was associated with an increase in secondary stressors, regardless of the mode of death. Findings based on guardian reports also revealed that parental death was related to increased internalizing distress, and that parental death due to homicide was related to increased externalizing distress. Furthermore, secondary stressors mediated the parental death–child distress relation such that parental death led to an increase in stressors, which in turn led to increased child distress. Implications for secondary and tertiary preventive interventions are discussed.     

The functional anatomy of word comprehension and production

This review describes the functional anatomy of word comprehension and production. Data from functional neuroimaging studies of normal subjects are used to determine the distributed set of brain regions that are engaged during particular language tasks and data from studies of patients with neurological damage are used to determine which of these regions are necessary for task performance. This combination of techniques indicates that the left inferior temporal and left posterior inferior parietal cortices are required for accessing semantic knowledge; the left posterior basal temporal lobe and the left frontal operculum are required for translating semantics into phonological output and the left anterior inferior parietal cortex is required for translating orthography to phonology. Further studies are required to establish the specific functions of the different regions and how these functions interact to provide our sophisticated language system.     

REEMERGENCE AND EXTINCTION OF SELF-INJURIOUS ESCAPE BEHAVIOR DURING STIMULUS (INSTRUCTIONAL) FADING

Based on results of a functional analysis indicating that the self-injurious behavior (SIB) of 3 individuals was maintained by negative reinforcement (escape from instructional situations), the effects of stimulus (instructional) fading were evaluated in a multiple baseline design across subjects. The rate of instructions was reduced to zero at the beginning of treatment and was gradually increased (faded in) across sessions as long as SIB remained low. However, if SIB remained high for 10 consecutive sessions, extinction was implemented until SIB decreased, at which point extinction was withdrawn and fading was resumed. Treatment was completed when the rate of instructions was the same as in baseline (two per minute), and SIB remained below 0.5 responses per minute for two consecutive sessions. Results showed that instructional fading (without extinction) virtually eliminated SIB initially, but these effects were not maintained. All 3 subjects required multiple exposures to extinction and over 150 treatment sessions in order to meet the end-of-treatment criteria. Advantages and limitations of fading procedures without an extinction component, as well as extensions of both interventions to other clinical problems, are discussed.     

Predictors of Accurate and Inaccurate Memories of Traumatic Events Experienced in Childhood

How likely is it that traumatic childhood events are misremembered or forgotten? Research on children′s recollections of painful or frightening medical procedures may help answer this question by identifying predictors of accurate versus inaccurate memory. In the present study, 46 3- to 10-year-old children were interviewed after undergoing a stressful medical procedure involving urethral catheterization. Age differences in memory emerged, especially when comparing 3- to 4-year-olds with older children. Children′s understanding of the event, parental communication and emotional support, and children′s own emotional reactions also predicted accuracy. Memory did not reliably vary for children who endured the medical procedure once versus multiple times. Results are discussed in relation to possible precursors of accurate and false memories, and forgetting, of traumatic events experienced in childhood.     

A study of area conservation using a simple method of adjustment

The method of adjustment was adapted to study conservation of area with Papua New Guinea High School students. Subjects were shown a standard field, representing “a block of land”, with a “house” in each corner. An identical comparison field. with adjustable borders was presented under one of two conditions. In one condition the houses were placed along one side, and in the other they were placed randomly about the field. Non-conservers were invited to adjust the borders of the comparison field to match the area of the standard. Non-conservers in the Edge condition reduced, and those in the Random condition increased, the size of the comparison field.     

THE ROLE OF ATTENTION IN THE TREATMENT OF ATTENTION-MAINTAINED SELF-INJURIOUS BEHAVIOR: NONCONTINGENT REINFORCEMENT AND DIFFERENTIAL REINFORCEMENT OF OTHER BEHAVIOR

Because there are potentially serious limitations to differential reinforcement of other behavior (DRO) (which is probably the most widely used treatment procedure for behavior problems), we examined an alternative procedure—noncontingent reinforcement (NCR). Three females with developmental disabilities, all of whom engaged in severe self-injurious behavior, participated. During a pretreatment functional analysis, each subject's self-injury was shown to be differentially sensitive to social attention as a maintaining consequence. Next, each subject was exposed to a DRO treatment and an NCR treatment. During DRO, attention was delivered contingent on the absence of self-injury for prespecified intervals. During NCR, attention was delivered on a fixed-time schedule that was not influenced by the subject's behavior. Results showed that both procedures were highly effective in reducing self-injury, probably because the functional reinforcer for self-injury was used during treatment. Furthermore, there was evidence that NCR attenuated several of the limitations of DRO. These results are particularly interesting in light of the long experimental history of NCR as a control rather than as a therapeutic procedure.     

Tonic and phasic orientation in full-term and preterm infants

Thirty-three full-term infants and thirty-eight preterm infants (on average born at 30 weeks gestation) were tested for their latency to turn toward checkered stimulus patterns (phasic orienting or "attention-getting") and for the duration of their initial fixation (tonic orienting or "attention-holding"). Plotted against the logarithm of the subjects' postconceptional age, turning latency fell linearly between 36 and 120 weeks, while fixation time fell abruptly at 53 weeks. Preterm and full-term infants showed the same developmental trends, implying that both of these attentional behaviors are biologically timetabled and that neither is greatly affected by premature extrauterine experience. Unexpectedly, phasic orientation in the first 30 postnatal days was significantly faster in preterm than in full-term infants, and fixation times failed to differ. Despite the necessary functional integration of phasic and tonic orienting in mature visual scanning and attention, the present results suggest an independence in their early postnatal development and that neither is mature at birth.     

Comparison of three antismoking interventions among pregnant women in an urban setting: a randomized trial

This study examined smoking cessation and cigarette reduction of indigent inner city pregnant women (n = 193) who completed one of three interventions: a special video program based on their perceptions of the effects of smoking during pregnancy, the American Lung Association's "Freedom From Smoking For You and Your Baby" program, or the usual physician's advice. Six percent of the women quit smoking, and 43% reduced the number of cigarettes they smoked. There were no significant differences among the three groups for either the number who quit smoking or who reduced the number of cigarettes smoked.