The relationship between Fisher's exact test and Pearson's chi-square test: A bayesian perspective

It is demonstrated in this paper that two major tests for 2 × 2 talbes are highly related from a Bayesian perspective. Although it is well-known that Fisher's exact and Pearson's chi-square tests are asymptotically equivalent, the present analysis shows that a formal similarity also exists in small samples. The key assumption that leads to the resemblance is the presence of a continuous parameter measuring association. In particular, it is shown that Pearson's probability can be obtained by integrating a two-moment approximation to the posterior distribution of the log-odds ratio. Furthermore, Pearson's chi-square test gave an excellent approximation to the actual Bayes probability in all 2×2 tables examined, except for those with extremely disproportionate marginal frequencies.     

应激对大鼠行为和部分脑区谷氨酸含量的影响

以旷场试验法测定动物在急、慢性躯体性和心理性应激时的行为变化,以快速断头冷冻匀浆法,用ＨＩＴＡＣＨＩ－８３５氨基酸分析仪测定应激各期视皮层、海马、下丘脑、小脑谷氨酸含量。并对正常动物经侧脑室微量注射Ｌ－ＡＰ４后观察行为变化。结果显示,急性应激期动物行为活动增加,慢性应激期减少：应激时,大鼠部分脑区的谷氨酸含量与对照组相比在不同时期呈显著性差异;侧脑室微量注射Ｌ－ＡＰ４提示行为活动减弱可能与脑内Ｇｌｕ系统的活动有关。     

模糊再认（FR）判断—元记忆领域的新方法

Ｈａｒｔ所开创的ＦＯＫ研究范式表明,在记忆的提取阶段由客体水平的回忆能引起元水平ＦＯＫ判断,但历来的研究都忽略了由再认也能引起一种元记忆判断,这就是“模糊再认判断”（即ＦＲ判断）．本文论述了ＦＲ判断的概念,特性和研究方法并加以实验验证．ＦＲ判断发生在记忆提取阶段,有着与ＦＯＫ判断同等重要的研究价值和相似的研究方法．ＦＲ研究范式给予元记忆研究以新的思想和方法．     

A psychometric examination of the multidimensional perfectionism scale

The Multidimensional Perfectionism Scale (MPS), developed by Frost, Marten, Lahart, and Rosenblate (1990), was constructed using an all female sample at an elite university. This study examined the psychometric properties of the instrument using a more typical sample (n=278) of college students from a large state university and a small liberal arts college, both located in the South. Significant differences were found on the overall MPS score as well as six of the seven subscales between this sample and that of Frostet al. No gender differences were found for any of the MPS scores. Internal reliability was found to be .88 for the total score, with subtests ranging from .57 to .95. Interscore correlations were relatively consistent with the Frostet al. sample except for a negative correlation between the PS subscale and the total score. There was a strong confirmation of the underlying factor structure reported by Frostet al. The overall impression was that the MPS is a psychometrically sound instrument of potential value in studying the construct of perfectionism.     

Moral growth in medical students

Although students bring to medical school a fairly well established value system, the potential for moral growth through the medical school environment and experience is substantial. The educational environment poses a succession of developmental and adaptive tasks to be accomplished. Several of these tasks are discussed here, tasks that are value-laden and involve, directly or indirectly, the interplay of ethical theory and practice. During the past quarter century, the two influences that have had the greatest impact on the moral growth and moral reasoning capacity of medical students have been the incorporation into the medical school curriculum of courses in medical humanities and the admission to medical school of an increasing number of female students. The female students have brought to medical school a level or dimension of moral reasoning (morality as care or responsibility for others) to augment the male students' focus on rights and justice considerations.     

Maternal attitudes during pregnancy predict mother-infant physical proximity six months after birth

The purpose of this study was to develop an instrument for assessing maternal attitudes. Three photographs representing infants or mother-infant dyads were presented to 26 mothers in the second half of pregnancy and six months after birth. Nine mothers were clinical cases, seventeen mothers were nonpathological controls. Thirty-three semantic categories were used to code the mothers' responses to the pictures. Mothers' responses were coded independently by two researchers. The factor analysis of the codes yielded an ‘attraction to, vs rejection of, children’ factor. Compared with the control group, the mean factor score of the clinical group was significantly lower, i. e. reflected less attraction (p < 0.01). To study the relation between the attraction factor and the physical proximity of mothers and infants, 21 of these mother-infant dyads were videotaped in a semi-structured play interaction six months after birth. Recordings were coded independently by two researchers for various indices of proximity (spatial proximity, kisses, embraces, touches). The factor analysis of the codes yielded a factor contrasting distant vs close and tender interaction. A significant correlation was found between the attraction scores of pregnant women and the proximity scores of mother-infant interaction (r = 0.46; p < 0.05). These results suggest that this instrument is useful in assessing maternal attitudes of psychiatrically disturbed pregnant women and that maternal attitudes of pregnant women are significant predictors of physical proximity in motherinfant interaction at the end of the first semester.     

Social support after the loss of an infant child: A long-term perspective

The article presents findings from a survey among 251 parents whose infant child had died. For most of the parents, the loss occurred several years ago. The survey assessed the amounts of instrumental, emotional and informational support received by these parents from various sources in connection with the death. The findings revealed that different sources provided different kinds of support. There was only one significant difference between bereaved males and females with regard to amount of support: females received more emotional support from their friends than males did. Furthermore, large amounts of support received by one spouse was associated with a similar level of support received by the other spouse. Social support in connection with the death was to some extent related to long-term psychological adaptation. Particularly support from neighbours and professionals was consistently associated with psychological adaptation. In general, however, the findings with regard to long-term effects of social support were ambiguous.     

Attention in the pigeon: a reevaluation

During training sessions, pigeons were successively exposed to compounds consisting of a white triangle on a red background and a white circle on a green background. Key pecking intermittently produced grain reinforcers in the presence of one form-color compound. Once key pecking was confined to the compound associated with reinforcement, the elements—red, green, triangle, and circle—were presented during a test in which no reinforcement was available. Each bird pecked nearly exclusively in the presence of the color previously associated with reinforcement, a result that might be interpreted as indicating that the subjects had attended to color, but not form during training. Pecking was next reinforced when either the triangle or the circle was present. Pecking in the presence of the form previously associated with reinforcement was acquired more rapidly. This result suggests that the birds had learned about the forms during training, and that conclusions about attention based on the lack of differential pecking in the nonreinforcement test may not be appropriate.     

Pseudo maximum likelihood estimation and a test for misspecification in mean and covariance structure models

Using the theory of pseudo maximum likelihood estimation the asymptotic covariance matrix of maximum likelihood estimates for mean and covariance structure models is given for the case where the variables are not multivariate normal. This asymptotic covariance matrix is consistently estimated without the computation of the empirical fourth order moment matrix. Using quasi-maximum likelihood theory a Hausman misspecification test is developed. This test is sensitive to misspecification caused by errors that are correlated with the independent variables. This misspecification cannot be detected by the test statistics currently used in covariance structure analysis.For helpful comments on a previous draft of the paper we are indebted to Kenneth A. Bollen, Ulrich L. Küsters, Michael E. Sobel and the anonymous reviewers of Psychometrika. For partial research support, the first author wishes to thank the Department of Sociology at the University of Arizona, where he was a visiting professor during the fall semester 1987.     

THE EFFECTS OF AN ENVIRONMENTAL “ENRICHMENT” PROGRAM ON THE BEHAVIOR OF INSTITUTIONALIZED PROFOUNDLY RETARDED CHILDREN

This study determined the effects of procedures designed to “enrich” the physical and social environment of an institutional ward on the “adaptive” and “maladaptive” child, adult, self, and object-directed behaviors of five profoundly retarded ambulatory females. Behavior observed in two treatment conditions, an environment “enriched” with toys and objects and an “enriched” environment coupled with differential reinforcement of adaptive behavior, was compared to behavior occurring in corresponding baseline or “austere” conditions and during a period of noncontingent reinforcement. The results generally revealed: (1) little change in adaptive and maladaptive child and adult-directed behavior across conditions, (2) an overall higher incidence of adaptive object-directed behavior and reduced self-directed maladaptive behavior in each treatment condition from that observed in corresponding control conditions, and (3) the use of an “enriched” environment and differential reinforcement of adaptive behavior resulted in maladaptive self-directed behavior being reduced and adaptive object-directed behavior being increased beyond that observed in the “enriched” environment alone. These behavioral gains were largely maintained during a follow-up condition by continuing the “enriched” environment and transferring the responsibility for differential reinforcement to direct-care staff.