Memory for medical history: Accuracy of recall

Medical diagnosis often depends on the ability of patients to recall and report their medical history. In this study 104 people kept health diaries for 3 months, recording the incidence, frequency, data, duration, and severity of health events (symptoms, illnesses, injuries, visits to health professionals, and medication). Memory for the events recorded was tested immediately after the diary-keeping period or at 1 month or 3 months later. Effects of age, gender, education, health status, anxiety, and retention interval were observed. With a free recall procedure only 47 per cent of health events were recalled. Following the free recall two different kinds of intervention were compared. Use of a recognition checklist yielded recall of 29 per cent of the forgotten events but with a cognitive interview procedure only 6 per cent of the forgotten items were retrieved.     

Adolescent sibling differences in suicidal symptoms: The role of parent-child relationships

This study examined concordance for symptoms of suicide among 178 pairs of adolescent siblings, and the association of youth and maternal reports of parenting with variation in suicide ideation both across families and between siblings. Crosstabulation analyses indicated a significant risk of suicide ideation among siblings of adolescents who had made suicide attempts, as well as a significant degree of concordance for suicide ideation among pairs of siblings. Regression analyses indicated that reported levels of maternal warmth and harsh discipline, especially youth reports, were associated with suicide ideation, and that sibling differences on these parenting indices were associated with differences in suicide ideation both across families as well as between siblings. However, sibling differences in reported parenting did not contribute to prediction of suicide ideation above the variance accounted for by the simple levels of parenting reported by adolescents.     

A method for evaluating the effectiveness of educational software

A method for executing a detailed evaluation of educational software is described. Several issues are discussed, including the use of an experimental setting versus a field study, and the design of assessment instruments suited to evaluation of educational software. The instruments include a test of remedial skills, a 103-item test of conceptual understanding, and a system for recording students’ use of the software. The method was used to evaluate ConStatS, a program for teaching conceptual understanding of probability and statistics. Preliminary results of the evaluation are presented.     

Role of the Leader in Therapy Groups Conducted With Illicit Drug Abusers: How Directive Does the Leader Have to Be?

A 17-hour marathon group was conducted in a residential treatment center established for inmates in a correctional setting in the southeastern United States. The Hill Interaction Matrix (HIM-G; Hill, 1965) was used to measure the types of leader activity and the types of member activity during portions of each hour of the group activity. It was found that when the group was most therapeutic, there was a relationship between the therapists' actions and behaviors and the types of issues that were discussed in the group. The results that were found do not agree with some of the established drug and alcohol abuse literature.     

Intra- and cross-dimensional visual search for single-feature targets

Cross-dimensional visual search for single-feature targets that differed from the distractors along two dimensions (color and orientation) was compared with intradimensional search for targets that differed from the distractors along a single dimension (either orientation or color). The design of the first three experiments differed from those of previous studies in that participants were required to respond differently to each of the targets. Experiments 1-3 were similar except that in Experiment 1, the distractors were homogeneous; in Experiment 2, two types of distractors were used in equal proportions; and in Experiment 3, two types of distractors were used but one of the distractors was a singleton. The findings, contrary to those of previous studies, revealed that cross-dimensional search is at least as efficient and for some targets even more efficient than intradimensional search. These results suggest that the details of stimulus-to-response mapping are essential in comparing intra- and cross-dimensional tasks. Experiment 4 used a priming design and did not support an explanation based on grouping processes. We outline an explanation for all the findings based on a recent cross-dimensional response selection model by Cohen and Shoup (1997).     

From parallel to serial processing: a computational study of visual search

A novel computational model of a preattentive system performing visual search is presented. The model processes displays of lines, reproduced from Wolfe, Friedman-Hill, Stewart, and O'Connell's (1992) and Treisman and Sato's (1990) visual-search experiments. The response times measured in these experiments suggest that some of the displays are searched serially, whereas others are scanned in parallel. Our neural network model operates in two phases. First, the visual displays are compressed via standard methods (principal component analysis), to overcome assumed biological capacity limitations. Second, the compressed representations are further processed to identify a target in the display. The model succeeds in fast detection of targets in experimentally labeled parallel displays, but fails with serial ones. Analysis of the compressed internal representations reveals that compressed parallel displays contain global information that enables instantaneous target detection. However, in representations of serial displays, this global information is obscure, and hence, a target detection system should resort to a serial, attentional scan of local features across the display. Our analysis provides a numerical criterion that is strongly correlated with the experimental response time slopes and enables us to reformulate Duncan and Humphreys's (1989) search surface, using precise quantitative measures. Our findings provide further insight into the important debate concerning the dichotomous versus continuous views of parallel/serial visual search.     

Neural dynamics of perceptual order and context effects for variable-rate speech syllables

How does the brain extract invariant properties of variable-rate speech? A neural model, called PHONET, is developed to explain aspects of this process and, along the way, data about perceptual context effects. For example, in consonant-vowel (CV) syllables, such as /ba/ and /wa/, an increase in the duration of the vowel can cause a switch in the percept of the preceding consonant from /w/ to /b/ (J.L. Miller & Liberman, 1979). The frequency extent of the initial formant transitions of fixed duration also influences the percept (Schwab, Sawusch, & Nusbaum, 1981). PHONET quantitatively simulates over 98% of the variance in these data, using a single set of parameters. The model also qualitatively explains many data about other perceptual context effects. In the model, C and V inputs are filtered by parallel auditory streams that respond preferentially to the transient and sustained properties of the acoustic signal before being stored in parallel working memories. A lateral inhibitory network of onset- and rate-sensitive cells in the transient channel extracts measures of frequency transition rate and extent. Greater activation of the transient stream can increase the processing rate in the sustained stream via a cross-stream automatic gain control interaction. The stored activities across these gain-controlled working memories provide a basis for rate-invariant perception, since the transient-to-sustained gain control tends to preserve the relative activities across the transient and sustained working memories as speech rate changes. Comparisons with alternative models tested suggest that the fit cannot be attributed to the simplicity of the data. Brain analogues of model cell types are described.     

Peer Status in the Middle School: A Natural Treatment for Unequal Participation

The focus of this study is on the problem of unequal participation of students within small cooperative learning groups in middle-school classrooms. According to previous research using Status Characteristic Theory, this unequal participation stems from differential expectations for competence based on academic and peer status. Previous research had also found that in classrooms where rank on these two status orders was uncorrelated (incongruent classrooms), problems of unequal participation were less severe. This study involved systematic observations of students in working groups in four middle-school science classrooms. The derivation of hypotheses required an extension of Status Characteristic Theory to handle three-to-five-person groups working in a multicharacteristic situation. The results showed good support for hypotheses explaining the effect of incongruence in the social structure on participation of low-status students. Incongruent classrooms had fewer small groups that were highly differentiated on status. Moreover, the degree of status differentiation in the groups was a direct predictor of the participation rates of the low-status students. Thus, the less differentiated groups in incongruent classrooms showed fewer status problems. As a practical matter, the tendency of students to construct peer status orders that are independent of academic status acts as a natural treatment for unequal participation.     

The Role of Psychological Characteristics in the Relation Between Socioeconomic Status and Perceived Health1

Separate analyses of United States and Finnish samples demonstrate a graded (almost linear) relation between socioeconomic status (SES) and risk of poor perceived health. In both studies, positive psychological factors (greater social support; less anger, depression, and perceived stress) and beneficial health practices (nonsmoking; drinking and exercising moderately) were associated with both higher levels of SES and better self-reported health. Psychological and health practice variables were both able to account for some of the SES and poor health gradient. However, contrary to expectations, these factors did not play a more important role in explaining decreased risk at the middle and highest levels of SES, and instead may be most important at lowest levels.