We examined the grouping of line segments into unitary shapes and attempted to identify procedures to diagnose when such grouping is taking place. Previous research has indicated that attentional measures may diagnose grouping: With grouped parts, selective attention to individual parts is difficult and divided attention across parts is easy, whereas with ungrouped parts selective attention is easy and divided attention is difficult. This result suggests that grouping operates via a perceptual glue binding parts into wholes that are difficult or impossible to divide. Other studies have suggested in addition that grouped parts produce emergent features, possibly including symmetry and closure, that make possible configural superiority effects, where whole shapes are more discriminable than are their distinguishing contours shown in isolation. The 13 experiments reported here indicate that perceptual glue is not needed to explain known findings about grouping, a claim that agrees with conclusions by other investigators using other criteria. Rather, emergent features alone may suffice to explain grouping, provided that reliable and accurate diagnostic criteria can be identified. It is shown that the diagnostics now available are not fully adequate for this purpose. Surprisingly, it appears that some prime candidates for emergent features--namely, closure and line terminators--may not be of central importance to form perception.

TWEAK is an acronym for Tolerance (T1 number of drinks to feel high; T2, number of drinks one can hold), Worry about drinking, Eye-opener (morning drinking), Amnesia (blackouts), and Cut down on drinking (K/C). In this study, two versions (T1 and T2) of the TWEAK were part of a questionnaire used to detect alcoholism or heavy alcohol intake in three populations, namely, alcoholics in treatment, patients in two outpatient clinics, and the general population. Similar to the CAGE and the 10-item brief MAST, the TWEAK identified most known alcoholics, but the TWEAK had a higher sensitivity and specificity than the CAGE and B-MAST in detecting alcoholism/heavy drinking in the clinical and general populations. Different cut-off values for tolerance (T1 and T2) are recommended for screening different populations.

No abstract

The brief MAST (B-MAST) questionnaire was used to detect alcoholism in three populations, namely, alcoholics in treatment, clinical outpatients, and the general population. Nearly all the alcoholics in treatment tested positive in the B-MAST (99.2%), for lifetime as well as for current (past year) alcohol-related problems. Among the clinical outpatients and general population, 35.6% and 20.2% respectively, tested positive for lifetime alcohol problems, but only 19.6% and 7.6%, respectively, tested positive for past-year alcohol problems. The sensitivity/specificity of the B-MAST (lifetime) was 64.7%/90.0% and 48.3%/96.4% in the clinical outpatients and general population, respectively. Even lower sensitivity (28.2%) was obtained when the B-MAST was used to detect past-year alcohol problems in the general population sample. The poor sensitivity of the B-MAST in the general population was probably because most of the B-MAST questions deal with severe alcohol problems, and they are not sufficiently sensitive to detect those who drank heavily but who had not yet developed these alcohol problems. Anomalous responses to the two questions about "normal drinker" and to the question about "attendance in AA meeting" also contributed (< 3%) to inflated positive B-MAST scores. There were gender differences, and to a lesser extent, racial differences (Whites versus Blacks), in the responses to individual B-MAST questions in the three subject populations, with more males than females in each group reporting more alcohol-related problems. However, there were no gender and racial differences in the average B-MAST scores among those clinical outpatients and general population subjects who tested positive.

The preattentive visual information processing of hypothetically psychosis-prone college subjects was evaluated using three different paradigms, target detection (n = 57), visual suffix effect (n = 57), and configural superiority effect (n = 68). It was hypothesized that anhedonic subjects would show the same perceptual organization deficits reported in process schizophrenics and that perceptual aberration-magical ideation subjects and depressed subjects would perform similarly to control subjects. In each study, anhedonics performed similarly to each comparison group, even though there was adequate power to detect performance differences if they existed. A framework for understanding the visual information-processing deficits of schizophrenics and high-risk subjects is proposed.