A basis for bias in geographical judgments

To determine why North Americans tend to locate European cities south of North American cities at similar latitudes (Tversky, 1981), we had observers provide bearing estimates between cities in the U.S. and Europe. Earlier research using latitude estimates of these cities has indicated that each continent has several subjective regions (Friedman & Brown, 2000a). Participants judged cities from two subjectively northern regions (Milwaukee-Munich), two subjectively southern regions (Memphis-Lisbon), and the two "crossed" regions (Albuquerque-Geneva; Minneapolis-Rome). Estimates were biased only when cities from the subjectively northern regions of North America were paired with cities from the subjectively southern region of Europe. In contrast to the view that biases are derived from distorted or aligned map-like representations, the data provide evidence that the subjective representation of global geography is principally categorical. Biases in numerical location estimates of individual cities and in bearing estimates between city pairs are derived from plausible reasoning processes operating on the same categorical representations.     

Diagnosing agoraphobia in the context of panic disorder: examining the effect of DSM-IV criteria on diagnostic decision-making

A diagnostic and statistical manual (DSM)-IV diagnosis of agoraphobia in the context of panic disorder (PD) is based on three nosologically sufficient criteria: (1) avoidance, (2) use of companions, and (3) endurance of situations despite distress. Therefore, an agoraphobia diagnosis can be made across an extremely broad range of cases including when there are no avoidance behaviors (e.g., the patient endures the situation). It was hypothesized that clinicians do not weight these criteria equally and that the DSMs individual, sufficient criteria lead to poor inter-rater reliability. Clinicians (N=48) rated hypothetical patients with symptom profiles emphasizing each of these three criteria. Consistent with expectation, clinicians differentially weighted these criteria. Avoidance was relatively more apt to produce a diagnosis when only one criterion was emphasized in clinical vignettes. Inter-rater reliability was poor in instances when only one sufficient criterion was highlighted. Knowledge concerning DSM criteria resulted in a greater rate of agoraphobia endorsement, but knowledge did not account for the overall pattern of findings.     

Evaluating the efficiency and community safety goals of the Broward County Mental Health Court

Mental health courts have developed as one response to persons with mental illness who are involved with the criminal justice system. This study investigated the efficiency and safety goals of one such court in Broward County, FL. Mental health court (MHC) clients spent significantly fewer days in jail for the index arrest associated with study enrollment than a comparison group. MHC clients had similar survival time to re-arrest up to one year after study enrollment. MHC clients did not significantly differ from the comparison group in self-reported aggressive acts over an 8 month follow-up period, while they did self-report significantly fewer acts of violence than the comparison group at the 8 month follow-up. These findings suggest that some of the benefits associated with the MHC reported in prior studies were not achieved at the expense of efficiency and safety.     

The visual perception of 3-D shape from multiple cues: are observers capable of perceiving metric structure?

Three experiments are reported in which observers judged the three-dimensional (3-D) structures of virtual or real objects defined by various combinations of texture, motion, and binocular disparity under a wide variety of conditions. The tasks employed in these studies involved adjusting the depth of an object to match its width, adjusting the planes of a dihedral angle so that they appeared orthogonal, and adjusting the shape of an object so that it appeared to match another at a different viewing distance. The results obtained on all of these tasks revealed large constant errors and large individual differences among observers. There were also systematic failures of constancy over changes in viewing distance, orientation, or response task. When considered in conjunction with other, similar reports in the literature, these findings provide strong evidence that human observers do not have accurate perceptions of 3-D metric structure.     

When Good Intentions Are Not Enough: Modeling Postdecisional Cognitive Correlates of Condom Use1

Measures of intention usually leave substantial proportions of the variance in behavior unexplained. It has been suggested that improved behavioral prediction could be achieved by identifying postdecisional cognitive processes capable of distinguishing between intenders who do act and those do not act. Condom-related self-report measures of postdecisional cognitive processes were developed and tested in a cross-sectional questionnaire study involving 447 heterosexual students. A discriminant function composed of postdecisional measures was found to significantly distinguish between intenders who reported use and non-use and to correctly classify 80% of intenders. The results indicate that measures of the relative importance of competing intentions, prior planning of specific preparatory actions, and action-specific self-efficacy may enhance the prediction of condom use among intenders.     

The detectability of geometric structure in rapidly changing optical patterns.

Human vision is sensitive to the coherent structure and motion of simple dot patterns undergoing rapid random transformations, even when the component dots are widely separated spatially. A study is reported in which visual sensitivity to translations, rotations, expansions, pure shear, and additive combinations of these transformations was investigated. Observers discriminated between coherent (correlated) movements, in which all the component dots moved simultaneously in corresponding directions and distances, and incoherent (uncorrelated) movements, in which the movements of individual dots were statistically independent. In experiment 1 the accuracy of coherence discrimination was found to be similar for all four of the basic transformations and to increase linearly with the distance of the movements. The discriminability of coherent versus incoherent motion was also found to be similar to the detectability of any motion, suggesting that concurrent movements of individual dots are visually interrelated. In experiments 2 and 3 the visual independence of these four groups of transformations was tested by comparing the accuracy of coherence discrimination of each of the transformations presented alone with that when added to background motions produced by each of the four transformations. Coherence discriminations were less accurate when the target transformation was added to another background transformation, indicating that these transformations are not visually independent. Rotations and expansions, however, were visually independent. In experiment 3 qualitatively similar effects for patterns of several different sizes and dot densities were found. In general, an impressive visual sensitivity to globally coherent structure and motion under several different geometric transformations was observed in these experiments. A basic theoretical issue concerns the local visual mechanisms underlying this sensitivity.     

The discriminability of smooth stereoscopic surfaces.

In this study the sensitivity of human vision to the smoothness of stereoscopic surface structure was investigated. In experiments 1 and 2 random-dot stereograms were used to evaluate the discrimination of smooth versus 'noisy' sinusoidal surfaces differing in the percentages of points on a single smooth surface. Fully coherent smooth surfaces were found to be much more discriminable than other less smooth randomly perturbed surfaces. In experiment 3 the discrimination between discontinuous triangle-wave surfaces and similarly shaped smoothly curved surfaces obtained from the addition of the fundamental and the third harmonic of the corresponding triangle-wave surface was evaluated. The triangle-wave surfaces were found to be more accurately discriminated from the smoothly curved surfaces than would be predicted from the detectability of the difference in their Fourier power spectra. This superior discriminability was attributed to differences between the curvature and/or discontinuity of the two surfaces. In experiment 3 the effects of incoherent 'noise' points on the discrimination between the two surface types were also evaluated. These randomly positioned noise points had a relatively small effect on the discrimination between the two surfaces. In general, the results of these experiments indicate that smooth surfaces are salient for stereopsis and that isolated local violations of smoothness are highly discriminable.