Object-based visual selective attention and perceptual organization

We report the results of four experiments that were conducted to examine both the representations that provide candidate entities available for object-based attentional selection and the influence of bottom-up factors (i.e., geometric and surface characteristics of objects) and top-down factors (i.e., context and expectancies) on the selection process. Subjects performed the same task in each of the experiments. They were asked to determine whether two target properties, a bent end and an open end of a wrench, appeared in a brief display of two wrenches. In each experiment, the target properties could occur on a single wrench or one property could occur on each of two wrenches. The question of central interest was whether a same-object effect (faster and/or more accurate performance when the target properties appeared on one vs. two wrenches) would be observed in different experimental conditions. Several interesting results were obtained. First, depending on the geometric (i.e., concave discontinuities on object contours) and surface characteristics (i.e., homogeneous regions of color and texture) of the stimuli, attention was preferentially directed to one of three representational levels, as indicated by the presence or absence of the same-object effect. Second, although geometric and surface characteristics defined the candidate objects available for attentional selection, top-down factors were quite influential in determining which representational level would be selected. Third, the results suggest that uniform connectedness plays an important role in defining the entities available for attention selection. These results are discussed in terms of the manner in which attention selects objects in the visual environment.     

BOOKS Reviews

William James and the Reinstatement of the Vague. By William Joseph Gavin.
Anti-foundationalism Old and New. Edited by Tom Rockmore and Beth Singer.     

Gender,role conflict,and the development of relativistic and dialectical thinking

Females have been found to experience greater role conflict. The present study explored whether this conflict fosters earlier social cognitive development. A battery of questionnaires, including a vocabulary test, a role conflict questionnaire, a role articulation questionnaire, and a questionnaire of social cognitive (i.e., absolute, relativistic, and dialectical) paradigm beliefs, was administered to a sample of 121 high-school freshmen, college freshmen, and college seniors. As predicted, females reported more role conflict, showed greater role articulation, and exhibited more advanced (i.e., relativistic and/or dialectical) social cognitive development. The role conflict questionnaire did not correlate with social cognition or mediate its relationship to gender, but future role articulation of family roles and the synthesis of family and work roles did. However, the causal relations were not unidirectional, and alternative hypotheses are discussed.     

Effects of stress on recall

Subjects in experimental conditions were exposed to a traumatic autopsy colour slide (labelled either as of New York Police Department (NYPD) or MGM studio origin) embedded in a neutral series of travel scenes, while control subjects saw a neutral target. Subjects in the high-stress condition showed a significant decrease in memory for neutral slides which followed the NYPD-labelled traumatic stimulus (p < 0.001). Results support evidence in the eyewitness memory field which indicate reduced recall under elevated levels of stress.     

Perceptual organization and focused attention: The role of objects and proximity in visual processing

The influence of the Gestalt grouping principles of similarity, closure, and proximity on the size of the response-compatibility effect was examined in a focused attention task. In three studies, subjects responded to a centrally located target and attempted to ignore adjacent distractors. The distractors, which served as targets on other trials, could be compatible, incompatible, or neutral with respect to the response of the target. In addition, the distractors and the target could be embedded in the same object, presented in the same color, presented on different objects, or presented in different colors. The typical response-compatibility effect (B. A. Eriksen & C. W. Eriksen, 1974) was found when the target and distractors were embedded in the same object or presented in the same color. Performance was poorer when the target was surrounded by response-incompatible distractors than when it was surrounded by response-compatible distractors. However, the response-compatibility effect was eliminated-w-hen. the target and distractors were embedded in different objects, even when the distance between the items was less than.25° of visual angle. Furthermore, the response-compatibility effect was of intermediate size when the distractors were not grouped strongly with the target or with neutral flankers. The results are discussed in terms of space- and object-based models of visual attention.     

Tracking the line of primary gaze in a walking simulator: modeling and calibration.

This article describes a system for tracking the line of primary gaze (LoPG) of participants as they view a large projection screen. Using a magnetic head tracker and a tracking algorithm, we find the onscreen location at which a participant is pointing a head-mounted crosshair. The algorithm presented for tracking the LoPG uses a polynomial function to correct for distortion in magnetic tracker readings, a geometric model for computing LoPG from corrected tracker measurements, and a method for finding the intersection of the LoPG with the screen. Calibration techniques for the above methods are presented. The results of two experiments validating the algorithm and calibration methods are also reported. Experiments showed an improvement in accuracy of LoPG tracking provided by each of the two presented calibration steps, yielding errors in LoPG measurements of less than 2 degrees over a wide range of head positions. Source code for the described algorithms can be downloaded from the Psychonomic Society Web archive, http://www.psychonomic.org/archive/.     

The Integration of Family and Group Therapy as an Alternative to Juvenile Incarceration: A Quasi‐Experimental Evaluation Using Parenting with Love and Limits

The current study employed a quasi‐experimental design using both intent‐to‐treat and protocol adherence analysis of 155 moderate‐ to high‐risk juvenile offenders to evaluate the effectiveness of Parenting with Love and Limits® (PLL), an integrative group and family therapy approach. Youth completing PLL had significantly lower rates of recidivism than the comparison group. Parents also reported statistically significant improvements in youth behavior. Lengths of service were also significantly shorter for the treatment sample than the matched comparison group by an average of 4 months. This study contributes to the literature by suggesting that intensive community‐based combined family and group treatment is effective in curbing recidivism among high‐risk juveniles.     

Measurement and Computational Skepticism

Putnam and Searle famously argue against computational theories of mind on the skeptical ground that there is no fact of the matter as to what mathematical function a physical system is computing: both conclude (albeit for somewhat different reasons) that virtually any physical object computes every computable function, implements every program or automaton. There has been considerable discussion of Putnam's and Searle's arguments, though as yet there is little consensus as to what, if anything, is wrong with these arguments. In the present paper we show that an analogous line of reasoning can be raised against the numerical measurement (i.e., numerical representation) of physical magnitudes, and we argue that this result is a reductio ad absurdum of the challenge to computational skepticism. We then use this reductio to get clearer about both (i) what's wrong with Putnam's and Searle's arguments against computationalism, and (ii) what can be learned about both computational implementation and numerical measurement from the shortcomings of both sorts of skeptical argument.