Visual search in scenes involves selective and nonselective pathways

How does one find objects in scenes? For decades, visual search models have been built on experiments in which observers search for targets, presented among distractor items, isolated and randomly arranged on blank backgrounds. Are these models relevant to search in continuous scenes? This article argues that the mechanisms that govern artificial, laboratory search tasks do play a role in visual search in scenes. However, scene-based information is used to guide search in ways that had no place in earlier models. Search in scenes might be best explained by a dual-path model: a 'selective' path in which candidate objects must be individually selected for recognition and a 'nonselective' path in which information can be extracted from global and/or statistical information.     

Handler beliefs affect scent detection dog outcomes

Our aim was to evaluate how human beliefs affect working dog outcomes in an applied environment. We asked whether beliefs of scent detection dog handlers affect team performance and evaluated relative importance of human versus dog influences on handlers’ beliefs. Eighteen drug and/or explosive detection dog/handler teams each completed two sets of four brief search scenarios (conditions). Handlers were falsely told that two conditions contained a paper marking scent location (human influence). Two conditions contained decoy scents (food/toy) to encourage dog interest in a false location (dog influence). Conditions were (1) control; (2) paper marker; (3) decoy scent; and (4) paper marker at decoy scent. No conditions contained drug or explosive scent; any alerting response was incorrect. A repeated measures analysis of variance was used with search condition as the independent variable and number of alerts as the dependent variable. Additional nonparametric tests compared human and dog influence. There were 225 incorrect responses, with no differences in mean responses across conditions. Response patterns differed by condition. There were more correct (no alert responses) searches in conditions without markers. Within marked conditions, handlers reported that dogs alerted more at marked locations than other locations. Handlers’ beliefs that scent was present potentiated handler identification of detection dog alerts. Human more than dog influences affected alert locations. This confirms that handler beliefs affect outcomes of scent detection dog deployments.     

Accidental communities: race, emergency medicine, and the problem of polyheme

This article focuses on emergency medical care in black urban populations, suggesting that the classification of a "community" within clinical trial language is problematic. The article references a cultural history of black Americans with pre-hospital emergency medical treatment as relevant to contemporary emergency medicine paradigms. Part I explores a relationship between "autonomy" and "community." The idea of community emerges as a displacement for the ethical principle of autonomy precisely at the moment that institutionalized medicine focuses on diversity. Part II examines a clinical trial for the blood substitute PolyHeme (Northfield Laboratories, Inc., Evanston, IL). It illustrates the ways in which bias in research paradigms and Institutional Review Board decisions attach to the notion and utility of the language of "community." The conclusion's contemporary anecdote makes apparent the vitality of the issues of prehospital emergency medical care and the ways in which decisions and practices fall too easily into a narrative of culturally biased treatment.     

Perception of objects in natural scenes: is it really attention free?

Studies have suggested attention-free semantic processing of natural scenes in which concurrent tasks leave category detection unimpaired (e.g., F. Li, R. VanRullen, C. Koch, & P. Perona, 2002). Could this ability reflect detection of disjunctive feature sets rather than high-level binding? Participants detected an animal target in a rapid serial visual presentation (RSVP) sequence and then reported its identity and location. They frequently failed to identify or to localize targets that they had correctly detected, suggesting that detection was based only on partial processing. Detection of targets was considerably worse in sequences that also contained humans, presumably because of shared features. When 2 targets were presented in RSVP, a prolonged attentional blink appeared that was almost eliminated when both targets were detected without being identified. The results suggest rapid feature analysis mediating detection, followed by attention-demanding binding for identification and localization.     

Brain mechanisms of extinction of the classically conditioned eyeblink response

It is well established that the cerebellum and its associated circuitry are essential for classical conditioning of the eyeblink response and other discrete motor responses (e.g., limb flexion, head turn, etc.) learned with an aversive unconditioned stimulus (US). However, brain mechanisms underlying extinction of these responses are still relatively unclear. Behavioral studies have demonstrated extinction as an active learning process distinct from acquisition. Experimental data in eyeblink conditioning suggest that plastic changes specific to extinction may play an important role in this process. Both cerebellar and hippocampal systems may be involved in extinction of these memories. The nature of this phenomenon and identification of the neural substrates necessary for extinction of originally learned responses is the topic of this review.     

The Influence of Physical Attractiveness and Gender on Ultimatum Game Decisions

Physical appearance influences behavior in a number of environments, yet surprisingly little is known about the influence of physical attractiveness on the bargaining process. We conducted an ultimatum game experiment to investigate the influence of physical attractiveness and gender on ultimatum game decisions. Results from this study revealed no significant differences in the offers or demands attractive and unattractive people made. However, attractive people and men were treated differently by others. Consistent with the notion of a “beauty premium,” attractive people were offered more, but more was demanded of them. Men were also offered more, and less was demanded of them. We discuss implications of these results with respect to bargaining and the labor market.     

Stigmatization of Non-Normative Family Size Status

Prior person perception studies exposednormative expectations about family size such thatvoluntary childfree and single-child women werestigmatized and large-family mothers were glorified. Incontrast, self-reports find no differences in subjectivewell-being among these non-normative and 2 to 3 child,normative women. To explore mostly white,college-educated, employed women's experiences withtheir real-life family size choices, interviews wereconducted with 15 voluntary childfree, 15 one-child, and15 supernormative mothers of 4+ children, and 15normative mothers completed a comparison survey. Quantitative and qualitative analyses revealedpatterns of universal satisfaction, yet stigmatizationacross the three non-normative groups, such as pressurefrom outsiders (including medical professionals) to stay within normative parameters persisted.One-child and supernormative mothers reported thatothers are critical of their child's well-being,intimating selfishness and neglect, respectively. These findings help coalesce the conclusions ofearlier studies.     

Do authorship policies impact students' judgments of perceived wrongdoing?

Although authorship policies exist, researchers understand little about their impact on perceptions of authorship scenarios. Graduate students (N=277) at a large university read 1 of 3 vignettes about a graduate student-faculty collaboration. One half of the surveys included the American Psychological Association's statement on authorship. Participants rated (a) the ethics of the professor as first author and (b) the likelihood of a dissatisfied student reporting the authorship result, as well as the effectiveness and negative consequences of reporting. Work arrangements on the project had a consistent main effect. Also, an authorship policy impacted women's ratings of first authorship when the student contributed the idea for a project. For men, a policy impacted only ratings of the likelihood of reporting when a professor was first author on a student's dissertation. Apart from sex, no other demographic variables on participants were predictive. Discussion focuses on the policy's potential for making only some specific issues salient.     

Auditory evoked brain responses: Comparison of ON and OFF responses at long and short durations

Average evoked brain responses (EBRs) to three durations of one kilohertz pure-tone stimuli were computed from human scalp recordings. Stimuli of 25, 75, and 2,000 msec duration were each presented binaurally at each of eight equally spaced intensity levels, ranging from 58 to 86 dB SPL. EBRs computed immediately following presentation, and immediately following removal of the 2,000-msec-duration stimulus result in ON and OFF responses, respectively. EBRs computed immediately following presentation of the 25- and 75-msec-duration stimuli appear to be the result of the sum of separate responses to stimulus onset and offset. Computer-dissected ON and OFF EBRs to short-duration stimuli are very similar in waveform and amplitude to the responses evoked by the onset and offset, respectively, of the 2,000-msec duration stimulus. Dissected ON and OFF responses demonstrate linear amplitude-intensity functions in amplitude ranges similar to respective ON and OFF responses to 2,000-msec stimulation. The data suggest that ON and OFF responses are mediated by independent physiological mechanisms.     

A BRIEF FUNCTIONAL ANALYSIS OF AGGRESSIVE AND ALTERNATIVE BEHAVIOR IN AN OUTCLINIC SETTING

We conducted a brief functional analysis to identify maintaining variables for aggressive behavior and an alternative replacement response during a 90-min outpatient evaluation of 3 individuals with severe handicaps. During the initial analogue assessment, which focused on identifying maintaining contingencies for aggressive behavior, each participant displayed a substantially greater frequency of aggressive behavior during one condition than during any other. The contingency that produced the highest percentage of aggressive behavior was then presented for the occurrence of a specific alternative behavior (a mand). During this contingency reversal phase, each participant displayed a substantial reduction in aggressive behavior and a substantial increase in alternative behavior, thus providing a direct analysis of the equivalency of the contingency for maintaining either behavior.