Binocularity and visual search—Revisited

Binocular rivalry is a phenomenon of visual competition in which perception alternates between two monocular images. When two eye’s images only differ in luminance, observers may perceive shininess, a form of rivalry called binocular luster. Does dichoptic information guide attention in visual search? Wolfe and Franzel (Perception & Psychophysics, 44(1), 81–93, 1988) reported that rivalry could guide attention only weakly, but that luster (shininess) “popped out,” producing very shallow Reaction Time (RT) × Set Size functions. In this study, we have revisited the topic with new and improved stimuli. By using a checkerboard pattern in rivalry experiments, we found that search for rivalry can be more efficient (16 ms/item) than standard, rivalrous grating (30 ms/item). The checkerboard may reduce distracting orientation signals that masked the salience of rivalry between simple orthogonal gratings. Lustrous stimuli did not pop out when potential contrast and luminance artifacts were reduced. However, search efficiency was substantially improved when luster was added to the search target. Both rivalry and luster tasks can produce search asymmetries, as is characteristic of guiding features in search. These results suggest that interocular differences that produce rivalry or luster can guide attention, but these effects are relatively weak and can be hidden by other features like luminance and orientation in visual search tasks.     

Efficiency and accuracy of visual search develop at different rates from early childhood through early adulthood

Psychonomic Bulletin & Review - Most studies of visual search across the life span have focused on classic feature and conjunction searches in which observers search for a fixed, simple shape...     

Delay discounting of different outcomes: Review and theory

Steep delay discounting is characterized by a preference for small immediate outcomes relative to larger delayed outcomes and is predictive of drug abuse, risky sexual behaviors, and other maladaptive behaviors. Nancy M. Petry was a pioneer in delay discounting research who demonstrated that people discount delayed monetary gains less steeply than they discount substances with abuse liability. Subsequent research found steep discounting for not only drugs, but other nonmonetary outcomes such as food, sex, and health. In this systematic review, we evaluate the hypotheses proposed to explain differences in discounting as a function of the type of outcome and explore the trait- and state-like nature of delay discounting. We found overwhelming evidence for the state-like quality of delay discounting: Consistent with Petry and others' work, nonmonetary outcomes are discounted more steeply than monetary outcomes. We propose two hypotheses that together may account for this effect: Decreasing Future Preference and Decreasing Future Worth. We also found clear evidence that delay discounting has trait-like qualities: People who steeply discount monetary outcomes steeply discount nonmonetary outcomes as well. The implication is that changing delay discounting for one outcome could change discounting for other outcomes.     

The Diffusion of Youth-Led Participatory Research in Urban Schools: The Role of the Prevention Support System in Implementation and Sustainability

This article discusses the dissemination of a process of youth-led participatory research in urban secondary schools within the Interactive Systems Framework for Dissemination and Implementation (ISF) developed in collaboration with the CDC and its university partners (Wandersman et al. American Journal of Community Psychology, 41(3-4) 2008). The focus here is on the development of the Prevention Support System with respect to general and innovation-specific capacity building. The specific process under study involves youth-led needs assessment and research to inform the planning of prevention programs and policies to address students' health and developmental needs. The article first briefly describes the youth-led research process, its potential benefits, and a case example in two urban secondary schools. It then describes challenges and responses in providing support for the diffusion of this model in 6 secondary schools. The settings are urban public schools with a majority of students of color from diverse ethnic groups: Asian-American, Latino, and African-American. This project constitutes a collaborative partnership with a university school of public health and community-based organizations (CBOs) to build capacity for long-term, sustainable implementation of this innovative process within the local school system. The perspectives of the university-based researcher and the CBO partners on the development and effectiveness of the Prevention Support System are presented.     

Alternative Schooling Strategies and the Religious Lives of American Adolescents

I analyze the effects of Catholic schooling, Protestant schooling, and homeschooling on adolescents' religious lives and test three mechanisms through which these schooling strategies might influence religiosity: friendship networks, network closure, and adult mentors. Data from Wave 1 of the National Survey of Youth and Religion suggest that Catholic schoolers attend religious services more frequently and value their faith more highly than public schoolers, but attend religious education classes and youth group less often. Protestant schoolers' involvement in their local congregation is similar to public schoolers', but their faith plays a more salient role in their life and they are more active in private religious activities. Homeschoolers do not differ significantly from public schoolers on any outcome considered. Moreover, friendship networks, network closure, and adult mentors play a very limited role in mediating the relationships between schooling strategies and adolescent religiosity. Interpretations of these findings are presented and discussed.     

Auditory event perception: the source-perception loop for posture in human gait

There is a small but growing literature on the perception of natural acoustic events, but few attempts have been made to investigate complex sounds not systematically controlled within a laboratory setting. The present study investigates listeners' ability to make judgments about the posture (upright-stooped) of the walker who generated acoustic stimuli contrasted on each trial. We use a comprehensive three-stage approach to event perception, in which we develop a solid understanding of the source event and its sound properties, as well as the relationships between these two event stages. Developing this understanding helps both to identify the limitations of common statistical procedures and to develop effective new procedures for investigating not only the two information stages above, but also the decision strategies employed by listeners in making source judgments from sound. The result is a comprehensive, ultimately logical, but not necessarily expected picture of both the source-sound-perception loop and the utility of alternative research tools.     

The role of memory and restricted context in repeated visual search

Previous studies have shown that the efficiency of visual search does not improve when participants search through the same unchanging display for hundreds of trials (repeated search), even though the participants have a clear memory of the search display. In this article, we ask two important questions. First, why do participants not use memory to help search the repeated display? Second, can context be introduced so that participants are able to guide their attention to the relevant repeated items? Experiments 1-4 show that participants choose not to use a memory strategy because, under these conditions, repeated memory search is actually less efficient than repeated visual search, even though the latter task is in itself relatively inefficient. However, when the visual search task is given context, so that only a subset of the items are ever pertinent, participants can learn to restrict their attention to the relevant stimuli (Experiments 5 and 6).     

The perfect murder: A philosophical whodunit

In his Reasons and Persons, Derek Parfit argues from the possibility of cases of fission and/or fusion of persons that one must reject identity as what matters for personal survival. Instead Parfit concludes that what matters is “psychological connectedness and/or continuity with the right kind of cause,” or what he calls an R-relation. In this paper, I argue that, if one accepts Parfit’s conclusion, one must accept that R-relations are what matter for moral responsibility as well. Unfortunately, it seems that accepting that the R-relation is what matters for both survival and moral responsibility leads to a contradiction. My goal, however, is not merely to point out a problem in Parfit’s account. Instead, I believe that once we understand the basic intuitions which lead to this contradiction, it is clear that there is no fully satisfactory way to account for what matters with respect to survival and moral responsibility.     

Can Models of God Compete?

Though the very task of modeling God implies that the reality of God is to some degree unknowable, there are a variety of positions one may take concerning the degree to which one has epistemic access to God. If our models of God are too influenced by subjectivity, it makes no sense to test them against each other in rational competition. In this essay, I define four possible positions that may underlie the task of God-modeling: mysteriosophy, theopoetics, critical realism, and fallibilism. Of these four, I propose that fallibilism is the most appropriate method for constructing models of God. Fallibilism simultaneously assumes that our models are able to refer to a divine reality, and yet always with a tentative stance, as absolute confirmation or universal consensus concerning them will almost certainly never be obtained. Models of God can engage in rational competition, but a final decision will probably be delayed indefinitely. This paper was delivered during the APA Pacific 2007 Mini-Conference on Models of God.     

Speech-associated gestures, Broca’s area, and the human mirror system

Speech-associated gestures are hand and arm movements that not only convey semantic information to listeners but are themselves actions. Broca’s area has been assumed to play an important role both in semantic retrieval or selection (as part of a language comprehension system) and in action recognition (as part of a “mirror” or “observation–execution matching” system). We asked whether the role that Broca’s area plays in processing speech-associated gestures is consistent with the semantic retrieval/selection account (predicting relatively weak interactions between Broca’s area and other cortical areas because the meaningful information that speech-associated gestures convey reduces semantic ambiguity and thus reduces the need for semantic retrieval/selection) or the action recognition account (predicting strong interactions between Broca’s area and other cortical areas because speech-associated gestures are goal-direct actions that are “mirrored”). We compared the functional connectivity of Broca’s area with other cortical areas when participants listened to stories while watching meaningful speech-associated gestures, speech-irrelevant self-grooming hand movements, or no hand movements. A network analysis of neuroimaging data showed that interactions involving Broca’s area and other cortical areas were weakest when spoken language was accompanied by meaningful speech-associated gestures, and strongest when spoken language was accompanied by self-grooming hand movements or by no hand movements at all. Results are discussed with respect to the role that the human mirror system plays in processing speech-associated movements.