Global and local covert visual attention: Evidence from a bayesian hidden markov model

Psychological, psychophysical and physiological research indicates that people switch between two covert attention states, local and global attention, while visually exploring complex scenes. The focus in the local attention state is on specific aspects and details of the scene, and on examining its content with greater visual detail. The focus in the global attention state is on exploring the informative and perceptually salient areas of the scene, and possibly on integrating the information contained therein. The existence of these two visual attention states, their relative prevalence and sequence in time has remained empirically untested to date. To fill this gap, we develop a psychometric model of visual covert attention that extends recent work on hidden Markov models, and we test it using eye-movement data. The model aims to describe the observed time series of saccades typically collected in eye-movement research by assuming a latent Markov process, indicative of the brain switching between global and local covert attention. We allow subjects to be in either state while exploring a stimulus visually, and to switch between them an arbitrary number of times. We relax the no-memory-property of the Markov chain. The model that we develop is estimated with MCMC methodology and calibrated on eye-movement data collected in a study of consumers' attention to print advertisements in magazines.We thank Dominique Claessens of Verify International for making the data available to us.     

Narrating survival and change in Guatemala and South Africa: the politics of representation and a liberatory community psychology

Peace accords and international interventions have contributed to the suspension of armed conflict and the censuring of repressive regimes in many parts of the world. Some governments and their opposition parties have agreed to the establishment of commissions or other bodies designed to create historical records of the violations of human rights and foster conditions that facilitate reparatory and reconciliatory processes. This paper explores selected roles that community psychologists have played in this process of remembering the past and constructing new identities towards creating a more just future. With reference to two community groups (in Guatemala and South Africa) we show how efforts to speak out about one's own experiences of political and military repression involve complex representational politics that go beyond the simple binary opposition of silencing versus giving voice. The Guatemalan group consisted of Mayan Ixil women who, together with the first author, used participatory action research and the PhotoVoice technique to produce a book about their past and present struggles. The South African group, working within the ambit of the Truth and Reconciliation Commission and in collaboration with the third author and others, explored ways of speaking about their roles in apartheid and post-apartheid society. Although both these initiatives can be seen as moments in on-going struggles to overcome externally-imposed repressive practices that censor the voices of marginalized communities, they also serve to dispel overly romanticized notions of univocal communities now liberated to express themselves in an unmediated and unequivocal fashion. The paper discusses how each group of women instead entered into subtly nuanced relationships with community psychologists involving a continual interplay between the authenticity of their self-representational accounts and the requirements of the discursive technologies into which they were being inducted and the material conditions within their sites of struggle. In both cases the group's agenda also evolved over time, so that what emerged was not so much a particular account of themselves, or even the development of a particular voice for speaking about themselves, but an unfolding process—for the groups and for the community psychologists who accompanied them—of becoming active players in the postmodern, mediated world of self-representational politics and social struggle.     

Mothers' Overreactive Discipline and Their Encoding and Appraisals of Toddler Behavior

The relations of observed overreactive discipline with mothers' tendencies to notice negative, relative to positive, child behavior (preferential negative encoding), and mothers' negative appraisals of neutral and positive child behavior (negative appraisal bias), were examined in mothers of toddlers. The mothers rated both their own children's and unfamiliar children's behavior. Negative appraisal bias with respect to mothers' own (but not unfamiliar) children was related to mothers' overreactivity, independent of child misbehavior. Overreactivity was not related to mothers' preferential negative encoding either of their own or of unfamiliar children's behavior. However, in the case of mothers' own children, preferential negative encoding moderated the relation between negative appraisal bias and overreactive discipline, such that the negative appraisal bias-overreactivity relation was significant only in the context of high preferential negative encoding.     

Examining the effectiveness of a community-based self-help program to increase women's readiness for smoking cessation

This study investigated the effectiveness of two components of a smoking cessation intervention: a reading manual and a series of televised programs. Female smokers in the Chicago metropolitan area with a high school education or less were interviewed at 4 different times: baseline, immediate postintervention, and 6 and 12 months. We examined the effects of several baseline measures (race, age, number of cigarettes smoked, and stage of readiness to change) and exposure to the intervention components on subsequent stage of change. Race, baseline smoking rate, baseline stage, and exposure to both intervention components had direct effects on stage at immediate postintervention, with both intervention components increasing readiness to quit. Furthermore, exposure to the manual interacted with baseline stage, such that the manual benefited women at earlier stages more than women at later stages. Effects of both components were sustained at 6 months, and the effects of the manual were sustained at 12 months.     

On Selective Left Neglect during Walking in a Child

In this article we describe a child affected by right parieto-occipital lesion due to head injury. The patient showed left hemianopia, but not unilateral spatial neglect on traditional paper-and-pencil tests and on "ecological" tests. However, his parents reported frequent collisions with obstacles on the left side. A specific test was set up: The patient had to kick down skittles put on both sides of a route traced on the floor. He kicked down 89% of skittles on the right, but only 38% on the left side. These findings are discussed in light of recent theories on unilateral neglect.     

Resistance to change of operant variation and repetition

A multiple chained schedule was used to compare the relative resistance to change of variable and fixed four-peck response sequences in pigeons. In one terminal link, a response sequence produced food only if it occurred infrequently relative to 15 other response sequences (vary). In the other terminal link, a single response sequence produced food (repeat). Identical variable-interval schedules operated in the initial links. During baseline, lower response rates generally occurred in the vary initial link, and similar response and reinforcement rates occurred in each terminal link. Resistance of responding to prefeeding and three rates of response-independent food delivered during the intercomponent intervals then was compared between components. During each disruption condition, initial- and terminal-link response rates generally were more resistant in the vary component than in the repeat component. During the response-independent food conditions, terminal-link response rates were more resistant than initial-link response rates in each component, but this did not occur during prefeeding. Variation (in vary) and repetition (in repeat) both decreased during the response-independent food conditions in the respective components, but with relatively greater disruption in repeat. These results extend earlier findings demonstrating that operant variation is more resistant to disruption than is operant repetition and suggest that theories of response strength, such as behavioral momentum theory, must consider factors other than reinforcement rate. The implications of the results for understanding operant response classes are discussed.     

Field Independence and Change Agent Correlation in Emerging Communities of Irian Jaya,Indonesia

Communities that are limited by oral traditions find theological truths communicated by missions a challenge to understand. Currently, linguists work in many of these minority language groups in order to create vital written languages and produce various literature titles that include the Scriptures. Development of a writing system requires indigenous language assistants who are adept in drawing meaning from unfamiliar cultural paradigms and accurately articulating them. Empirical studies in cognitive style conducted among the minority language groups of Irian Jaya, Indonesia show a correlation between field independence (a dimension of cognitive style) and the ability to grasp abstract linguistic concepts. The Brantley/Larsen Test was developed to identify language assistants, also known as change agents, in a culturally appropriate manner for Irian Jaya. Furthermore, this study suggests that the church would benefit from community lay counselors who manifest field independence, which indicates comprehension of abstract and complex linguistic notions found in Scriptures.Indonesia as Organizational Consultant;     

Does Differential Cohort Socialization Matter? The “Age Invariance” Hypothesis and Political Socialization

In classical and contemporary social theory alike, the key to understanding how cultural change comes about has been thought to lie in the long-term effect of differential cohort socialization. Cultural change is thought to proceed as differently socialized cohorts replace each other in the course of time. Moreover, distinct generations have been claimed to emerge. Thisarticle addresses the impact of cohort replacement and the presence of generations, including discussions of the theoretical framework underlying these concepts and the problem of disentangling age, period, and cohort effects. Analyses of Dutch survey data substantiate that cohort membership matters. Yet the impact of cohort replacement on cultural change turns out to be limited, and little evidence is found in support of the idea that specific generations arediscernible.     

Severe Withdrawal (and Recovery)

The problem of how to remove information from an agent's stock of beliefs is of paramount concern in the belief change literature. An inquiring agent may remove beliefs for a variety of reasons: a belief may be called into doubt or the agent may simply wish to entertain other possibilities. In the prominent AGM framework for belief change, upon which the work here is based, one of the three central operations, contraction, addresses this concern (the other two deal with the incorporation of new information). Makinson has generalised this work by introducing the notion of a withdrawal operation. Underlying the account proffered by AGM is the idea of rational belief change. A belief change operation should be guided by certain principles or integrity constraints in order to characterise change by a rational agent. One of the most noted principles within the context of AGM is the Principle of Informational Economy. However, adoption of this principle in its purest form has been rejected by AGM leading to a more relaxed interpretation. In this paper, we argue that this weakening of the Principle of Informational Economy suggests that it is only one of a number of principles which should be taken into account. Furthermore, this weakening points toward a Principle of Indifference. This motivates the introduction of a belief removal operation that we call severe withdrawal. We provide rationality postulates for severe withdrawal and explore its relationship with AGM contraction. Moreover, we furnish possible worlds and epistemic entrenchment semantics for severe withdrawals.