Spatial versus tree representations of proximity data

In this paper we investigated two of the most common representations of proximities, two-dimensional euclidean planes and additive trees. Our purpose was to develop guidelines for comparing these representations, and to discover properties that could help diagnose which representation is more appropriate for a given set of data. In a simulation study, artificial data generated either by a plane or by a tree were scaled using procedures for fitting either a plane (KYST) or a tree (ADDTREE). As expected, the appropriate model fit the data better than the inappropriate model for all noise levels. Furthermore, the two models were roughly comparable: for all noise levels, KYST accounted for plane data about as well as ADDTREE accounted for tree data. Two properties of the data proved useful in distinguishing between the models: the skewness of the distribution of distances, and the proportion of elongated triangles, which measures departures from the ultrametric inequality, Applications of KYST and ADDTREE to some twenty sets of real data, collected by other investigators, showed that most of these data could be classified clearly as favoring either a tree or a two-dimensional representation.A portable PASCAL program implementing the Sattath and Tversky [1977] ADDTREE algorithm is available from J. Corter, Department of Psychology, Stanford University, Stanford, California 94305.     

Recall of common and distinctive features of verbal and pictorial stimuli

Subjects first rated similarity of verbal and of pictorial stimuli. The same pairs of stimuli were presented again, without one common component and one distinctive component. Subjects were asked to recall the missing components and identify them as common or distinctive. The results show that components encoded as common are recalled relatively better than components encoded as distinctive, and the difference in recall is significantly greater in verbal than in pictorial stimuli.     

Visual angle and the word superiority effect

Two experiments are reported in which a word superiority effect is obtained under conditions where a fixed set of alternatives are employed with positional certainty as to the critical letter, trial type (word or nonword) is mixed, and the subject is told to fixate the position of the critical letter. A third experiment employed the same methodology except for the fact that the stimuli subtended a larger retinal angle. No word superiority effect was observed in the third experiment. It is suggested that the visual angle of the stimulus display is a crucial factor in experiments on the word superiority effect.     

COMPARISON OF EXTINCTION,DRO 0-SEC,AND DRO 6-SEC IN THE ELIMINATION OF IMITATIVE RESPONDING UNDER DISCRETE-TRIAL PARADIGMS1

Imitative response levels were observed for normal 5-yr-old children within a discrete-trial imitation paradigm. Following imitation training sessions, children were observed under conditions of contingent reinforcement for three experimental sessions. Following the contingent reinforcement phase, children were then observed under reversal conditions for four sessions. A 3 × 4 repeated measures design was employed for observing response decrements under conditions of extinction, DRO 6-sec, and DRO 0-sec. The DRO 0-sec group demonstrated a significantly greater decrement in imitative responding than did the DRO 6-sec and extinction group. The differences in effects between the two DRO conditions and results from previous studies in which DRO procedures have had little effect in reducing imitative responding, suggest an incomplete understanding of the ways in which DRO procedures may operate.     

Resident-Led Neighborhood Development to Support Health: Identifying Strategies Using CBPR

Evidence suggests that where people live, learn, work, and play affects a range of health outcomes for children and adults. Differential access to social, economic, and environmental supports puts some community members at greater risk, leading to disparities in health and well-being. The 2014 release of the For the Sake of All report highlighted persistent health disparities for African Americans in St. Louis, Missouri, and their social and economic impacts on the St. Louis region. This study extends this work by developing partnerships with community organizations and neighborhood residents to address health disparities. Community-based participatory research (CBPR) methods were utilized to engage partners in a 10-month research process to address community concerns that impact health. Seven community residents, neighborhood researchers, engaged in workshops to learn about the research process and used techniques to gather information to implement action strategies. Neighborhood researchers selected 14 vacant lots to implement their action plan, which included visions for repurposing the land into a community park, produced a report for dissemination, and organized a community action forum to communicate their findings. This study highlights a promising approach to promote healthy communities and health equity by empowering neighborhood residents using participatory methodologies.     

The Making of an Interdisciplinary Partnership: The Case of the Chicago Food System Collaborative

Interdisciplinary partnerships foster innovation to address pressing social problems. This paper describes an interdisciplinary partnership called the Chicago Food System Collaborative (CFSC) composed of a team of partners from four academic institutions and three community-based organizations representing a total of eight disciplines that included: community development and community organizing, community psychology, geography, nursing, nutrition, public health, sociology, and urban planning and policy. Partners came together to address the issue of access to healthy foods and nutrition in a working class African American neighborhood. We analyze and discuss the core principles that guided the partnership and its impact across three dimensions: understanding through interdisciplinary action research, building capacity, and facilitating innovations in practices and policies. Despite the challenges of interdisciplinary partnerships, the potential benefits and impact of such efforts reflect their value as a comprehensive approach to addressing complex social problems.