Effect of intermittent reinforcement on acquisition and retention in delayed matching-to-sample in pigeons

Experiments 1 and 2 involved independent groups that received primary reinforcement after a correct match with a probability of 1.0, .50 or .25. Correct matches that did not produce primary reinforcement produced a conditioned reinforcer. Both experiments revealed little evidence that acquisition or retention was adversely affected by use of intermittent reinforcement. Experiment 3 involved a group that received 100% reinforcement and two others that received 25% reinforcement, one of which received conditioned reinforcement and the other did not. Following acquisition and retention testing, birds in group 100% and group 25% with conditioned reinforcement were exposed to 25% reinforcement and no conditioned reinforcement. Results revealed that conditioned reinforcement was important in promoting acquisition but was irrelevant in maintaining performance. It was concluded that intermittent reinforcement, especially when combined with conditioned reinforcement during acquisition, supports levels of acquisition and retention comparable to that of continuous reinforcement. Theoretically, the findings are consistent with an extension of Blough's instance-based theory of discrimination performance and, practically, they suggest that use of intermittent reinforcement could result in increased efficiency and economy in labs using delayed matching.     

Support for anterior temporal involvement in semantic error production in aphasia: new evidence from VLSM

Semantic errors in aphasia (e.g., naming a horse as “dog”) frequently arise from faulty mapping of concepts onto lexical items. A recent study by our group used voxel-based lesion-symptom mapping (VLSM) methods with 64 patients with chronic aphasia to identify voxels that carry an association with semantic errors. The strongest associations were found in the left anterior temporal lobe (L-ATL), in the mid- to anterior MTG region. The absence of findings in Wernicke’s area was surprising, as were indications that ATL voxels made an essential contribution to the post-semantic stage of lexical access. In this follow-up study, we sought to validate these results by re-defining semantic errors in a manner that was less theory dependent and more consistent with prior lesion studies. As this change also increased the robustness of the dependent variable, it made it possible to perform additional statistical analyses that further refined the interpretation. The results strengthen the evidence for a causal relationship between ATL damage and lexically-based semantic errors in naming and lend confidence to the conclusion that chronic lesions in Wernicke’s area are not causally implicated in semantic error production.     

Outsourcing inspiration: The performance effects of ideological messages from leaders and beneficiaries

Although ideological messages are thought to inspire employee performance, research has shown mixed results. Typically, ideological messages are delivered by leaders, but employees may be suspicious of ulterior motives—leaders may merely be seeking to inspire higher performance. As such, we propose that these messages are often more effective when outsourced to a more neutral third party—the beneficiaries of employees’ work. In Study 1, a field quasi-experiment with fundraisers, ideological messages from a beneficiary—but not from two leaders—increased performance. In Study 2, a laboratory experiment with an editing task, participants achieved higher task and citizenship performance when an ideological message was delivered by a speaker portrayed as a beneficiary vs. a leader, mediated by suspicion. In Study 3, a laboratory experiment with a marketing task, the beneficiary source advantage was contingent on message content: beneficiaries motivated higher task and citizenship performance than leaders with prosocial messages but not achievement messages.     

Can We Consume Our Way Out of Climate Change? A Call for Analysis

The problem of climate change is analyzed as a manifestation of economic growth, and the steady-state economy of ecological economics is proposed as a system-wide solution. Four classes of more specific solutions are described. In the absence of analysis, cultural inertia will bias solutions in favor of green consumption as a generalized solution strategy. By itself, green consumption is a flawed solution to climate change because it perpetuates or even accelerates economic growth that is incompatible with a sustainable culture. Addressing climate change requires an integration of regulatory, energy efficiency, skill-based, and dissemination solutions. Behavioral scientists are encouraged to work with others in ecological economics and other social sciences who recognize cultural reinvention as a means of achieving sustainability.     

Postulates for revising BDI structures

The process of rationally revising beliefs in the light of new information is a topic of great importance and long-standing interest in artificial intelligence. Moreover, significant progress has been made in understanding the philosophical, logical, and computational foundations of belief revision. However, very little research has been reported with respect to the revision of other mental states, most notably propositional attitudes such as desires and intentions. In this paper, we present a first attempt to formulate a general framework for understanding the revision of mental states. We develop an abstract belief-desire-intention model of agents, and introduce a notion of rationality for this model. We then present a series of formal postulates characterizing the processes of adding beliefs, desires, and intentions, updating costs and values, and removing beliefs, desires, and intentions. We also investigate the computational complexity of several problems involving the abstract model and comment on algorithms for revision.     

Living in the Borderlands—An Identity and a Proposal

Abstract :  We live in the borderlands, a place not of separation but of coming together, of connection. The continuing efforts to discern what it means to express who we are as religious people, and what it means regarding the religious identity of those who live in the borderlands is the focus of this study. In many ways, this identity is one that is in the process of being restored, renewed, and reaffirmed after many years of a combination of benign neglect and overt suppression.     

Medical science, culture, and truth

There is a fairly closed circle between culture, language, meaning, and truth such that the world of a given culture is a world understood in terms of the meanings produced in that culture. Medicine is, in fact, a subculture of a powerful type and has its own language and understanding of the range of illnesses that affect human beings. So how does medicine get at the truth of people and their ills in such a way as to escape its own limited constructions? There is a way out of the closed circle implicit in the idea of a praxis and the engagement with reality that is central to it and the further possibility introduced by Jacques Lacan that signification is never comprehensive in relation to the subject's encounter with the real. I will explore both of these so as to develop a conception of truth that is apt for the knowledge that arises in the clinic.     

An Intensive Outpatient Program for Veterans With Posttraumatic Stress Disorder and Traumatic Brain Injury

Post-9/11 service members may return from military service with a complicated set of symptoms and conditions, such as posttraumatic stress disorder (PTSD), depression, substance misuse, and traumatic brain injury (TBI), that interfere with reintegration and impair functioning. Although evidence-based treatments that facilitate recovery exist, their successful delivery at a sufficient dose is limited. Barriers to accessing treatment combined with challenges compiling a comprehensive treatment team further delay delivery of effective evidence-based care for PTSD, TBI, and co-occurring mental health conditions. This paper describes the development of a comprehensive, multidisciplinary, 2-week intensive day program for post-9/11 veterans with complex mental health concerns. The treatment program combines skill building groups, family education, and integrative health approaches with evidence-based individual PTSD or TBI care. Initial results from the first 132 participants were notable for a 97% completion rate, as well as statistically significant and clinically meaningful reductions in PTSD, neurobehavioral, and depression symptom severity for the 107 veterans who completed the PTSD track and the 21 who completed the TBI track. These data suggest the intensive program approach is an effective, well-tolerated model of treatment for post-9/11 veterans with PTSD and/or TBI. Future controlled studies should examine the effectiveness of this intensive model compared to standard evidence-based therapy delivery, as well as longitudinal outcomes.     

Post-Traumatic Reactions in Adolescents: How Well Do the DSM-IV PTSD Criteria Fit the Real Life Experience of Trauma Exposed Youth?

This study examined the structure and symptom specific patterns of post traumatic distress in a sample of 1,581 adolescents who reported exposure to at least one traumatic event. Symptom reporting patterns are consistent with past literature in that females reported more symptoms than males and older youth reported more symptoms than did their younger peers. Young people reporting exposure to exclusively violent type traumas were also found to be more likely to endorse symptoms than peers exposed exclusively to non violent type traumas. Confirmatory factor analysis provided stronger support for a four-factor model of PTSD than either the DSM-IV model or an alternate model. Further examination of the four factor model revealed gender differences in factor loadings with small to moderate effect sizes for recurrent, distressing memories, flashbacks, restricted affect, difficulty remember details, detachment, limited future orientation, hypervigilance and startle symptoms. Differences in factor loadings with the four factor model were also noted between younger and older adolescents, with medium to large effect sizes on the arousal items. In contract, comparison of the factor loadings revealed only small differences between youth exposed exclusively to violent traumatic stressors and those exposed exclusively to non violent traumatic stressors, suggesting relative similarity between these two groups.