Some effects of stimulant medication on response allocation: a double-blind analysis

Children who are diagnosed with attention deficit hyperactivity disorder (or who engage in behavior consistent with such a diagnosis) are often prescribed stimulant medications for hyperactive or inattentive behaviors. However, the mechanisms by which stimulant medications affect individuals' behavior are rarely evaluated. The purpose of the current study was to evaluate the effects of stimulant medication on response allocation when antecedents and consequences were held constant and equated. Results indicated that the presence of an amphetamine medication (Adderall) influenced response allocation across two concurrently available responses while all other stimulus conditions were held constant.     

A paradoxical effect of presession attention on stereotypy: antecedent attention as an establishing, not an abolishing, operation

Previous studies have shown that presession attention for problem behavior can serve as an abolishing operation when attention functions as a positive reinforcer. In the current study, we show that the stereotypy of a child with severe disabilities was undifferentiated during standard analogue functional analysis conditions. However, when noncontingent presession attention was provided, stereotypy occurred for social attention as a positive reinforcer, suggesting that the antecedent manipulation functioned as an establishing operation.     

Simulating single word processing in the classic aphasia syndromes based on the Wernicke-Lichtheim-Geschwind theory

The Wernicke-Lichtheim-Geschwind (WLG) theory of the neurobiological basis of language is of great historical importance, and it continues to exert a substantial influence on most contemporary theories of language in spite of its widely recognized limitations. Here, we suggest that neurobiologically grounded computational models based on the WLG theory can provide a deeper understanding of which of its features are plausible and where the theory fails. As a first step in this direction, we created a model of the interconnected left and right neocortical areas that are most relevant to the WLG theory, and used it to study visual-confrontation naming, auditory repetition, and auditory comprehension performance. No specific functionality is assigned a priori to model cortical regions, other than that implicitly present due to their locations in the cortical network and a higher learning rate in left hemisphere regions. Following learning, the model successfully simulates confrontation naming and word repetition, and acquires a unique internal representation in parietal regions for each named object. Simulated lesions to the language-dominant cortical regions produce patterns of single word processing impairment reminiscent of those postulated historically in the classic aphasia syndromes. These results indicate that WLG theory, instantiated as a simple interconnected network of model neocortical regions familiar to any neuropsychologist/neurologist, captures several fundamental "low-level" aspects of neurobiological word processing and their impairment in aphasia.     

Exogenous attention differentially modulates the processing of categorical and coordinate spatial relations

Carrasco and her colleagues have suggested that exogenous attention reduces the size of receptive fields at an attended location (Gobell & Carrasco, 2005; Yeshurun & Carrasco, 1998, 2000). Based on the hypothesis that categorical and coordinate spatial relations are more efficiently processed by smaller and larger receptive fields, respectively, we predicted that exogenous attention would be more beneficial to the processing of categorical spatial relations than coordinate spatial relations while it would disrupt the processing of coordinate spatial relations. To test these hypotheses, participants were tested using a variant of Posner's (1980) attentional cueing paradigm. Exogenous attention produced larger facilitative effects on categorical spatial processing than on coordinate spatial processing at a short cue-target stimulus onset asynchrony (100 ms, Experiment 1, N = 28), and this result was replicated regardless of cue size in Experiment 2 (N = 24). When the coordinate judgment was sufficiently difficult, exogenous attention disrupted the processing of coordinate spatial relations (Experiment 3, N = 28). These findings indicate that exogenous attention can differentially modulate the processing of categorical and coordinate spatial relations.     

Suicide schemas in non-affective psychosis: An empirical investigation

Suicide is the leading cause of premature death among individuals experiencing psychosis. The risk of suicide is proposed to increase with a greater potential for activation of suicide related schemas. Empirical representations of suicide schemas were compared between individuals experiencing non-affective psychosis, with and without a history of suicidal behaviour. Employing a cross-sectional between-groups comparison design, 84 participants, previously diagnosed with a non-affective psychotic disorder, were recruited from community mental health services. Participants completed a demographic questionnaire and clinical measures of psychopathology. To assess participants’ suicide schemas, a series of direct and indirect cognitive tasks were designed and administered. Pathfinder analysis enabled the construction of empirically derived representations of the groups’ suicide schemas based on responses to the cognitive tasks. The suicide group achieved significantly greater scores on measures of anxiety, depression, hopelessness and suicidality than the non-suicide group, but not on measures indicative of the severity of psychosis. The suicide schema for the suicide group was more elaborate and extensive than for the non-suicide group, even when clinical measures were taken into account. Clinical and theoretical implications are discussed.     

An investigation of differential reinforcement of alternative behavior without extinction

We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of each (Experiment 4), such that reinforcement favored appropriate behavior rather than problem behavior even though problem behavior still produced reinforcement. Results of Experiments 1 to 3 showed that behavior was often sensitive to manipulations of duration, quality, and delay in isolation, but the largest and most consistent behavior change was observed when several dimensions of reinforcement were combined to favor appropriate behavior (Experiment 4). Results suggest strategies for reducing problem behavior and increasing appropriate behavior without extinction.     

Functional analysis and treatment of aggression maintained by preferred conversational topics

After an initial functional analysis of a participant's aggression showed unclear outcomes, we conducted preference and reinforcer assessments to identify preferred forms of attention that may maintain problem behavior. Next, we conducted an extended functional analysis that included a modified attention condition. Results showed that the participant's aggression was maintained by access to preferred conversational topics. A function-based intervention decreased aggression and increased an appropriate communicative response.     

Looking away from death: Defensive attention as a form of terror management

Previous research has suggested that the physical aspects of human nature in general, and physical human frailties in particular become disagreeable and repugnant following death primes. The current research tested this hypothesis in two studies using an eye-tracking methodology. Participants were subliminally primed with death or with a control word and then viewed a series of arrays containing four pictures each, during which their eye-movements were monitored. In Study 1, the arrays included pictures of physical injury or neutral objects, and in Study 2 pictures of physical injury, threatening images, and neutral objects. The results indicated that in both studies death primes significantly decreased gaze duration towards pictures of physical injury, and did not have a significant effect on gaze duration towards neutral images. However, in Study 2 death primes increased gaze duration towards threatening images. The discussion examines the role of motivated unconscious attention in terror management processes.     

VIRTUE, EMOTION, AND ATTENTION

Abstract: The perceptual model of emotions maintains that emotions involve, or are at least analogous to, perceptions of value. On this account, emotions purport to tell us about the evaluative realm, in much the same way that sensory perceptions inform us about the sensible world. An important development of this position, prominent in recent work by Peter Goldie amongst others, concerns the essential role that virtuous habits of attention play in enabling us to gain perceptual and evaluative knowledge. I think that there are good reasons to be sceptical about this picture of virtue. In this essay I set out these reasons, and explain the consequences this scepticism has for our understanding of the relation between virtue, emotion, and attention. In particular, I argue that our primary capacity for recognizing value is in fact a non-emotional capacity.     

A Bayesian-optimal principle for learner-friendly adaptation in learning games

Adaptive learning games should provide opportunities for the student to learn as well as motivate playing until goals have been reached. In this paper, we give a mathematically rigorous treatment of the problem in the framework of Bayesian decision theory. To quantify the opportunities for learning, we assume that the learning tasks that yield the most information about the current skills of the student, while being desirable for measurement in their own right, would also be among those that are efficient for learning. Indeed, optimization of the expected information gain appears to naturally avoid tasks that are exceedingly demanding or exceedingly easy as their results are predictable and thus uninformative. Still, tasks that are efficient for learning may be experienced as too challenging, and the resulting failures can lower motivation. Therefore, in addition to quantifying the expected informational benefit for learning of any prospective task to be presented next, we also model the expected motivational cost of its presentation, measured simply as the estimated probability of failure in our example model. We propose a “learner-friendly” adaptation algorithm that chooses the learning tasks by optimizing the expected benefit divided by the expected cost. We apply this algorithm to a Rasch-like student model implemented within a real-world application and present initial results of a pilot experiment.