Control of pigeons' matching-to-sample performance by differential sample response requirements

Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice.     

Rounding Out the Cube: Evolution to a Global Model for Counseling Centers

This article discusses the present realities of college and university counseling centers as the bases for proposing a more adaptive and interactive model of the original Cube developed by W. H. Morrill, E, R. Oetting, and J. C. Hurst (1974). The article conceptualizes an evolved model of the Cube, here termed the global model, which allows counseling centers to function, in light of current and future demands, with greater flexibility, interdependency, and collaboration vis-á-vis the campus community.     

Diamond-winged variants of the Müller-Lyer figure: A test of Virsu’s (1971) centroid theory

Diamond-winged variants of the Müller-Lyer figure were used to test predictions of Virsu’s (1971) theory of the Müller-Lyer illusion based on efferent readiness for eye movements toward the figure’s center of gravity, A Müller-Lyer figure with diamond-shaped wings resulted in a greater center-of-gravity distance than the corresponding, conventional Müller-Lyer figure, but fin length and the rest of the figure remained constant; in Virsu’s study, fin length and center-of-gravity distance covaried. Results were consistent with Virsu’s data when we used the stimulus conditions that he reported. Results from a wider range of stimuli challenge Virsu’s theory, and thus are consistent with the conclusions of Brigell, Uhlarik, and Goldhorn (1977).     

WHAT MAKES EXTINCTION WORK: AN ANALYSIS OF PROCEDURAL FORM AND FUNCTION

We examined methods for determining how extinction should be applied to different functions of self-injurious behavior (SIB). Assessment data indicated that the head banging of 3 children with developmental disabilities was maintained by different reinforcement contingencies: One subject's SIB was positively reinforced by attention from adults, the 2nd subject's SIB was negatively reinforced by escape from educational tasks, and the 3rd subject's SIB appeared to be automatically reinforced or “self-stimulatory” in nature. Three functional variations of extinction—EXT (attention), EXT (escape), and EXT (sensory)—were evaluated, and each subject was exposed to at least two of these variations in reversal or multiple baseline designs. Reductions in SIB were observed only when implementation of “extinction” involved the discontinuation of reinforcement previously shown to be responsible for maintaining the behavior. These results highlight important differences among treatment techniques based on the same behavioral principle (extinction) when applied to topographically similar but functionally dissimilar responses, and further illustrate the practical implications of a functional analysis of behavior disorders for designing, selecting, and classifying therapeutic interventions.     

Semantic processing of unattended parafoveal words

The influence that a context word presented either foveally or parafoveally, may exert on the processing of a subsequent target word was studied in a semantic decision task. Fourteen subjects participated in the experiment. They were presented with word-nonword pairs (prime). One member of the pair (which the subjects had to attend to) appeared centrally, the other parafoveally. The prime was followed by a target at two inter-stimulus intervals (ISI; 200 and 2000 msec). The word stimulus of the pair could be semantically related or unrelated to the target. The subjects' task was to classify the target as animal or not animal by pressing one of two buttons as quickly as possible. When the target word was semantically associated with the foveal (attended) word the reaction times were faster for both ISIs; when it was associated with the parafoveal (unattended) word in the prime pair, there were facilitatory effects only in the short ISI condition. A second experiment was run in order to evaluate the possibility that the obtained results were due to identification of the parafoveal stimulus. The same prime-target pairs of experiment 1 (without the target stimuli) were used. The prime-target pairs were presented to fourteen subjects who were requested to name the foveal (attended) stimulus and subsequently, if possible, the parafoveal (unattended) one. Even in this condition, percentage of identification of the unattended word was only 15%, suggesting that previous findings were not due to identification of unattended stimuli. Results are discussed in relation to Posner and Snyder's (1975) dual coding theory.     

Using performance feedback to improve treatment integrity of classwide behavior plans: an investigation of observer reactivity

The current study replicated the positive effects of performance feedback on treatment integrity and extended previous work by examining reactivity using a multiple baseline design with alternating treatments for observer-present and observer-absent conditions on teachers' implementation of a classwide behavior plan. No differences were found between conditions, and treatment integrity improved across all teachers, suggesting that performance feedback, rather than observer reactivity, was responsible for reported behavior changes.     

Modeling dynamic resource utilization in populations with unique constraints: preadolescents with and without Down syndrome

In this study we used a damped inverted pendulum and spring with an escapement function model to compare the global levels of stiffness and forcing used by 12 preadolescents with Down syndrome (DS) and 12 with typical development (TD). Participants walked overground at their self-selected speed and on a treadmill at speeds slower and faster than overground. Children with DS, who are characterized as hypotonic with reduced capacity for producing muscle force, exhibited significantly higher levels of stiffness and forcing (angular impulse) when walking on the treadmill and higher forcing but not stiffness overground, than children with TD. Both groups adapted to imposed speed increases similarly by increasing their global stiffness and angular impulse. We propose children with DS increased stiffness in order to overcome their hypotonia and joint laxity, thus, optimizing on stability, rather than metabolic efficiency. Higher angular impulse values for children with DS may reflect higher energy cost associated with increasing stiffness and their inherent biomechanical and physiological characteristics that reduce efficiency. We conclude that the inverted pendulum and spring with escapement function model is a useful tool for uncovering solutions to movement problems-solutions that reflect the dynamic resources of the individual and ones that are discovered, rather than prescribed.     

Word length effect in early reading and in developmental dyslexia

Vocal reaction times were measured in Italian dyslexics and in proficient readers while they read single words. Three groups of control participants (for a total of 79) were tested. All were in the first, second or third grade of elementary school. Nine third graders with a low level of reading ability when assessed by standard reading procedures were also tested. Results indicated that vocal RTs of control participants were faster and less sensitive to word length as a function of age; also, there was a particularly marked change between first and second graders. Dyslexics' vocal RTs and errors were much worse than those of peer control participants and resembled those of first grade controls. It is suggested that normal readers in an orthographically transparent language (Italian) adopt a lexical strategy quite early in their learning. On the contrary, dyslexics seem unable to learn this mode of processing and continue to use a sub-lexical reading procedure.     

Development and Validation of an Explicit Aggressive Beliefs and Attitudes Scale

This work outlines the development and validation of a new self-report measure that assesses explicit aggressive beliefs and attitudes within the normal adult population (using 7 samples, total N = 3,533). These explicit aggressive beliefs and attitudes are expected to reflect aggressive biases including hostile attribution, potency, retribution, victimization by powerful others, derogation of target, and social discounting. The resulting scale is reliable with a hierarchical 6-factor structure, and displays convergent and discriminant validity. Criterion-related validity studies indicate incremental effects over socially desirable response bias, related implicit and explicit aggression measures, and is predictive of self-reported and other-reported aggression-related behaviors.