Andrew Watt

Motivational control after extended instrumental training

Hungry rats were trained to press a lever for food pellets prior to an assessment of the effect of a shift in their motivational state on instrumental performance in extinction. The first study replicated the finding that a reduction in the level of food deprivation has no detectable effect on extinction performance unless the animals receive prior experience with the food pellets in the nondeprived state (Balleine, 1992; Balleine & Dickinson, 1994). When tested in the nondeprived state, only animals that were reexposed to the food pellets in this state between training and testing showed a reduction in the level of pressing during the extinction test relative to animals tested in the deprived state. The magnitude of this reexposure effect depended, however, on the amount of instrumental training. Following more extended instrumental training, extinction performance was unaffected by reexposure to the food pellets in the nondeprived state whether or not the animals were food deprived at the time of testing. A second study demonstrated that the resistance to the reexposure treatment engendered by overtraining was due to the animals’ increased experience of the food pellets in the deprived state during training rather than to the more extensive exposure to the instrumental contingency. In contrast to the results of the first two experiments, however, a reliable reexposure effect was detected after overtraining in a final study, in which the animals were given greater reexposure to the food pellets in the nondeprived state.

Acquired relational equivalence: Implications for the nature of associative structures

In 2 experiments, rats received discrimination training in which separate presentations of A and B signaled a common pair of relationships or associations (X-->food and Y-->no food), whereas presentations of C and D signaled a different pair of relationships (X-->no food and Y->food). To assess the nature of the associative structures acquired during this training, rats then received 2 types of reevaluation procedure: In Experiment 1, A was paired with shock and C was not. In Experiment 2, the relationships that A and B had previously signaled (X-->food and Y-->no food) were paired with shock, whereas those that C and D had signaled (Y-->food and X-->no food) were not. After both types of reevaluation treatment, rats showed greater generalized conditioned suppression in the presence of B than D. These results indicate that A, B, C, and D come to evoke memories of the relationship or associations that they have signaled.

Acquired relational equivalence between contexts and features

In 2 .experiments, rats received a biconditional discrimination wherein separate presentations of A and B signaled 1 pair of associations (X —> food and Y —> no food) and presentations of C and D signaled a different pair of associations (X —> no food and Y —> food). In Experiment 1, A, B, C, and D were diffuse contextual stimuli in which the associations were embedded. In Experiment 2, A and C were contextual stimuli whereas B and D were features that immediately preceded the associations. To assess the associative structures acquired during training, all rats then received a revaluation procedure in which A was paired with shock and C was not. In both experiments, greater generalized suppression of behavior was observed in the presence of B than in the presence of D. These results indicate that contextual stimuli share with features the capacity to evoke the associations that they have signaled.

Brittain's Sadistic Murderer Syndrome reconsidered: an associative account of the aetiology of sadistic sexual fantasy

The ground-breaking work of Brittain (1970) provided the template for subsequent investigations of the aetiology, development and careers of sadistic murderers. The current article revisits some of the key observations that Brittain made, reviews briefly some of the empirical/theoretical developments that followed and offers an associative account of how sadistic fantasy may be initiated. We conclude by calling on clinicians working with sadists to apply the single case-study to collect sufficient information so that models of the aetiology of this population may be refined.

Content of command hallucinations predicts self-harm but not violence in a medium secure unit

Evidence to date has supported negative relationships, a null relationship and a positive relationship between command hallucinations and violence or self-harm. This study was designed to determine the relationship between command hallucinations with violent or self-harm content and incidents of violence and self-harm in forensic inpatients. Patients with (n = 56) and without (n = 54) a lifetime history of command hallucinations and resident in a medium-security hospital were identified through clinical and legal records over 51 months. Measures included: staff-observed violence and self-harm; presence and content of command hallucinations; paranoid delusions; previous violent convictions; length of stay; gender; history of alcohol or illicit drug abuse. Statistical analyses used negative binomial regression. Violent command hallucinations and inpatient violence were unrelated. Self-harming command hallucinations and an absence of paranoid delusions were positively associated with self-harm. The processes that determine compliance with command hallucinations remain unclear.

Behavioral indicators of sadistic sexual murder predict the presence of sadistic sexual fantasy in a normative sample.

Burgess, Hartman, Ressler, Douglas, and McCormack noted a high prevalence of certain behavioral and experiential characteristics in sexual murderers and argued for their etiological importance. The present study aimed to measure the prevalence of these indicators in a nonoffending control population and to evaluate whether they identified sadistic sexual fantasy. The prevalence of behavioral and experiential indicators and degree of sadistic sexual interest were measured in 50 healthy nonoffenders. Compared to Burgess et al.s sexual murderers, higher prevalence levels for most experiential indicators were found, whereas many of the behavioral indicators were less prevalent. Three of the behavioral indicators were significantly associated with the presence of sadistic sexual fantasies. The presence of behavioral indicators that predict sadistic sexual fantasy confirms the importance of these factors in the etiology of the development of sadistic sexual fantasy in both offenders and nonoffenders and may be useful in risk assessment.

Combining CSs Associated with the Same or Different USs

In three experiments, hungry rats received appetitive training with four stimuli, A, B, X, and Y. In each Experiment, A and B were paired with one unconditioned stimulus (US; e.g. food pellets) whereas X and Y were paired with a second US (e.g. sucrose). Subsequently, rats responded more vigorously to combinations of stimuli associated with different USs (A-Y & X-B) than to combinations of stimuli associated with the same US (A-B &X-Y; Experiments 1, 2, & 3). This effect was observed when the stimuli were presented simultaneously and during the second elements of serial compounds (Experiments 2 & 3). Moreover, combining CSs associated with different USs resulted in a more marked CR than combining CSs that had each been paired with both US1 and US2 (Experiment 3). These results suggest that the sensory properties of appetitive reinforcers have an important influence on performance.

To what extent does nonanalytic reasoning contribute to visual learning in cytopathology

Acquisition of visual interpretation skills in cytopathology may involve 2 strategies. Analytic strategies require trainees to base their interpretive decisions on carefully considered and often exhaustive cytomorphologic feature lists, a process that can be time‐consuming and inefficient. In contrast, nonanalytic pattern recognition strategies are rarely encouraged during training, even though this approach is characteristic of expert diagnostic behavior. This study evaluated the potential role of nonanalytic learning in cytopathology as an efficient alternative to analytic training.

Untutored discrimination training on paired cell images influences visual learning in cytopathology

Cytologists must learn how to discriminate cells that might be visually very similar but have different neoplastic potential. The mechanism by which trainees learn this task is poorly researched and is the focus of the current investigation. Cognitive science offers a theoretical platform from which to design meaningful experiments that could lead to novel training strategies.

Visual distraction in cytopathology: should we be concerned?

Visual distraction in cytopathology has not been investigated previously as a source of diagnostic error, presumably because the viewing field of a conventional light microscope is considered to be large enough to minimise interference from peripheral visual stimuli. Virtual microscopy, which involves the examination of digitised images of pathology specimens on computer screens, is beginning to challenge the central role of light microscopy as a diagnostic tool in cytopathology. The relatively narrow visual angle offered by virtual microscopy makes it conceivable that users of these systems will be more vulnerable to visual interference. Using a variant of a visual distraction paradigm (the Eriksen flanker task), the aim of this study was to determine whether the accuracy and speed of the interpretation of cells on a central target screen are affected by images of cells and text displayed on neighbouring monitors under realistic reading room conditions.