The Scientific Method is the series of processes by which hypotheses, ideas and theories are shown to be true beyond a reasonable scientific doubt. Most science "fact" is expressed in terms of probabilities rather than certainties. Thus, by means of statistical calculations, researchers aim to determine whether an observed association…

The delivery of food contingent on 10 s of consecutive toy engagement resulted in a decrease in engagement and a corresponding increase in other responses that had been previously reinforced with food. Similar effects were not observed when tokens exchangeable for the same food were delivered, suggesting that engagement was disrupted by the…

We describe a procedure for differentiating among potential precursor responses for use in a functional analysis. Conditional probability analysis of descriptive assessment data identified three potential precursors. Results from the indirect assessment corresponded with those obtained from the descriptive assessment. The top-ranked response…

The valuation of academic achievements in students with severe language impairment is problematic if they also have difficulties in sustaining attention and in praxic skills. In severe autism all of these difficulties may occur together. Multiple-choice tests offer the advantage that simple praxic skills are required, allowing the tasks to be…

The first case study of identical male twins concordant for DSM-IV Asperger's disorder (ASD) was presented. Their monozygocity was confirmed by short tandem repeat analyses with a probability of 99.999963%. Despite sharing the same DNA and environment, the twins are different in comorbidity (i.e., major depressive disorder in the elder and absence…