Several recent studies have explored what Michael (e.g., 1982) termed the "value-altering" effect and the "behavior-altering" effect of motivating operations. One aspect of the behavior-altering effect that has garnered no recent attention involves changes in stimulus control produced by motivating operations. To call attention to this aspect of…

Stimulus over-selectivity refers to behavior being controlled by one element of the environment at the expense of other equally salient aspects of the environment. Four experiments trained and tested non-clinical participants on a two-component trial-and-error discrimination task to explore the effects of different training regimes on…

Conditional discrimination or matching-to-sample procedures have been used to study a wide range of complex psychological phenomena with infrahuman and human subjects. In most studies, the percentage of trials in which a subject selects the comparison stimulus that is related to the sample stimulus is used to index the control exerted by the…

Restricted stimulus control refers to discrimination learning with atypical limitations in the range of controlling stimuli or stimulus features. In the study reported here, 4 normally capable individuals and 10 individuals with intellectual disabilities (ID) performed two-sample delayed matching to sample. Sample-stimulus observing was recorded…

Lowenkron and colleagues (Lowenkron, 1984; 1991; 1998; 2006; Lowenkron and Colvin, 1992) describe a model that explains complex behavior using only well-established behavioral principles, concepts and terms. The model, called "joint control," is especially useful for understanding complex and delayed discriminations within a purely behavioral…

In this article, I discuss the concepts of "private stimuli," "covert responses," and "private events," emphasizing three aspects: the conditions under which private stimuli may acquire discriminative functions to verbal responses, the conditions of unobservability of covert responses, and the complexity of events or phenomena described as…

Studied developmental changes in optional shift discriminations using kindergartners, second graders, sixth graders, and college students. (DR)

This report summarizes research concerning stimulus analyzing mechanisms, giving the main experimental findings and theoretical developments. Most of the data and the experimental findings are to be found in the 89 publications listed in the bibliography. The research is discussed under five main headings: (1) shape recognition, (2) selective…

This experiment examined the effects of reinforcement probability on resistance to change of remembering and response rate. Pigeons responded on a two- component multiple schedule in which completion of a variable-interval 20-s schedule produced delayed matching-to-sample trials in both components. Each session included four delays (0.1 s, 2 s, 4…