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J L WILLIAMS

Publications and source records attributed to J L WILLIAMS.

At least 19 recordsLinked to original sources
PubMed1964

MAMMOGRAPHY.

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Breast Neoplasms↗
PubMed1963

Stimulus generalization of a positive conditioned reinforcer.

Stimulus generalization has been observed for discriminative, eliciting, and emotional functions of stimuli. In our study, in order to investigate the generalization of the reinforcing function of stimuli, pigeons were trained in a Skinner box to peck at an unlighted key to obtain aperiodic, brief exposures of light at a wavelength of 550 mmicro, the positive conditioned reinforcer, which was immediately followed by food reward. Testing in extinction, we obtained generalization gradients for the number of responses and the time the pigeons expended to produce exposures on the unlighted key of 550 mmicro, 530 mmicro) 510 mmicro, or no light. This finding suggests that stimulus generalization occurs with all functions of stimuli.

Animals↗
PubMed1963

A further study of stimulus generalization following three-stimulus discrimination training.

A group of pigeons was trained in a Skinner box to peck for VI reinforcement when the key was illuminated by a monochromatic light of 540 or 580 mmu but were non-reinforced for responding to 560 mmu. Two control groups, differing in amount of training, received only the two positive stimuli. At the completion of training all Ss received generalization tests under extinction. Both control groups produced bi-modal generalization gradients with the peaks of responding at the S+ values. The post-discrimination gradient revealed peaks displaced from the S+ values in the direction away from the S-, low responding and increased steepness in the region of S- and a general elevation of the gradient.

Animals↗