Effects of d-amphetamine on the “breaking point” of progressive-ratio performance

Document Type


Publication Date



When d-amphetamine was administered intramuscularly to pigeons 30 min presession, the “breaking point” of their progressive-ratio performance increased as the dose increased from 0.5 to 2 mg/kg and then decreased to below control values at the largest dose (4 mg/kg). The maximum increase in breaking point induced by d-amphetamine was substantially less than that found with the optimal dose of phenobarbital (40 mg/kg). An attempt to mimic the large disruptive effect of the 4-mg/kg dose of d-amphetamine by prefeeding the Ss 60 g of grain produced only a small decrease in breaking point compared to the drug condition. © 1972, The Psychonomic Society, Inc.. All rights reserved.

Publication Source (Journal or Book title)

Psychonomic Science

First Page


Last Page


This document is currently not available here.