An inverse relationship between baseline fixed-interval response rate and the effects of a tandem response requirement.
Previous experiments examining the effects of adding a tandem fixed-ratio response requirement on fixed-interval schedule performance have reported inconsistent results. One variable that may account for such inconsistencies is the baseline response rate in the fixed-interval condition. This possibility was investigated in the present study. Rats were given histories with either interresponse times greater than 11 s or fixed-ratio 40 schedules of reinforcement, which engendered either relatively low or high rates of responding, respectively, in the subsequent fixed-interval condition. A tandem ratio response requirement (fixed-ratio 9) was then introduced. The effects of adding this tandem response requirement were inversely related to the baseline fixed-interval response rates; low rates of responding in the fixed-interval condition were markedly increased, whereas high rates of responding were relatively unaffected. This inverse relationship appears to be similar to the rate-dependent relations observed in behavioral pharmacology. These results may provide an explanation for the inconsistent findings reported in previous studies on tandem fixed-interval fixed-ratio schedules and suggest that principles of behavioral pharmacology research may be applicable to the study of the effects of nonpharmacological variables on schedule-controlled behavior.
Bickel
W K
WK
Department of Psychiatry, University of Vermont College of Medicine, Burlington 05401.
Higgins
S T
ST
Kirby
K
K
Johnson
L M
LM
D000818:Animals; D001288:Attention; D003216:Conditioning, Operant; D004326:Drinking; D008297:Male; D008568:Memory; D011939:Mental Recall; D011597:Psychomotor Performance; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule