Effects of barbiturates and other sedative hypnotics in pigeons trained to discriminate phencyclidine from saline.
Under weakened stimulus control, pigeons switched from color to key position, reminding us to watch for location cues stealing control.
01Research in Context
What this study did
Researchers taught pigeons to peck one key when they felt the drug PCP and a different key when they felt plain saline.
After the birds learned the drug-versus-saline game, the team gave them barbiturates instead and watched which key they chose.
What they found
High barbiturate doses pushed most pigeons to peck the PCP key, showing the drug acted like PCP to the birds.
When birds pecked both keys, they now followed key position, not key color, showing a hidden cue had taken over.
How this fits with other research
Van Hemel (1973) showed color alone can steer pigeon pecking, but E et al. now show color control can collapse under drugs.
Rasing et al. (1992) later proved drug feelings can join equivalence classes with pictures, extending the idea that internal states work like external cues.
Gadow et al. (2006) used the same pigeon-drug setup with amphetamine and ethanol, confirming different drugs warp operant control in unique ways.
Why it matters
When stimulus control weakens, location can beat color. Check your materials: if a learner starts responding to where the card sits instead of the picture on it, move the card or add extra cues. This small shift can save a program from slow progress that looks like non-compliance but is really cue confusion.
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02At a glance
03Original abstract
Pigeons were trained to peck the center key (lighted white) of three response keys to turn off the center keylight and to light one of the side keys with a red keylight and the other side key with a green keylight. Five responses (fixed-ratio component) on either side key relighted the center key. Food was delivered following 10 fixed-ratio components on the red key if 1.5 mg/kg phencyclidine had been given before the session. The position of the red and green keylights on the side keys varied randomly each time they were lighted by a peck on the center key. Subsequently, increasing doses of phencyclidine, barbital, amobarbital, phenobarbital, methaqualone, methyprylon, diazepam, oxazepam, and d-amphetamine were substituted for the training dose of phencyclidine, using a cumulative dosing procedure. At low doses of the sedative hypnotics, birds pecked the keylight color associated with saline. At higher doses, birds pecked both key colors. At the highest doses of pentobarbital and amobarbital, some birds responded almost exclusively On he color associated with phencyclidine. When responding on keys of both colors occurred following administration of phencyclidine or other sedative hypnotics, this responding was controlled by key position rather than by key color.
Journal of the experimental analysis of behavior, 1983 · doi:10.1901/jeab.1983.40-133