Generalization of excitation and inhibition after different amounts of training of an avoidance baseline.
More discrimination training under avoidance sharpens both excitatory and inhibitory stimulus control.
01Research in Context
What this study did
Researchers worked with pigeons on a two-key avoidance task. One key had a tone. The other stayed quiet.
Birds learned to peck the tone key to avoid shock. After different amounts of training, the team tested how the birds responded to new tones close to the trained one.
What they found
More training made the excitatory gradient steeper. Birds responded mostly to the exact tone that had signaled safety.
The inhibitory gradient also sharpened a little. Birds stopped responding when the tone had signaled extinction under higher shock.
How this fits with other research
Baer (1974) saw the same steepening after massed extinction sessions. Both studies show that extra aversive-based training tightens stimulus control.
Brinker et al. (1975) found that only three minutes of experience after extinction can create peak shift. The two papers together map a range: a little training gives you peak shift; a lot gives you steep walls.
Schmidt et al. (1969) showed that making reinforcement duration differences obvious also sharpens control. The 1975 paper extends that idea to avoidance schedules.
Why it matters
If you want clean stimulus control with escape or avoidance programs, run more discrimination trials. Extra practice narrows the range of stimuli that control the response, just like with positive reinforcement. When you probe generalization later, you will see sharper boundaries and fewer errors.
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02At a glance
03Original abstract
After acquisition of a treadle-pressing response maintained by an avoidance contingency, four groups of pigeons received interdimensional discrimination training. For two groups, the positive stimulus was a 1000-Hertz tone correlated with the avoidance schedule and the negative stimulus was noise correlated with extinction. The discriminative stimuli were reversed for the other two groups. For two groups, the test stimuli were presented during extinction without any shocks during the test stimuli, for the other two groups, an unavoidable shock was presented during each test stimulus. Generalization was measured daily during discrimination training by randomly substituting each of six test frequencies for the 1000-Hertz tone. When the 1000-Hertz tone was correlated with the avoidance schedule, the number of responses to it increased and the excitatory gradient became steeper as a function of the amount of training. When the 1000-Hertz tone was associated with extinction, the number of responses to it decreased as a function of days of training and the inhibitory gradient became slightly steeper, provided that responding to the test stimulus was elevated by unavoidable shock. The training effects parallel those obtained with positive reinforcement.
Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.23-207