Stimulus factors in aversive controls: conditioned suppression after equal training to two stimuli.
Training two similar stimuli creates a double-peak fear pattern with weaker responding in between.
01Research in Context
What this study did
The team trained pigeons to peck for food.
Two different tones were paired with shocks.
They then tested many tones between the trained ones.
They watched how much the birds stopped pecking.
What they found
The birds showed two clear peaks of fear.
One peak sat at each trained tone.
A middle tone got weaker fear.
The pattern looked like two hills with a valley between them.
How this fits with other research
HOFFMAN et al. (1963) used the same lab setup but looked at long-term memory.
Their birds kept fear for 2.5 years, showing the method works.
Terrace (1969) later showed steady gradients with light instead of sound.
That work proved the double-peak pattern holds across senses.
Okouchi (2003) found the same shape with college kids and line lengths.
This means the double-peak rule works for people too.
Why it matters
When you teach two similar sounds, watch for gaps in learning.
The middle sound may need extra training.
Test probes between targets to spot weak spots.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Probe one untrained tone between your two trained ones to check for weak generalization
02At a glance
03Original abstract
Pigeons trained to peck a key for food were periodically presented with tones ending with electrical shock until tone presentation consistently suppressed ongoing pecks. Shock was then discontinued and gradients of stimulus generalization were assessed by presenting tones with frequencies above, below, and at the frequencies of those used to develop conditioned suppression. When the training tones had frequencies at 670 and 1500 cps, resulting gradients were bi-modal with peak suppression at 670 and 1500 cps. Of the other test tones, 1000 cps produced the most suppression. When the training tones had frequencies at 450 and 2250 cps, bi-modal gradients were again obtained with peak suppression to the 450 and 2250 cps tones. Of the other test tones, 1000 cps produced the least suppression. These results support the hypothesis that generalized response tendencies summate.
Journal of the experimental analysis of behavior, 1966 · doi:10.1901/jeab.1966.9-649