Generalization and response mediation of a conditional discrimination.
Requiring the learner to move or respond before viewing the sample turns that action into an extra cue that sharpens conditional discrimination.
01Research in Context
What this study did
Pigeons had to peck one key to see a sample color, then peck a second key to pick the matching color. The keys were either close together or far apart.
The team moved the sample key farther from the choice keys in small steps. They tracked how often the birds picked the correct color.
What they found
When the sample key sat farther away, the birds made fewer mistakes. The long walk itself became a cue that helped them choose correctly.
Even after the team removed the color, the birds still used the walk as the signal.
How this fits with other research
Lydersen et al. (1974) got the same boost by adding a short fixed-ratio before the sample. Both papers show that making the bird do something before the choice sharpens control.
Kohlenberg et al. (1976) pushed further. They gave one sample a heavy work schedule and the other a light one. Differential work sped learning, proving the response rule, not just distance, matters.
Blough (1980) warns us not to trust accuracy alone. A bird can score 80% while peeking at the wrong cue. The 1970 paper only used accuracy, so we should probe what really controls the choice.
Why it matters
Build a tiny response before the learner sees the sample. Have the child tap a card, walk two steps, or say the name aloud. The extra response becomes part of the cue and can cut errors without more trials. Probe afterward to be sure the right stimuli, not the movement alone, now drive the choice.
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02At a glance
03Original abstract
Fifteen pigeons were given conditional discrimination training in which a colored sample stimulus determined which of two line comparison stimuli (vertical and horizontal) was correct. As part of the conditional discrimination procedure, birds were required to make an "observing response" to the sample stimulus presented on a wide key. The location on this key of the required observing response for the two sample stimuli differed by 0, 3, or 6 in. (0, 7.6, or 15.2 cm) for three groups of birds. Accuracy of conditional discrimination performance was directly related to the amount of separation. In subsequent generalization tests with novel sample stimuli, both observing-response location and comparison responding changed within the same region of the wavelength continuum from that appropriate for one of the training samples to that appropriate for the other. A maintained generalization test (continued reinforcement for training stimuli) revealed this relation more strongly. A test in which observing-response location was the only sample stimulus of a conditional discrimination revealed stimulus control by this observing response, supporting a response mediation interpretation of the data.
Journal of the experimental analysis of behavior, 1970 · doi:10.1901/jeab.1970.13-301