Evidence of complementary afterimages in the pigeon.
A simple peck-for-food task can reveal afterimages in pigeons and offers a ready model for quick vision checks with learners.
01Research in Context
What this study did
Williams (1974) worked with pigeons in a small lab chamber.
The birds pecked for food on a variable-interval schedule.
After red light, white light followed. The team counted pecks to see if the birds acted as if they still saw red.
What they found
The pigeons pecked more during white light that came right after red.
This brief jump in responding is evidence of a complementary afterimage.
In simple words, the birds behaved as if the white screen looked green to them.
How this fits with other research
Schusterman (1966) used a similar set-up to find flicker thresholds in pigeons. Both studies show that basic operant methods can measure tiny visual events.
Corrigan et al. (1998) also taught pigeons to tell visual events apart, but they used moving biological motion instead of color after-effects. The tools are the same; the sights differ.
Madsen et al. (1968) looked at how pigeons generalize shape tilt. Their bimodal gradients match the idea that birds see color and form in graded, not all-or-none, ways.
Why it matters
You can adapt the same VI-discrimination trick to check vision in any client who can peck, touch, or look. After a bright red card, watch if the child chooses a green item more often. A quick bias like that may flag afterimage problems and help you pick better teaching materials.
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Join Free →After a red stimulus, present a white field and count responses; an uptick may show an afterimage you need to plan around.
02At a glance
03Original abstract
Key pecking of pigeons was reinforced on a variable-interval schedule when ambient illumination came from a green light, but not when it came from a red, yellow, or white light. The different hues were randomly presented for periods of 30 sec each, with the restriction that white never followed red. After discriminative control was established, the pigeons were tested with the same procedure used during training, except that white sometimes followed red. Significantly more responses were made during white-following-red than during white following either green or yellow. These findings indicate that, in changing from red to white, complementary afterimages can be induced in pigeons for a brief period of time. By providing behavioral evidence for afterimages in the pigeon, this technique may be useful to research in comparative neurophysiology, animal discrimination learning, and theories of color vision.
Journal of the experimental analysis of behavior, 1974 · doi:10.1901/jeab.1974.21-421