Responding by exclusion in Wistar rats in a simultaneous visual discrimination task.
Rats prove exclusion responding is real—reject the known wrong and you pick the new right.
01Research in Context
What this study did
Matheus and colleagues taught six lab rats a simple picture game. The rats saw two pictures on a screen and learned to tap the one that gave food.
After the rats always picked the correct picture, the team slipped in new tests. One old picture they knew was 'wrong' sat next to a brand-new picture.
What they found
Five of the six rats chose the new picture. They acted as if they said, 'I know that old one never pays, so this new one must be right.'
This is called exclusion: picking the unknown by ruling out the known bad option.
How this fits with other research
Cippola et al. (2014) got the same effect with college students, but used time lengths instead of pictures. Together the studies show exclusion works across eyes and ears, rats and humans.
Mandel et al. (2022) moved the idea into kids with autism. After teaching only two picture names, the children tacted and pointed to a third new picture by exclusion, saving hours of direct teaching.
Scienza et al. (2019) looked for exclusion in bees and mostly came up empty. The bees kept flying to the old reward cue and ignored the 'reject' hint, showing exclusion is not a sure thing in every species.
Why it matters
If a rat can learn by exclusion, so can many human learners. Build probe trials that pair a known wrong item with a new stimulus; you may see fast, untaught selections. This trick can cut teaching time for tacts, listener responses, and visual discriminations in half.
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02At a glance
03Original abstract
Responding by exclusion is to select a correct alternative by rejecting other potential alternatives. Studies describe this ability in some mammals and birds. However, this type of performance has not been reported in rodents. The aim of this study was to verify the occurrence of responding by exclusion in Wistar rats after a baseline of simple simultaneous visual discrimination. Six male Wistar learned nose-poking tunnels displaying visual stimuli (projected geometric shapes) in an operant chamber. After establishing the simultaneous discrimination baseline, three probe sessions were conducted. In each session, there was a novelty-control probe (a new stimulus was presented together with a stimulus trained as the S(+)) and an exclusion probe (a second new stimulus was presented simultaneously with a stimulus trained as the S(-)). Only one rat responded to the new stimulus in one of the three novelty probe trials. Four rats responded to the three new stimuli and one responded to the new stimulus in two of the three exclusion probes. One subject responded to the S(-) in all the exclusion probes. Five of the six subjects were therefore able to choose the new stimulus, rejecting stimuli trained as the S(-). This is the first experimental evidence for performance by exclusion in rats.
Journal of the experimental analysis of behavior, 2014 · doi:10.1002/jeab.106