Three different experiments using different pigeons
(Wasserman et al., 1993; Kirkpatrick-Steger, Wasserman, Biederman, 1996, 1998) involved testing
with scrambled versions of the watering can, the iron, the desk lamp, and
the sailboat. In all three studies, the original drawings were discriminated
above 80% correct at the end of training. Performance to the scrambled
versions was significantly poorer than the performance to the original
versions in all three studies. However, performance to the scrambled versions
consistently exceeded the chance level of 25%. The level of performance
to the scrambled versions is consistent with the notion that the pigeons
were sensitive to the change in the spatial organization of the components,
but they must have still recognized some features of the original objects
because of the above-chance performance to the scrambled versions.
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