Same/different discrimination of motion by pigeons.

Abstract

Telling that one object or moment is different from another one is fundamental to cognition and intelligent behavior. Most investigations examining same/different (S/D) concepts in animals have relied on testing static visual stimuli. To move beyond this limitation, we investigated how five pigeons learned and performed a motion S/D discrimination. Using a go/no-go task, dynamic motion fields built from dot elements were presented in sequence to display repeating (same) or changing (different) motions. Each trial consisted of 10 motion segments presented in succession using the direction and rate of dot movement in the motion field to exemplify the S/D relations. The pigeons learned this motion S/D discrimination. We further tested their performance by varying the number and persistence of the dots in the motion fields. The results indicated the pigeons likely extracted globally integrated perceptual summaries of the motions for comparison across the segments. Testing differing organizations of the S/D relations across segments indicated that this discrimination could be determined from as few as two segments and involved an updating comparison of at least four or more segments of the sequence during their presentation. Collectively, the experiments establish for the first time that pigeons can use motion features to classify sequential same and different experiences.