Pigeons encode absolute distance but relational direction from landmarks and walls

In recent studies, researchers have examined animals' use of absolute or relational distances in finding a hidden goal. When trained with an array of landmarks, most animals use the default strategy of searching at an absolute distance from 1 or more landmarks. In contrast, when trained in enclosures, animals often use the relationship among walls. In the present study, pigeons were trained to find the center of an array of landmarks or a set of short walls that did not block external cues. Expansion tests showed that both groups of pigeons primarily used an absolute distance strategy. However, on rotational tests, pigeons continued to search in the center of the array, suggesting that direction was learned in relation to array.