title: Visual memory of shapes in quail chicks: discrimination among 2-dimensional objects.
abstract: Newly hatched chicks spontaneously peck at conspicuous objects, and soon learn to discriminate between edible food particles and inedible objects. To examine whether this discrimination is based on a chick's ability to memorize objects by shape cues, we analyzed the pecking behavior. One- to 3-day old quail chicks (Coturnix japonica) were presented with dry objects of different shapes (ball, disk, triangle and T-shape) of similar size (4 mm) and color (green). Habituation occurred after repeated presentation of any one of these objects (duration: 30 sec; interval: 4 min). When chicks showed significantly more pecks at a novel object (dishabituation), we assumed that chicks had memorized the habituated shapes and distinguished the novel object. Chicks did not show dishabituation between a ball and a disk. On the other hand, chicks discriminated a triangle or T-shape from the memorized image of disk, but did not memorize either triangle or T-shape by its shape. Similarly, chicks did not memorize the size of disks as a reference for subsequent pecking behavior. Chicks proved to have a limited ability to memorize shape and size cues for selective pecking behavior, in strong contrast to their accurate memorization of colors.
authors.affiliation: Laboratory of Animal Information Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ono
authors.forename: Isako
authors.initials: I
authors.lastname: Hayashi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Matsushima
mesh_terms: D000818:Animals; D003370:Coturnix; D003463:Cues; D004193:Discrimination Learning / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005556:Form Perception / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D011784:Quail / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*