Population density and food dispersion on the development of prism-induced aftereffects in newly hatched chicks
✍ Scribed by Patrick J. Rossi
- Publisher
- John Wiley and Sons
- Year
- 1972
- Tongue
- English
- Weight
- 634 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0012-1630
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✦ Synopsis
Tempe, A riz o na
Newly hatched Leghorn cockerels (124) wearing hoods containing 8.5" prisms were reared in large or small groups and with high or low ratios of spatially distributed seeds on a sand filler. Only chicks reared in large groups demonstrated negative aftereffects when 0' plates were substituted for the prisms on the seventh day. For large groups, high seed density resulted in smaller lateral pecking errors with prism displacement but larger negative aftereffect errors without displacement than did low seed density. For small groups, however, high seed density produced a reversal of negative aftereffect directions. High group density was necessary for negative aftereffect development, probably by its influence on socially mediated pecking rates.
Several attempts have been initiated to determine if pecking behavior in fowl could be modified in some characteristic other than rate or frequency. Those attempts relevant to the present study originated from the comparative visual-motor plasticity issue, that is, whether the visual-motor aiming mechanism involved in a pecking sequence could be modified by experience with novel rearrangement of the visual field (see discussions in Gregory, 1966; Held & Bossom, 1961; Smith &Smith, 1962; Taub, 1968). Hess (1956), for example. found that newly hatched Leghorn chicks did not adapt to 7" of lateral optical displacement up to the fourth day of age. In contrast, Rossi (1967Rossi ( , 1968Rossi ( , 1969Rossi ( , 1971) ) found that newly hatched Leghorn chicks demonstrate either negative aftereffects or positive adaptation, or both, depending on the factors cited below.
Rossi (1967, 1968) reported both positive adaptation and negative aftereffects to lateral optical displacement. Subsequent studies (Rossi, 1969(Rossi, , 1971) ) reported only negative aftereffects without apparent initial positive adaptation. There were, however, marked differences in experimental procedures and in the type of inbred chick strains used. All studies which had reported both positive adaptation and negative aftereffects