An investigation into blocking of filial imprinting in the chick during exposure to a compound stimulus

Investigated the occurrence of blocking in jungle fowl chicks in an imprinting situation. In Exp 1, Ss were simultaneously exposed to 2 red (RR), a yellow and a red (YR), or 2 yellow (YY) stationary cylinders. After 6 days, these cylinders were replaced by a yellow and a blue cylinder for 7 days (Phase 2). When the blue cylinder was presented alone during tests in Phase 2, RR Ss spent significantly more time with this cylinder and emitted fewer shrill calls than YR and YY Ss. In Exp 2, development of attachment to a blue cylinder only in Phase 2 proceeded similarly in RR and YY Ss. In Exp 3, Ss reared with a yellow and a red cylinder preferred the latter. Results suggest that imprinting to a novel stimulus is blocked when that stimulus is presented in compound with a familiar stimulus.