Stimulus configuration and valence-enhanced pecking by neonatal chicks

Valence-enhanced pecking occurs when hatchling chicks preferentially peck at releasing stimuli that have been assigned increased releasing power or valence. Enhanced valence is assigned by another releasing stimulus—here a “pecking” arrow. Pecking movements by the arrow have two separate effects: the stimulation or release of pecking by chicks and releasing valence enhancement, that is, pecking directed to particular stimuli. Exposure of chicks to the moving arrow yields pecking significantly increased over that accruing to a stationary arrow. A distinctive stimulus placed on the floor at the tip of the arrow, or, most effective, attached to the tip of the moving arrow, produces enhanced valence: pecking by observing chicks that is selectively increased to matching stimuli.