| Abstract: | Negative afteraffects (NAE) to prism displacement should not exist without prior positive adaptation (PA) during initial prism exposure. In 4 experiments, chicks wearing hoods containing 8.5° wedge prisms from the day of hatching showed: (a) significant NAE (pecking overcompensation in the direction opposite to their initial displacement error when matched O-degree clear plates were substituted for the prisms), but not significant PA (reduction in the lateral error of pecking while wearing the prisms) at the sixth day; (b) NAE exceeding the theoretically predicted PA on the sixteenth day; (c) significant short and long duration NAE, and significant short and long duration reversal overcompensation effects (ROE) (left-right pecking asymmetry following reversal of the prism base directions) on the seventh and eighth days, without prior PA on the seventh day; (d) neither significant NAE nor significant PA on the fourth day. Both significant NAE and significant PA had been reported previously on the eighth day. Geometrical analyses suggest that variables latent in unrestricted application of adult sensory rearrangement techniques to rapidly growing chicks of low sensory-motor plasticity produce an ontogenetic-development-related reciprocity paradox. |
