These studies examined the effects of altered developmental experience (rearing history) and altered behavioral context (testing environment) on the alarm call responsiveness of maternally naive, incubator-reared bobwhite quail chicks. Experiment 1 assessed alarm call responsiveness in socially-reared, socially-tested hatchlings across the first 96 hours following hatch. No significant age effects were revealed. Hatchlings tested at 24 hours did not differ significantly from birds tested at 48, 72, or 96 hours on the two principle behavioral measures (number of grid crossings and vocalizations per one-minute trials). Experiment 2 assessed whether hatchlings' alarm call responsiveness is at least partially dependent on the availability of cover (i.e., hiding sites) in the testing situation. No significant differences in responding were found in comparisons between hiding sites and social (non-hiding sites) testing conditions. However, behavioral observations did indicate that hatchlings in the hiding site condition utilized the hiding site as an attractor, in that chicks typically huddled and froze around the hiding site structure. Experiment 3 examined the relative effects of individual testing on socially-reared bobwhite quail hatchlings. Results revealed that individually tested hatchlings increased their locomotor activity following initial exposure to the maternal alarm call when compared to socially tested chicks. Vocalizations were significantly reduced in post-alarm call testing from pre-alarm call levels. However, hatchlings tested individually had higher levels of vocal activity when compared to socially tested chicks. In comparison with socially-reared/socially-tested subjects, socially-reared/individually tested subjects were more active following exposure to the maternal alarm call than they were prior to exposure to the call. Results from the three experiments are discussed in terms of species-typical experience and development. It is maintained that species-typical responding to the bobwhite maternal alarm call is partially influenced by social context. An argument for continued polythetic research on behavioral development in avian communication is also made. / Master of Science

The present study examined whether previously reported effects of altered prenatal sensory experience on the subsequent acceleration of intersensory functions are mediated by mechanisms sensitive to the overall amount of stimulation. Results reveal that chicks exposed to augmented amounts of prenatal visual stimulation show interference in subsequent species-typical perceptual development. Specifically, chicks continued to respond to maternal auditory cues into later stages of postnatal development and failed to respond to maternal visual cues at the age when normally reared chicks to exhibit this species-specific ability. Embryos in this study also failed to demonstrate early auditory learning of an individual maternal call, a behavior reliably seen in unmanipulated embryos. These findings suggest that substantially increased amounts of visual stimulation appear to prevent the emergence of species-typical patterns of intersensory functioning and lend support to the notion that stimulation that falls within some optimal range seems to maintain or facilitate normal patterns of perceptual functioning, while stimulation beyond the range of the species norm appears to result in intersensory interference. / Master of Science

The present study examined the role of the relationship between the type and amount of prenatal and postnatal stimulus cues in directing the perceptual preferences of bobwhite quail chicks. Results reveal that chicks prefer postnatal stimulus cues that matched the particular type of prenatal stimulation they received as embryos over stimulus cues that match the amount of prenatal stimulus cues they received. Specifically, when chicks were tested with novel stimuli, or when the preference for matching types of stimulus cues was controlled for, chicks exposed to prenatal auditory/visual cues showed a preference for combined auditory/visual cues over auditory cues presented alone. These findings suggest that exposure to enhanced prenatal auditory/visual stimulation can accelerate chicks perceptual responsiveness. However, this effect can be masked depending upon the relationship between the specific type of auditory stimulus cues used during prenatal exposure and subsequent postnatal testing. Further results indicate that preference for familiar type of stimuli can account for why exposure to enhanced prenatal stimulation does not always appear to accelerate responsiveness to combined auditory/visual cues. Therefore, studies examining the effects of prenatal sensory manipulations on postnatal perceptual responsiveness must take into account the specific nature of the relationship between the type and amount of prenatal and postnatal stimulus cues employed in the experiment. In a more general sense, these results suggest that the study of early perceptual development requires the incorporation of complex, dynamic, and hierarchically based notions about the mechanisms associated with behavioral development. / Ph. D.