Speech experience and cue trading in budgerigars

Abstract

The current project investigates how experience with human speech can influence speech perception in budgerigars. Budgerigars are vocal mimics and speech exposure can be tightly controlled in a laboratory setting. The data collected include behavioral responses from 30 budgerigars, tested using a cue-trading paradigm with synthetic speech stimuli. Prior to testing, the birds were divided into three exposure groups: Passive speech exposure (regular exposure to human speech), no speech exposure (completely isolated), and speech-trained (using the Model-Rival Method). After the exposure period, all budgerigars were tested using operant conditioning procedures. Birds were trained to peck keys in response to hearing different synthetic speech sounds that began with either “d” or “t.” Sounds varied in VOT and in the frequency of the first formant. Once training performance reached 80% on the series endpoints, budgerigars were presented with the entire series, including ambiguous sounds. The responses on these trials were used to determine which speech cues the birds use, if cue trading behavior was present, and whether speech exposure had an influence on perception. Preliminary data suggest experience with speech sounds is not necessary for cue trading by budgerigars.