"Square-wave stimuli" and neonatal auditory behavior: some comments on Ashton (1971), Hutt el al. (1968) and Lenard et al. (1969)

Recent work reporting neonatal auditory responses to complex tones generated by applying electrical square-wave stimuli to loudspeakers is reviewed with reference to the nature of the acoustic stimulus. Attention is particularly drawn to the harmonic structure of such tones in relation to the nonlinear frequency response of small loudspeakers. A $\text{1}\text{3}\text{-}\text{octave}$ band analysis of some “square-wave tones” is given to illustrate the difficulties of interpreting the results of work using such complex stimuli. The findings of the previous studies are ascribed essentially to differences in the stimulus bandwidth, rather than to differences in audiofrequency, and difficulties apparently generated by using differences in stimulus bandwidth as the sole explanation are at least partially resolved.