Developmental Changes in Locating Voice and Sound in Space

Abstract

We know little about how infants locate voice and sound in a complex multi-modal space. Using a naturalistic laboratory experiment the present study tested 35 infants at 3 ages: 4 months (15 infants), 5 months (12 infants), and 7 months (8 infants). While they were engaged frontally with one experimenter, infants were presented with (a) a second experimenter’s voice and (b) castanet sounds from three different locations (left, right, and behind). There were clear increases with age in the successful localization of sounds from all directions, and a decrease in the number of repetitions required for success. Nonetheless even at 4 months two-thirds of the infants attempted to search for the voice or sound. At all ages localizing sounds from behind was more difficult and was clearly present only at 7 months. Perseverative errors (looking at the last location) were present at all ages and appeared to be task specific (only present in the 7 month-olds for the behind location). Spontaneous attention shifts by the infants between the two experimenters, evident at 7 months, suggest early evidence for infant initiation of triadic attentional engagements. There was no advantage found for voice over castanet sounds in this study. Auditory localization is a complex and contextual process emerging gradually in the first half of the first year.

Sharing sounds: The development of auditory joint engagement during early parent–child interaction.

“…However, we also expected that there might be subtle differences in initial alerting and orienting due to the location of the sound source relative to the child, such that children might be more apt to alert and to orient to sounds that initially emanated from the spaces beside rather than behind them (Hypothesis 1.3a). This expectation is consistent with research on the effect of target location on visual attention (e.g., Butterworth & Jarrett, 1991) and on turning toward sounds (Kezuka, Amano, & Reddy, 2017) that found that young infants are most adept at turning toward voices and castanets when they are located to the side rather than behind them, presumably because it is easier to visualize peripheral rather than hidden spaces. However, we also expected that as toddlers begin to develop the capacity to represent space (Butterworth & Jarrett, 1991), differences in alerting and orienting associated with a sound’s location would become less pronounced with age (Hypothesis 1.3b).…”

“…infants may prefer listening to speech over nonspeech sounds (Vouloumanos & Curtin, 2014, but see Kezuka et al, 2017). Thus we expected that speech might attract more initial alerting and orienting in the ignore-sound phase than the environmental sounds of animal calls and mechanical noises (Hypothesis 5.1).…”

“…Trehub, Trainor, & Unyk, 1993). Our interest in exploring the possibility that the type of sound influences attention to and sharing of sounds was piqued by findings that speech processing is differentiated from other sound processing early in infancy (Lloyd-Fox, Blasi, Mercure, Elwell, & Johnson, 2012) and that young infants may prefer listening to speech over nonspeech sounds (Vouloumanos & Curtin, 2014, but see Kezuka et al, 2017). Thus we expected that speech might attract more initial alerting and orienting in the ignore-sound phase than the environmental sounds of animal calls and mechanical noises (Hypothesis 5.1).…”