Newborn Infants Detect Cues of Concurrent Sound Segregation

Abstract

Separating concurrent sounds is fundamental for a veridical perception of one's auditory surroundings. Sound components that are harmonically related and start at the same time are usually grouped into a common perceptual object, whereas components that are not in harmonic relation or have different onset times are more likely to be perceived in terms of separate objects. Here we tested whether neonates are able to pick up the cues supporting this sound organization principle. We presented newborn infants with a series of complex tones with their harmonics in tune (creating the percept of a unitary sound object) and with manipulated variants, which gave the impression of two concurrently active sound sources. The manipulated variant had either one mistuned partial (single-cue condition) or the onset of this mistuned partial was also delayed (double-cue condition). Tuned and manipulated sounds were presented in random order with equal probabilities. Recording the neonates' electroencephalographic responses allowed us to evaluate their processing of the sounds. Results show that, in both conditions, mistuned sounds elicited a negative displacement of the event-related potential (ERP) relative to tuned sounds from 360 to 400 ms after sound onset. The mistuning-related ERP component resembles the object-related negativity (ORN) component in adults, which is associated with concurrent sound segregation. Delayed onset additionally led to a negative displacement from 160 to 200 ms, which was probably more related to the physical parameters of the sounds than to their perceptual segregation. The elicitation of an ORN-like response in newborn infants suggests that neonates possess the basic capabilities of segregating concurrent sounds by detecting inharmonic relations between the co-occurring sounds.

EEG signatures accompanying auditory figure-ground segregation

“…Thus, the P400 amplitude is linked directly to behavioral performance in two different ways, whereas the ORN amplitude does not show a similar correspondence to behavior. Furthermore, while ORN is elicited in passive situations (similarly to the brain electric activity observed by O’Sullivan et al, 2015) and has been observed in newborns and 6-month-old infants (Bendixen et. al, 2015; Folland, Butler, Smith, & Trainor, 2012), P400 is only elicited when listeners are instructed to report whether they heard one or two concurrent objects (e.g., Alain et al2001; McDonald and Alain 2005; Kocsis et al, 2014).…”

Evolution of tonal organization in music mirrors symbolic representation of perceptual reality. Part-1: Prehistoric

“…However, the ability to distinguish melodic consonance/dissonance appears to have genetic roots—just as its harmonic counterpart—according to the EEG measurements during newborn infants' sleep (Stefanics et al, 2009 ). The newborns can segregate concurrent tones into separate audio streams by detecting inharmonic relations between the co-occurring sounds (Bendixen et al, 2015 ).…”

“…Unlike vision, hearing makes environmental information readily available for the brain right from birth. Neonates are found to have all the main auditory functionality that characterizes adults' hearing in place (Bendixen et al, 2015 ). This includes discrimination between melodic intervals (Stefanics et al, 2009 ).…”

Infants use onset asynchrony cues in auditory scene analysis

“…However, whether infants are able to use auditory cues to group and separate frequency components is less clear. The results of several studies suggest that infants are able to use frequency separation (Demany, 1982;Winkler et al, 2003), harmonicity (Bendixen et al, 2015;Folland et al, 2015;Folland et al, 2012), and spatial location cues (Nozza, 1988). However, the results of these studies fail to provide a cohesive account of the development of sound segregation for several reasons.…”

“…Furthermore, the auditory cue is rarely systematically varied in developmental studies. Instead, infants are presented with a cue that is large enough to allow adults to easily segregate the sounds involved (e.g., Bendixen et al, 2015;Winkler et al, 2003). Although this approach demonstrates that infants can use a specific cue, it does not provide a way to assess how efficiently infants use that auditory cue relative to adults.…”