Poster #: 36
Topic: Development (infancy, childhood, adolescence, and aging)
Friday, Sep 11, 2015
Detection of violation in two streams: a feasibility study in 6-9 months old infants
1School of Psychology, University of East London, London, United Kingdom
2University of Warsaw, Poland
3University of Surrey, United Kingdom
The ability to segregate auditory streams is essential for efficient speech processing and, therefore, attainment in school. Previously, it has been reported that infants already at birth can segregate auditory information in separate streams and detect a violation in one of them (Winkler et al, 2003). In this study, we explored a possibility of simultaneous processing of two streams both containing deviant stimuli. The aim was twofold: 1) to test whether it is feasible to record reliable data for two paradigms at the same time, 2) to test infants’ speech processing capacity in auditory distracting environment. Infants (6-9 months old) were tested with two paradigms either presented simultaneously (Streaming) or separately (Control). While we expected to obtain an ERP signature of mismatch detection in both streams at the group level, we also expected to reveal a differential ability to segregate auditory streams at individual level. We examined ERPs in response to videos of audio-visually matching and mismatched syllables /ba/ and /ga/ (Kushnerenko et al, 2008) presented together with an auditory oddball paradigm including pitch and white-noise deviants (Kushnerenko et al, 2007). Our results demonstrate that at the group level the detection of audiovisual mismatch in Streaming condition is decreased, although still present in individual infants; processing of the white-noise segment is not affected significantly, while processing of the pitch deviant resulted in change of polarity of mismatch response. The results suggest that in situation of auditory overload, a different mechanism might be involved in detecting acoustic violations in infants.