Attention is critical for spatial auditory object formation

Abstract

The precedence effect provides a novel way to examine the role of attention in auditory object formation. When presented with two identical sounds from different locations separated by a short stimulus onset asynchrony (SOA), listeners report a single auditory object at the location of the lead sound. When the SOA is above the echo threshold, listeners report hearing two auditory objects with different locations. Event-related potential (ERP) studies have shown that the number of perceived auditory objects is reflected in an object-related negativity (ORN) 100–250 ms after onset and in a posterior late positivity (LP) 300–500 ms after onset. In the present study, we tested whether these ERP effects are modulated by attention by presenting lead/lag click pairs at and around listeners’ echo thresholds, while in separate blocks the listeners (1) attended to the sounds and reported whether the lag sound was a separate source, and (2) performed a two-back visual task. When attention was directed away from the sounds, neither the ORN nor the LP observed in the attend condition was evident. Instead, unattended click pairs above the echo threshold elicited an anterior positivity 250–450 ms after onset. However, an effect resembling an ORN was found in comparing the ERPs elicited by unattended click pairs with SOAs below the attended echo threshold, indicating that the echo threshold may have been lowered when attention was directed away from the sounds. These results suggest that attention modulates early perceptual processes that are critical for auditory object formation.

The Electrophysiological Correlates of Rhythm and Syntax in Music and Langauge

“…Hillyard et al, 1973, Luck 2014, Näätänen et al, 1981Zobel et al, 2015). Moreover, the N1 component depends on the psychoacoustic properties of sound, such as pitch (Hillayrd et al, 1973;Horváth, 2015;Näätänen et al, 1981), timbre (Moreno & Bidelman, 2014), and temporal expectancy (Besson & Faïta, 1995;Escoffier et al, 2015), and is modulated by deviants in chord sequences (Virtala et al, 2014), various properties of speech such as emotional prosody, phonetics, and vowel perception (Bidelman & Alain, 2015;Pinheiro et al, 2015;Polat & Atas, 2014), as well as properties of auditory stream segregation (Francois et al, 2014;Zobel et al, 2015). The auditory N1 component is then followed by a positivity (P2), peaking in latency at 150-275ms after event onset, that is associated with auditory learning, and is enhanced by deviant tones in auditory oddball tasks (e.g.…”