Properties of distracting speech affect attentional entrainment to audiovisual “cocktail-party” speech

The attentional effects caused by characteristics of
unattended speech in cocktail-party settings are poorly
understood. We measured EEG (n = 19) and fMRI (n = 20)
to naturalistic audiovisual dialogues with concurrent
distracting speech, varying in semantic and physical
similarity to the attended speaker. We used EEG speech
reconstruction analysis to study how the temporal
dynamics of selective attention depended on features of
the unattended speech, across and within sentences. For
the fMRI data we used representational similarity
analysis, Procustes analysis, and hierarchical clustering
to explore spatiotemporal changes in attentional
modulation across sentences. Attentional entrainment to
the relevant speech stream was affected by the
properties of distracting speech. The fMRI data revealed
that the representational structure of attended speech
changed distinctly across time in different nodes of the
speech processing network. We underscore the value of
using multiple measurement techniques, incorporating
different spatial and timescales, in attention research.