The role of spatial separation of two talkers' auditory stimuli in the listener's memory of running speech: listening effort in a non-noisy conversational setting.

OBJECTIVE: To investigate the role of the spatial position of conversing talkers, that is, spatially separated or co-located, in the listener's short-term memory of running speech and listening effort. DESIGN: In two experiments (between-subject), participants underwent a dual-task paradigm, including a listening (primary) task wherein male and female talkers spoke coherent texts. Talkers were either spatially separated or co-located (within-subject). As a secondary task, visually presented tasks were used. Experiment I involved a number-judgement task, and Experiment II entailed switching between number and letter-judgement task. STUDY SAMPLE: Twenty-four young adults who reported normal hearing and normal or corrected to normal vision participated in each experiment. They were all students from the RWTH Aachen University. RESULTS: In both experiments, similar short-term memory performance of running speech was found independently of talkers being spatially separated or co-located. Performance in the secondary tasks, however, differed between these two talkers' auditory stimuli conditions, indicating that spatially separated talkers imposed reduced listening effort compared to their co-location. CONCLUSION: The findings indicated that auditory-perceptive information, such as the spatial position of talkers, plays a role in higher-level auditory cognition, that is, short-term memory of running speech, even when listening in quiet.