Speech-on-speech listening involves selectively attending to a target talker while ignoring a simultaneous competing talker. Spatially separating the talkers improves performance, a phenomenon known as spatial release from masking (spatial RM). However, it is also possible to improve performance by spectrally separating the talkers, i.e., filtering them into non-overlapping frequency bands (spectral RM). In both cases, RM benefits derive from enhanced availability of the target signal.

The relative benefit of spatial vs. spectral RM is currently unknown. Furthermore, it is unclear how listeners’ ability to exploit spatial vs. spectral cues is related to individual differences in cognitive abilities. It has been suggested that cognitive resources are of greater utility when less of the target signal is available, implying that the cognition/performance relationship should be strongest when spatial and/or spectral separation (i.e., RM) is limited or absent. However, the data-limit account (Norman & Bobrow, 1975, Cognitive Psychol 7(1):44) suggests that cognitive resources cease to be of use when the target is severely degraded, implying that the cognition/performance relationship should in fact be weakest when there is no RM.

In this study, participants (N=240) completed a selective listening task in which they transcribed the speech of one of two simultaneously-presented talkers. We filtered the speech into frequency bands such that the talkers were either spectrally overlapping or interleaved (spectral RM vs. no spectral RM). We also manipulated perceived spatial distance between talkers, presenting them either at +/-90º azimuth (dichotic) or collocated (diotic) (spatial RM vs. no spatial RM). We additionally administered a battery of cognitive tasks to assess three key components of WM/attention: phonological loop, executive function and selective/divided attentional control. Factor analysis was used to derive a single cognitive score for each participant.

Spectral RM was at least as effective as spatial RM in improving transcription performance, with the best performance observed when both types of RM were present. Cognitive scores were significantly positively correlated with both spatial and spectral RM benefits. Additionally, cognitive scores best predicted performance in the three RM conditions, with the weakest correlation observed in the condition with neither spatial nor spectral RM.

These results suggest that listeners can gain as much benefit from spectral as spatial cues during speech-on-speech listening. These RM benefits appear to be supported by cognitive processes, with larger RM benefits associated with better cognition. Finally, cognitive abilities were least predictive of performance when no RM was present, supporting a data-limit account.