Focusing on one voice requires both listening and ignoring
Imagine chatting at a party and trying to listen to your friend telling you about her day while there are other people talking, laughing and celebrating at the same time – difficult, isn’t it? The challenge of listening to one speaker when several people speak at once is called the cocktail party problem. Researchers from the Max-Planck-Institute for Human Cognitive and Brain Sciences and Leipzig University in collaboration with colleagues from the Max-Planck-Institute for Empirical Aesthetics and Lübeck University investigated what happens in the brain when we try to focus on one talker while ignoring another one. In the new study, now published in the Journal of Neuroscience, they show that the processing of both the voice we attend to and the voice we ignore plays a key role in how well we understand speech.
© Pexels.com
Bernstein member involved: Jonas Obleser
In a study with 43 participants, Vivien Barchet and Gesa Hartwigsen presented two spoken sentences at the same time – one to focus on, the other to ignore – and recorded participants’ brain activity via EEG. They analyzed how strongly the brain synchronized with both the acoustic patterns and the linguistic patterns of each voice.
The results reveal a delicate balancing act:
- Stronger neural tracking by the brain of the target speaker was associated with better comprehension.
- Surprisingly, some tracking of the ignored speaker’s sounds (but not their words) correlated with better performance, suggesting that some low-level awareness of irrelevant voices may help segregate auditory streams.
- However, if the brain started to track the meaning or words of the distractor, comprehension of the target speech decreased.
These findings suggest that successful listening in noisy environments relies on enhancing the relevant sound stream, while suppressing the distractor before it gains semantic processing. However, initial acoustic analysis of the distractor streams seems to improve the segmentation of the target and distractor streams.
This means that, when you’re chatting at a busy party, your brain doesn’t just tune out everyone else. It still picks up some sounds from other speakers to keep track of who’s talking, but if you start understanding their words, you’ll likely lose focus on your friend.
