This study explores to what extent social cognition impacts early auditory processing. We measured the Mismatch Negativity (MMN) response to three non-linguistic biological sounds (flatulence, coughs and sniffs) that differ in terms of social markedness: flatulence is socially marked, while coughs and sniffs are not. We found that the MMN to the pairing flatulence/cough is larger when flatulence is the oddball than when cough is the oddball – an asymmetrical MMN. We found no evidence of an asymmetrical MMN for the pairing cough/sniff. Crucially, this pattern tracks the social-markedness properties of these stimuli, but does not track their physical properties. The MMN response has long been used for research in language and music; these results suggest that it may also be used for research in social cognition.