Inter-brain amplitude correlation differentiates cooperation from competition in a motion-sensing sports game

Abstract

Cooperation and competition are two basic modes of human interaction. Their underlying neural mechanisms, especially from an interpersonal perspective, have not been fully explored. Using the electroencephalograph-based hyperscanning technique, the present study investigated the neural correlates of both cooperation and competition within the same ecological paradigm using a classic motion-sensing tennis game. Both the inter-brain coupling (the inter-brain amplitude correlation and inter-brain phase-locking) and the intra-brain spectral power were analyzed. Only the inter-brain amplitude correlation showed a significant difference between cooperation and competition, with different spatial patterns at theta, alpha and beta frequency bands. Further inspection revealed distinct inter-brain coupling patterns for cooperation and competition; cooperation elicited positive inter-brain amplitude correlation at the delta and theta bands in extensive brain regions, while competition was associated with negative occipital inter-brain amplitude correlation at the alpha and beta bands. These findings add to our knowledge of the neural mechanisms of cooperation and competition and suggest the significance of adopting an inter-brain perspective in exploring the neural underpinnings of social interaction in ecological contexts.

Keywords: competition; cooperation; electroencephalogram; hyperscanning; inter-brain coupling.

Fig. 1.

Experimental paradigm. (A) Screenshot from the competitive condition: the screen was divided into left and right parts, each of which presented one participant’s main view. (B) A photo of two participants playing the game while their electroencephalographs were recorded. (C) Illustration of the cooperation and competition conditions.

Fig. 2.

An illustration of one typical electroencephalograph segment before and after the artifact rejection procedure. Vertical dashed lines indicate onset and offset of the epochs. The eye-movement artifacts at the frontal channels and the muscle artifacts at the temporal and occipital channels were largely removed by ICA. The two epochs with still extensive artifacts after ICA were manually identified and rejected.

Fig. 3.

(A) T-maps from comparison of the cooperation and competition conditions for different neural measures. Color represents t-value from the comparison of cooperation and competition conditions (a positive t-value indicates that the neural measure is larger during cooperation than cooperation, and a negative t-value indicates the opposite). Black dots denote channel clusters with significantly different outcomes between the two contexts (all the dots in each topoplot belong to one single cluster). (B) Permutation distributions for the three significant clusters of inter-brain amplitude correlation (AmpCorr) in (A). Red lines indicate the positions of true cluster t-values.

Fig. 4.

Inter-brain amplitude correlation (AmpCorr) results. (A) T-maps of AmpCorr during cooperation, competition and their contrasts. Color in the first two columns represents t-values from the comparison of Coop/Comp AmpCorr and zero. Black dots denote channel clusters with significant AmpCorr in certain context). Color in the third column represents t-values from the comparison of AmpCorr during the cooperation and competition conditions. Black dots denote channel clusters with significantly different AmpCorr between the two contexts (all the dots in each topoplot belong to one single cluster). (B) Individual differences of the AmpCorr values between the two contexts at three representative channels. Each linked pair of points represents data from a single participant. (C) Permutation distributions for the four clusters with significant Coop/Comp AmpCorr in (A). Red lines indicate the positions of the true cluster-t.