Selected studies
| Study | Country Language | Sample size# Relationship | Age M | SD | Activity | Oral communication | Channels Phase analysis IBS regions | IBS comparison |
|---|---|---|---|---|---|---|---|---|
| Liu et al. (2016) | • United States • English | • 18 F-F = 2 F-M = 5 M-M = 2 • Strangers | 21.1 | 1.7 | Jenga game | Yes | • 19 • WTC • IFG/MFG | Cooperation > dialogue |
| Fishburn et al. (2018) | • United States • English | • 60 (57) F = 37 • Strangers | 19.73 | 1.02 | Tangram puzzle | Yes | • 18 spread over triad • Autoregressive model and robust correlation • IFG/MFG | Together active > apart |
| Xue et al. (2018) | • China • Chinese | • 90 (60) F = 43 • Strangers | 20 | 2.13 | Realistic presented problem | Yes | • 46 • WTC • DLPFC and TPJ | More cooperative dyads > less/no cooperative dyads |
| Lu and Hao (2019) | • China • Chinese | • 44 (42) F = 40 • Strangers | 20.66 | 2.29 | Realistic presented problem | Yes | • 22 • WTC • DLPFC | Real participants > confederate |
| Lu et al. (2019a) | • China • Chinese | • 118 F = 102 • Strangers | 20.72 | 2.47 | Realistic presented problem | Yes | • 22 • WTC • FPC and DLPFC | Positive and negative feedback > control |
| Lu et al. (2019b) | • China • Chinese | • 104 (102) F = 64 • Strangers | 21 | 1.52 | Creativity task | Yes | • 46 • WTC • DLPFC and TPJ | Cooperation > competition |
| Duan et al. (2020) | • China • Chinese | • 84 F-M dyads • Lovers = 20 Strangers = 22 | 20.3 | 0.84 | Realistic presented problem | Yes | • 19 • WTC • FPC, TPJ | Lovers (cooperative) > strangers (no cooperative) |
| Sun et al. (2020) | • China • Chinese | • 68 • 16 novice teachers (M = 3) • 18 expert teachers (M = 4) • 34 students (M = 7) • Same sex dyads • Strangers | NT (25.81) ET (38.00) S (20.15) | NT (4.69) ET (4.30) S (1.67) | Math task | No | • 22 • WTC • DLPFC | Cooperative > independent |
| Y. Li et al. (2021) | • China • Chinese | • 90 (86) F = 45 M-M = 13 M- F = 15 F-F = 15. • Strangers | 21.14 | 2.01 | Jenga game | No | • 22 • WTC • IFG/MFG | Cooperation > competition |
| Dai et al. (2018) | • China • Chinese | • 84 • Same sex dyads • Strangers | 22.77 | 2.19 | Joint tapping task | No | • 22 • Correlation • IFG/MFG | Biderection > unidirectional |
| Osaka et al. (2015) | • Japan • Japanese | • Singing 30 M-M = 8 F-F = 7 • Humming 28 M-M = 9 F-F = 5 • Stranger | S (22) H (21) | Missing | Singing | No | • 22 • WTC • IFG/MFG • Parietal cortex • MTG • IT | Cooperative > alone |
| Li et al. (2020) | • China • Chinese | • 48 • Familiar | 19.8 | 1.65 | Joint drawing task | No | • 22 • WTC • DLPFC | Cooperative > alone |
| Cui et al. (2012) | • United States • English | • 22 F = 12 M-M = 1 M-F = 8 F-F = 2 | 26 | 6 | Joint tap | No | • 22 • WTC • SFG | Cooperation > competition |
↵#Figures in parentheses = sample size after removing unused data; relationship = participants either known or unknown to each other; F = female; M = male; PFC = prefrontal cortex; MFG = middle frontal gyrus; IFG = inferior frontal gyrus; FPC = frontopolar cortex; DLPFC = dorsolateral PFC; SFG = superior frontal gyrus; TPJ = temporoparietal junction; MTG = middle temporal gyrus; IT = inferior temporal cortex; WTC = wavelet transform coherence.