Table 2.
Estimate and standard error (s.e.) of fixed effects in mixed models predicting participants’ partner choices, Prisoner’s Dilemma Game behaviour and beliefs about partner behaviour.
| Partner choice | Prisoner’s Dilemma Game behaviour | Beliefs about partner behaviour | ||||||
|---|---|---|---|---|---|---|---|---|
| Null | Full | Null | Full | Reduced | Null | Full | Reduced | |
| Intercept | −2.39 (0.25)*** | −3.26 (0.55)*** | −2.26 (0.18)*** | −2.86 (0.43)*** | −2.72 (0.34)*** | −0.94 (0.13)*** | −1.06 (0.33)** | −1.11 (0.28)*** |
| Age group: 8 & 9 | 1.70 (0.66)** | 0.44 (0.57) | 0.49 (0.29) | −0.62 (0.48) | −0.47 (0.26) | |||
| Condition: Disadvantageous | 0.82 (0.68) | 0.41 (0.56) | −0.01 (0.35) | −0.19 (0.46) | 0.00 (0.31) | |||
| Condition: Equal | 0.60 (0.68) | 0.14 (0.57) | 0.17 (0.35) | 0.28 (0.45) | 0.20 (0.31) | |||
| Gender: Male | 0.47 (0.39) | 0.18 (0.29) | 0.21 (0.29) | 0.07 (0.26) | 0.06 (0.26) | |||
| Age group x Condition: 8 & 9 x Disadvantageous | −2.22 (0.94)* | −0.27 (0.78) | 0.36 (0.67) | |||||
| Age group x Condition: 8 & 9 x Equal | −1.57 (0.94) | 0.31 (0.78) | −0.12 (0.67) | |||||
| Partner choice: Rejector | 1.21 (0.73) | 0.35 (0.26) | −1.01 (0.65) | −0.23 (0.23) | ||||
| Age group x Partner choice: 8 & 9 x Rejector | −0.43 (0.91) | 1.14 (0.81) | ||||||
| Condition x Partner choice: Disadvantageous x Rejector | −2.51 (1.17)* | 1.17 (0.88) | ||||||
| Condition x Partner choice: Equal x Rejector | −0.32 (1.01) | 0.46 (0.88) | ||||||
| Age group x Condition x Partner choice: 8 & 9 x Disadvantageous x Rejector | 2.10 (1.44) | −1.70 (1.19) | ||||||
| Age group x Condition x Partner choice: 8 & 9 x Equal x Rejector | −0.59 (1.30) | −0.61 (1.14) | ||||||
| Prisoner’s Dilemma Game decision: Cooperate | 2.15 (0.25)*** | 2.12 (0.25)*** | ||||||
| AIC | 820.28 | 822.73 | 777.24 | 788.21 | 781.39 | 1184.90 | 1122.31 | 1111.53 |
| BIC | 830.10 | 862.00 | 787.05 | 856.88 | 815.72 | 1194.71 | 1195.88 | 1150.77 |
| Log Likelihood | −408.14 | −403.37 | −386.62 | −380.11 | −383.69 | −590.45 | −546.15 | −547.77 |
| Number of trials | 1001 | 1001 | 997 | 997 | 997 | 997 | 997 | 997 |
| Number of participants | 143 | 143 | 143 | 143 | 143 | 143 | 143 | 143 |
| Variance: Participant ID (Intercept) | 3.57 | 3.12 | 1.36 | 1.38 | 1.25 | 1.33 | 1.37 | 1.35 |
In these models, age group was fit as a categorical predictor. Baselines for factors were: age group = 6- and 7-year-olds, condition = advantageous, gender = female, partner choice = acceptor, Prisoner’s Dilemma Game decision = defect. Table also shows goodness-of-fit statistics.
***p < 0.001, **p < 0.01, *p < 0.05.