TABLE 1

Specifications of statistical models derived from general linear mixed model analysisa

Term for included response variableEstimateSELower CLbUpper CLbχ2DFP
Hunting monkeyc
    Intercept−6.2991.014−9.177−4.773
    Sex: male4.8381.0163.3057.71740.0951<0.001
    Aged0.0640.145−0.2570.4370.19510.659
    Country: DRC0.7060.3150.0231.4934.05110.044
Dismembering monkeye
    Intercept−2.4280.236−2.966−2.000
    Sex: male2.2220.2831.6062.794
    Aged0.1700.201−0.2380.595
    Country: DRC0.6430.330−0.0861.3803.12010.077
    Sex and age−0.6630.218−1.094−0.2339.03110.003
Preparing monkeyf
    Intercept0.3950.228−0.0700.905
    Sex: male−1.8490.249−2.450−1.347
    Aged0.2930.196−0.1350.682
    Country: DRC2.4450.5041.4373.53314.5411<0.001
    Sex and age−0.7660.233−1.228−0.31010.82110.001
Eating monkeyg
    Intercept0.4650.244−0.0511.010
    Sex: male0.6680.2190.2411.122
    Aged0.4260.1630.0950.769
    Country: DRC2.9860.5521.9104.24416.9671<0.001
    Sex and age−0.9030.223−1.345−0.46716.4701<0.001
Hunting great apeh
    Intercept−6.0451.024−8.933−4.498
    Sex: male2.7891.0481.1315.69711.24310.001
    Aged0.2920.266−0.2400.8141.18210.277
    Country: DRC0.1110.588−1.1891.3140.03510.851
Dismembering great apei
    Intercept−4.7160.531−5.946−3.805
    Sex: male2.0890.5551.0993.33515.4511<0.001
    Aged−0.0530.206−0.4740.3590.06610.797
    Country: DRC0.2840.425−0.6461.2510.43810.508
Eating great apej
    Intercept−2.2930.232−2.797−1.841
    Sex: male1.6000.2361.1322.16918.9191<0.001
    Aged−0.1370.114−0.3660.0991.43010.232
    Country: DRC−0.9090.352−2.152−0.1585.26610.022
  • a Participants' sex, age, and country of residence were included as test predictors, and sampling village was included as random effect. The model including preparing great ape as a response variable was not significantly better than the null model comprising only the random effects (likelihood ratio test: χ2 = 7.974; P = 0.093; n = 684) and was therefore not considered further. DF, degrees of freedom; DRC, Democratic Republic of the Congo. Significant results are shown in bold.

  • b Based on a model without the correlation between random slope and intercept.

  • c The full model was highly significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 42.269; DF = 4; P < 0.001; n = 696) but not significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 1.083; DF = 1; P = 0.298). Therefore, results from the reduced model excluding the interaction are reported. It explained 64.11% of the variance (conditional R2). Intercept of random effects: variance = 0.00; SE = 0.00.

  • d Age was z-transformed to a mean of 0 and standard error of 1.

  • e The full model was highly significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 30.899; DF = 4; P < 0.001; n = 702) and significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 9.031; DF = 1; P = 0.003). Therefore, results from the full model including the interaction are reported. It explained 30.24% of the variance (conditional R2). Intercept of random effects: variance = 0.04; SE = 0.20.

  • f The full model was highly significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 47.620; DF = 4; P < 0.001; n = 702) and highly significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 10.821; DF = 1; P = 0.001). Therefore, results from the full model including the interaction are reported. It explained 41.90% of the variance (conditional R2). Intercept of random effects: variance = 0.22; SE = 0.47.

  • g The full model was highly significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 40.332; DF = 4; P < 0.001; n = 716) and highly significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 16.470; DF = 1; P < 0.001). Therefore, results from the full model including the interaction are reported. It explained 41.94% of the variance (conditional R2). Intercept of random effects: variance = 0.29; SE = 0.54.

  • h The full model was significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 14.740; DF = 4; P = 0.005; n = 689), but not significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 1.766; DF = 1; P = 0.184). Therefore, results from the reduced model excluding the interaction are reported. It explained 39.05% of the variance (conditional R2). Intercept of random effects: variance = 0.00; SE = 0.00.

  • i The full model was significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 16.022; DF = 4; P = 0.003; n = 690), but not significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 0.531; DF = 1; P = 0.466). Therefore, results from the reduced model excluding the interaction are reported. It explained 24.48% of the variance (conditional R2). Intercept of random effects: variance = 0.00; SE = 0.00.

  • j The full model was highly significant compared to the null model comprising only the random effects (likelihood ratio test: χ2 = 30.346; DF = 4; P < 0.001; n = 714), but not significant compared to a reduced model excluding the interaction term between sex and age (likelihood ratio test: χ2 = 0.434; DF = 1; P = 0.510). Therefore, results from the reduced model excluding the interaction are reported. It explained 19.42% of the variance (conditional R2). Intercept of random effects: variance = 0.11; SE = 0.33.