Table 1.
Models explaining variation in judgement bias among young female domestic fowl. Judgement bias was measured as individual change in latency to approach colour cues between two judgement bias tests (for more details, see main text). Models are ranked according to their AICc value and weight (ω), where lower AICc values and ω weight imply a better goodness of fit. Models shown are within ΔAICc <2. For comparison, ‘Null’ models are shown despite having ΔAICc >2. Estimates for all supported variables are given. In cases where several variables are included in a model, variables are presented in the same order as they are presented in the ‘Model column’, separated by a straight line. Estimates (mean ± SE) for categorical explanatory variables are given in the results section.
| Model | Rank | Estimate | AICc | ΔAICc | ω |
|---|---|---|---|---|---|
| Individual change in latency to colour cues | |||||
| (i) Influence of cold stress, environmental complexity, and norepinephrine | |||||
| EC | 1 | + | 2173.30 | 0.00 | 0.37 |
| EC | Tel_NE | 2 | +| 0.01 | 2174.80 | 1.50 | 0.18 |
| EC | Ot_NE | 3 | +| 0.00 | 2174.90 | 1.62 | 0.17 |
| EC | Cue | 4 | +| −0.63 | 2175.10 | 1.84 | 0.15 |
| EC | Mes_NE | 5 | +| 0.00 | 2175.20 | 1.95 | 0.14 |
| Null | 24 | 2178.10 | 4.79 | 0.01 | |
| (ii) Influence of cold stress, environmental complexity, and dopamine | |||||
| EC | 1 | + | 2173.30 | 0.00 | 0.44 |
| EC | Ht_DA | 2 | +| −0.08 | 2174.60 | 1.32 | 0.23 |
| EC | Cue | 3 | +| −0.63 | 2175.10 | 1.84 | 0.17 |
| EC | Mes_DA | 4 | +| −0.11 | 2175.20 | 1.93 | 0.17 |
| Null | 24 | 2178.10 | 4.79 | 0.00 | |
| (iii) Influence of cold stress, environmental complexity, and serotonin | |||||
| EC | 1 | + | 2173.30 | 0.00 | 0.45 |
| EC | Ht_5-HT | 2 | +| 0.00 | 2174.90 | 1.66 | 0.20 |
| EC | Cue | 3 | +| −0.63 | 2175.10 | 1.84 | 0.18 |
| EC | Tel_5-HT | 4 | +| 0.00 | 2175.20 | 1.93 | 0.17 |
| Null | 24 | 2178.10 | 4.79 | 0.00 | |
| (iv) Influence of cold stress, environmental complexity, and dopamine turnover rate | |||||
| EC | Mes_DOPAC/DA | 1 | +| 5.85 | 2171.80 | 0.00 | 0.36 |
| EC | Mes_DOPAC/DA | Ot_DOPAC/DA | 2 | +| 6.65 | −0.35 | 2173.10 | 1.31 | 0.19 |
| EC | 3 | + | 2173.30 | 1.50 | 0.17 |
| EC | Mes_DOPAC/DA | Cue | 4 | +| 5.85 | −0.63 | 2173.60 | 1.86 | 0.14 |
| EC | Mes_DOPAC/DA | Ht_DOPAC/DA | 5 | +| 5.97 | −0.41 | 2173.70 | 1.89 | 0.14 |
| Null | 50 | 2178.10 | 6.29 | 0.00 | |
| (v) Influence of cold stress, environmental complexity, and serotonin turnover rate | |||||
| EC | 1 | + | 2173.30 | 0.00 | 0.36 |
| EC, Tel_5-HIAA/5-HT | 2 | +| −71.51 | 2174.70 | 1.41 | 0.18 |
| EC, HT_5-HIAA/5-HT | 3 | +| −7.55 | 2174.70 | 1.42 | 0.18 |
| EC, Cue | 4 | +| −0.63 | 2175.10 | 1.84 | 0.14 |
| EC, Mes_5-HIAA/5-HT | 5 | +|−13.79 | 2175.10 | 1.88 | 0.14 |
| Null | 24 | 2178.10 | 4.79 | 0.00 | |
CS – Cold stress, EC – Environmental complexity, Cue – Colour cues, NE – Norepinephrine, DA – Dopamine, 5-HT – Serotonin, DOPAC/DA – Dopamine turnover rate, 5-HIAA/5-HT – Serotonin turnover rate, Ht – Hypothalamus/thalamus, Tel – Telencephalon, Mes – Mesencephalon, Ot – Optic tectum.