Table 3.
Performance of alternative models for the evolution of skull length.
| BM | OU.2 | OU.3 | OU.4 | OU.5 | |
|---|---|---|---|---|---|
| AICc | 307.59 | 309.30 | 311.75 | 311.86 | 298.11 |
| Δ(AICc) | 9.48 | 11.19 | 13.64 | 13.74 | 0 |
| w(AICc) | 0.0086 | 0.0037 | 0.0011 | 0.0010 | 0.9856 |
| SIC | 311.11 | 315.96 | 319.82 | 321.21 | 308.62 |
| Δ(SIC) | 2.49 | 7.33 | 11.19 | 12.58 | 0 |
| w(SIC) | 0.2184 | 0.0194 | 0.0028 | 0.0014 | 0.7580 |
| DOF | 2 | 4 | 5 | 6 | 7 |
Model names defined as follows: BM - Brownian motion, OU - Ornstein-Uhlenbeck with two (OU.2), three (OU.3), four (OU.4), and five (OU.5) adaptive optima (see text and Fig. 7 for details). AICc is the corrected Akaike Information Criterion for small sample sizes, Δ(AICc) is the difference relative to the model with smaller AICc, w(AICc) is the Akaike weight for each model. SIC is the Schwartz Information Criterion, Δ(SIC) and w(SIC) are the differences and weights as defined above. DOF are the numbers of parameters estimated by each model.