Effect of the four conditions on eye wrinkle expression.

The effect of the four conditions (Grooming (G), Food anticipation (FA), Food competition (FC), Plastic bag (PB)) on the six outcome measures is shown with respect to phase (Control (C), Treatment (T)). (a, b) ‘angle’, ‘number’: boxplots with median (black line), interquartile range (box), 1.5 x interquartile range (whiskers). (c) ‘eye white’: bar chart±binomial confidence interval. (d, e, f) ‘qualitative assessment’, ‘eyelid shape’, ‘markedness’: stacked bar charts with the three colours representing the three different scores. (d) ‘qualitative assessment’: ‘no wrinkle’ (black), ‘weak’ (dark grey), ‘strong’ (light grey). (e) ‘eyelid shape’: ‘round’ (black), ‘weakly pulled’ (dark grey), ‘strongly pulled’ (light grey). (f) ‘markedness’: ‘no wrinkle’ (black), ‘weak’ (dark grey), ‘strong’ (light grey).