Hit rate and reaction times at different picture locations.

To analyze biases toward selecting a P at any angle from the center of the touchscreen, we performed a one-way ANOVA, False Discovery Rate corrected for multiple pairwise comparisons. Monkey M showed no location bias (p-values > 0.034). Monkey G, however, exhibited a significant effect for the monkey face position (F [15, 160.67] = 1.97; p = 0.014) and the cow face (F [15, 150.619] = 2.51; p = 0.001), but not for the human (p = 0.988). Post-hoc analysis (Tukey’s HSD) revealed these differences occurred in angles < 90° within each screen quadrant. In other words, while there were biases in selecting pictures at angles, there was no consistent preference for a specific quadrant. Based on these findings, the behavioral results presented here correspond to subsequent experiments presenting pictures only in four quadrants. (PDF)