Binary competitive behavior analyses. (A-F) The order of predominance of the four tested behaviors. Chemotaxis vs Phototaxis (A), Chemotaxis vs Thermotaxis (B), Chemotaxis vs Thigmotaxis/kinesis (C), Phototaxis vs Thermotaxis (D), Phototaxis vs Thigmotaxis/kinesis (E), and Thermotaxis vs Thigmotaxis/kinesis (F). n = 20; t = 300 sec. (G) Under the conditions of this study, planarians gave first priority to chemotaxis, and lowest priority to thigmotaxis/kinesis.