Psychology 2210A/B Lecture Notes - Stimulus Control, Red Color, Noctuidae
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Demonstrating that an organism responds differently to one stimulus than to another is necessary for concluding that behavior is under stimulus control. When a key-light is illuminated with red light pecks to the key are reinforced, but when the key is illuminated with green light pecks are not reinforced. After several training sessions, pigeons will display high rates of pecking when the red stimulus is present and near-zero rates when the green stimulus is presented. Pigeons thus show differential responding responding one way to one stimulus and a different way to a different stimulus. Consider an experiment involving a more complex stimulus. In this experiment, pigeons were reinforced on a vi schedule for pecking a key that was illuminated with a white triangle on a red background. Note that such a stimulus has two prominent elements: red color and a white triangle. (a stimulus with multiple elements is called a compound stimulus in reality, every stimulus is a compound stimulus).