Question

Male stickleback fish develop red colour on their ventral side in the breeding season and maintain territories. When a conspecific male intruder enters their territory, resident males perform an aggressive display. The ethologist Niko Tinbergen presented models of different shapes to territorial male stickleback fish. He found that models of any shape elicited aggressive displays, provided the ventral part of the models was coloured red. This observation led to the development of which one of the following concepts?

• A. Supernormal stimuli
• B. Sign stimuli
• C. Gestalt stimuli
• D. Internal stimuli

Hint:

Supernormal stimuli are exaggerated cues that elicit stronger reactions than natural ones, while sign stimuli are natural cues that trigger specific behavioral responses.

Answer 1

The Correct Option is B

Step 1: Understanding Niko Tinbergen's work.
Niko Tinbergen's experiments with stickleback fish led to the development of the concepts of sign stimuli and supernormal stimuli. In his study, he found that male sticklebacks would respond aggressively to models of any shape, as long as the ventral part of the model was coloured red, a feature that served as a "sign stimulus" for aggression.

Step 2: Explanation of each concept.
(A) Supernormal stimuli are exaggerated versions of natural stimuli that elicit stronger responses than the natural stimuli themselves. Tinbergen's models could be considered supernormal stimuli because they elicited exaggerated aggressive responses. (B) Sign stimuli are cues or triggers in the environment that evoke a fixed action pattern, like the red ventral coloration in the stickleback fish. (C) Gestalt stimuli refer to perceptual phenomena, often unrelated to animal behavior and learning. (D) Internal stimuli refer to stimuli originating inside the organism, not external environmental triggers like the red color in the models.

Step 3: Conclusion.
The correct answers are (B) Sign stimuli and (A) Supernormal stimuli, as these concepts best describe the response elicited by the red coloration in the models.