Ants carry dead ants out of an anthill and dump them on a "trash" pile. If a chemical from a dead ant is applied to a live ant, other ants will carry it, kicking and struggling, from the anthill, until the substance wears off. Which of the following explains this behavior?

• A. The ants have become imprinted on the chemical.
• B. The ants are following a stimulus-response chain.
• C. The ants can only learn by operant conditioning.
• D. The ants are responding to a circadian clock.
• E. The chemical is a sign stimulus for a fixed action pattern.

Answer: (E)

Verified step by step guidance

1. Begin by understanding the concept of a fixed action pattern (FAP). A fixed action pattern is a sequence of unlearned, innate behaviors that is triggered by a specific stimulus. Once initiated, the sequence is carried out to completion, regardless of changes in the environment.
2. Identify the stimulus in this scenario. The chemical from the dead ant acts as a sign stimulus, which is a specific external trigger that initiates the fixed action pattern in the ants.
3. Consider the behavior of the ants. When the chemical is applied to a live ant, other ants respond by carrying it out of the anthill. This behavior is consistent and predictable, indicating it is an innate response rather than a learned behavior.
4. Differentiate this behavior from other types of learning or responses. Imprinting, operant conditioning, and circadian rhythms involve learning or time-based responses, which do not apply to the innate and immediate reaction seen in the ants.
5. Conclude that the ants' behavior is best explained by the chemical acting as a sign stimulus for a fixed action pattern, as it triggers an innate and automatic response in the ants.