Final answer:
The phenomenon where toddlers conditioned to fear moving cars also fear similar stimuli like trucks and motorcycles is known as stimulus generalization. It refers to the extension of a conditioned response to stimuli that resemble the original conditioned stimulus. ( Option B).
Step-by-step explanation:
When toddlers are conditioned to fear moving cars, and this fear then extends to moving trucks and motorcycles, this best illustrates the process of stimulus generalization. This is a learning process wherein the conditioned response is elicited by stimuli that are similar to, but not identical to, the conditioned stimulus that was originally associated with the unconditioned stimulus.
For example, in classical conditioning experiments like those conducted by Watson and Rayner with Little Albert, the child was conditioned to fear a white rat, and then he began to demonstrate fear in response to other furry white objects. This indicates that the conditioning has generalized from the specific stimulus (a white rat) to encompass a broader range of stimuli (other furry white objects).
An alternative to this is stimulus discrimination, where an organism learns to respond differently to various stimuli that are similar but not the same, such as distinguishing the sound of a can opener which signals food, from the sound of an electric mixer which does not. This contrast showcases how stimulus generalization and stimulus discrimination are considered opposites. (Option B).