Final answer:
A toddler's generalized fear of speeding cars, trucks, and motorcycles is an example of stimulus generalization, which occurs when similar stimuli elicit the same conditioned response.
Step-by-step explanation:
When toddlers are taught to fear speeding cars begin to also fear speeding trucks and motorcycles, this illustrates stimulus generalization. Stimulus generalization occurs when a conditioned response to one stimulus is elicited by similar, yet distinct, stimuli. This is seen in classical conditioning, a learning process identified by Ivan Pavlov and later researchers like John Watson and Rosalie Rayner. In their famous experiment, Little Albert was conditioned to fear a white rat, and subsequently, began to fear other white, furry objects. This ability to generalize helps organisms adapt to their environment by enabling them to respond to new situations that resemble past experiences.
In the context of our question, the initial fear of speeding cars as a conditioned response has generalized to include similar stimuli, like trucks and motorcycles, indicating that the child perceives these as similar threats. A concept closely related to this is stimulus discrimination, where an organism learns to distinguish between different stimuli and responds only to certain stimuli. Stimulus generalization and discrimination are important aspects of the learning process, which also includes concepts like acquisition, extinction, spontaneous recovery, and shaping.