Which term describes a stimulus change that increases the frequency of any behavior that precedes it, often a primary reinforcer?

• A. UNCONDITIONED STIMULUS
• B. UNCONDITIONED REINFORCER
• C. CONDITIONED REINFORCER
• D. CONDITIONED STIMULUS

Answer: (B)

Reinforcement is any stimulus change that increases the likelihood that the behavior that produced it will occur again. When that reinforcing change is something the organism naturally values because of biology—like food, water, or warmth—it’s called an unconditioned reinforcer (a primary reinforcer). Its effect is built in, so it doesn’t require prior learning to be rewarding; presenting it after a behavior makes that behavior more likely to happen again in the future. This fits the description because the stimulus change boosts the frequency of the preceding behavior and is often a primary reinforcer. By contrast, an unconditioned stimulus is something that naturally elicits a reflex, a conditioned reinforcer is something learned to be rewarding through association (like praise or money), and a conditioned stimulus is a cue that has gained power to signal reinforcement through learning.