How can learning theory help to explain why diet drinks are ineffective in helping people lose weight?

A) Sugar acts as a positive reinforcer, but artificial sweeteners act as a negative reinforcer.
B) Stimulus discrimination allows the body to tell the difference between real sugar and artificial sweeteners.
C) Extinction occurs when artificial sweeteners are introduced, but spontaneous recovery leads to a return of overeating.
D) People normally learn that sweet tastes (CS) predict calories (US), but artificial sweeteners weaken this association.

Answer: D
Rationale: Sweet tastes send a message to the body that a high dose of calories is on the way. For example, the taste of a candy bar is a conditioned stimulus (CS) that tells the body that a large amount of calories (the US) is soon to arrive in the gut. This relationship is an important one for the body to learn, as it helps maintain an energy balance—eventually your body tells you it is time to stop eating sweets and switch to something else, perhaps with fewer calories. Artificially sweetened beverages disrupt this relationship between the sugary sweet CS and high-calorie food US.