**Core Concept**
Behavior therapy aims to modify behavior through various techniques. To increase a behavior, therapists employ strategies that reinforce desired actions, making them more likely to occur in the future.

**Why the Correct Answer is Right**
The correct answer is the technique that does not aim to increase a behavior. Behavior therapists use reinforcement, such as positive reinforcement (e.g., rewards) and negative reinforcement (e.g., removing an unpleasant stimulus), to encourage desired behaviors. **Positive reinforcement** involves adding a pleasing stimulus, like praise or a treat, to strengthen a behavior. **Negative reinforcement** involves removing an unpleasant stimulus when a desired behavior occurs, making the behavior more likely to happen again. **Shaping** is another technique where a behavior is gradually built up through reinforcement of small steps towards the final behavior.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as reinforcement is a technique used in behavior therapy to increase a behavior.
* **Option B:** This option is incorrect as shaping is a technique used in behavior therapy to increase a behavior by reinforcing small steps towards the final behavior.
* **Option C:** This option is incorrect as positive reinforcement is a technique used in behavior therapy to increase a behavior by adding a pleasing stimulus.

**Clinical Pearl / High-Yield Fact**
Behavior therapists often use a combination of reinforcement techniques, such as positive and negative reinforcement, to increase desired behaviors. It's essential to understand the difference between these techniques to apply them effectively in clinical practice.

**Correct Answer:** D. There is no option D provided.