Which of the following is an example of MASS TRIALS?

• A. A teacher presents a worksheet to a student with 100 problems on it and says 'You have 5 minutes. Do your best!'
• B. A scientist mass produces hundreds of samples of a new chemical during a clinical trial
• C. A teacher runs through dozens of multiplication drills with their students
• D. A therapist presents the same SD repeatedly to a student, prompting the same specific behavior trial after trial until 5 prompted correct consecutive trials occur.

Answer: (D)

Mass trials involve delivering a large number of identical practice opportunities in rapid succession, using the same antecedent and prompt, with immediate reinforcement to build fluency. In the described scenario, the therapist repeatedly presents the same discriminative stimulus and uses the same prompting method across many trials, continuing until a streak of correct responses occurs. This setup—high-frequency, uniform trials aimed at rapid, accurate responding—perfectly matches the mass trial approach.

The other scenarios don’t fit this pattern. A worksheet with a time limit is a timed task, not a rapid, repeated practice of the same prompt with consistent reinforcement. Producing many chemical samples is unrelated to instructional trial structure. Running dozens of multiplication drills may involve repetition, but it isn’t described as a rapid, uniform sequence of the same SD with prompts and reinforcement across many trials to build fluency, which is central to mass trials.