Final answer:
Brittany's efforts as a telemarketer operate under a variable ratio schedule of reinforcement, where she receives reinforcement after an unpredictable number of calls.
Step-by-step explanation:
Brittany, the telemarketer trying to sell life insurance, operates under a variable ratio schedule of reinforcement. This particular reinforcement schedule is used because it delivers reinforcement after an unpredictable number of responses, similar to a gambler receiving a payout after an unknown number of lever pulls on a slot machine. Each call Brittany makes is a new opportunity for a sale, but she cannot predict which call will result in a sale. This unpredictability encourages a high and steady rate of responses, as she continues calling in the hopes that the next call will produce a reinforcement - in this case, a sale.