Final answer:
In a variable ratio reinforcement schedule, the number signifies the number of responses required before reinforcement is given. This schedule is unpredictable, which leads to high response rates and is highly resistant to extinction.
Step-by-step explanation:
When using variable ratio reinforcement, the number in the notation represents the number of responses required for reinforcement. In a variable ratio reinforcement schedule, reinforcement is delivered after an unpredictable number of responses, making it highly effective and resistant to extinction.
For example, slot machines reward gamblers with money following a variable ratio reinforcement schedule. The reinforcement in this case (winning money) is delivered after a variable number of responses (e.g., the gambler's plays), which makes it unpredictable and maintains a high and steady rate of gambling behavior.
Another example of a variable ratio schedule is how a salesperson might earn a commission: the commission comes after an unpredictable number of sales, rather than a set number. Variable ratio schedules are known to produce a high level of response with very little pause following reinforcement, in contrast to fixed ratio schedules, which can lead to a pause right after the reinforcement is delivered.