Reinforcement Schedule INTERVALS = TIME

Does it Deal with Time?• Fixed Interval (FI) – A reinforcer is delivered for the

first response after a preset time interval has elapsed.– Number of responses tends to increase as the time for the next

reinforcer draws near then long pause occurs after reinforcement.

• Variable Interval (VI) – A reinforcer is delivered for the first response after an average time interval has elapsed. The interval is unpredictable.– Number of responses will be moderately steady because

reinforcement could occur at any time.

Reinforcement Schedule

RATIOS = RESPONSES• Fixed Ratio (FR) – Reinforcement occurs after a fixed number of responses. Every fifth time.– Results in a burst-pause-burst-pause pattern

• Variable Ratio (VR) – Reinforcement occurs after an average number of responses. Number of responses required for reinforcement is unpredictable. 1st , 3rd, 5th, 2nd time.– Results in high, steady rates of responding with

almost no pauses

Example 1

A business that advertises that it will change your oil in 20 minutes offers you a free oil change after you have had your oil changed 5 times at their business.

Example 1 ANSWER

• FIXED RATIO (FR)

Example 4

A bank employee is given a bonus of a $30 restaurant coupon for every 4 hours of overtime he volunteers to work.

Example 4 ANSWER

• FIXED INTERVAL (FI)

Example 5

A young child demands a candy bar each time she is in the checkout line at the grocery store. Sometimes the parent gives her one and sometime he doesn’t.

Example 5 ANSWER

• VARIABLE RATIO (VR)

Example 6

A piano teacher gives a 6-year-old student a sticker for each song he plays well.

Example 6 ANSWER

• FIXED RATIO (FR)

Example 8

You do piece work in a factory. For every 2 sleeves you sew on garments, you get $0.50.

Example 8 ANSWER

• FIXED RATIO (FR)

Example 9

For each half day that a second grader pays attention and works well, the teacher gives her a “Good Behavior” dollar that she can trade in at the end of the week for desired objects from the store.

Example 9 ANSWER

• FIXED INTERVAL (FI)

Example 10

A vacuum cleaner salesperson does numerous presentations in people’s homes and gets paid a bonus each time he or she sells a vacuum. Sometimes the salesperson does 5 presentations before a customer buys a vacuum, sometimes 2 customers in a row purchase the product.

Example 10 ANSWER

• VARIABLE RATIO (VR)

Example 11

Your paycheck arrives on the 1st and the 15th of every month.

Example 11 ANSWER

• FIXED INTERVAL (FI)

Example 12

Buying state lottery tickets & winning.

Example 12 ANSWER

• Variable Ratio (VR)

Example 13

A hotel maid may take a 15-minute break only after having cleaned three rooms.

Example 13 ANSWER

• Fixed Ratio (FR)

Example 14

Watching and seeing shooting stars on a dark night.

Example 14 ANSWER

• Variable Interval (VI)

Example 15

A teenager receives an allowance every Saturday.

Example 15 ANSWER

• Fixed Interval (FI)

Example 16

Checking the front porch for a newspaper when the delivery person is extremely unpredictable.

Example 16 ANSWER

• Variable Interval (VI)

Example 17

A professional baseball player gets a hit approximately every third time at bat.

Example 17 ANSWER

• Variable Ratio (VR)

Example 18

Checking the oven to see if chocolate chip cookies are done, when the baking time is known.

Example 18 ANSWER

• Fixed Interval (FI)

Example 19

A blueberry picker receives $1 after filling 3 pint boxes.

Example 19 ANSWER

• Fixed Ratio (FR)

Example 20

A charitable organization makes an average of ten phone calls for every donation it receives.

Example 20 ANSWER

• Variable Ratio (VR)

Example 21

Calling a garage mechanic to see if your car is fixed yet.

Example 21 ANSWER

• Variable Interval (VI)

Example 22

A student’s final grade improves one level for every three book reviews submitted.

Example 22 ANSWER

• Fixed Ratio (FR)

Example 23

Going to the cafeteria to see if the next meal is available.

Example 23 ANSWER

• Fixed Interval (FI)