| Introduction |
| So far you've learned about ratio schedules,
where reinforcer presentations are dependent on the number of responses emitted.
Another common type of schedule is an interval schedule. Interval
schedules (as well as ratio schedules) come in two flavors: fixed and
variable. In the case of fixed interval (FI) schedules, reinforcer
presentations are produced by the first response following a fixed amount
of time has elapsed. For example, in an FI-30 s schedule, reinforcers
are delivered following the first response after 30 seconds has elapsed.
Note that an important difference between FI and FR schedules is that
in order to meet the reinforcer requirement for FI, two criteria must be
met: a fixed amount of time needs to have elapsed and a response needs
to be emitted. The purpose of this assignment is very similar to assignment four: to train Sniffy to eventually respond on an FI-60 s schedule of reinforcement. I will only provide a brief set of instructions. If you need any additional help, please feel free to email me or come by my office. |
| Instructions |
| 1. Start Sniffy Lite. 2. Close the "Operant Associations" window. 3. Open the data file you created from assignment two (the one where you've got him responding pretty consistently on an FR-1 schedule). 4. Change the schedule of reinforcement from FR-1 or CRF to FI-60. Note: Sniffy's user interface is a little weird when it comes to telling it to use interval schedules. In order to go to FI-60, go to "Design Operant Experiment", click on "Fixed", enter in "60", click on "Seconds", and finally click "Ok." Sniffy will probably soon stop responding just like it did for Assignments 3 and 4. When he stops or when you've demonstrated that he doesn't stop at FI-60 (by running it out for a while, i.e., 4 intervals) go on to the next step. 5. Change the schedule of reinforcement back to FR-1. Stay here until responding returns and stabilizes. 6. Gradually increase the ratio requirement from FR-1 to FI-60. You can use as many or as few steps as you want (I recommend at least 3) but Sniffy should eventually be responding on an FI-60 s schedule and each step should be a fixed interval (not variable or ratio based). Remain at each step until responding stabilizes. When you get to FI-60, stay there until the data stabilize. 7. Save your data file!!! Make sure you name it something different (e.g., "assign5"). |
| Assessment |
| Print out your entire cumulative record.
You may have noticed that running Sniffy for a long time takes up
several cumulative record windows. If you click on "Window" at the
top of the screen, you'll see them all listed. You'll have to print
them out each individually by clicking on each one and then clicking on
"File" -> "Print Window." Staple your cumulative records together
and write your name on the top. Your grade will be determined by the degree to which your cumulative record maps on to the instructions above. Specifically, I'll be looking to see if you've met the criteria that were underlined. By stable, you should remain at that point for at least 4 intervals. Also, please write the assignment number by your name. |