BA410 Unit 5 Operant Conditioning Paper Example

Shaping a Lever Press, Finding Land Mines and Hiding From a Noise: A BA410 Unit 5 Operant Conditioning Paper

[Student Name]

Purdue University Global

BA410: Introduction to Experimental Analysis of Behavior

Unit 5 Operant Conditioning Paper

[Instructor Name]

[Date]

The writer, the lab and its animals are composite; the studies and books cited are real.

Shaping in the Chamber

This spring I watched training in the lab where I care for twelve rats several mornings a week. In February I watched a graduate student carefully shape a new rat to press a lever, a process that took one afternoon. The rat had already learned through magazine training that a click from the pellet dispenser meant food was coming. The student began by delivering the click and a pellet whenever the rat turned toward the lever. Once the rat was oriented toward the lever often, she required a step closer, then a paw raised near it, then a touch, then a press. Each step reinforced a closer approximation to the final response and stopped reinforcing earlier ones. By the end of the hour, the rat was pressing steadily, and the cumulative record on the computer screen showed a line climbing at a steady angle where an hour earlier it had been flat.

Skinner (1953) described this process as shaping by successive approximation, and it illustrates the core of operant conditioning: behavior that produces reinforcing consequences becomes more frequent, and by changing which variations are reinforced, a trainer can build a response the animal has never made.

Rats in a Minefield

The same principle has been used far from any laboratory. Poling et al. (2011) described a program in which African giant pouched rats were trained to detect land mines by smell. The rats were first taught, using a click paired with food, to associate the scent of explosives with reinforcement, then trained to indicate the scent by scratching at the ground. Their training progressed from controlled cages to test fields with known mine locations and finally to real minefields, where their indications guided human deminers. The authors reported that the rats searched ground quickly and accurately enough to contribute substantially to clearing land in Mozambique, and they called the work another victory for operant conditioning.

A pouched rat scratching at a buried mine is pressing a lever in a much larger chamber, with lives depending on the response.

The parallels with my lab are surprisingly close. A click becomes a conditioned reinforcer through pairing with food. Shaping builds a specific response. Stimulus control brings that response under the control of a particular stimulus, the scent of explosives. And data on every trial show whether the training works, and rats that do not meet accuracy standards in test fields are not sent to real minefields.

Avoidance Without Awareness

Operant conditioning also includes behavior that is maintained by the removal or prevention of aversive events. Hefferline et al. (1959) recorded tiny muscle movements in human participants' thumbs while they listened to music overlaid with an unpleasant noise. When a very small thumb twitch, too small for participants to notice, occurred, the noise stopped or was postponed. Over time, participants made the twitch more often, effectively escaping and avoiding the noise, though most were not aware of making any response at all.

The study shows that negative reinforcement can shape behavior even when people do not know what they are doing or why. That has practical implications: a person may develop avoidance habits, such as leaving a room before a conversation becomes uncomfortable, without being able to explain them.

When Positive Reinforcement Has Costs

It is easy to treat positive reinforcement as the gentle side of behavior analysis. Perone (2003) challenged that view, arguing that positive reinforcement can have negative effects. Arrangements that deliver positive reinforcers can also contain aversive features: the reinforcer may be withheld, the schedule may be lean, or the situation may include demands that the person would escape if they could. Perone noted that organisms will sometimes work to escape from schedules of positive reinforcement, and that reinforcement can be used to maintain behaviors that are harmful in the long run, as in gambling or overeating.

The lab shows some of these effects. Food-restricted rats work hard for pellets, but when a schedule becomes very lean, some rats spend long periods away from the lever, and in some studies rats will press a second lever that pauses the session. A pellet is a positive reinforcer, but a session built around scarce pellets has aversive features too, which the lab's protocol limits by capping session length and stopping any session in which a rat stops responding for an extended period.

Shaping Outside the Lab

After watching the rat shaped, I tried the same procedure with my dog, Juniper, who had never learned to ring a bell hung on the back door to go outside. I paired a clicker with small treats until she turned toward the click, then clicked and treated any look at the bell, then a step toward it, then a nose touch, then a touch hard enough to make it ring. The first sessions were frustrating because I clicked too late, after she had already moved on, and she learned nothing in particular. Watching the graduate student's timing again, I saw that the click had to come at the exact moment of the response. Within a week, Juniper was ringing the bell to go out, and within two weeks she was ringing it to come back in from the cold too, a reminder that shaping produces whatever the contingencies select, not only what the trainer intends.

What the Examples Share

The three examples, a lever press, a mine detection and a thumb twitch, share a structure. Each involves a response, a consequence and a change in the response's frequency as a result. The differences matter too: the rat in my lab and the mine-detection rats were shaped deliberately, while Hefferline's participants were conditioned without knowing it. The comparison makes clear that operant conditioning is a process that happens whether or not anyone plans it, which is why understanding it matters for people who design environments for others.

Conclusion

Shaping a lever press, training rats to find land mines and conditioning an unnoticed thumb twitch all illustrate the operant principle that consequences select behavior. Skinner's account of shaping, Poling and colleagues' mine-detection program and Hefferline's avoidance study show the principle's power and reach, while Perone's analysis reminds practitioners that even positive reinforcement carries costs that deserve attention.

References

Hefferline, R. F., Keenan, B., & Harford, R. A. (1959). Escape and avoidance conditioning in human subjects without their observation of the response. Science, 130(3385), 1338-1339. https://doi.org/10.1126/science.130.3385.1338

Perone, M. (2003). Negative effects of positive reinforcement. The Behavior Analyst, 26(1), 1-14. https://doi.org/10.1007/BF03392064

Poling, A., Weetjens, B., Cox, C., Beyene, N. W., Bach, H., & Sully, A. (2011). Using trained pouched rats to detect land mines: Another victory for operant conditioning. Journal of Applied Behavior Analysis, 44(2), 351-355. https://doi.org/10.1901/jaba.2011.44-351

Skinner, B. F. (1953). Science and human behavior. Macmillan.