Friday, June 12, 2015

Extinction Burst: Throwing Tantrums When There Are No More Free Handouts

Extinction and extinction burst graph from
In psychology, an "extinction" is the gradual decrease of a behavior. When an animal is operantly conditioned (for example, given a food reward to reinforce behavior), reinforced behavior will gradually decrease when that behavior is no longer reinforced with a reward. At the onset of "extinction", an animal will exhibit something call "extinction burst". An extinction burst is when an animal frantically and erratically exhibit reinforced behavior with increased frequency and eventually that behavior decreases and becomes "extinct". I assume it's called "extinction burst" due to a burst of reinforced behavior prior to extinction. Extinction burst is evolutionarily beneficial as animals that exhibit extinction burst is increasing the reinforced behavior for a positive outcome as opposed to those that gives up (extinction without extinction burst). These are important concepts to remember when you train animals. But obviously, these are text book definitions.

Textbook definitions be like ...
I'm writing about this because I am currently experiencing extinction burst with my lemurs. It has been about 4 weeks since I have started training them. Aside from my one star student (Good job, Halley!) all my other lemurs are either starting to associate touching the screen or approaching the apparatus for a food reward. Those that are reinforced to touch the screen for a food reward are currently being shaped (refining their behavior) to touch the red square on the screen for a food reward. However, this requires the lemur to understand that by merely touching the screen will no longer be reinforced and that only touching the red square will a food reward be given.

This new development in cognitive test has given these lemurs much anguish and despair. If you know ruffed lemurs, you know how dramatic they can become. Have you seen those sad face? When their arms and legs are outstretched as if they are saying "FML......". Yea, I've seen it.

Imagine this is a ruffed lemur instead of a sloth
Some of these lemurs are currently exhibiting extinction burst. They are swiping or tapping frantically at the screen while staring at the apparatus chute expecting a food reward. We know that, based on this series of behavior, these lemurs are operantly conditioned by food reward to touch the screen. Shaping them to target the red box instead of any surface of the screen is resulting in some lemurs exhibiting extinction burst. They look like they are throwing tantrums because there are no more free handouts. Compared to previous weeks where they get a food reward for just staring at the apparatus or approaching it.

A black-and-white ruffed lemur. He's just over it.
And to be quite honest, only half of these lemurs are exhibiting extinction burst while the other half are slowly getting shaped to target the red box. Although it is interesting to note that all the lemurs that I am currently training are black-and-white ruffed lemurs. What I would do for these red ruffed lemurs to be exhibiting extinction burst but instead they are herp derping their way into realizing that approaching my apparatus gives them a food reward.

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