TOEFL Speaking Task 3

The concept of 'behavioral momentum' refers to the tendency of a behavior to persist even when conditions change, because it has been reinforced consistently in the past. Just as physical momentum keeps an object moving in the same direction, behavioral momentum keeps an organism performing a learned behavior. The key is that the behavior has a history of reinforcement, making it resistant to disruption, such as changes in rewards or the introduction of distractions.

Professor: Let me give you an example from a study with rats. We trained rats to press a lever for food. In the first phase, we gave them a food pellet every time they pressed the lever. This was consistent reinforcement. Then, we introduced a change—we added a loud noise, a distraction, and also we sometimes delayed the food. But the rats kept pressing the lever at a high rate. Interestingly, even when we stopped giving food altogether for a short period, the rats continued pressing for a while. The key was that the behavior had high behavioral momentum because it was so strongly reinforced before. In contrast, another group of rats that received food only occasionally, say every third press, showed much weaker momentum. When the noise came, they stopped pressing quickly. So the history of reinforcement made all the difference.