Answer:
How does learning take place? Answering this question has motivated psychologists to study the learning process, to conduct experiments and to develop theories which should help us understand how we learn. Running experiments on learning and developing a theory of learning is simply trying to answer that question. If you are curious about it, as many psychologists are, you could carry out your own experiments and develop a theory that might improve the current ones. You can start by imagining a simple theory that could explain basic observations of actual learning.
Explanation:
Some tips to answer this kind of question are the following:
1. Pay attention to modal verbs (can, could, may, might, should). They are followed by verbs in their base form without "to". Example: You can start.
2. Pay attention to prepositions, since they are usually followed by verbs with -ing. Example: experiments on learning / by imagining.
3. Usually, but not necessarily always, verbs that function as subjects of the sentence come with -ing. Example: Answering this question has motivated.
4. Some verbs are usually followed by an infinitive with "to". Example: trying to answer. NOTE: The verb "help" can be followed by "to" or not.