Topic interest is the first step in Ainley's idea about interest theory. Topic interest is what immediately sparks curiosity or anticipation. It is thought that topic interest is linked to who the student is and the environment that is provided; this then leads to different behavioral outcomes. Students who have a high level of interest in a subject are more likely to choose to continue reading, complete their work, and engage with the material more quickly than students who have low topic interest. For example, a student who is interested in animals may be more excited to learn about ecosystems and spend extra time reading about different species because the topic connects to something they already enjoy.

Affective response is the second step in Ainley's idea about interest theory. Affective response is the psychological and emotional experience a student has while actively interacting with learning material. For example, a student may feel excited and interested when learning about a topic they enjoy, which can increase their motivation to participate and learn. This can lead to activating achievement emotions such as curiosity or focused attention, or deactivating emotions such as boredom. This link proves that emotional reactions during learning cause an immediate psychological checkpoint of whether the student checks out or stays focused. 

Task persistence is the third step in Ainley's idea about interest theory. Task persistence is how much a student is willing to interact with the learning material for a prolonged time. During the study conducted by Ainley, it was proven that task persistence is fragile when interest in the topic decreases. In the study, only 25% of students completed the reading; the rest of them decided to quit during parts one or two.