Thinking:
* Analyze: To examine something carefully in order to understand it.
* Consider: To think carefully about something.
* Contemplate: To think deeply about something.
* Decide: To make a choice after thinking about something.
* Evaluate: To judge the value or quality of something.
* Imagine: To form a mental picture of something.
* Memorize: To learn something so that you can remember it exactly.
* Plan: To make a detailed proposal for doing something.
* Recall: To bring something back into your mind.
* Reflect: To think carefully about something.
* Research: To investigate or study something systematically.
* Solve: To find the answer to a problem.
* Understand: To grasp the meaning of something.
Feeling:
* Believe: To have confidence in the truth of something.
* Fear: To be afraid of something.
* Hope: To want something to happen and think it is possible.
* Love: To feel a strong affection for someone.
* Regret: To feel sorry for something you have done.
* Think: To have an opinion or belief.
* Want: To desire something.
* Wish: To hope that something will happen.
Perceiving:
* Hear: To be aware of a sound.
* Observe: To watch or notice something carefully.
* See: To be aware of something with your eyes.
* Smell: To be aware of a scent.
* Taste: To be aware of a flavor.
Other:
* Acknowledge: To recognize or admit something.
* Agree: To have the same opinion as someone else.
* Disagree: To have a different opinion from someone else.
* Forget: To be unable to remember something.
* Know: To be certain of something.
* Learn: To gain knowledge or skill.
* Remember: To bring something back into your mind.
* Realize: To become aware of something.
These are just a few examples of mental action verbs. There are many others, and the specific verbs you choose will depend on the context of your writing.