Psychologists have concentrated on thinking as an intellectual exertion aimed at finding an answer to a question or the solution of a practical problem. Cognitive psychology is a branch of psychology that investigates internal mental processes such as problem solving, memory, and language.

noun: thinking
  1. 1.
    the process of considering or reasoning about something.
    “the selectors have some thinking to do before the match”
    • a person’s ideas or opinions.
      “his thinking is reflected in his later autobiography”
      synonyms: reasoning, idea(s), theory, thoughts, line of thoughtphilosophy, beliefs; More

    • archaic
      thoughts; meditations.
      plural noun: thinkings
      “I am wrap’d in dismal thinkings”
adjective: thinking
  1. 1.
    using thought or rational judgement; intelligent.
    “he seemed a thinking man”
    synonyms: intelligentsensiblereasonablerationalreasoningMore

    antonyms: stupidirrational
    Who is a Slow Thinker?
    In his latest book, Thinking, Fast and Slow, Kahneman describes two types ofthinkers. System 1 thinkers operate automatically and quickly, with little sense of voluntary control, and little or no effort. … Kahneman describes President Obama as a System 2 thinker. “He is a slow thinker.Sep 24, 2012

    Slow Thinking Is Wise Thinking – Association for Psychological Science

    What is a slow thinker?
    Most people are not x10 thinkers. It’s not because of their brain but because of their brain software. Many people are slow thinkers, not because they are short on brainpower, but because they’re using very sluggish, outdated brain software that favors only the left half of their brain.

    Why are some thinkers slow thinkers?

    Of course, there are some who struggle with various cognitive challenges. However, being a slow thinker is not always an indication of a lack of intelligence as many assume. Introverts often tend to think more slowly than extroverts.
    My own sense is Thinking is all about asking Questions. Ability to ask questions.  I have read that Questions are never stupid – the answers usually are.  Questioning, asking right questions is an ability of a curious mind in search of new knowledge, questioning could also lead to Challenging with or without provocation.
    A Mentor Provokes by asking difficult questions, challenging the minds of the brightest and the slowest.  The response may be slow or fast – the outcomes are what are more important for the mentor.
    Hence – iMHO a Questioning mind is a fertile brain which needs the fertilizer, growth promoters, micronutrients and prophylaxis controls by Mentors at different stages.   Good mentors also know when to apply Growth inhibitors for overly active brains as they lead you away from your focus. If you can Question – You can Think is my humble submission.