Learning algorithms for people: Supervised learning

Access to education is widely considered a human right, and, as such, many people spend years at school learning. Many of these people also spend a lot of time practising sport, musical instruments and other hobbies and skills. But how exactly do people go about trying to learn? In machine learning, algorithms are clearly defined procedures for learning. Strangely, though the human brain is a machine of sorts, we don’t really consider experimenting with “algorithms” for our own learning. Perhaps we should.

Machine learning is typically divided into three paradigms: supervised learning, reinforcement learning, and unsupervised learning. These roughly translate into “learning with detailed feedback”, “learning with rewards and punishments” and “learning without any feedback” respectively. These types of learning have some close relationships to the learning that people and animals already do.

Many people already do supervised learning, although probably much more haphazardly than a machine algorithm might dictate. Supervised learning  is good when the answers are available. So when practising for a quiz, or practising a motor skill, we make attempts, then try to adjust based on error we observe. A basic algorithm for people to perform supervised learning to memorise discrete facts could be written as:

given quiz questions, Q, correct answers, A, and stopping criteria, S
    do
        for each quiz question q in Q
            record predicted answer p
        for each predicted answer p
            compare p with correct answer, a
            record error, e
    while stopping criteria, S, are not met

Anyone could use this procedure for rote memorisation of facts, using a certain percentage of correct answers and a set time as the stopping criteria. However, this algorithm supposes the existence of questions associated with the facts to memorise. Memorisation can be difficult without a context to prompt recall and questions can also help links these facts together. Much like it being common for people to find recall better when knowledge is presented visually, aurally and in tactile formats. The machine learning equivalent would be adding extra input dimensions to associate with the output. Supervised learning also makes sense for trying to learn motor skills, this is roughly what many people do already when practising skills for sports or musical instruments.

It makes sense to use slightly different procedures for practising motor skills compared to doing quizzes. In addition to getting the desired outcome, gaining proficiency also requires the practising the technique of the skill.  Good outcomes can often be achieved with poor technique, and poor outcomes might occur with good technique. But to attain a high proficiency, technique is very important. To learn a skill well, it is necessary to pay attention not only to errors in the outcome, but also errors in the technique. For this reason, it is good to first spend time focusing practise on the technique. Once the technique is correct, focus can then be more effectively directed toward achieving the desired outcome.

given correct skill technique, T, and stopping criteria, S
    do
        attempt skill
        compare attempt technique to correct technique, T
        note required adjustments to technique
     while stopping criteria, S, not met

given desired skill outcome, O, and stopping criteria, S
     do
         attempt skill
         compare attempt outcome to desired outcome, O
         note required adjustments to skill
     while stopping criteria, S, are not met

These basic, general algorithms spell out the obvious of what many people already do: learn through repetition of phases of attempts, evaluations and adjustments. It’s possible to continue to describe current methods of teaching and learning as algorithms. And it’s also possible to search for optimal learning processes, characterising the learning algorithms we use, and the structure of education, to discover what is most effective. It may be that different people learn more effectively using different algorithms, or that some people could benefit from practising these algorithms to get better at learning. In future, I will try to write some further posts about learning topics and skills, and applications for different paradigms of learning, as well as algorithms describing systems of education.

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