And this is not about procrastination (I'm almost certain).

I've been noticing it since childhood that people (me included) tend to do unnecessary side activity, especially if they're invested in the main activity.

Examples of main activity: having a thoughtful conversation, watching an interesting movie, crafting something manually.

Examples of side activities: doing tricks with a pen, playing with shirt buttons, doodling, tearing a piece of paper into smaller parts, attaching and detaching magnets, in other words almost anything slightly amusing/interesting/touch-pleasant.

The side activity tends to increase with the intensity of main activity, only ceasing at the point where the main activity takes all the concentration a person can manage to attain.

What causes this? Does it somehow help us perform the main activity? Then how exactly? Or is it a reaction to performing something effortsome?

  • $\begingroup$ If you know more suitable tags, please add them. $\endgroup$ Dec 29, 2013 at 6:10
  • $\begingroup$ I think what you are describing is unconscious movements...autonomic functions...like scratching an itch or empathy yawning. $\endgroup$
    – user3832
    Dec 29, 2013 at 9:52
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    $\begingroup$ I have nearly the same question: cogsci.stackexchange.com/questions/5021/… $\endgroup$
    – drabsv
    May 24, 2015 at 18:17
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    $\begingroup$ Something related: additudemag.com/adhd/article/3967.html $\endgroup$ Jun 10, 2015 at 22:05

2 Answers 2


In the whole scheme of human consciousness, these movements may be a result of what one individual person's autonomic and central nervous system has been conditioned to expect. While awake during different hours of different days, implying different variables to be present depending on [social code] etc, our central nervous system (CNS) has a threshold for response- the level of response/arousal to sensory input accompanied by these variables stated above will ultimately help someone read what their basal level of arousal is. If that basal level arousal is not met in a certain social context (this basal level has increased via techna-cultural advancement) than the body may expend this energy via other methods of movement or concentration.

  • $\begingroup$ Something tells me that CNS can't be the sole cause of toying around with little things around you. Maybe it's the phrasing, but I find it hard to follow your argumentation. $\endgroup$ Dec 30, 2013 at 6:14

Based on the article in my answer here, shifting attention and voluntary movement cause changes in the brain. In the example below, the cat's Raphe nucleus firing is subdued as the cat is orienting to look.

I would hypothesize that shifting focus between the fun activity (ex:playing with a pen) and conversational partner can help with the thinking process.

enter image description here

  • 2
    $\begingroup$ A shifting-based explanation could be interesting, but I don't think this answer makes so much as implies the argument. Maybe you could try to find some research along these lines? $\endgroup$ Apr 27, 2015 at 12:27
  • $\begingroup$ @ChristianHummeluhr +1. My (not professional) guess is that distractions help alter attention and restart the main task. Without distractions, a person does more of unnecessary work, which happens when he writes something, for example. $\endgroup$ Jun 22, 2015 at 19:26

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