• Question: how does are body know what to do other then sit, walk

    Asked by anon-267030 on 30 Oct 2020.
    • Photo: Vrushali Patil

      Vrushali Patil answered on 30 Oct 2020:


      Our bodies have several ‘systems’ that are needed to keep it alive – such as breathing, pumping blood to the brain (and other parts) and digesting food to generate energy. Our nervous system (brain and spinal cord) keeps track of these without needing our physical ‘action’. These things are being taken care of ‘autonomously’ or in the background. In order to keep it going well, we must keep our bodies and mind well-fed with nutritious food and exercise.

    • Photo: Paola Galdi

      Paola Galdi answered on 30 Oct 2020:


      Whatever we do with our body is primarily controlled by our brain. There are two main types of actions that our brain controls. Some are automatic, meaning that we don’t have to think about it to perform them, like breathing, digesting and keep our heart beating.
      Others require us to make the decision to move, like running or looking at the screen of our phone.

      For automatic actions, we know how to do them because we are programmed to do so.
      Every cell in our body has a sort on instruction manual, the DNA, that contains all the information necessary to know how to accomplish different tasks. Different cells do different jobs, some builds organs and they all work together to perform different actions.

      For the actions we decide to take, our body (or more precisely our brain controlling our body) knows what to do because it has learnt it over time. Since we are born (and even before that, when we are still in the womb of our mothers) our brain is collecting information about what is happening around us through our senses. For example, if I move my hand to reach out for an object, I will see my hand moving, and when I reach the object I will feel it with my skin.
      You might have noticed that when you repeat an action over and over, it becomes so natural to you that you don’t have to actively think about it: turning on a switch when entering a dark room, taking the stairs, typing on a keyboard, hitting back a ball that is thrown to you, and so on. This happens because our brain loves learning sequences and make predictions about what is going to happen next. When you put your foot on the first step of a staircase, your brain uses your previous experience to predict that you are likely going to need to put your other foot on the next step.
      By memorizing sequences of steps your brain let you be more efficient: instead of focussing on putting a step after the other, you can devote your attention to something else, like listening to a song or talking to a friend.

      Through observation, learning, and repetition, our body is able to learn how to do anything (with varying degree of success: I, for instance, am very bad at volleyball, but maybe I would be better If I had practised more…)

    • Photo: Ivan Andrew

      Ivan Andrew answered on 2 Nov 2020:


      We have a very inportant control centre called our brain which sends very important messages to our organs and other parts of our body to get them to do the things we do.
      Our organs and other parts of our body are made up of cells but these cells are different depending on where they are and what they are doing.

    • Photo: Romain Laine

      Romain Laine answered on 2 Nov 2020:


      Our body and our brain are constantly talking to each other, whether you are aware of it or not. So the brain gets some information from the body, then decides what needs to be done to keep things working, and then sends the information back to the body, a little bit like a reflex movement.

      So there’s constant activities going on. You can imagine that your inner body has more “senses” than the ones you feel (sight, hearing etc.).

    • Photo: Thomas Williams

      Thomas Williams answered on 3 Nov 2020:


      Your brain tells the body what to do, using nerves. Your brain is very clever and does a lot of things in the background, like a computer. So, while sitting, walking etc can be actively controlled by you, other actions, like blinking, which you don’t have to think about are also controlled by the brain.

    • Photo: Guy Yona

      Guy Yona answered on 4 Nov 2020: last edited 4 Nov 2020 12:45 pm


      That’s a wonderful question that has puzzled scientists for ages, and still does!
      As is often the case with great questions, there are many answers – and I can only try to offer a window to how some scientists think about this question.

      Since human beings are very complex creatures, with a huge variety of possible actions, it may be useful to think about simpler animals first, and then consider how that would be relevant to us. Let’s think of a squirrel – it does a lot of the things we do, like eating and running and playing, but it doesn’t do the dishes and other things us people do, so it’s perfect. Researches sometimes use the term “goal-directed behaviour” to describe a great deal of what the squirrel is doing: it has a goal, to get a nut for example, and it will do whatever it takes to get it. Its brain, then, will plan for the most proper set of actions to attain this goal. It can be planning a course up the tree, searching the branches, or reaching for the nut.

      We think, that the brain has general “programs” for each of these actions (like climbing, running on a branch, reaching), and that each time the brain “chooses” which programs to execute. This “choosing” has to do with the predicted value of the choice, that’s based on the experience of the animal. For example, if the squirrel previously found a lot of nuts in the highest branches, it will prefer the “climbing” action rather than the “running on a branch” action. The same thing also works for people, but we may have a more complex set of goals, so our “action selection” mechanism has a more difficult job to do! How many times has our goal of getting an “A” in that exam been in conflict with the no-less-important goal of finding out what happens in the next episode of The Unmissable Show?

      In some conditions, the “action selection” mechanism can become broken. This is what happens in addictions, when the addicted person repeatedly “selects” a damaging action (think about gambling, for example). In Parkinson’s disease, this mechanism fails in a different way, so the afflicted person has a problem translating the choice into action. For example, they can consciously decide they want to start walking, but the body just wouldn’t start.

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