1. Why do babies show more anger once they can crawl?
A research team including Penn State scientists watched 20 babies at three times: before they crawled, and 2 and 6 weeks after crawling began. Each time, the team used an arm restraint procedure, in which the baby's arms are held, and observed how often the baby showed anger [1].
The key finding is about age. At each stage, a baby's age was unrelated to how often it showed anger. The authors concluded that the experience of crawling on one's own had an effect on anger, independent of age [1].
A simple way to picture it is this: once you can go where you like, more things can stop you. That reading is an interpretation, not something the study measured directly. The experiment looked at one situation, arms held still, with a small group of babies. It does not explain all anger.
The study also found that babies differ. Babies whom their mothers rated as easily upset by limits showed a bigger rise in anger six weeks after crawling began, and took longer to calm down once they were let go [1]. Different babies react differently to the same experience, and that is not good or bad.
2. Does anger make us run away, or step forward?
Anger and fear are both unpleasant. Yet they may point in opposite directions. Imagine someone cuts in front of you in a line. One person feels scared and wants to move away. Another feels like saying, "Hey, wait a moment."
In 2009, the psychologists Charles Carver and Eddie Harmon-Jones reviewed a range of evidence on this. They concluded that anger relates to an approach motivational system, which moves us toward something we want, while anxiety relates to an avoidance system [2].
Under this view, anger is unpleasant but not a "get away" feeling. It points toward the thing in the way. That describes what anger does inside us. It does not mean that anger gives anyone the right to hurt others.
3. Could anger be a way of asking others to treat us better?
If anger pushes us toward an obstacle, what does it do when the obstacle is another person? The evolutionary psychologists Aaron Sell, John Tooby and Leda Cosmides proposed the recalibrational theory. It says anger comes from a mental program shaped by natural selection to use bargaining tactics in conflicts of interest, so that the angry person's side wins out [3].
In other words, anger could work as a signal: "treat my interests better, or this will cost you." The team tested predictions from this theory in 2009 [3].
This is one scientific theory, built mostly on adults, and it does not claim to explain every angry moment. We cannot say from it that children's anger works the same way.
4. Does anger really fade after six seconds?
You may have heard advice like "count to ten" or "wait six seconds and the anger passes." The six-second version turns up in Japan, and Nobuyuki Kawai writes that anger-management classes there appear to teach it. The behavioral scientist Nobuyuki Kawai of Nagoya University says he does not know what it is based on [4].
He writes that one suggested reason is a peak in adrenaline production after about six seconds. He found no academic basis for it, and points out that adrenaline already released into the blood would not vanish that fast [4]. In his team's experiment, they made people angry while measuring eight body responses, such as brain waves and heart rate. He reports that in every measure, the anger response had not settled during three minutes of measuring [4].
There are limits. This comes from one popular article by a researcher describing his lab's work, not from a paper we could read in full. It also tests anger made in a lab, not every real-life moment. The criticism is aimed at the "six seconds" number. It does not show that pausing before you react is useless.
5. How can you look at your own anger?
Next time you feel a flash of anger, you could jot down three short notes, only if you want to: what was blocking you, what you felt just before, and whether your body felt different a few seconds later. Skipping a day is fine. If anger feels too big, talk with an adult you trust.
Some health and school materials describe anger as a "secondary emotion" that can sit on top of sadness or worry. That is a teaching idea, not a proven law, so treat it as a question to ask yourself rather than an answer.
To read further, search for the three papers listed below. Their abstracts are free to read online.