A lot of times, when you think of something such as a kid’s room or a teenager’s outfit, you will tend to think of brighter colors than those which typify those of an adult. As a person gets older, their color choices tend to get a bit deeper, as well as a bit darker. While some people would say that this comes about as the result of having less energy as an adult, this also tends to happen because a person becomes more restrained as they grow older. When it comes to childhood, energy seems to be almost boundless- at least if there is not work to be done.
And because of this incredible amount of energy, a child feels the need to express themselves in an energetic fashion. This will naturally lead them into wanting to wear a lot of bright colors, and just visually explode with their wardrobe. But of course, over time (and helped to no small extent by social pressure) a child begins to see that extremely bright colors can look ridiculous if they are presented with the indiscriminant scatter effect of a field full of flowers or something. So as time goes on, a person’s wardrobe choices tend to go a good deal darker and less vibrant as they get older.
You can rather easily see the differences between adult choices and childhood choices in wardrobe when you look at those of a teenager. For the girls who want to look especially cute, they may carry on with the childhood color scheme into their early twenties (and sometimes for even longer), while the teens who want to look older (and believe it or not, not all of them do) will wear a lot darker colors, often with more complex accoutrements added to them. By the time many people reach adulthood, rarely is anything much lighter than a dark khaki seen.