We remember things by association. Every piece of information in our memory is connected to other pieces in some way or another. For example, if you are given the word "apple", what do you think of? Perhaps something like this:
APPLE: red, round, sweet, teacher, tree, fruit
But it's unlikely that we might see "apple" and think of "dog" (unless you remember some funny incident in which your dog investigated an apple). And what if you were asked what the 7th letter of the alphabet was? Chances are, you wouldn't know that "G = 7," but you could easily think to yourself, "A B C D E F G," and then say "G". You used association to get to the letter G, because you knew A was the first letter, then you kept choosing the next letter in the sequence until you got to the right one.
Why do most of us have a bad memory?
Most of us don't. Most of us have a really good memory, but we just don't have practice in using it efficiently.
If the above is true, then why is it so hard for me to remember things?
As stated before, our memory works by association. If there is no obvious association between things, it's very difficult to remember them. For example, suppose you needed to remember that your plane takes off at 2 P.M. There is nothing about the plane that would suggest the number 2 more than it would any other number (at least at first glance). Therefore, 2 is easily forgotten. Likewise, how does your best friend relate to his phone number, an arbitrary string of digits? Or how does a new word, like "hypothalamus," relate to what it represents?
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