You are not in control of most of your memory systems. Your brain has many types of memory to suit different needs to keep you alive. Those memories do different jobs. Some of them have names:

• Short-term memory lets you remember a name or phone number long enough to enter it. It's brother...
• Medium-term memory lets you remember what you had for breakfast yesterday that didn't agree with you today.
• Working memory (the first to go) lets you keep a lot of data in mind while you sort through it to save what is important to you.
• Primitive memory systems are similar to those of a reptile. They tell your human heart to pump blood to your cheeks when you are embarrassed or breath faster when your boss's secretary calls to say he wants to see you in his office.
• Motor memory lets you steer a bike or soap up in the shower while you are thinking of something else.
• Explicit memory clicks in when you rehearse something a lot until it comes naturally,
  because your system thinks it must be important to your survival. Teacher time.
• Implicit memory already knows what just happened is so important for your survival it acts on your body before you know it. You cannot control it but it can control you. (Example: "If an acquaintance betrays me I can't remember her phone number any more.")
  

Learn More About Memory

Your cortex, the thinking part of the human brain, is endlessly fascinating and loves its job of maintaining the “You” of you. When it emerged 2.4 million years ago, the big issues were dodging dangers, locating mates, finding and killing food. Among the most recent changes in cortical design are the ability to perceive patterns among events, social skills like altruism and emotional control, planning ahead and writing language. Such cortical skills are the last to develop in infancy, the first to decline with age.

Learn More About Your Brain

Everyone who spends part of the year in a cold climate knows that it’s not unusual for people to feel a little more “down” in the winter than in the summer — an experience some have described as a kind of “emotional hibernation.” But for others winter can bring on a much more acute form of the common winter blues, a condition that triggers severe depression and sometimes even suicide. It has recently acquired a name: Seasonal Affective Disorder, or SAD.

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Memory and Concentration
Storing memories

Never underestimate your ability to forget. Your whole life — at age 5, 15, 35 — you’ve demonstrated expert skill at forgetting things, and you’ll remain that way until the end of your days. How does it help to know that? For one thing, it changes the questions you have to answer. Instead of asking “Why do I
forget?” maybe what you should really be asking is “Why do I remember?” That question has many answers, but if you’re worrying about your memory the simplest answer is probably this: because you paid attention.

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