Does everybody dream? Why is it that I don't remember my dreams?
verybody dreams. Not only all humans, but in fact all mammals are shown to have REM sleep, which is associated with dreams. It is a normal and necessary function of the body (though the details, especially the exact reason why it is important, are unknown). So if you think you don't dream you probably just don't remember. People vary greatly in how much they remember of their dreams. The perhaps most important reason why people forget their dreams is that they don't care. Western culture does not regard dreams as especially important, rather it regards getting out of the bed in time as a prevalent survival factor. This is bad in two respects as most dreams occur at the end of the sleeping cycle and are often interrupted, and the necessity of getting up fast and keeping up with the schedule occupies peoples' minds and prevents them from thinking about their dreams in the morning. Dream recall can be trained. Try to think over all what you have dreamed for some time before getting up and write it down soon afterwards.
How do external stimuli affect my dreams?
Sensual "input" while sleeping is incorporated into dreams. Most notably, while sleeping, you hear as well as while waking - the ears are never turned off. This leads to the consequence that what you hear while sleeping, you'll hear in your dreams. The sound is always coming from "somewhere". Common experiences of this kind are a telephone ringing or music from the radio. The same holds for the other senses. Note that it is not important how loud some noise is to get noticed while sleeping - even an otherwise unnoticed sound, like a mouse running over your floor, can wake you up if it is uncommon or otherwise alarming to you - on the other hand, you can get accustomed to high levels of noise, like construction work nearby. (What definitely will wake you up is someone knocking at your window if you live at the 10th floor ;-) It is an interesting experience that you can hear exactly what is going on, but will forget it on waking up along with forgetting the rest of your dream. This includes things such as news broadcast heard on the radio - after waking up, you have forgotten it. It is like you have dreamed the news broadcast as well - but distinguishing this fact is a good clue to lucid dreaming and the way "lucidity inducing devices" work.
How do my dreams interact with my waking life?
Dreams seem to be a way for the subconscious mind to sort out and process all the input and problems that are encountered in waking life. Therefore, a scientist could be working on a problem ... say the structure of the DNA molecule. Then said scientist could have a dream in which he sees two snakes intertwining in a double helix. When he wakes, he has discovered the structure of the DNA molecule (true story). Students who study and get some good REM sleep retain the information better and for longer periods of time than students who study longer, but have no sleep. This is because the brain needs time to process the information, form sensible pattern out of it, and place it in long term memory. Dreams can also improve your emotional well-being, reduce stress, improve your creativity, and provide a playground for your mind while your body recovers and repairs itself. [Comment by Brian Hostetler