Box 1: Sensory Memory (abbreviated SM)-- a very brief, exact copy (a trace) of what you just sensed

Imagine that you are looking at the television, but not paying attention to the program because you are talking to a friend. Suddenly, your friend points to the television set. Thanks to your sensory memory, you can hit a rewind button in your mind that allows you to replay the last little bit of the program.
If you replay the audio from the program, you are using your echoic memory: the sensory memory for hearing that allows you to, in a sense, hear an echo of what just happened. 
  Being able to use your echoic memory to replay the last 3-5 seconds of what your ears just sensed, allows you to

If you replay the image that was on the television screen, you are using your visual sensory memory (typically called iconic memory). Iconic memory is, in a sense, a picture drawn in rapidly disappearing ink. See a very short (less than a second) demonstration of how quickly information decays from iconic memory Because pictures in  iconic memory are copies of what you just saw, are "drawn" automatically, and usually fade in less than half a second, it wasn't until

A note about iconic memory's role in seeing movies:

    If slides are projected on a screen at a rate of 12 slides or more per second,  the slide on the screen stays in your iconic memory during the gap between slides. Because you are "seeing" the memory of the previous slide instead of the gap between the slides, you see "moving pictures" (i.e., "movies" or "motion pictures"). 
    If, on the other hand, slides are projected at a rate slower than 12 a second, the previous image is gone from iconic memory before you see the next image. Because you are not seeing a memory of the previous slide and are instead seeing the gaps between each slide, you see a slide show rather than a movie.

Iconic memory is not just valuable when watching movies. To get a rough idea of how confusing the world be if you didn't have both iconic memory and visual short-term memory, watch this 48-second animation/simulation.

 Iconic memory does not seem to be related to what we consider intelligence:

Key Characteristics of Sensory Memory
Types At least 2: Your sensory memory for vision--iconic memory--and your sensory memory for hearing--echoic memory. You may also have ones for some of your other senses.
Encoding Automatic: To encode information, you just need to sense the information.
Storage Size  Enormous (maybe as much as 14 trillion bits!)
Storage Duration Short--Less than half a second for iconic memory; about 3- 5 seconds for echoic memory
Silly summary "I have a good memory, but it's short" would be silly to say about your long-term memory, but is probably accurate to say about your iconic memory.

 Drag and drop matching game to test your knowledge of sensory memory  (Play several rounds of this game; each round gets a little harder. Try to rack up at least 9 points.)

Getting information from Sensory Memory to Short Term Memory

Short Term Memory

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