External Stimuli
External stimuli exist as “sensory registers.” (Orey, 2001). This includes all of our senses: hearing, seeing, tasting, touching, and smelling. Orey established that each “memory stage has four attributes: representation, capacity, duration, and cause of forgetting.” (2001) Orey found hearing (echoic) and seeing (iconic) to be the best understood with our vision sensory register lasting for about 250 milliseconds and the auditory register lasts for 2 – 3 seconds (2001). Both of these sensory registers are forgotten quickly by primary decay.