Sense memory is the ability to recall the exact sensation of an experience after the experience has finished. The stimuli that create the experience can stimulate any one of the human senses. The person consciously or subconsciously decides if he or she wants to ignore the stimuli or if he or she wants to perceive it. The sense memory of an ignored stimulant is nearly nonexistent, while the sense memory of something perceived is still fleeting, up to a matter of seconds, but is existent.
The types of sense memory are divided into first senses and then types of memory. The five basic senses are sight, sound, smell, taste and touch. There are other senses such as the vestibular sense, thermoception, nociception and proprioception. Sense memory is often broken down into three main types: iconic, echoic and haptic.
Iconic memory is the ability to maintain an image of something in the mind after the image that stimulated it has gone out of sight. It is the basic sense memory of sight. Iconic memory is divided into visible persistence and informational persistence. Visible persistence is like a brief photograph of something, whereas informational persistence is a visual memory that becomes long-lasting.
Echoic memory recalls sounds after the sound has stopped reaching the ears. Such auditory information lasts in the memory for approximately three to four seconds. Neuroscience has tested echoic memory to prove not only its existence, but also how long it lasts. It is noticeably shorter than iconic memory.
Haptic memory relates to touch memory. Initial memory of how something felt to touch is fleeting, but longer-term memory can be created with regards to whether something felt nice or not, or how much pressure to put on the object. Haptic memory may relate to texture memory when eating and to thermoception, the memory of heat. Nociception, the sense of pressure, pain and itching as stimulated by nerve endings, also falls under haptic memory.
The three main types of sense memory leave out many of the human senses. Smell and taste recall are the two most obvious ones ignored by sense memory. Smells and tastes clearly linger on after the stimulation has finished, but whether this a memory or lingering stimulation is unclear.
Sense memory is linked to long- and short-term memory by the ability to recognize something when the stimulus starts again. For example, the subject may not be able to recall or describe the smell of bread offhand, but as soon as he or she smells bread, he or she may recognize it as bread. The difference between the two is active information recall and information recognition. The combination of the two allows the brain to both perceive the world and to build a recognition library to draw upon when needed.