Visual Memory

Visual memory is recollected information about what one has seen. It involves both the mental storage of such information and the ability to retrieve it. The recalled image of a sunset, the memory of a font type, the remembrance of a tree's appearance: these are all instances of visual memory. Psychologists refer to visual memory to help account for memory in general. It is distinct from other kinds of memory, such as auditory memory (recollection of what one has heard). Some researchers believe visual memory plays an important role in learning. For example, some learning disabilities (including dyslexia) are linked to poor visual memory, such as the inability to remember the sequence of letters in words.

Memory Encoding

Visual encoding is the process of encoding images and visual sensory information. Visual sensory information is temporarily stored within the iconic memory before being encoded into long-term storage. The amygdala (within the medial temporal lobe of the brain which has a primary role in the processing of emotional reactions) fulfills an important role in visual encoding, as it accepts visual input in addition to input from other systems and encodes the positive or negative values of conditioned stimuli.

Higher Accuracy

Visual memory is surprisingly detailed. In the novel test, subjects correctly identified the correct image 93 percent of the time. The exemplar and state test conditions were handled with slightly less accuracy but, at 87 percent and 88 percent, respectively, the margin wasn't large. The test subjects were also very accurate in their ability to detect repeated images, with 96 percent of repeat images being identified, and only a 1.3 percent false positive rate.For details see Experiment

Associating words with images is commonly used mnemonic device, providing two alternative methods of remembering, and creating additional associations in the mind. Taking this to a higher level, another method of improving memory encoding and consolidation is the use of a so-called memory palace (also known as the method of loci), a mnemonic techniques that relies on memorized spatial relationships to establish, order and recollect other memories. The method is to assign objects or facts to different rooms in an imaginary house or palace, so that recall of the facts can be cued by mentally “walking though” the palace until it is found. Many top memorizers today use the memory palace method to a greater or lesser degree. Similar techniques involve placing the items at different landmarks on a favourite hike or trip (known as the journey method), or weaving them into a story.

Experiment to test Accuracy

In the PNAS study, the volunteers were shown 2,500 images, each for 3 seconds. In contrast to prior research, the images were stripped of any background details. The subjects were then shown a pair of images, one of which was previously seen and one that was new. The paired images were shown in three ways; novel, where the image was paired with an image of something from a completely different category (for example, false teeth and a DNA double helix), exemplar, where the image was paired with a different, but similar image (two slightly different starfish for example), or state, where the images were of exactly the same image, but in different conditions (such as a telephone on and off the hook).

One of the major lessons of memory research has been that human memory is fallible, imprecise, and subject to interference. Thus, although observers can remember thousands of images, it is widely assumed that these memories lack detail. Contrary to this assumption, here we show that long-term memory is capable of storing a massive number of objects with details from the image. Participants viewed pictures of 2,500 objects over the course of 5.5 h. Afterward, they were shown pairs of images and indicated which of the two they had seen. The previously viewed item could be paired with either an object from a novel category, an object of the same basic-level category, or the same object in a different state or pose. Performance in each of these conditions was remarkably high (92%, 88%, and 87%, respectively), suggesting that participants successfully maintained detailed representations of thousands of images. These results have implications for cognitive models, in which capacity limitations impose a primary computational constraint (e.g., models of object recognition), and pose a challenge to neural models of memory storage and retrieval, which must be able to account for such a large and detailed storage capacity.