The human processor model uses the cognitive, perceptual, and motor processors along with the visual image, working memory, and long term memory storages. A diagram is shown below. Each processor has a cycle time and each memory has a decay time. These values are also included below. By following the connections diagrammed below, along with the associated cycle or decay times, the time it takes a user to perform a certain task can be calculated. Studies into this field were initially done by Stuart K. Card, Thomas P. Moran, & Allen Newell in 1983. Current studies in the field include work to distinguish process times in older adults by Tiffany Jastrembski and Neil Charness (2007).