The "divided attention" phenomenon is the idea that an individual has the ability to divide their attention between two or more tasks (multitasking). Models of focused attention such as Broadbent's theory, Treisman's theory and the Deutsch and Deutsch model explain how all of our inputs are focused on one task at a time, however it is clear from looking at everyday life that we are able to divide our attention, successfully managing to complete more than one task at the same time. One area of ​​everyday experience where divided attention is very relevant is the question of whether we can drive and talk on the cell phone at the same time. The answer is a pretty obvious “yes,” but the argument is that by doing so we endanger ourselves and others because we're not very good at it. We struggle to do both tasks at the same time and do them effectively. Our attention span is exceeded, often with catastrophic results (Strayer & Johnston, 2001). Khaneman (1973) devised an attention model because he believed that a limited amount of attention was allocated to tasks by a central processor. Many factors determine how much attentional capacity can be allocated and how much is needed to perform a task, as the central processor has a variable but limited capacity that depends on motivation and arousal. The central processor performs a variety of motor, visual, auditory, memory, and so on tasks. The central processor evaluates the amount of concentration needed to meet the demands of the task, which forms the basis of capacity allocation. Khaneman (1973) composed an analysis of the factors that determine the allocation of attention in which cognitive systems are formed and are held responsible for the allocation of cognits... in the center of the paper... requires capacity. This may well be the case, but there is no independent definition of central processing capacity. Therefore, the difficulty of the task cannot be defined. The argument is circular since difficult tasks require more attention and tasks that require more attention are difficult.ReferenceBalota, DA and Marsh, EJ Cognitive psychology. Key readings. (2004) Hove: East Sussex: Psychology Press.Pashler,H.(1990) Gradual skill sharing in dual-task interference?. Journal of Experimental Psychology: Human Perception and Performance, 1994, Vol. 20, No. 2. 330-342 Strayer, D.L. & Johnston, W.A. (2001) Driven to distraction: studies of two tasks of simulated driving and conversing on a cell phone. Psychological Science, 12, 462-466 ​​Weiner, I. Healy, A. Freedheim, D. Proctor, R.W., Schinka, J.A. (2003) Handbook of Psychology: Experimental Psychology, 18, pp 500