Cognition is a multi-dimensional process which needs a many-sided approach. The psychological approach to cognition is defined as the psychology of understanding and knowing. It is also the study of mental processes. It is concerned with the way we take in information from the outside world, and how we make sense of that information, and what use we make of it. According to Groome, there have been three main approaches to the study of cognitive psychology, namely, experimental psychology, computer modelling, and cognitive neuropsychology. Firstly, experimental psychology involves the use of psychological experiments on human subjects to investigate the ways in which we perceive, learn, remember or think. Secondly, cognitive psychol ogy is the use of computer mo delling of cognitive processes. This approach involves the simu lation of some aspects of huma n cognitive function by writing computer programs, in order to test out mode ls of possible brain function. Lastly, cognitive neuropsychology is concerned with the activities of the human brain during cognitive processing. These three approaches of cogn itive psychology explain the psychol ogical levels of cognitions. The representational theory of cognition tries to show how ou r knowledge of the world is represented in the mind. When human knowledge is represented in an abstract format, we call it propositions.