Experimental research and computational research on working memory and visual attention.
Introduction
Psychology is the scientific study of our behaviour and experience (Hayes, 1999, p.1). Through research psychologists can determine the way human beings behave and the experiences they share around them. The scientific methods used in the study of human behaviour and mind have been undertaken through neuropsychological case studies, experimental research and computational modelling, in which they formulate theories, test hypotheses through observation and experiment, and analyse the findings with statistical techniques that help them identify important findings.
The following explanation will highlight and describe working memory and visual attention, and how psychologists have sought to understand through two of the following research methods: experimental research and computational modelling.
Working memory basically refers to the brain ability to temporarily store information.
Visual attention as describe by Triesman et al. (1984), the features that are attractors of covert visual attention are those parts of an image that differ from all the other parts by a single aspect.
Psychologists have sought to understand both working memory and visual attention through experimental research and computational modelling.
The experimental research was first set up by Wilhelm Wundt in his laboratory in 1879. His first researches were based on visual illusions and perception. In 1885, Herman Ebbinghaus published the first experimental research on memory and after behaviourism was eliminated, the cognitivist argued that all studies connected to psychology and the undertaken of the mind and human behaviour must be conducted through empirical means. A move from the empirical means saw the introduction of computer systems as new ideas for the processing of information. These computer programs were developed and would carry out perceptual processes such as the recognition of complex stimuli. These programs made use of feature detector systems and this discovery of feature detectors can be regarded as an example of different approaches to cognition being combined, with contributions from both neuroscience and computer modelling.
On visual attention, there are experiments, which has been conducted by Navon (1977) and proposed that it may be the norm to process the global attributes conducted for visual attention is the one in which subjects to attend to a physical property such as colour or spatial location. There are other experiments like the visual search task.
One computational modelling of the visual attention research method is the one conducted by Neisser (1964, 67) and experimented on the considerable variation in the ease which we can identify a given object from other object. Neisser modelled the visual search task by having subjects search among an array of letters represented in paper or on a computer screen for a specified target. The relationship between targets and distracters could then be manipulated.
On working memory, psychologists have performed many experiments, which sought to explain how memory is organised, and works within the brain by using the working memory model, which was provided by Baddley, A. and Hitch, G. It has been possible in recent years to use magnetic and positron scanning devices to observe what is happening in different parts of the brain while people are doing various mental tasks. Additional evidence about brain functioning is gathered by observing the performance of people whose brains have been damaged in identifiable ways.
Therefore, in cognitive psychology experiments and theory development are frequently aided by developing computational models of the behaviour of groups of neurons as in the working memory.
According to Groome, D. (2006, p.132) working memory is define as the process of storing information and experiences for possible retrieval at some point in the future. This ability to create and bring back memories is very important when it comes to the understanding of cognition and this helps our ability as human beings to function properly. Our memories allow us to store information about the world so that we can understand and deal with future situations on the basis of our experience.
Encoding refers to getting information into the system by translating it into a neural code that your brain processes. What happens this a little life when you type on a computer keyboard, as your key strokes are translated into on electrical code that the computer can understand and process storage involves retaining information over time. Once in the system, information must be filed away and saved, as happens when a computer stores information temporarily in the RAM (Random Access Memory) and permanently on a hard drive. Finally, retrieval refers to processes that access stored information. On a computer, retrieval occurs when you give a software command ( e.g: open file) that transfers information from the hard drive back to the RAM and the screen, where you can scroll through it. Keep in mind, however, that this analogy between human and computer is crude. For one thing, people routinely forget and distort information and sometime “remember” events that never occurred
According to Loftus & Bernstein (2005), has described human memory is highly dynamic, and its complexity cannot be fully captured by any existing information processing model. Encoding, storage and retrieval represent what our memory system does with information. Before exploring these processes more fully, let us examine some basic components of memory.
The fascinating thing about this unilateral visual neglect is that these effects occur even though the pathways from the receptors to the central nervous system for the neglected information remain intact.
Treisman has proposed that separate systems analyze objects different visual features. Through parallel processing, these systems all process information at the same time and we can attend selectively to one feature by effectively blocking the further processing of the others ( Treisman & Gelade, 1980). In studies, employing Treisman’s visual search tasks (also called feature search tasks), participants look at a display of different objects on a computer screen, searching for ones, called targets that differ from the others in only one feature.
The visual attention search task is one of the most widely used measures in the study of visual perception and attention. A work centred on the locating of targets or items among distracters and the differences in visual attention stimulus between the feature search and the conjunctive search resulted to a reaction time that varies due to the variable number of distracters in which a search item could be found. The research findings were based on the above factor. Treisman and Gelade (1980) provided the Feature Integration Theory (FIT) on focused attention that embraces the conceptualisation of perception of features and objects also known as the visual search method. In trying to integrate the two features-feature search and conjunctive search, Treisman and Gelade (1980) maintained that hence in the process, the primary visual features should be presented in two separate feature maps and in the end of the process integrated in a saliency map and accessed to direct attention to an area where items could easily be seen. In all the visual search tasks, which have been provided for our understanding of visual attention, was the pre-attentive stage that processes targets and non-targets differentially and was provided through the works of Neisser (1967), that in this hypothesis the separable features are independently coded and in parallel through detecting multiple target. The method is however considered to be very slower mechanism through the ‘focal attentive’ stage. Neisser (1967) approach notes that visual search for dissimilar letters was faster than for similar letters in which he concluded there is no need to attend to background letter in the lists as letters. All what is required is to look for features in a background of rounded features. If background items are similar to the target, it is necessary to consider more features and this would take longer.
Neisser also argues that in visual search where only targets required response, the non-targets are rejected in the preliminary stage and allow targets to pass through and be identified. Thus, Neisser concluded that there is a pre-attentive stage of visual processing which allows us to detect a target without having consciously attended to and decode each background item. Another claim on this theory is about pre-attentive grouping process, which suggests that features within a given map can be formed into coherent clusters. But this view was rejected when Quinlan, (2003) mentioned that in the first stage of the visual search task the position of features from the one object doesn’t need to correspond with one another in a coherent fashion, because coordination of information also does not exist between the different feature maps. As this method fails, it requires an additional process for such positional information to be cross-referenced and accessed.
References:
Treisman A. and Gelade, G. (1980). A feature integration theory of attention Cognitive Psychology, 12(1), p.97-136.
Richard Gross (2005). The Science of mind and behaviour in psychology. 4th Ed. London
Michael W. Passer and Ronald E. Smith (2008). Science of mind and behaviour. 4th Ed. New York.
Michael S. Gazzaniga, Todd F. Heatherton and Diane F. Halpern (2010). Psychological Science. 3th Ed. New York: Psychology Press.
Nick Braisby and Angus Gellatly (2005). Cognitive Psychology. New York.
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