attention attention attention is the concentration of awareness on some phenomenon to the exclusion of other stimuli. it is a process of selectively concentrating on a discrete aspect of information, whether considered subjective or objective. william james (1890) wrote that "attention is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. focalization, concentration, of consciousness are of its essence." attention has also been described as the allocation of limited cognitive processing resources. attention is manifested by an attentional bottleneck, in terms of the amount of data the brain can process each second; for example, in human vision, only less than 1% of the visual input data (at around one megabyte per second) can enter the bottleneck, leading to inattentional blindness. cognitive psychology perception visual perception object recognition face recognition pattern recognition attention memory aging and memory emotional memory learning long-term memory metacognition language metalanguage thinking cognition concept reasoning decision making problem solving numerical cognition numerosity adaptation effect approximate number system parallel individuation system focused attention attention remains a crucial area of investigation within education, psychology, neuroscience, cognitive neuroscience, and neuropsychology. areas of active investigation involve determining the source of the sensory cues and signals that generate attention, the effects of these sensory cues and signals on the tuning properties of sensory neurons, and the relationship between attention and other behavioral and cognitive processes, which may include working memory and psychological vigilance. a relatively new body of research, which expands upon earlier research within psychopathology, is investigating the diagnostic symptoms associated with traumatic brain injury and its effects on attention. attention also varies across cultures. the relationships between attention and consciousness are complex enough that they have warranted perennial philosophical exploration. such exploration is both ancient and continually relevant, as it can have effects in fields ranging from mental health and the study of disorders of consciousness to artificial intelligence and its domains of research. contemporary definition and research prior to the founding of psychology as a scientific discipline, attention was studied in the field of philosophy. thus, many of the discoveries in the field of attention were made by philosophers. psychologist john b. watson calls juan luis vives the father of modern psychology because, in his book de anima et vita (the soul and life), he was the first to recognize the importance of empirical investigation. in his work on memory, vives found that the more closely one attends to stimuli, the better they will be retained. by the 1990s, psychologists began using positron emission tomography (pet) and later functional magnetic resonance imaging (fmri) to image the brain while monitoring tasks involving attention. considering this expensive equipment was generally only available in hospitals, psychologists sought cooperation with neurologists. psychologist michael posner (then already renowned for his influential work on visual selective attention) and neurologist marcus raichle pioneered brain imaging studies of selective attention. their results soon sparked interest from the neuroscience community, which until then had simply been focused on monkey brains. with the development of these technological innovations, neuroscientists became interested in this type of research that combines sophisticated experimental paradigms from cognitive psychology with these new brain imaging techniques. although the older technique of electroencephalography (eeg) had long been used to study the brain activity underlying selective attention by cognitive psychophysiologists, the ability of the newer techniques to actually measure precisely localized activity inside the brain generated renewed interest by a wider community of researchers. a growing body of such neuroimaging research has identified a frontoparietal attention network which appears to be responsible for control of attention. selective and visual in cognitive psychology there are at least two models which describe how visual attention operates. these models may be considered metaphors which are used to describe internal processes and to generate hypotheses that are falsifiable. generally speaking, visual attention is thought to operate as a two-stage process. in the first stage, attention is distributed uniformly over the external visual scene and processing of information is performed in parallel. in the second stage, attention is concentrated to a specific area of the visual scene (i.e., it is focused), and processing is performed in a serial fashion. the first of these models to appear in the literature is the spotlight model. the term "spotlight" was inspired by the work of william james, who described attention as having a focus, a margin, and a fringe. the focus is an area that extracts information from the visual scene with a high-resolution, the geometric center of which being where visual attention is directed. surrounding the focus is the fringe of attention, which extracts information in a much more crude fashion (i.e., low-resolution). this fringe extends out to a specified area, and the cut-off is called the margin. the second model is called the zoom-lens model and was first introduced in 1986. this model inherits all properties of the spotlight model (i.e., the focus, the fringe, and the margin), but it has the added property of changing in size. this size-change mechanism was inspired by the zoom lens one might find on a camera, and any change in size can be described by a trade-off in the efficiency of processing. the zoom-lens of attention can be described in terms of an inverse trade-off between the size of focus and the efficiency of processing: because attention resources are assumed to be fixed, then it follows that the larger the focus is, the slower processing will be of that region of the visual scene, since this fixed resource will be distributed over a larger area. it is thought that the focus of attention can subtend a minimum of 1° of visual angle, however the maximum size has not yet been determined. a significant debate emerged in the last decade of the 20th century in which treisman's 1993 feature integration theory (fit) was compared to duncan and humphrey's 1989 attentional engagement theory (aet).: 5–7 fit posits that "objects are retrieved from scenes by means of selective spatial attention that picks out objects' features, forms feature maps, and integrates those features that are found at the same location into forming objects." treismans's theory is based on a two-stage process to help solve the binding problem of attention. these two stages are the preattentive stage and the focused attention stage. preattentive stage: the unconscious detection and separation of features of an item (color, shape, size). treisman suggests that this happens early in cognitive processing and that individuals are not aware of the occurrence due to the counter intuitiveness of separating a whole into its part. evidence shows that preattentive focuses are accurate due to illusory conjunctions. focused attention stage: the combining of all feature identifiers to perceive all parts as one whole. this is possible through prior knowledge and cognitive mapping. when an item is seen within a known location and has features that people have knowledge of, then prior knowledge will help bring features all together to make sense of what is perceived. the case of r.m's damage to his parietal lobe, also known as balint's syndrome, shows the incorporation of focused attention and combination of features in the role of attention. through sequencing these steps, parallel and serial search is better exhibited through the formation of conjunctions of objects. conjunctive searches, according to treismans, are done through both stages in order to create selective and focused attention on an object, though duncan and humphrey would disagree. duncan and humphrey's aet understanding of attention maintained that "there is an initial pre-attentive parallel phase of perceptual segmentation and analysis that encompasses all of the visual items present in a scene. at this phase, descriptions of the objects in a visual scene are generated into structural units; the outcome of this parallel phase is a multiple-spatial-scale structured representation. selective attention intervenes after this stage to select information that will be entered into visual short-term memory.": 5–7 the contrast of the two theories placed a new emphasis on the separation of visual attention tasks alone and those mediated by supplementary cognitive processes. as rastophopoulos summarizes the debate: "against treisman's fit, which posits spatial attention as a necessary condition for detection of objects, humphreys argues that visual elements are encoded and bound together in an initial parallel phase without focal attention, and that attention serves to select among the objects that result from this initial grouping.": 8 neuropsychological model in the twentieth century, the pioneering research of lev vygotsky and alexander luria led to the three-part model of neuropsychology defining the working brain as being represented by three co-active processes listed as attention, memory, and activation. a.r. luria published his well-known book the working brain in 1973 as a concise adjunct volume to his previous 1962 book higher cortical functions in man. in this volume, luria summarized his three-part global theory of the working brain as being composed of three constantly co-active processes which he described as the; (1) attention system, (2) mnestic (memory) system, and (3) cortical activation system. the two books together are considered by homskaya's account as "among luria's major works in neuropsychology, most fully reflecting all the aspects (theoretical, clinical, experimental) of this new discipline." the product of the combined research of vygotsky and luria have determined a large part of the contemporary understanding and definition of attention as it is understood at the start of the 21st-century. multitasking and divided multitasking can be defined as the attempt to perform two or more tasks simultaneously; however, research shows that when multitasking, people make more mistakes or perform their tasks more slowly. attention must be divided among all of the component tasks to perform them. in divided attention, individuals attend or give attention to multiple sources of information at once or perform more than one task at the same time. older research involved looking at the limits of people performing simultaneous tasks like reading stories, while listening and writing something else, or listening to two separate messages through different ears (i.e., dichotic listening). generally, classical research into attention investigated the ability of people to learn new information when there were multiple tasks to be performed, or to probe the limits of our perception (c.f. donald broadbent). there is also older literature on people's performance on multiple tasks performed simultaneously, such as driving a car while tuning a radio or driving while being on the phone. the vast majority of current research on human multitasking is based on performance of doing two tasks simultaneously, usually that involves driving while performing another task, such as texting, eating, or even speaking to passengers in the vehicle, or with a friend over a cellphone. this research reveals that the human attentional system has limits for what it can process: driving performance is worse while engaged in other tasks; drivers make more mistakes, brake harder and later, get into more accidents, veer into other lanes, and/or are less aware of their surroundings when engaged in the previously discussed tasks. there has been little difference found between speaking on a hands-free cell phone or a hand-held cell phone, which suggests that it is the strain of attentional system that causes problems, rather than what the driver is doing with his or her hands. while speaking with a passenger is as cognitively demanding as speaking with a friend over the phone, passengers are able to change the conversation based upon the needs of the driver. for example, if traffic intensifies, a passenger may stop talking to allow the driver to navigate the increasingly difficult roadway; a conversation partner over a phone would not be aware of the change in environment. there have been multiple theories regarding divided attention. one, conceived by kahneman, explains that there is a single pool of attentional resources that can be freely divided among multiple tasks. this model seems oversimplified, however, due to the different modalities (e.g., visual, auditory, verbal) that are perceived. when the two simultaneous tasks use the same modality, such as listening to a radio station and writing a paper, it is much more difficult to concentrate on both because the tasks are likely to interfere with each other. the specific modality model was theorized by navon and gopher in 1979. however, more recent research using well controlled dual-task paradigms points