Analysis and Description of the Concept of Selective Attention - Essay Example

Spatial Attention in Referencing Structure Your name Institutional Affiliations High level vision is a process that involves object recognition, selective attention, and visuomotor action, at the interface of perception and cognition. This article focuses mainly on the selective attention. This is a set of process that allows selection of some stimuli over others and the performance of multiple tasks in a coordinated manner. Visuospatial attention is the process that select visual stimuli based on their spatial location (Wu, 2007). Therefore, spatial attention refers to the most widely studied variety of attention in normal population and neurologic populations. Attentional process is used to protect an organism from information overload and is selective in that they allow some processes of some stimuli while disregarding others. Thus, attention can be referred to as the process that permits an organism to choose some environmental inputs over the others. The term “attention” appears in everyday language, but this initiative which folk psychology use does not provide facts on the definition of solid. Task defined attention does not explain the process that permit the selection to occur. For example, when an observer views two spatially adjacent letters, red and green, and asked to report the red letter (LoBosco & City University of New York, 2006). Although this task requires the observer to pay maximum attention to the red letter, it does not eliminate the mechanism of attention, such as whether or not if they attended letter is facilitated relative to the unattended letter, whether or not the unattended letter is inhibited average to the attended letter or both. Li & The University of Wisconsin- Madison (2008) assert that a process oriented definition of attention proposes how attention allows the red letter so that to be attended and reported and how the green light is unattended. For instance, the most well known process oriented definition of attention comes from Williams James, who defined attention as the process that involves withdrawal from some things in order to deal effectively with others. According to James, attention restricts processing items over others and allows the attended item to become more salient. He relays on the process oriented definition of attention and consider mechanisms that allow observers to select one spatial location over other locations. Initially, understanding the operation of spatial attention in neurologically normal observers can help guide assessment in brain damage patients. Through knowing the process of spatial attention, disruption may be of much significance for developing assessment techniques or care giving strategies and rehabilitation. The whole process involves selecting a stimulus on the basis of its spatial location. The place occupied by the item is selected and then receives further cognitive processing (Li & The University of Wisconsin- Madison, 2008). Visuospatial attention also intersects with much other attentional process. For instance, it can select groups of items, based on how they adhere or grouped together. This form of selection has being referred as object formed selection. This spatial attention is closely associated with early processing, before stimulus identity is known. Attention is directed to a location in which visual space and an item is identified, through facilitating the perception or binding the features of that item. There are many varieties of attention and attentional selection. Attentional mechanisms operate earlier and others later in this framework. Two experimental paradigms which were carried out have contributed to the understanding of spatial attention. They include the spatial cuing paradigms and visual search paradigms. In a typical spatial cuing paradigm, there is a stimulus or instruction which precedes a target stimulus. This instruction is referred to as the “precue”; hence the cue either predicts the target’s location or does not predict the target location. When this is put into an experiment, they came up with a result that observers typically respond fastest to valid trials and slowest to invalids trials, and this difference can be referred to as an attentional effect (Horowitz, 2005). Much researcher use combined cue and target durations of less than 200ms so that to ensure they are studying effects of covert spatial attention shifts and not overt eye fixation position changes. However, this minimizes the chance of making eye movements to cued location since it typically takes approximately 200 ms so that to program and execute a saccadic eye movement to a location. Other study monitored eye position so that to ensure fixation does not deviate from the central fixation point. Moreover, observers typically detect validly cued targets faster than invalidly cued targets, hence indicating that attention can affect the time to detect a target, even in the absence of an eye movement. According to Itti et al. (2005), spatial attention investigators have researched the effects of the two types of spatial precues. This include: peripheral precues that appear abruptly at a potential target location and central, symbolic precues, such as arrows that point towards a potential target location. Central cues and peripheral control attention differently observers cannot ignore peripheral cues, which appear to attract the attention to the cued location automatically, and observers can ignore central cues if instructed to do so. Secondly, peripheral cues tend to operate faster than central cues hence the difference between valid and invalid trials emerges sooner with peripheral cues than with central cues. Moreover, peripheral cues are not affected by the concurrent working memory task in which observers remember a string of digits; central precues, in contrast, are less capable to direct attention when working memory is occupied with digit string (Itti et al., 2005). Fourthly, peripheral cues can interrupt the attentional orienting products by central cue, but central cues affect orienting from peripheral cues little, if at all. Finally, studies that use central symbolic cues tend to present more valid trials than invalid trials so that to encourage observers to attend to the cued location. For example, 75% of the trials may be valid and 25% invalid. In contrast, peripheral cues summon attention to the cued location even if there is equality in valid and invalid trials occur equally and even if valid trials are less frequent than invalid trails e.g. in the ration 1:3 respectively. Mangun (2012) stipulates that even though observers usually respond faster in valid trials than invalid trials, this pattern, referred to as attentional effect can be reversed under some situations. This is because invalid cued targets can be detected faster than validly cued targets. During the study of unpredictable peripheral cues, observers respond faster to valid trials than invalid trails when the interval between the cue and the target is less than 200ms. When the interval exceeds 200ms, observers respond faster to targets at the invalid trials. This effect is known as inhibition of return. It has been recommended because it facilitates visual search, or visual foraging, by reducing the chances that previously attended location be re-attended shortly after attention is withdrawn from that region. Furthermore, research is needed to test this hypothesis since the findings of inhibitory tagging in visual search have not always been replicated. According to Bundesen (2008), a second paradigm used to investigate spatial selection is the visual search paradigm. Visual search is the act of looking for a visual target among distracters e.g. finding a friend’s face in a crowded room. It mostly emphasizes on the numbers of distracters the set size is varied across trials, and reaction time is being measured as a function of the set size. There are two approaches of spatial attention: how is spatial attention controlled and what are the effects of directing spatial attention controlled. Attentional control involves those processes and parameters that determine which items become attended and which do not. These parameters determine which items attention selects. For example, abrupt appearance of stimuli, such as peripheral cue, controls the allocation of the attention of capturing the attention automatically. Another important issue in the study of attention is how an attended stimulus tends to processed differently from an unattended stimulus. For example, the representation of the neural of an attended item could be facilitated relative to the representations of unattended items (Mangun, 2012). There are several effects of attention which were highlighted in recent theories and supported by empirical data: I. Attention reduces an observer uncertainty in making judgments about stimulus. Under this, maximum performance decreases as the number of stimuli increases, because each stimulus contains some uncertainty. Therefore, attention reduces the random noise which is associated with the attended stimulus. II. Attention also may reduce noise at a perceptual level of representation by enhancing the signal to noise ratio of attended items. This effect of attention is to allow attended items to be of higher fidelity than unattended items. III. Attention is needed to bind together the features of an object. This is done by giving the attention on single stimulus, thereby gluing the features together (Mangun, 2012). By directing spatial attention to a specific location, reduces the number of incorrect feature combinations at that attended locations. IV. It has the effect of increasing the spatial resolution of perception. Multiple stimuli that appear in the lower visual field can be distinguished from one another than multiple stimuli which appear in the upper visual field, possible as a result of parietal lobe attentional processes. Thus, the difference in spatial attention between the upper and lower fields are produced when multiple stimuli are close to one another and require attention to be “narrowed” around single target stimulus (Mangun, 2012). V. Lastly, spatial attention influences the entry of items into visual short-term memory. When the appearance of many visual objects must be retrained across a delay, the short term memory process is required to retrain three to four of the objects. Attention can be controlled by several factors. Some are environmental factors such as the appearance of new events. Others are endogenous factors that arise from within the observer based on goals or expectations. The disorder of attention in parietal damaged patients seems to involve bottom up control parameters (Freksa, 2005). However, this does not suggest that neglect is a sensory level impairment. Perceptual that comes as result of processing may be largely intact in neglect patients, but attention is not effectively captured by stimuli on the other side of space. Spatial attention seems to increase the spatial resolution of perception. Parietal patients help to solve the binding problem of spatial attention. Also, results of parietal patients suggest that spatial attention involves in binding the features of objects, because these patients misconjoin features and shows high rates of illusory conjunctions. Patients with damage network of structures that mediate attention, especially parietal lobe areas, have a variety of different attentional impairments (Freksa, 2005). The lack of capture also, may prevent the damage of hemisphere from competing with the intact hemisphere for attention, resulting in an attentional imbalance that seems to favor the ipsilesional. One area of spatial attention studied in patients with frontal lobe damage is the control of the production of eye movements. Initially, directing the eyes to a region of space is preceded by directing covert spatial attention to the target regions lesions of superior frontal lobe areas that include the frontal eye fields seem to disrupt some types of overt eye movements (Bundesen, 2008). In summary, attention can be viewed as a general term in everyday folk and psychological use. Through research, cognitive psychology allows focus on the process associated with attention. Attention is necessary for eliminating unwanted sensory input or irrelevant behavioral tasks and is useful when some cognitive system receives too many inputs. Its role is to restrict the number of inputs and allow the processing to continue in an effective manner. Even though there are many forms of attention, spatial attention is the most studied and perhaps the best to understood the form of selection. Despite the knowledge of attention, there are gaps that still remain in the knowledge of the mechanisms involved in attending to space. In this paper, we presented an analysis of frames of references, positional information, and their interdependencies. We examined what types of frames of reference and positional information can be distinguished, hence we can review their results in setting of navigational assistance. In the future, we plan to investigate further means to enable a system to adapt to varying conditions in terms of information quality and re-source availability. One point that we intend to focus on is the adaption to incomplete positional information by means of contextual reasoning with the human user. References Bundesen (2008). Visual Selective Attention: A Special Issue Of The Journal Visial Cognition. Oxford: Psychology Press. Freksa, C. (2005). Spatial cognition 4. New York: Springer. Horowitz, T. (2005). Spatial Attention: Inhibition of Distractor Locations. University of California: University of California Press. Itti, L., Rees, G. and Tsotsos, J. (2005). Neurobiology Of Attention. London: Academic Press. Li, X. and The University of Wisconsin- Madison (2008). Saccade Target Selection and Spatial Attention in the Superior Colliculus. New York: ProQuest. LoBosco, J. and City University of New York, (2006). Assessing Spatial Attention in Healthy Younger and Older Adults. New York: ProQuest. Mangun, G. (2012). Neuroscience of Attention: Attentional Control and Selection. Oxford University: Oxford University Press. Wu, C. (2007). Inhibition of Return: Is Spatial Attention Necessary for Visual Word Recognition? New York: ProQuest. Read More