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Chapter 3

Chapter 3

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Chapter 3: Attention Attention is the process that enhances some information and inhibits other information. The enhancement enables us to select some information for further processing and inhibition allows us to set some information aside Attention has three components; orienting to sensory events, detecting signals for focused processing and maintaining an alert state Failures of Selection When there is a lot of information simultaneously present in front of us, we fail to notice all the information all at once. This failure is referred to as failures of selection in space When new information arrives in a rapid stream, spending tie processing it will cause us to miss some other incoming information resulting in failures of selection in time These failures to attend to information are a by-product of a system that prevents us from becoming overloaded with irrelevant information and use a system of selective attention Failures of selection in space An experiment was conducted where experimenter asking for direction was changed. Change blindness: is the failure to detect changes in the physical aspect of a scene Change deafness: is the failure to detect changes in the auditory aspect of a scene The selection of information is not by chance but we select only partial information from the world and leave out the unimportant information Changes in central interest; those that are related to the thematic content of a scene are detected much more quickly than changes of marginal interest Attention is controlled and driven by top-down processing which can change in flexible and dynamic manner Our knowledge, beliefs, goals and expectations can alter the speed and accuracy of processes that select meaningful and desired information from the flood of inputs When there are too many competing stimuli, the top-down processing may be overrriden by a sensory event i.e. by bottom up processing We may also fail to attend to information in space when although there were fewer stimuli but you are required to pay attention to two stimuli at once 1 Concentration on one source of input to the exclusion of the other is known as focused attention When more than one source of information is attended at the same time, the information selected is imperfect and leads to divided attention The loss of information when attention is divided may be because of limited attentional resources; mental effort. When the available capacity is less than required for completion of a task, failures are frequent Failures of Selection in Time We have limitations in terms of the amount of information that we can register at a particular period of time Attentional blink is a short period of time during which incoming information is not registered similar in effect to the physical blanking out of visual information during the blink of an eye. The phenomenon of attentional blind also occurs for two objects that are presented in rapid succession. We detect the earlier stimulus and fail to detect the latter. A similar type of effect involves failure to detect objects presented in a rapid sequence wehen some of these stimuli are identical even when the stimuli are shown for a long enough time to avoid the attentional blink. E.g. study where the first and third stimuli were identical but people failed to notice it and registered the information as just one stimuli Repetition blindness is the failure to detect the later appearance of a stimulus when the stimuli are present in a rapid sequence. Such type of blindness can occur for words as well as for objects Blindness to a repetition can also be observed if several words come between the 2 instances of the repeated word or even if the repeated ones are written in different styles. The second event is just assimilated into the first one Sources of Limitation Limitation is not due to vision but it has to do with the quantity of information. Bottleneck is a restriction on the amount of information that can be processed at once; because of bottleneck some critical mental operations have to be carried out sequentially 2 Divided attention studies demonstrate that performance is hampered when we attend to two stimuli simultaneously Dual-task interference: refers to the added cost in accuracy or reaction time when you attempt to perform two tasks at once. The decrement in the performance is greater when the source of the information is similar e.g. both visual and less when we are attending to information from two different sources e.g. visual and auditory The failure to select information can occur even if the information is presented through two different sensory modalities The extent of interference also depends on the extent of cross-talk between the representations and processes; if similar processes and representations are activated in the two tasks then they may be confused A bottleneck in attention can also occur when even with a single sensory input you are required to provide two outputs i.e. you cannot do two tasks at a time. This corresponds to the failure in motor output when we try to do a number of things at once and this is not because muscles cannot move fast but because brain needs to organize the processing Response bottleneck: The interference in the form of as slowing down of your actions and arises when we try to select between two possible responses through a single sensory stimulus The effect of response bottleneck has been observed in driving where drivers try to use cellphone and drive at the same time which creates a problem and leads to accidents. Study was conducted to test the difference between use of a cellphone, use of a hands-free cellphone and listening to radio. Although, divided attention was observed in all cases but were more pronounced when people were talking rather than listening Problems in Interpretation An effective strategy for multi-tasking would be to simply switch back and forth between the two tasks rather than fully deal with the two situations simultaneously. But the problem is how do we decide the amount of time to spend on each task and when to switch to a different task. When we dual-task, often dual-tasks morph into a single task and make it difficult for us to separate out and quantify performance on each of the tasks. Also, in this procedure of task 3
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