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Chapter 4

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Simon Fraser University
PSYC 221
Thomas Spalek

Chapter 4: Attention Multiple Meanings of Attention Four meanings of attention that we will use: 1. Alertness and arousal 2. Orienting and searching 3. Filtering and selecting 4. Mental resources and conscious processing Basics of Attention 2 rather general definitions for attention: Attention as a Mental Process Attention – the mental process of concentrating effort on a stimulus or a mental event - Attention is an activity that occurs within the cognitive system, a process which focuses a mental commodity (effort) on either an external stimulus or an internal event - Here we are focusing on driving the mental event of remembering, searching for information stored in your long-term memory, attempting to comprehend Attention as a Limited Mental Resources Here, attention is the limited mental energy or resource that powers the mental system - Attention is the all-important mental resource necessary to run the cognitive system, to make it operate Fundamentally important idea: notion of limitations: attention is limited, finite - The attentional system has a limited capacity to attend to stimuli, to remember events that just happened, to remember things we are supposed to do o There is a limit to how many different things we can attend to and do all at once Alertness and Arousal Alertness – the basic capacity to respond to the environment Arousal – a necessary state of the nervous system Physiological level – arousal is at least partly a function of the reticular activating system (RAS), a lower brain stem system in charge of, among other things, basic arousal and consciousness States of alertness and arousal may last for relatively long periods of time and change rather gradually - Changes are called tonic o Best example of tonic changes: sleep-wakefulness cycle – light-dark cycle, a biological clock controls many physiological parameters (like body temperature), 1 Psychology 221 and causes us to become tired and fall asleep (usually in the evening) and wake up from sleep (usually in the morning) - Alertness and arousal may also be controlled phasically o For example: when a sudden, unexpected change in the environment is detected o These changes can also be produced voluntarily Explicit Processing – conscious processing, conscious awareness that a task is being performed, and usually conscious awareness of the outcome of that performance Implicit Processing – processing in which there is no necessary involvement of conscious awareness - Ex: demonstrating memory for information without being aware of remembering it Some important mental processing can be accomplished with only minimal attentional involvement Orienting and Searching Orienting refers to the alignment of information pickup mechanism with a source of information - It can be controlled reflexively in response to sudden changes in the environment or voluntarily in response to our own intentions o Distinction is called bottom-up and top-down processing Reflexive Orienting Orienting Reflex (Orienting Response) – the reflexive redirection of attention that orients you toward the unexpected stimulus - It is initiated by external stimulation and often involves the redirection of sensory receptors toward the source of this stimulation o In visions this is accomplished by eye and head movements  When such an orienting reflex can be observed in the behavior of the organism – is referred to as an overt reflexive orienting o When one’s eyes and head remain stationary, unexpected events can elicit reflexive redirection of attention in the form of internal (mental) adjustments of information processing  Is called covert reflexive orienting – is a kind of orienting of attention without the assistance of an overt response - Whether the orienting reflex is overt or covert, current thinking suggests that is it a location-finding response of the nervous system o An unexpected stimulus can trigger the reflex so that you can locate the stimulus, find where it is in space, and respond to it approximately 2 Psychology 221 o The orienting reflex enables you to protect yourself against danger, in the reflexive, survival sense There are 2 basic categories of stimuli that trigger the orienting reflex: 1. Stimuli that are significant for the organism 2. Stimuli that are novel a. We orient toward a novel stimulus in an otherwise constant, unchanging, even monotonous background - We orient when something different occurs: the unexpected sound in the quiet library, sudden and unexpected movement, the change in pitch in a professor’s voice during a lecture, maybe the word different in italics in a textbook paragraph o Orienting focuses the organism so it can devote deliberate attention to the stimulus if warranted  Cowan called these voluntary attentive processes - Sometimes a stimuli can become habituated (habituation) – a gradual reduction of the orienting response back to baseline with repeated stimulation Voluntary Orienting Voluntary control over orienting can and often does involve overt changes, as when we shift our gaze so that the sensitive fovea will be directed to objects in and regions of space containing the information we are seeking But just as reflexive orienting can control attention covertly without an overt shift of gaze, so too can voluntary orienting A Spatial Cueing Task for Exploring the Spotlight of Attention Posner + Colleagues – developed a model task for exploring covert orienting of attention in the visual modality - 2 versions of this task: o 1. For exploring voluntary control o 2. For exploring o g reflexive control Read 3 and 4 paragraph of page 131 to page 134 Visual Search Disjunction condition – the search for a simple feature Conjunction condition – the search for two simultaneous features Tresman and Gelade – concluded: visual search for a dimension. Like shape or colour, occurs in oarallel across the entire region of visual attention 3 Psychology 221 - such a search must be largely automatic and must represent very early processing For conjuction of features, they took more time - so these sarches must be ccuring in a more serial, one-by-one fashion and seemed to be a far more conscious and deliberate act One clear-cut conclusion: Treismans 2 conditions provided clear evidence of both a very quick, automatic attentional process, and a much slower, serial, and more deliberate attention - more accurate to consider each search mode as having both reflexive and voluntary components, with the balance favouring reflexivive control in ‘pop-out’ search (disconjunction condition) and favouring voluntary control in serial search - Unless the items are very small or the target is camouflaged (foveation), these function are more or less the same whether subjects are allowed to move their eyes or are precluded from moving their eyes in their search for the target o Foveation – an eye movement that places the region of a scene that requires fine, detailed processing onto the sensitive fovea Two qustions about he guidance system for the serial search: 1. How does the system decide the order in which objects or regions of the display will be inspected 2. Once a sequence of inspections has begun, how does the system keep trach of which objects and regions have already been inspected Generally believed: bottom-up and top-down signals contribute to something call an activation map that controls orienting - The most activated region in this map will guide attention toward inspecting the object(s) in the selected region o Problem with this: after this region is inspected, without some reduction in its activation level, two things happen:  1. It will remain the most activated region  2. The inspection process will perseverate (keep returning to the most salient region)  3. Search will fail (unless this region contains the target) Filtering: Voluntary Control of Selective Attention Controlled attention – form of processing in which there is a deliberate, voluntary allocation of mental effort or concentration Critical feature of situation requiring controlled attention ins the competition between inputs for the control of actions - Ex: You decide which stimulus to pay attention to 4 Psychology 221 Selective Attention – the ability to attend to one source of information while ignoring or excluding other ongoing messages around us Dividing our attention between two demanding tasks is difficult Selective Attention and the Cocktail Party Effect Filtering/ Selecting- the mental process of eliminating distractions and unwanted messages - Does this so we can select the one message we want to pay attention to For seeing – choose what we want to see by directing our eyes towards it For hearing – if we cannot avoid hearing something, we then must select among the stimuli by some mental process, filtering out the unimportant and attending to the important Dual Task Procedures We can overload the sensory system by presenting more information than it can handle at once and then test accuracy for some part of the information In studies of auditory perception, this has usually involved a dual task procedure – two tasks or messages are presented such that one task or message consumes the person’s attentional resources as completely as possible The initial encoding of the messages in auditory sensory memory included purely auditory features like pitch and intonation The Shadowing Experiments Shadowing task – a task in which subjects hear a spoken message and must repeat the message out loud in a very short time - Often used as one of the two tasks in a dual task method (experiment) Selection moods People can select a message based on Stage 1 sensory information – based on loudness, location of the sound source, pitch, etc Broadbent’s Filter Theory The auditory mechanism acts as a selective filter - Regardless of how many competing channels or messages are coming in, the filter can be tuned, or switched, to any one of the messages, based on characteristics like loudness or pitch - Only one message can be passed through the filter at a time o So only one message can enter the “limited capacity decision channel” at a time - Only the information on the attended, “passed-along” message can affect performance because only it gets past the filtering mechanism Broadbent’s Theory shortcomings: 1. Intuition tells us that we often notice information from a message we are not attending to 5 Psychology 221 a. Unattended information could somehow slip past the filter Treisman’s Attenuation Theory Treisman – semantic elements of the unattended channel must be receiving some analysis - He rejected the ‘early selection’ notion embodied in Broadbent’s theory, Eysenck’s stage 1 selection - Claimed all incoming messages receive some amount of low-level analysis – including the analysis of the physical characteristics of the message - When the attenuated, in Treisman’s terms; they reduced not in their volume or physical characteristics but in their informational importance to ongoing processing - In the process of shadowing, we arrive at an identification of the words and phrases on the attended message Decided it was during the process of semantic analysis that we make our selection among messages (stage 2) - Permits attention to be affected by the semantic aspects of the message – top-down effect Extreme view by Deustch and Deustch – selection takes place only after all messages have received full acoustic and semantic analysis - It’s is the late selection theory (Stage 3 in Eysenck’s terminology) - The outcome of all earlier analyses become more conscious Norman’s Pertinence Model Usefully modified Treisman’s scheme His model included a mechanism for top-down processing Model claims that at any instant in time, attention to some piece of information, some messag, is determined by two factors: 1. Sensory activation a. If the message is loud, in a distinct voice, or otherwise salient from a sensory standpoint  sensory activation will be high 2. Pertinence a. At any moment in time, certain things – ideas, words, and so forth – are highly
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