Attention1 PDF

Attention 1 Dr Ntaniella R. Pylarinou  Today’s Session Attention Types of Attention Attention Theories Experiments  Attention Attention is the means by which we actively process a limited amount of information from the enormous amount of information ava...

Attention 1 Dr Ntaniella R. Pylarinou  Today’s Session Attention Types of Attention Attention Theories Experiments  Attention Attention is the means by which we actively process a limited amount of information from the enormous amount of information available through our senses, our stored memories, and our other cognitive processes (De Weerd, 2003a; Rao, 2003). It includes both conscious and unconscious processes. Attention allows us to use our limited mental resources judiciously. By dimming the lights on many stimuli from outside (sensations) and inside (thoughts and memories), we can highlight the stimuli that interest us. This heightened focus increases the likelihood that we can respond speedily and accurately to interesting stimuli. Attention  Attention Heightened attention also paves the way for memory processes. We are more likely to remember information to which we paid attention than information we ignored. Consciousness includes both the feeling of awareness and the content of awareness, some of which may be under the focus of attention (Bourguignon, 2000; Farthing, 1992, 2000; Taylor, 2002). Therefore, attention and consciousness form two partially overlapping sets (Srinivasan, 2008; DiGirolamo & Griffin, 2003).  Attention The concentration of awareness on some phenomenon to the exclusion of other stimuli. Often we need to focus on more than one stimulus operating in the environment Attention is the cognitive process which allows us to do this When paying attention We select We shift We fail We wander We get divided How?  Attention Definition Actively processing a limited amount of information/stimuli from a much-much larger body of information/stimuli that we access via the senses and other cognitive processes. Attention is the cognitive function that allows us to do this Conscious and unconscious processes Limited processing resources Attention allows better use of them Unconscious processing a way to achieve this Memory involved Attending to something carefully maximizes our chances to remember it. Attention “It 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.....It implies withdrawal from some things in order to deal effectively with others.”  Relevant Terminology Orienting Response Responding to a change in the environment Changes ‘grab’ our attention Orienting Reflex Doing the above automatically Channels (of information) Sources of information we may attend to Competing channels exist around us all the time. Filtering Excluding information when focusing on something specific  What is a Filter? First of all, a filter is a metaphorical and theorized device We assume it exists in some form somewhere in the brain/mind Because behaviour when we attend to something makes it imperative that something like it should exist Its role, invariably, is to block some incoming (input) information and allow some to pass through to the next stages in the cognitive system (for processing) This is a technical way to describe how you may be focusing on this presentation when other things are going on around you at the same time The theoretical/metaphorical/assumed device in your minds that allows you to do so is a filter See also later and next lecture  Channels & Filters 3 channels of information in this example ‘Moving’ from left to right Each is carrying specific information  Channels & Filters The filter blocks two channels, allowing only one to pass through to perception We perceive only information from the top channel We have ‘paid attention’ to it  Conscious Attention Three roles Interactions monitoring With the environment Feedback mechanism tells us how well we are adapting to demands of situations Linking of past and present Memories and present experiences Granting a sense of personal continuity Personal identity Future planning Using the information from the first two ‘Manipulating’ information consciously ‘in the mind’. The 4 Types of Attention  Types of Attention Selective Attention Divided Attention Focusing on Allocating attention on one resources on more task at the than one tasks at exclusion of others the same time  The 4 Functions of Attention Signal Detection and Vigilance Detecting appearance of stimuli actively in a busy environment Search Locating one signal/stimulus among distracting stimuli More active than previous Selective Focusing Choosing to focus on one stimulus, ignoring others Mostly what we mean when we say ‘attention’ Divided Focusing Allocating (limited) attentional resources on more than one tasks at the same time  Generally In (visual) search, one has to detect a target in an array with a lot of distractions – What exactly is involved in it? – How do we accomplish it?  Important The previous four functions can also be understood as ‘types’ of attention One should be mindful of this In the rest of the presentations on attention the two, types and functions, will be assumed to be one Mostly, here we shall be taking them and referring to them as ‘types’ However, always, the same four items can and should also be understood as the functions of attention  Signal Detection - Vigilance How do we discriminate between stimuli? Signal Detection Theory (SDT) Framework to explain detection of stimuli Based on criteria used for detection Four possible outcomes  Four possible outcomes: Four possible Hits False alarms Misses Rejections outcomes: True False False True positives positives negatives negatives  Signal Detection - Vigilance Signal detection depends on the criteria used. Too strict criteria Too many misses of targets Too lax criteria Too many false alarms Vigilance “ability to attend to a field of stimulations over a prolonged period, during which the person seeks to detect the appearance of a particular target stimulus of interest.” (p.142) Prolonged vigilance affected by time More misses when tired Expectations of location/appearance Greatly affect performance If/when detected, signals outside the field of focus are detected more slowly  Signal Detection - Vigilance Expectations of locations/ appearance The Greatly affect performance If/when detected, signals outside the field of focus are detected more slowly Have you ever looked for you friends and family in a crowd?  Search Search refers to a scan of the environment for particular features—actively looking for something when you are not sure where it will appear. As with vigilance, when we are searching for something, we may respond by making false alarms. Search is made more difficult by distracters, nontarget stimuli that divert our attention away from the target stimulus. In the case of search, false alarms usually arise when we encounter such distracters while searching for the target stimulus  Search How do we identify target stimuli when distracters are present? Search Scanning the environment for particular features Distracters Divert attention from active scanning Away from the target  Types of search Feature search On the basis of specific features Featural singletons: targets with very distinctive features Capture attention But: distracters can also be featural singletons Conjunction search Looking for a non distinctive item “…identify a red X (target) amongst distracters composed of black Xs (same shape) and red Os (same color)” https://en.wikipedia.org/wiki/Visual_search#Conjunction_search Example of Conjunctive Search  Feature integration theory Feature integration theory is a theory of attention developed in 1980 by Anne Treisman and Garry Gelade that suggests that when perceiving a stimulus, features are "registered early, automatically, and in parallel, while objects are identified separately" and at a later stage in processing. The first stage of the feature integration theory is the preattentive stage. During this stage, different parts of the brain automatically gather information about basic features (colors, shape, movement) that are found in the visual field. The idea that features are automatically separated appears counterintuitive. However, we are not aware of this process because it occurs early in perceptual processing, before we become conscious of the object. The second stage of feature integration theory is the focused attention stage, where a subject combines individual features of an object to perceive the whole object. Combining individual features of an object requires attention, and selecting that object occurs within a "master map" of locations. The master map of locations contains all the locations in which features have been detected, with each location in the master map having access to the multiple feature maps. When attention is focused at a particular location on the map, the features currently in that position are attended to and are stored in "object files". If the object is familiar, associations are made between the object and prior knowledge, which results in identification of that object.  Similarity theory Similarity theory suggests that attention is not drawn to locations but rather to image objects, and that search efficiency depends on similarities between objects in the scene and possible targets (target–distractor similarity) and between objects within the scene (distractor heterogeneity). Feature integration theory and Similarity theory Feature Integration Theory Treisman, 1980 For each possible feature of a stimulus, we have a mental map for representing the given feature across the visual field (p.145) Similarity Theory Duncan and Humphrey, 1989 The more similar a target is to a distracter, the more difficult it is to detect it. “…the difficulty of search tasks depends on the degree of disparity among the distracters. But it does not depend on the number of features to be integrated.” (p.145) Find the Letter R  Types of Searches Guided Search Theory: information from top-down and bottom-up processing of the stimulus is used to create a ranking of items in order of their attentional priority. In a visual search, attention will be directed to the item with the highest priority. If that item is rejected, then attention will move on to the next item and the next, and so forth. The guided search theory follows that of parallel search processing.  Types of Search Guided Search Theory Wolfe, et al, 1994 All searches, feature or conjunction, involve two consecutive stages Parallel All mental representations of potential targets activated Each feature is activated Serial Evaluation of each activated element, according to degree of activation Target is selected from activated Activation guides selection Find the black circle within a field of white circles and black squares.  Selective Attention Selective Attention Ability to focus on one stimulus (or source, channel, target, etc) and ignore another/others What exactly is involved in it? How do we accomplish it?  Dichotic Presentation Paradigm Dichotic presentation (Cherry, 1953) Aka ‘Dichotic listening’, ‘dichotic task’ etc Research paradigm/method in selective attention Different message to each ear Headphones Repeat back one one of the messages as soon as heard Shadowing Significant concentration needed  Dichotic Listening Task Cherry’s participants Successfully shadowed the attended channel Physical changes were also detected in the unattended channel Words to tone Male to female voice Unable to detect semantic changes in the unattended channel Language change from English to German Message played backwards Able to hear their names in the unattended channel The Cocktail Party Phenomenon (‘Effect’) a. Being able to focus on one selected channel of information When in a noisy environment A lot of distracters When engaged in a conversation Attending to a specific information channel b. Being able to hear one’s name In environment with a lot of competing sources of information Noise According to the CPP (or CPE) Spontaneous orienting responses are produced when certain types of information become available. The Cocktail Party Phenomenon (‘Effect’) If attention involves processing the attended information channel only, How is the CPP possible? How is knowing some characteristics of the information in the non-shadowed channel possible? (In Cherry’s dichotic presentation) Clearly unattended information must get processed. How?  Examples of Attention Selective attention https://www.youtube.com/watch?v=vJG698U2Mvo https://www.youtube.com/watch?v=U1saQoMRD8A Door study https://www.youtube.com/watch?v=vBPG_OBgTWg Distorted faces https://www.youtube.com/watch?v=ZtzZZfacBYc  Sources Matlin & Farmer : Chapter 3 – 46-53 – 57-59 Sternberg and Sternberg Chapter 4