Cognitive Psychology Lesson 5 Selective Attention PDF

COGNITIVE PSYCHOLOGY LESSON 4 The study of attention What is attention? [Attention] is the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thoughts. … It implies withdrawal from some things in order to d...

COGNITIVE PSYCHOLOGY LESSON 4 The study of attention What is attention? [Attention] is the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thoughts. … It implies withdrawal from some things in order to deal effectively with others. —William James, Principles of Psychology Signal detection and vigilance Visual search Selective attention Divided attention [multi-tasking]  Signal detection WWII How easy or difficult it is for radar to detect an aircraft when it is also being exposed to a lot of “background noise” (e.g., birds, light aircraft, clouds) How easy or difficult it is for someone to detect Origins effectives of radar (detecting a plane vs something when they’re also being exposed to a detecting noise) lot of background noise Applications eyewitness testimony Humans notice things based on how strong the effectiveness of medication and side effects stimulus is and how much attention they’re Driving tech – traffic signals in fog / impact detection paying Signal detection theory – detecting a target Sensitivity is the ability to distinguish the presence of a signal from its absence [percentage of Hits + Correct Rejections] Bias is the overall tendency to state that a signal is present (e.g., incentive, importance of detection) Norms for any task, one can develop norms from which to compare a new performance against Vigilance - Vigilance decreases over time, increasing misses and reducing response accuracy (air traffic controllers). Amygdala and thalamus are crucial for vigilance; emotional stimuli can enhance alertness Signal detection theory These measures are now routinely assessed in such diverse areas as memory medicine and clinical diagnosis library science weather forecasting and automatic hazard detection by motor vehicles A frequent goal is to examine how closely human decision-making approaches the theoretical optimum described by SDT How humans make decisions under uncertainty The goal of any person with a choice to make involves cutting through all the nonsense to get to the heart of the matter Examples: eyewitness testimony, perception of crime, language (“acceptability of a sentence” for native speakers Visual Search Scanning the environment for specific items Searching for a person in a crowd Searching for products on a shelf Ignoring “distractors” Feature-Integration Theory (Anne Treisman, 1986) Features [color, shape, size, visual orientation, etc] are processed in parallel / simultaneously That’s why we can find the T and the red dot easily Evidence: Feature detectors in the cortex respond to specific orientations (Hubel & Wiesel, 1979) Share features Fewer features Distinguishing to process features Visual Search Similarity Theory (John Duncan, 1992) The difficulty of detecting a target stimulus increases as its similarity to distractors increases Target detection is influenced more by feature similarity than by the process of integrating multiple features It is less influenced by the number of features Example: even with few features, it’s the strength of similarity that makes the task on the right difficult ➔ Example: words written in lower case are easier to read than words written in uppercase Upper case letters have greater similarity and few distinguishing features Find the black filled circle  Visual Search – dot probe task Effects of emotional state on visual search (Eysenck, Mathews, and MacLeod, 1987) Visual search is guided by emotional state Stimulus that is congruent with one’s emotional concerns attracts attention and is easier to notice Example: a person who finds angry faces especially concerning and threatening, will direct their attention to an angry face before a face with any other expression The task is to detect the ‘probe’ which can be on the left or the right, as quickly as possible Before the probe appears, angry and non-angry faces are flashed on the screen, and replaced by the probe If the participant is quicker to detect the probe when it is on the same side as the angry face than when it is on the other face, then this speeded response must be because the participant was already looking at the angry face when the probe appeared In fact, there is an anger superiority effect for faces in a crowd (next page) Similar findings have been found with sad faces when the respondent has been diagnosed with depression  Selective Attention The dot-probe is like to measure selective attention - the process of focusing on a specific stimulus while ignoring others. Cherry’s Cocktail Party Problem: How can you be ignoring all conversations in a room and just focussing on one, yet be able to recognise your name (if someone mentions it) in the conversations you are ‘ignoring’. You are tracking one conversation among other distracting [more interesting] conversations  Dichotic listening Two different auditory stimuli are presented, one to the left each only and another one to the right ear only. The respondent is instructed to shadow one of the messages (the left or right channel) They are then asked questions about the unshadowed channel Key findings Right-ear advantage In the unshadowed message, people can detect Physical changes Their own name They cannot detect Change in language Voice recording was played backwards  Selective Attention How do people achieve focussing on one conversation in a crowded room? They identify the distinctive features of the speaker’s voice They move close to increase the loudness They prefer to have them on their right-hand side Bottleneck theories of selective attention An assumption: limited capacity So, attention has to be selective Broadbent’s Filter Model (1958) Early stage filtering Filters information early at the sensory level Only one channel is processed Respondent attends to features High level information in unshadowed channel is missed Bottleneck theories of selective attention Moray’s Filter Model (1959) Bottom-up and top-down model Biological & social significance filtering All stimuli are analysed for significance Von Wright et al. (1975): pairing a word with a shock amplify Emotional significance detector Bottleneck theories of selective attention Treisman’s Attenuation Model (1964) Late stage filtering Message switching Bi-lingual respondents Attenuators are like mini volume controls If early detected features seem relevant (not just significance) they are allowed to pass to the next stage Treisman’s model does not explain how exactly semantic analysis works The nature of the attenuation process has never been precisely specified Bottleneck theories of selective attention Deutsch & Deutsch (1963) Late stage filtering All stimuli are analysed for meaning and importance Important stimuli increase an Analysis of arousal response meaning The arousal response affects attentional processing Bottleneck theories of selective attention Neisser (1967) Synthesis model Selective looking – two videos superimposed 80% of respondents did not notice odd events in the unattended video Person walking across the screen with a black umbrella Inattentional blindness Contemporary view: What people notice or fail to notice in unattended ‘distractors’ is dependent upon the extent of ‘high level perceptual load’ (Lavie, 2005) → capacity models of attention Attention Models Single-Pool Models: A single pool of attentional resources can be divided among various tasks. Example: Kahneman's (1973) model suggests that attention can be allocated flexibly across tasks depending on their demands. Limitation: This model oversimplifies attention, as people often perform better with multiple tasks when they are in different modalities. 18