Selective Attention & Inattentional Blindness PDF

Experimental psychologists were able to observe that we seem to perceive only information that receives the focus of our cognitive effort ( = attention ) SELECTIVE LISTENING Dichotic listening → different audio streams are presented to each ear. The task is to repeat each syllable spoken into th...

Experimental psychologists were able to observe that we seem to perceive only information that receives the focus of our cognitive effort ( = attention ) SELECTIVE LISTENING Dichotic listening → different audio streams are presented to each ear. The task is to repeat each syllable spoken into the left ear as quickly and accurately as possible. At this point you won't be able to realize any changes in the speech given in the right ear. → even if the speaker on your right says your name, you will notice it only about one-third of the time. INATTENTIONAL BLINDNESS=the failure to notice unexpected objects or events when attention is focused elsewhere. → we appear to be able to process only one stream of info at a time , effectively filtering other information from awareness→ we perceive only what the focus of our attention is N.B. valid for both auditory ( inattentional deafness) and visual ( inattentional blindness) Study by Neisser: subjects viewed a video of two distinct but partially transparent and overlapping events (so they both produce sensory signals of the retina). Participants were asked to monitor one of the events by counting the number of times the actors performed an action. Results : participants were unaware of events happening outside the focus of their attention A variant of this task was also studied subjects watched a video of two teams of players , one wearing white and one wearing black. They were asked to press a key whenever the players in white successfully passed the ball. Throughout the video , a person wearing a raincoat and carrying an umbrella strolled through the scene Results: people were unable to notice the random person crossing the scene Chabris and Simons Gorilla experiment→ They reviewed these findings after a decade and replicated the experiment but added one change Participants watched a video in which two teams ( white and black t-shirts) are passing a ball to the same team members.. at a certain point in the video, a woman dressed as a gorilla walks into the scene, stops to face the camera, thumps her chest, and then walks off the other side after nine seconds on screen Results : Fully half the observers missed the gorilla when counting passes by the team in white. It is possible now to understand better the factors that cause failures of awareness: how many features an object shares with the attended items in a display e.g. if you count passes by the players wearing black, you are more likely to notice the gorilla than if you count the passes of the white team → even unique items can go unnoticed how mucheffort people put into the attention-demanding task e.g. less likely to notice if the moving is fast and if you have to keep separate counts → you can even miss unexpected visual objects when you devote your limited cognitive resources to a memory task, so not only visual Inattentional Blindness also occurs in the real world under natural conditions Study by Chabris and colleagues: A famous police misconduct case was simulated in which Boston police officer was convicted of lying because he claimes not to have seen a brutal.At the time, he had been chasing a murder suspect and ran right past the scene of a brutal assault. In Chabris' simulation, subjects jogged behind an experimenter who ran right past a simulated fight scene. Results: At night, 65 %missed the fight scene.\-- Even during broad daylight, 44 % of observers jogged right passed it without noticing, lending some plausibility to the Boston cop's story that he was telling the truth and never saw the beating. auditory distractions can induce failures to see e.g. talking on the phone while driving decreases awareness INATTENTIONAL DEAFNESS= people fail to notice an unexpected sound or voice when attention is devoted to other aspects of a scene. 1\. how much attention is needed 2\. how much they ignore some items on a scene 3\. how much we are distracted →few studies suggest that those people who have a greater working memory capacity are more likely to notice unexpected objects → more resources available when focusing attention → more likely to spot and focus on different aspects criticism : contrary study results that show that if you have working memory you will be not able to notice more things →controversial , needs more research Why do we have such mistaken intuitions ?- we might let our experiences mislead us→ we use ourexperiences to analyze the world ( we don't think we have missed ) → we assume our experiences are representative of the state of the world e.g. drivers do not notice how distracted they are when they are talking non a phone, so they believe they can drive just as well ATTENTION AND CONSCIOUSNESS Colin Cherry observed the phenomenon of the cocktail party problem = process of tracking one conversation in the face of the distraction of other conversations. He wanted to study selective attention in a more experimental setting by designing a task known asshadowing→you listen to two different measures simultaneously ( = dichotic presentation ). You are required to repeat back only one of the messages as soon as possible after you hear it. In other words, you are to follow one message (think of a detective "shadowing" a suspect) but ignore the other. Results : Subjects were quite successful in shadowing distinct messages but it required significant concentration.\-- subjects were able to notice physical, sensory changes in the unattended message but could not notice semantic changes in the unattended message. About ⅓ of people will switch their attention if they hear their name → they tend to have limited working-memory capacity→ easily distracted. Three factors help people to attend to a message 1\. distinctive sensory characteristic of the target's speech ( most important factor ) e.g. high/low pitch, pacing, rhythmicity 2\. sound intensity (loudness) 3\. location of the sound source THEORIES OF SELECTIVE ATTENTION These theories belong to the group of filter and bottleneck theories → they explain how we cannot attend to all sensory inputs at one time in the conscious level a filter blocks some of the info going through and thereby selects only a part of the total of info to pass though the next stage bottleneck slows down info passing through Broadbent\'s Model → we filter information right after we notice it at a sensory level. → multiple channels of sensory input reach an attentional filter ( each one with different characteristics ) which permits only one channel of sensory information to proceed and reach the processes of perception N.B. Sensory information sometimes may be noticed by an unattended ear if it does not have to be processed elaborately e.g. you may notice that the voice in your unattended ear switches to a tone. But information requiring higher perceptual processes is not noticed if not attended to e.g., you would likely not notice that the language in your unattended ear switches from English to German. Selective Filter Model ( Moray) →selective filter blocks out most information at the sensory level but some personally important messages are so powerful that they burst through the f ilter. → Moray found that even when participants ignore most other high-level aspects of an unattended message, they frequently still recognize their names in an unattended ear However , Moray's modification of Broadbent's filtering mechanism was clearly not sufficient to explain Treisman's Attenuation Model Attenuation Model ( Treisman) → at least some information about unattended signals is being analyzed → She proposed that a filtering mechanism is present and instead of blocking stimuli out, the filter merely weakens (attenuates) the strength of stimuli other than the target stimulus. In the next step, we perceptually analyze the meaning of the stimuli and their relevance to us, so that even a message from the unattended ear that is supposedly irrelevant can come into consciousness IF it has some meaning for us. Study by Treisman: She had subjects shadowing coherent messages and switched at some point from the attended to the unattended ear. Participants were able to pick up the first few words of the message they had been shadowing. Late-filter model ( Deutsch and Deutsch ) →they developed a model in which the stimuli are filtered out only after they have been analyzed for both their physical properties and their meaning → even a later filter than Treisman's and allows people to recognize info entering the unattended ear e.g. recognize the sound of their name N.B. Both the early and the late-filtering mechanisms propose that there is an attentional bottleneck through which only a single source of information can pass. The two models differ only in terms of where they hypothesize the bottle neck to be positioned. A SYNTHESIS OF EARLY-FILTER AND LATE-FILTER MODELS In 1967, Ulric Neisser synthesized the early-filter and the late-filter models proposed that there are two processes governing attention : pre-attentive processes: these automatic processes are rapid and occur in parallel. They can be used to notice only physical sensory characteristics of the unattended message but they do not discern meaning or relationships Attentive , controlled processes : these processes occur later. They are executed serially and consume time and attentional resources ( such working memory ). They also can be used to observe relationships among features→ they serve to synthesize fragments into a mental representation of an object The Beneficial Effect of concurrent Task-Irrelevant Mental Activity on Temporal Attention Attentional Blink= impaired ability to identify a second of two visual targets presented in close succession → believed that the cognitive system is not able to maintain attention over time → it can't identify the second of two targets when it appears close in time to the first HYPOTHESIS: participants improved T2 performance when being somewhat unfocused on the task PROCEDURE: 1\. fixation cross was presented at the centre of the display 2\. series of 13-21 letters were then displayed in succession, with 2 digits ( T1 and T2) included in the series 3\. number of letters between T1 and T2 varied each trial 4\. participants had to identify both T1 and T2 under their respective condition METHOD : Each trial consists of a series of letters presented rapidly at the center of the display. among the letters are two target digits ( T1 and T2). The observer task if to report these at the end of the trial 66 subjects randomly assigned to 4 conditions : standard condition : each block was preceded by the usual instruction to concentrate on the task and report as many digits as possible\-- free-association condition : participants were invited to think about their holidays (in one block) or about their shopping plans for a dinner with friends listen-to-music condition : participants were presented (through a set of headphones) with a continuous rhythmic tune running at 120 beats per minute. In one block, participants were asked to just listen to the beat while doing the task. In the other block (again block order was counterbalanced), they were asked to detect an occasional yell that was part of the music (there were no other verbal elements in the music) reward condition : participants were paid according to their performance. RESULTS : performance on an attentionally demanding visual detection task may improve when the task is accompanied by task-irrelevant mental activity → target detection may benefit from adiffusion of attention → providing some distraction (either through instruction to think about something else or through music) causes considerable improvements in detecting visual targets in a rapidly presented stream of items when there is more time between the first target and the second , performance improves Why?\-\-\-- listen to music group is the group that performed better effects may be related to arousal→ overall arousal levels influence attentional focusing positive affective state→ thinking about one's holiday or listening to music may induce a positive affective state→ improved performance on several cognitive tasks, especially those requiring a broad,flexible operating mode the additional task itself that induces a more distributed state of attention→ as attention widens to incorporate the extra work, it may have also widened temporarily and thus included the second target. could be that funny instructions or the presence of music might contribute to a higher appreciation of what would otherwise be a boring experiment→ more motivation for the task in the reward group T1-T2 lag= digits between the first target and the second target→ when there is more time between the first target and the second → performance improves →providing some distraction ( either through instruction to think about something else or through music) causes considerable improvements in detecting visual targets in a rapidly presented stream of items