PSGY1010 Cognitive Psychology 1 - Attention 3 Limits of Attention PDF

PSGY1010 Cognitive Psychology 1 Attention III: Limits of Attention Dr Chung Kai Li [email protected]  Previously ▪ We have seen that attention is capacity limited. ▪ We have seen that attention can be selective. ▪ We have seen evidence that unattended/irrelevant information is...

PSGY1010 Cognitive Psychology 1 Attention III: Limits of Attention Dr Chung Kai Li [email protected]  Previously ▪ We have seen that attention is capacity limited. ▪ We have seen that attention can be selective. ▪ We have seen evidence that unattended/irrelevant information is usually not processed ▪ We have seen evidence for slippage/leakage/spillover of unattended/irrelevant information into the focus of attention. 2  Today’s lecture Learning objectives: ▪ Be able to describe change blindness and inattentional blindness ▪ Explain commonalities and differences between change and inattentional blindness ▪ Have an appreciation of the difficulties involved in measuring alleged subliminal perception 3 Inattentional blindness Simons & Chabris (1999); Simons (2010) 4  ‘Gorillas in our midst:…’ Simons & Chabris (1999) ▪ What is the percentage of participants noticing the gorilla? Count white team passes Count black team passes 42% 83% 5  The unicycling clown Hyman et al. (2010) ▪ Participants crossed a square at Western Washington University and passed a unicycling clown ▪ After crossing the square, two questions: ▪ Did you notice anything unusual? ▪ Did you notice the clown? 6  The unicycling clown ▪ Participants were divided into four groups ▪ Cell phone users ▪ Single persons ▪ Music player users ▪ Pairs Music player (%) Cell phone (%) Anything unusual? 32 8 See the clown? 61 25 7  “Real-world” examples of inattentional blindness ▪ Chabris & Simons (2010) ▪ “I never saw the bicyclist! He came out of nowhere!” ▪ Drew, Vo, & Wolfe (2013) ▪ When examining CT scans expert radiologists may often miss anomalies, even when looking directly at them. 8  Change blindness Whodunnit 9 Change blindness – example 1 10 Change blindness – example 2 11 The “Door” study 12  Change blindness ▪ Can be surprisingly difficult to detect changes ▪ There are certain conditions where change blindness is more likely ▪ Empty frame shown between two pictures (Rensink et al., 1997) ▪ Temporary occlusion (“Door study”) ▪ Change occurs very slowly (Simons et al., 2000; e.g., curtain in gorilla movie) ▪ Good overview: Simons & Rensink (2005) 13 Limits to change blindness 14  Change blindness and inattentional blindness ▪ In common (Rensink, 2009) ▪ Failure to perceive things easily seen once noticed ▪ Both due to lack of attention ▪ If change/inattentional blindness occurs due to early selection: the stimulus should never be perceived. ▪ If it occurs due to late selection: the stimulus might be perceived but not remembered. 15  Change blindness vs. inattentional blindness Change blindness Inattentional blindness Memory might play a role: one Memory not required to notice that there picture/movie scene needs to be is something unexpected/odd about compared to another picture/movie scene Looking at each picture/scene separately: nothing unusual Can occur even if finding the change is Typically occurs when observer is the actual task (as in the flicker performing another task; becomes very examples; but can also be implicit as easy if participants are instructed to look seen in door study) out for something odd 16  Subliminal influences on behaviour Subliminal ▪ Below the threshold (of awareness) ▪ Sub = below ▪ Limen = threshold Prime ▪ Very briefly presented (e.g., ~ 20-30ms) ▪ Masked 17  The case of James Vicary ▪ Claimed to have successfully used subliminal advertising to increase Coke and popcorn sales James Vicary, 1957, in an interview 18  The case of James Vicary ▪ “We applied for a patent, after testing the thing in a movie theater in Fort Lee, N. J. The story leaked out to some newspaper guys and we were forced to come out with subliminal before we were ready. Worse than the timing, though, was the fact that we hadn't done any research, except what was needed for filing a patent. I had only (…) a small amount of data—too small to be meaningful.” (James Vicary, 1962, in an interview) ▪ Perhaps initial test, but numbers from 1957 interview almost certainly false 19  The case of Diederik Stapel ▪ In 2008, Ruys and Stapel published this paper: E D C T R A ET R 20  The case of Diederik Stapel ▪ Renowned Dutch professor who manipulated and fabricated data for over 50 publications ▪ Suspended in 2011 ▪ Data manipulation probably already started in 2004 21  Fraud in academia ▪ Extreme examples ▪ In all likelihood, outright data manipulation or fabrication is very rare ▪ However, be aware of these cases and remain sceptical ▪ In particular, if results seem “too good to be true” and effect sizes are implausibly high 22  Recent claims of successful subliminal priming Karremans et al. (2006) ▪ Claim: subliminal priming with the words “Lipton Ice” vs. “Npeic Tol” increases probability to choose Lipton Ice Tea over mineral water 23  Recent claims of ▪ Effect shown in two successful experiments, but it seems no subliminal priming direct replications published ▪ However: conceptual replication (Bermeitinger et al., 2009) Karremans et al. (2006) ▪ Primes presented for 23ms ▪ Assessment of subliminal presentation: Can you guess the prime word? 24  Methodological problems ▪ Very difficult to unequivocally show that supposedly subliminal stimuli are in fact subliminal ▪ Problem 1: response bias ▪ “Subjects may partially or even fully see the stimulus, yet claim that they have not seen it because they need a higher level of certainty.” (Kouider & Dehaene, 2007, p. 859) ▪ Problem 2: motivation ▪ Prime identification task might be so difficult that participants lose motivation 25  Methodological problems ▪ For a discussion, see: ▪ Newell & Shanks, Unconscious influences on decision making: a critical review (2014, Behav Brain Sci): Section 5.1, replies by Finkbeiner & Coltheart, Snodgrass et al., Section R5, and the references therein ▪ Behavioural and Brain Sciences ▪ Interesting format: target article + comments + reply 26  Exam revision for ‘Attention’ lectures ▪ Lecture slides ▪ Eysenck & Keane ▪ Chapter 5, pp. 178-200 (8th ed.) ▪ Chapter 4, pp. 163-174 (8th ed.) ▪ Focus on key facts and concepts, not details 27 Thank you Any questions?