3 – Selective Attention selective attention attending to part of the environment while ignoring the rest Examples Listening to instructor while ignoring everything else Looking around a room for the face of your friend Spotlight Metaphor We must limit the scope of our attention because “attentional resources” are limited Example basketball pass demo (1:22) www.dansimons.com/videos.html (videos 1 and 2) or www.youtube.com/watch?v=vJG698U2Mvo
Inattentional Blindness failure to notice salient object even if looking directly at it. Experiment Ss watched video of people passing basketballs. Ss told to count passes. About 50% of Ss didn’t notice gorilla. (Simons & Chabris, 2001) Real world example Car driver makes left turn without noticing oncoming motorcycle. Note that unnoticed object is 1) not expected 2) not looked for
Radiologists were shown this lung scan and asked to look for “cancer nodule” 83% failed to notice Drew and Wolfe (201X)
Change Blindness failure to notice change in object while it is briefly out of view Person-Swap Experiment S entered laboratory to participate in study and meets E. E surreptitiously traded places with different E. Some Ss didn’t notice. Note the distinction: inattentional blindness Not noticing object change blindness Not noticing change in object (or scene) Videos with Demos Person-Swap in lab (3:59) www.youtube.com/watch?v=38XO7ac9eSs&feature=related More demos (2:10, 1:17) www.dansimons.com/videos.html (first panel, videos 3 and 4) Dan Simons
Another Person-Swap Experiment E asks S for directions. S begins to give directions. While E briefly out of view, E covertly trades places with another E. About 50% of Ss didn’t notice. (Simons & Levin, 1998) video (1:36) www.dansimons.com/videos.html second panel, video 1
Flicker task demo (photos from Rensink et al., 1997) use cursor keys: R…R, R, L, L, R, R, L, L,
Flicker task demo (photos from Hollingworth, Schrock, & Henderson, 2001) use cursor keys: R…R, R, L, L, R, R, L, L,
Flicker task demo (photos from Rensink et al., 1997) use cursor keys: R…R, R, L, L, R, R, L, L,
Flicker Effect 1. S sees scene, brief blank screen, and then altered version of scene brief blank screen 2. Alternations continue (“flickers”) until S identifies change 3. S is told to find the change 4. Finding the change takes a long time (flicker effect) Note: the flicker effect is a kind of change blindness Demos www2.psych.ubc.ca/~rensink/flicker/download/indeT.html
Flicker Effect Experiment Original and altered scenes scene alternated until S identified the change blank screen blank screen 240 ms X ms 240 ms X ms Duration of blank screen = 0 or 80 ms Results Blank DurationMean # of Alternations 0 1 (no change blindness) 80 ms 16 (change blindness) Conclusions Change blindness occurs if scene must be stored in memory - even for a moment. Thus, we can store only a very brief amount of the information in a visual scene (Rensink et al., 1997) no gap demo nivea.psycho.univ-paris5.fr/ECS/bagchangeNoflick.gif
Attentional Capture Noticing a sudden change in object (or part of scene) to which you are not attending Stimuli that capture attention Flicker Task without intervening blank screen Scream Siren Ringing phone Brake lights on the car in front of you
Some changes capture attention better than others. Change in StimulusEfficacyExample Increased intensity okay Tail lights get brighter. Onset good Rear window light turns on. Repeated onset-offset better Brake lights flash. Example. On some cars, brake lights flash if speed > 50 km /hr 500sec.com/adaptive-brake-light/
Resisting Attentional Capture In most situations, attentional capture is adaptive While walking in woods, we notice snake in our path. Air traffic controller notices flashing red light In some situations, we must be able to resist attentional capture. Example School bus driver must ignore yelling kids Student taking test must ignore coughs, door slams, etc. Naturally, people vary in the ability to resist attentional capture
Experiment : Resisting Attentional Capture Ss told to look at cross (+) and ignore intermittently flashing circles. Square appeared in top or bottom location. (This repeated many times) Ss pressed top or bottom key, respectively. Results: ADHD kids made far more errors than controls did. Implication: ADHD kids have a hard time resisting attentional capture. (Bourel-Ponchelet al., 2010)
Right EarLeft Ear In 1913 Danish physicist Neils Bohr’s eponymous Model postulated atoms were formed of electrons orbiting a nucleus, much like planets around the sun – only using electrostatic attraction rather than gravity. Electrons have since been shown to be more akin to waves surrounding the nucleus, but teams in Austria and the US have shown they can be made to perform in the same way as planetary systems, and the technique can be used to change the overall size of the atom. The research, published in the journal Physical Review Letters was inspired in part by the function of Jupiter’s Lagrange points: Two specific points where forces of the Sun and the largest planetary gravity well in the Solar System cancel each other out. These collect matter, known as the Trojans, and the best guess is that the two belts contain more than a million asteroids over a kilometer in diameter. A team at the Vienna University of Technology performed the mathematics for the experiment and Rice University performed the actual experiment. They fired an atomic beam through a vacuum chamber and then crossed the stream with a tuned laser oscillating with the orbital period frequency of the electron around the nucleus. The laser created a localized electronic state that moves in a near-circular orbit around the nucleus, and they could then extend and reduce the size of the orbit by modulating the laser’s frequency. The team got an atom up to the size of a human blood cell during testing. The electron can only be controlled when the force is applied and then reverts to its natural state within a few cycles. Then again, Jupiter is not perfect either. Simulations suggest 17 per cent of the Trojans are unstable enough to fall out of the orbits and go wandering, potentially Earthward bound. The next step is to see if the technique can be used on multiple atoms simultaneously, and to monitor how they interact with each other during operations. Sandwiched between venerable classical physics and the extremes of quantum studies, mesoscopic physics is very much the red-headed stepchild of the physical sciences, but has huge potential. It generally deals with objects from an atom up to 1,000 nanometers – about the size of the average bacterium. By investigating the boundaries between the sub-atomic quantum world and everyday physics, mesoscopic scientists hope to find usable results that could have applications in both fields. A team of scientists have discovered over 40 new species in southwestern Suriname survey. The team performed a three-week survey in three remote sites along the Kutari and Sipaliwini Rivers. “The goal of this expedition was to bring together the knowledge and expertise of local people with scientific knowledge to study and plan for monitoring of biological and cultural resources of the region.” The scientists surveyed a total of 1,300 species, including 400 plants, 90 aquatic beetles, 90 dung beetles, 76 katydids, 93 dragonflies and damselflies, 100 fishes, 57 reptiles and amphibians, 323 birds, 41 small mammals, 29 medium and large mammals. They also saw 14 threatened species of plants and animals that are listed on the International Union for Conservation of Nature’s Red List. Part of the list of new species includes a “cowboy frog” and a spiked species of armored catfish. The cowboy frog has white fringes along the legs, and a spur on the “heel.” The armored catfish has external bony plates and is covered with spines to help defend itself from giant piranhas. The researchers said that one of the local guides was about to eat the armored catfish as a snack, until scientists noticed its unique characteristics and preserved it. The team also found a “Great Horned Beetle” on their expedition. This beetle is “the size of a tangerine” and weighs over 0.2 ounces. It is metallic blue and purple, and posses a horn on its head used as a weapon to fight in battle. “The area was paradise for the entomologists among us, with spectacular and unique insects everywhere. I didn’t even have to look for ants because they jumped out at me”, Dr. Leeanne Alonso, a former CI RAP Director who is now with Global Wildlife Conservation, said in a press release.
Right EarLeft Ear scooter mission amplitude kitchen genre selection maroon double expression bucketful accentuate spectacular gargantuan heading pivot humanist mainsail collectible xylophone collection neurology intersect apparent defective treatable orangutan qualitative illusion totem pole dangle penetrate alphabetical teacup sarcophagus moonlight formulation motif bondage furthermore integration charging trample mansion revision bluebird streaky famous remover uplifting sought overrun cohabit exhortation envoy widen platitude opulence uncover ruckus difficulty perpetuate crouch veritable deflect foray cape redundancy transposition capability geese inhabit cafeteria intellectual induction ammonia reindeer wrench sidetrack biology instance
Dichotic Listening Procedure S hears words in one ear while simultaneously hearing different words in other ear. S is told “left” or “right” and then attends to the message in that ear. S repeats attended message aloud (shadow) Trial continues for 10-60 s. Then, S is asked about unattended message.
Dichotic Listening Experiment S heard prose in one ear; word list in other ear. Subjects shadowed the prose. Immediately afterwards, S asked about unattended message Results: Ss can say unattended words were English But Ss couldn’t recall any of the words! This was true even if the list included the same word 35 times in a row! Conclusion Our mind does not “process” the meaning of unattended message. (e.g., Broadbent, 1957; Cherry, 1953; Moray, 1959) It was the best of times, it was the worst of times. dog, wall, green, bell, anger, wish, tiger, sky,
Early dichotic listening studies suggest that we can process only one message at a time. However, we know that this is not entirely true. Example cocktail party effect - we notice our name used in nearby unattended conversation Might our minds process information other than our name, without our awareness?
Dichotic Listening Experiment 2 Ss heard two stories, one in each ear. After 20-30 s, and without warning, the stories unexpectedly switched ears. Results After switch, Ss often shadowed wrong prose because it made sense. “I saw the girl skipping, er, big gray rabbit …” Conclusion Ss understood the meaning of the unattended message! (Treisman, 1960) Since then, 1000s of follow-up studies have been done. Most researchers believe we can “partly” process meaning of unattended message. The fox chased [switch] skipping rope I saw the girl [switch] big gray rabbit
Neglect disorder in which patient “ignores” objects in left or right visual field. Example Patient asked to copy model on left. Patient’s drawing is shown on right. (continued)
Facts about neglect Left neglect is far more common than right neglect. Common symptoms Leave one shoe off Leave food on one side of plate Shave one half of face Patients notice object on left side if they turn all the way around to the right. Video Patient draws daisies (3:19) www.youtube.com/watch?v=ymKvS0XsM4w (Bisiach, 1996)
Visual Search search for an object within a visual scene Examples Looking for car in crowded parking lot Finding certain brand of cereal on grocery story shelf Airport worker looking for knife in luggage scan (Image from McCarley et al., 2004)
Typical Visual Search Experiment S told what the target is. Computer screen shows one target and 1 – 50 distractors. S presses yes-key if target is there, no-key if target is not. E measures RT. Examples Find the I Find the I 1 distractor 50 distractors (Treisman & Souther, 1985; Wolfe, 2001) L LLLLLLLL L L LL L LLLLLLLLLLLLL LL L LL L LLL I L LLLLL L LLLLLLL L I
Find I among Ls L LLLLLL L LLLL L LL I L L L LLLLLL L LLLLLL L L L L L LLLLLLLLLLLLLLL
Find I among Ls (again) L LLLLLL L LLLLLL L LLLLL L LLLLLLLLL L LLLLLL L LLLLL L LLLL I L LLLLLLL
Find I among Ls (again) L LLLL L LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
Find I among Ls (again) L LLLLLLLLL L LLLLLLL L LLL I L L LLLLLLLLLLLLLL L LLLLL
Find P among Bs B BBBBBB B BBBB B BBBB B BBBBBB B B BBBBB B B P B B B BBB B BBBBBBBBBBB
Find P among Bs (again) B B B BBBB B B B B B BB B B P B BBB B BBBBBBBBB B BBBBBB B BBBBB B BBBBB B BBBBBBB
Find P among Bs (again) B BBBB B BBBBBBBB B BBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
Find P among Bs (again) B BBB B BBBBB B B BBB B BB B BBB P B B BBBBBBBB B BBBBB B BBBBB
Find Tamong Ts T TTTTTTTTT T TTTTTTT T TTTTTTT T TTTTTTTTTTTTTTTT T TTTTTTTT
Find among s
Can a target pop out if it’s the same color as the distractors?
Find Xamong Os O OO O OOOOO O OOOOOO O O OOOOO O X O OOOOO O OOOOOO O OOOOOOOO
Find Xamong Os (again) O OO O OOOOO O OOOOOO O O OOOOO O O OOOOO O OOOOO O O OOOOOOOO
Find |among • • | • • • •
Two kinds of visual searches pop-out RT unaffected by more distractors serial RT increases with more distractors (as if checking all items at once) (as if checking one object at a time) Find X Find P slope 0 slope 30 ms / item Thus, all items are checked “instantly” Thus, 30 ms = average time to check RT RT RT # of distractors # of distractors # of distractors 30 ms 1 item
Theoretical interpretation Pop-out search is Serial search is pre-attentional attentional 1) automatic 1) volitional 2) nearly unlimited capacity 2) very limited capacity The big question: What determines whether a target pops-out (i.e., is found without attention)?
Find O among Qs Q QQQ QQ Q QQ Q QQQQQQQQ Q O Q QQQQQQQ Q QQQQQQQ Q QQQQQQQQ