The Monkey Business Illusion

My submission to the Best Illusion of the Year competition at this year’s Vision Sciences Society meeting is titled “The Monkey Business Illusion.” The contest judges selected it to be among the 10 finalists, so I got to present it to an audience of more than 1000 people attending the show this evening (May 10, 2010).

The audience voted for their favorite illusions, with the top 3 finishers winning cool illusion sculptures. Although I wasn’t one of the three winners, I had a great time with the show. There were some truly wonderful illusions this time.

I gave my presentation while wearing a full-body gorilla suit (any excuse to wear a gorilla suit in front of 1000 of my colleagues is a good thing!). I’m hoping to be able to post a video of my presentation soon. In the meantime, try the illusion for yourself
here.

Vision Sciences Stuff -- a moving color demo

This week I’m attending the annual meeting of the Vision Sciences Society in Naples Florida. Every day or so, I’ll post about a subset of the cool, interesting, funny, or quirky (I won’t say which) talks/posters I happened to catch. You can read the first installments here.

This morning had a great new color illusion/demo presented in a talk by Jordan Suchow and George Alvarez entitled “Silent updating: Cross-dimensional change suppression.” The effect is pretty similar to one presented by Jun Saiki and Alex Holcombe a couple years ago at Vision Sciences (“Surface-based, unpaired feature representations mediate detection of change to feature pairings”), but this one was a particularly dramatic demonstration.

If you show people a dot that continuously cycles through all the colors in the spectrum, you can see it changing systematically. If you arrange 300 such dots in a thick ring around the center of the display (imagine Saturn and one of its rings) and you maintain your gaze at the center of the display (e.g., on Saturn), you can see all of the colors flickering and changing. But, if you start the entire ring rotating around where you’re looking, all the color-changing appears to halt. The effect is dramatic, and Suchow and Alvarez generate several possible explanations for it. They argue that people are silently updating the colors of the objects in the ring so that if the display halts and suddenly reverts to the original colors, people notice. I didn’t find that explanation particularly compelling — it’s unlikely people can update all of the individual colors simultaneously, and reverting to the original colors will produce a big luminance signal. My bet is that they store little if anything about the colors, but they are really good at seeing motion. The explanation I prefer is one suggested by a questioner in the talk: The rotation of the entire ring produces a big motion signal for the visual system, and that signal masks the smaller changes of the individual dots. That principle–big motions hide smaller ones–is used in magic as well. A big arm movement can hide a subtle change to something held in your hand.

Vision Sciences Stuff -- the skinny on a new illusion

This week I’m attending the annual meeting of the Vision Sciences Society in Naples Florida. Every day or so, I’ll post about a subset of the cool, interesting, funny, or quirky (I won’t say which) talks/posters I happened to catch. You can read the first installment here. Here’s a fun one from my University of Illinois colleague Diane Beck.

“Why women wear heals: A new size illusion?” by Diane Beck, Barbara Emanuele, and Silvia Savazzi. This study looks at why tall people sometimes look thinner than short people of comparable girth and also looks to see whether thin people look taller. The task was simple: view two stimuli and judge which is wider (or taller). On most trials, the stimuli differed in width, but on critical trials they were actually identical on the judged dimension. Look at the image below — the tall figure looks skinnier even though the two are exactly the same width.

Which body looks skinnier? They're actually identical in width.

When the stimuli have the same width, people should pick at random — there is no correct answer. Yet, people judge the taller one to be skinnier more than 80% of the time. They also judged skinnier bodies to be taller more than 70% of the time. The clinching experiments showed that the effect is a more general illusion rather than some bias about person perception: People judge a taller rectangle to be narrower nearly 70% of the time and a narrow rectangle to be taller nearly 60% of the time. Apparently, being tall makes you look thin, so those of you who are trying to lose some weight just need to try being taller instead.

Vision Sciences Stuff - Friday

This week I’m attending the annual meeting of the Vision Sciences Society in Naples Florida. Because I have limited endurance for talks, I tend to sample a fairly small number each day. That means I missed a lot of cool research. Rather than posting a “top 3″ or “best of” list, I’ll just post about a subset of the cool, interesting, funny, or quirky (I won’t say which) talks/posters I happened to catch each day. Here are a couple of posters that caught my eye on Friday.

1) “When walls are no longer barriers: Perception of obstacle height in Parkour” by Eric Taylor, Mila Sugovic, and Jessica Witt. This poster reported a study of skilled Parkour athletes—the sort of street running, wall-climbing, and and jumping showcased at the start of the latest James Bond movie. Parkour athletes can scale walls that are too high for untrained athletes to clear, so the question was whether these athletes would perceive those high walls as shorter than would people who couldn’t scale them. The authors used 3 wall heights. The Parkour athletes could consistently scale the smaller two sizes, but the novices could only scale the smaller one. The interesting finding: Parkour athletes judged the size of the two smaller walls to be roughly the same height and somewhat underestimated the height of the middle one. In contrast, the novices overestimated the height of the middle wall, the one they couldn’t clear. The finding suggests that the different actions that a person can perform on an object affect a judgment of size in an interesting way.

A) “Distinguishing losses as wins in multi-line video slot machines” by Mike Dixon & Kevin Harrigan. This one isn’t really a study of vision, but it has interesting implications for the discrepancy between rational decision making and what people actually do. For some slot machines, gamblers can bet on up to 15 lines per spin, and when all the items on a line match, the player wins. When that happens, the items flash and the machine tallies up the winnings. When no lines match, the player loses and there is no feedback. Unlike traditional slots in which the player either wins or loses on each bet, here the player could win on one line and lose on all the others. Depending on the amount of the winnings and on the number of lines bet, it’s possible to win on one line, but still lose money. For example, you could bet on 15 lines at a cost of $1.00/line. You might then “win” $7.00 if one line matched up, but you’d still have lost $8.00 on the bet overall. The reinforcement the gambler receives is based on whether any line “won” and not on whether they actually won any money on the overall bet. The authors describe this result as a “loss disguised as a win” (an LDW). The key result: skin conductance responses following an LDW was elevated in the same way as for an actual win, with both more elevated than following a loss. Apparently, these LDWs produce the same sort of rush as a win even though the gambler actually lost, which makes it more likely they’ll continue gambling. That sort of arousal reinforces the gambler and encourages them to continue gambling, probably more than they would if they had just lost the same amount of money. My bet is that people might be even less likely to think through the consequences of their bets when they are losing but still experiencing the arousal that accompanies winning.

Cognitive and moral limits

[ed. note] I just posted the following thoughts on our Psychology Today blog, The Gorilla Guys. With the permission of the Psychology Today admins, I’m posting it here as well. –Dan

Paul Bloom has a fascinating overview of moral reasoning in infants and toddlers in the New York Times. Studying moral reasoning in infants is a challenge – you can’t just ask infants what they think about another person’s actions. Instead, you have to infer their moral beliefs from their actions: where do they look, who they favor or punish, etc. One of the take-home messages of Bloom’s essay is that the primitive morality system available to infants is essential as the basis for more sophisticated moral reasoning in adulthood, moral reasoning that can come under more cognitive control. In many respects, this limited moral system is akin to intuition.

Intuitive systems work well under restricted conditions. They serve an important purpose. As Bloom notes, some primitive structure is needed to acquire more complex structures. But, they can also operate quite differently than those more complex processes.

The same principle applies to the sort of intuitions we discuss in The Invisible Gorilla. Intuitions often serve us well, especially when the decisions we make map onto the relatively simple situations in which these mechanisms evolved. Where they lead us astray is when we face situations that lack clear black and white distinctions or when the complexity of modern society renders the intuitions faulty.

Just as an infant’s rudimentary moral reasoning differs from that of an adult (at least of an adult with time to reason about the situation and make a more principled judgment), our rapid, intuitive judgments often differ from what we might decide if we took the time to reason it out. The difference, though, is that infants lack the ability to reason it out. We can decide to override our intuitions, but we often don’t recognize when it would be a wise thing to do.

Gaze-averting glasses

When you look at gorillas at the zoo, they might feel that you are threatening them. We don’t like being stared at. Fortunately, most of the time we’re invisible, so even when you’re staring at us, you might not see us (see this nice journal article by a particularly sharp hairless primate I know in Germany).

For those times when you know a gorilla is there and you actually do see it, these cool glasses will help you avoid threatening them or scaring them away. Of course, if you wear them, you might inadvertently threaten the invisible gorillas standing near by.

gorilla video used in a murder trial

To my knowledge, this is the first time that the gorilla/basketball video has been shown during expert testimony in a court case. Unfortunately, at least from the description in the article, it seems like the point of the video and demonstration wasn’t particularly relevant to the case.

The trial is in New Zealand, and the video was shown by Dr. Joseph Sakdalan, a clinical psychologist in Aukland, on behalf of the defense. The man on trial allegedly drove over the victim after grabbing her purse. According to the defense lawyer, “He didn’t think what he did was likely to kill. He didn’t realise she was so badly injured until the 6pm news that night.” To me, that implies that he knew he was driving toward the victim, but just wasn’t trying to kill her (the defense is arguing for manslaughter). Oddly, if that is what happened, then the gorilla video was completely irrelevant to the case; if he knew that he was going to bump her with the car, that means he DID see her and this wasn’t an example of inattentional blindness at all. It was just a case of bad judgment (not surprising that he had lousy judgment — he had just tried to grab her purse).

If it wasn’t really relevant to the case, I’m not sure why this expert was allowed to use it in testimony. I’m also not sure what point the expert was trying to make, other than that people sometimes don’t see things. But, at least according to the quote from the defense lawyer, that wasn’t even the claim the defense was making. Strange.

The Invisible Gorilla in the news

If you look really carefully, you might start spotting discussions of our book, The Invisible Gorilla, in some popular magazines and media outlets. The May issue of Psychology Today (on newsstands this week) has a short review and a feature about everyday illusion. Southwest Airlines’ Spirit Magazine also has a feature about the book that will be in all of their planes for the month of May. You can read the latest updates and news on the main page of our website. We also post occasional updates for our Facebook fans. Please consider becoming a fan of the book if you aren’t already (link below).
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blogging from the Vision Sciences Meeting

I will be attending the annual meeting of the Vision Sciences Society later this week. While there, I will be blogging about some of the cool new vision and cognition research posters and talks. I will also be presenting a new demo at the Best Illusion of the Year contest on the evening of Monday May 10. I’ll post video of that demo as soon as the contest is over. If all goes well, I might try live-blogging the event itself (assuming Wordpress for the ipad works well enough and that I can get a 3G signal in the concert hall — I’m testing out the Wordpress app with this post).

interview of Tom Vanderbilt by StreetFilms

Streetfilms.org has posted an extended video interview with Tom Vanderbilt, author of the bestselling book Traffic and the How We Drive blog. In the interview, Tom discusses the psychology and behavior of drivers, including “looked but failed to see” accidents — what we consider to be an example of inattentional blindness on the roads. The wide-ranging 10-minute interview covers everything from texting while driving to the use of drive-cam technology that records what drivers are doing as they drive (including examples of collisions due to distracted driving). He also mentions The Invisible Gorilla (about 2 minutes into the interview). You can read more about the interview here. It’s fascinating stuff.