August 7, 2008
Category: Emotion • Perception • Reasoning • Research • Social
[This article was originally published in April, 2007]
There is a considerable body of research showing that eye contact is a key component of social interaction. Not only are people more aroused when they are looked at directly, but if you consistently look at the person you speak to, you will have much more social influence over that person than you would if you averted your gaze.
The problem arises when you address a group of people. How do you pick who to engage visually? Most public speakers are encouraged to look around the room, alternating eye contact with individuals in the audience. But there's no way to look at everyone at once -- so some of your potential social influence will by necessity be lost.
Now, a team led by Jeremy Bailenson has figured out a way to get around that limitation. In a virtual reality environment, there is no need for the representations of other people to be consistent. Since each individual's virtual experience is generated separately, in a "room" full of people, each person could experience the phenomenon of everyone else looking at them. Everyone can be the center of attention, all at the same time!
In the figure, person A believes that both B and C are looking at her. But in C's virtual world, both A and B could be shown as looking at her instead.
Bailenson's team wanted to see if they could use this method to allow one person to increase his or her influence over more than one other person simultaneously, by programming her "avatar" -- the virtual representation of herself -- to be looking directly at each of the others.
Read on »
Posted by Dave Munger at 10:21 AM • Comments (4)
August 4, 2008
Category: Attention • Color perception • Perception • Research
[Originally posted in May, 2007]
"I just didn't see him" is a claim that's repeated over and over in accident reports. Drivers earnestly claim that they simply didn't notice the bicycle/pedestrian/motorcycle they crashed into. The claim is made so frequently that certainly there must be a grain of truth to it. Yet it certainly isn't the case that car drivers can't see such obstacles -- after all, they can see traffic signals that are much smaller than a bike or a motorcycle.
What they mean to say is that their attention was otherwise engaged -- perhaps by a phone conversation, perhaps by other traffic, or perhaps because they were trying to find something -- a street sign, a restaurant, a gas station. Human attention is a fickle thing, and in many cases we don't notice very obvious details changing right before our eyes.
Consider the following movie (QuickTime required): One image will be displayed for a number of seconds, followed by a white screen, and then a second picture -- the same image with one very obvious detail changed. Can you spot the change (don't cheat--just watch it once!)?
Read on »
Posted by Dave Munger at 10:25 AM • Comments (26)
July 31, 2008
Category: Reasoning • Research
[This post was originally published in March 2007]
Earlier today I posted a poll [and I republished that poll yesterday] challenging Cognitive Daily readers to show me that they understand error bars -- those little I-shaped indicators of statistical power you sometimes see on graphs. I was quite confident that they wouldn't succeed. Why was I so sure? Because in 2005, a team led by Sarah Belia conducted a study of hundreds of researchers who had published articles in top psychology, neuroscience, and medical journals. Only a small portion of them could demonstrate accurate knowledge of how error bars relate to significance. If published researchers can't do it, should we expect casual blog readers to?
Read on »
Posted by Dave Munger at 10:57 AM • Comments (14)
July 30, 2008
Category: General / Site news
Cognitive Daily gets a lot of complaints about graphs, mostly from readers who say the graphs are useless without error bars. My response is that error bars are confusing to most readers. But perhaps I'm wrong about that. Last year I posted about this issue, and backed it up with a short quiz about error bars, which most of our readers failed. After another 16 months of Cognitive Daily, maybe they've improved. So here's the test again.
Take a look at this graph. It represents a fictional experiment where two different groups of 50 people took a memory test. The mean scores of each group are shown, along with error bars showing standard error:
Based on this graph, can you tell if there is a significant difference (p<.05) between the scores of the two groups? Let's make this a poll (for the sake of accuracy, please respond as best you can even if you don't know what the error bars represent).
Below I've included a similar graph, again testing two different groups of 50 people but using a different type of error bar:
Read on »
Posted by Dave Munger at 11:41 AM • Comments (34)
July 28, 2008
Category: Development / Aging • Research • Social
One of the key components of "normal" child development is social competence. We expect kids to become gradually better at behaving respectfully towards peers, to comply with requests made by others, to understand the thoughts of others, to play together with kids and adults, to sustain attention, and to be motivated to learn. But what makes the difference between a child who becomes socially competent and one who doesn't? Obviously there are some risk factors, such as whether they have autism, whether both parents are present in the household, and the education and poverty level of the family. But some kids who seem to have all the advantages still have trouble getting along with others. Why?
Some studies have found that at-risk babies show some early warning signs that are associated with later poor social competence. It's possible, for example, to measure several dimensions of "joint attention." Take a look at this old picture of Jim and Nora playing with their kitchen set:
Aside from the fact that they're absolutely adorable, you can see that Jim is reaching for some utensils and Nora is following his reach and looking at the same thing. This is an example of Nora responding to joint attention. (I should add that it's not the best example because the classic case would have Jim pointing, not touching an object -- but it's the best I could find right now, flying cross-country at 30,000 feet.)
Read on »
Posted by Dave Munger at 9:42 AM • Comments (10)
July 25, 2008
Category: General / Site news
I'm about to head out of town for three weeks. You may have noticed posting getting lighter the last couple weeks as I attempted to tie up loose ends before the trip. Posting will be getting even lighter for the next three weeks as I head west to visit family. Then, a week from now, Nora and I will be heading out into the true wilderness, miles out of range of any cell phone tower, and certainly out of reach of the internet.
Here's a description of part of our route:
One of Washington's granddaddy trails, Boundary Trail runs across the entirety of America's largest wilderness, the Pasayten. The route follows the Canadian border, hence the name. It is an extremely high route, much of it occurring at 6,000 feet or more. The area is completely wild and one of the few places in the lower 48 where grizzly bears and gray wolves still roam. The route needn't be hiked end to end; there are many great trips accessing just a part of the trail. At least eight major trails provide access for small loops.
The Boundary Trail begins at Castle Pass on Pacific Crest Trail. Start at Hart's Pass and hike north 18 miles to Castle Pass and "Ol' 533," the trail's number. From here it heads east 73 miles to Iron Gate Trailhead, in the middle of nowhere. Along the way it climbs dozens of high passes and ridges, crosses the Pasayten River, and basks in endless views of mountains. The summer is a prime time to visit, when wildflowers are in bloom, as is the fall, when larches do their thing. Established camps are littered along the route, and off-trail camping is OK as long as it's low-impact. Also, if you hike this route without the maps, you likely won't come back. Good luck.
Yes. We will have maps. Anyway, here's my request: We'll be on the trail for 12 days, and after that long, you tend to run out of conversation. Can you suggest games that can be played while hiking on a mountain trail and are appropriate for a 15-year-old girl and her dad? I'll list some of the games I've found online below.
Read on »
Posted by Dave Munger at 12:23 PM • Comments (19)
July 24, 2008
Category: Memory • Music • Perception • Research
Several recent large-scale studies have confirmed a curious finding: Asians are much more likely to have "perfect pitch" than non-Asians. Perfect pitch, more properly called "Absolute pitch," is an extremely rare phenomenon, but it's several times more likely to occur in Asians than in others.
Studies have found that only 1 in 1,500 to 10,000 individuals possess absolute pitch. Part of the ability's rarity is due to the fact that it's really a combination of two abilities: pitch-memory -- the ability to remember what a pitch sounds like, and pitch-labeling -- the ability to name a pitch (A, B-flat, and so on). Pitch labeling can only come through training, but pitch memory does not require training.
So does the Asian advantage come from pitch labeling or pitch memory? Many people, even those with very little training, are able to remember the pitch of familiar songs. Daniel Levitin, for example, has found that most people can sing their favorite songs at pitches nearly identical to the popular versions played on the radio.
Glenn Shellenberg and Sandra Trehub realized that pitch memory might be the best way to uncover differences between Asians and non-Asians. They asked 70 kids, age 9 to 12, all living in the Toronto area, what their six favorite TV shows were. Half these kids were Asian and half were non-Asian. Then they played two different versions of each show's theme song: one accurate, and one shifted up or down by two semitones (so if the original melody was C - D - E , the new version might be be D - E - F-sharp). The child was asked which was the correct melody -- the one they heard on TV. Here are the results:
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Posted by Dave Munger at 3:47 PM • Comments (20)
July 21, 2008
Category: Development / Aging • Perception • Research
A number of studies have found that older adults aren't as good at certain visual tasks compared to younger adults. Mental rotation, for example, is both slower and less accurate. But other studies have found that for certain types of mental rotation, older adults do just as well as younger adults. The dividing line, these researchers argued, was based on whether the viewer was rotating or the objects themselves were rotating.
So in a classic mental rotation task like Shepard and Metzler's, older adults don't do as well, but in many other tasks, their performance isn't much different from younger adults.
But a new study by a team led by Mélanie Joanisse challenges the notion that the frame of reference -- objects rotating relative to the viewer or to themselves -- isn't the key factor. Instead, they suggest, it has to do with how that rotation is being processed.
They had 24 college students (average age 23) and 24 older adults (average age 72.1) sit on a desk chair in the center of a small round room. Seven different drawings (a cup, shoe, book, box, plate, jar, and hairbrush) were spaced at even intervals on the wall. The viewers memorized the positions of the objects, and then were blindfolded, rotated in the chair, and asked to point to one of the four nearest neighbors of the object they were facing. The key to the study was how they were rotated:
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Posted by Dave Munger at 4:42 PM • Comments (1)
July 17, 2008
Category: Attention • Perception • Research • Video Games / Technology
When we're in a crowded space, making visual judgments becomes more difficult. But it doesn't take much to trigger a crowding effect. Clicking on the picture below will take you to a quick movie (QuickTime required) that should demonstrate the effect. Focus on the cross to the left, then start the movie (it may start automatically, depending on your browser). In two seconds, a "T" will flash briefly on the right side of the screen. Your job is to determine whether the T is upright or inverted (upside-down). After another two seconds, three Ts will appear. This time, you must judge only the middle T, which appears in the same place as the first T you judged.
If you don't get the hang of it the first time you watch, go ahead and watch the movie one more time -- but no more! Which T was more difficult to judge? Because the second T was "crowded" by the other two, it should be more difficult for most people. The two polls below should indicate whether we found the effect -- I'll give the correct answers at the end of this post.
Read on »
Posted by Dave Munger at 2:21 PM • Comments (7)
July 16, 2008
Category: In other news
Bora's hosting the first-ever edition of a new history of science carnival, "The Giant's Shoulders," which promises to focus attention on great research from years past, once a month.
All participants review a journal article or other report of science from their field of expertise. The catch is that the science being reviewed must be at least ten years old. This edition recaps all the entries from Skulls in the Stars' original challenge, so if you missed that, now's your chance to catch up, in addition to reading all the new entries for this edition.
Posted by Dave Munger at 10:50 AM • Comments (0)
July 15, 2008
Category: Movement and exercise • Perception • Research
Imagine yourself in a room surrounded by eleven objects arranged in a circle. You memorize the position of the objects, then you close your eyes, and rotate a third of the way around (120°). Keeping your eyes closed, can you point to the object that was behind you before? Most people can do this without much difficulty, and only take an instant longer than if they'd stayed in the same position.
Now imagine the objects are rotating on a turntable as you yourself rotate, so that the same object is still in front of you -- in many respects, it's as if you've never turned and the objects never moved. Yet for most people, it actually takes longer to point to the objects than when they had changed position relative to the objects. What's going on here?
It shouldn't be especially surprising that we're quick to remember the location of objects in a room when we have rotated -- after all, this is the kind of thing we must do all the time, like when we look from left to right to decide whether it's safe to cross the road. But there are also times when an object or set of objects move along with us. If you're driving a car and turn around a corner, you still remember that the groceries are right behind you in the trunk. So why is it difficult for us to imagine objects moving along with us?
The first two scenarios I described above correspond to an experiment conducted by Weimin Mou, Xiaoou Li, and Timothy McNamara. They paid students to enter a room configured like this:
Instead of symbols, the room contained real objects, like a candle, a hat, and a ball. Standing in the center of the room, the students first memorized the position of all the objects, then were blindfolded and told to point to the objects one at a time using a joystick (e.g. "point to the candle."). Then they were told to rotate their bodies in place, imagining the objects rotating along with them. Again, still blindfolded, they were tested on the positions of each object. They were also asked to imagine the objects rotating while they remained in place, and to rotate while imagining the objects remained in place. Here are the results:
Read on »
Posted by Dave Munger at 8:00 AM • Comments (8)
July 9, 2008
Category: Perception • Reasoning • Research • Social
In 2005, E. Ashby Plant and B. Michelle Peruche tested 48 Florida police officers and found that they were initially more likely to shoot unarmed Black "suspects" in a crime-fighting simulation than White people holding similar objects. Interestingly, however, as the test went on, the officers improved, and by the end of the session, any bias had been removed.
But in the real world, officers don't get a second chance, and accidental shootings do occur. In many communities, racial tensions are already running high, and an interracial shooting by a police officer can bring those tensions to the boiling point -- causing even more damage than the shooting itself. It's critical to understand why these accidents happen and what can be done to prevent them, not only to protect innocent suspects, but also to build community trust in police officers and increase the effectiveness of law enforcement.
Joshua Correll and five other researchers devised a test to assess racial bias shooting that was similar to Plant and Peruche's, but also more realistic. Twenty-five Black actors and twenty-five White actors were photographed holding either a gun or a benign object like a wallet or can of cola in several different poses. In the new test, random backgrounds (urban scenes, country roads, etc.) were flashed on a computer screen. At random intervals, one of the actors was inserted into the screen. Then the police officer had to decide whether to shoot or not shoot as quickly as possible, and press a button registering his or her response.
Read on »
Posted by Dave Munger at 2:57 PM • Comments (8)
July 8, 2008
Category: General / Site news
Last year when the family was in Europe I snapped this photo of Jim looking at a triptych of three blank canvases:
The accompanying blog post generated heated discussion about whether the work depicted in the photo was "art" (the discussion became so heated that I decided to close the comments on the thread). Now the photo itself has been used (with our permission) in the brochure for a Danish firm that specializes in placing artwork in business environments:
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Posted by Dave Munger at 2:31 PM • Comments (32)
July 7, 2008
Category: Perception • Reasoning • Research • Video Games / Technology
Last year we discussed a great deal of research about the gender disparity in math and science. Even while women are more successful overall in school than men, in certain fields there is a very large deficit in the number of women participating. We mentioned one explanation in particular:
The male math advantage in a number of different studies appears to be directly related to visuospatial skills, the most important being mental rotation. In tests on calculation or other mathematical problems that don't require visuospatial skills, females perform just as well as -- or better than -- males.
What's more, at least one study has found that it's possible to teach these visuospatial skills. Such a course has been offered at Michigan Tech for many years, and students taking the course have not only shown measurable improvement on visuospatial tests, they have gotten better grades in subsequent engineering and graphics courses.
But where did men acquire these superior skills in the first place? One possible answer is video games. While obviously video games weren't available to boys more than about 30 years ago, prior to that, boys may have acquired similar skills through male-dominated sports like baseball and hunting.
Shortly after our report, Jing Feng, Ian Spence, and Jay Pratt found that men and women who played action video games for more than four hours per week showed no disparity in one test of visuospatial ability, a Field of Vision task where they had to spot a dot flashing for 1/100 of a second in their peripheral vision. They were significantly better than men or women who didn't play action games. But male non-players were still better than females.
Could video game training erase this gender gap?
Read on »
Posted by Dave Munger at 3:03 PM • Comments (29)
July 3, 2008
Category: Language • Research • Social
Have you ever seen Singin' in the Rain? One of the movie's most hilarious moments is when the beautiful silent movie star Lina Lamont is asked to start making "talking pictures." As soon as this gorgeous screen siren opens her mouth, the illusion of her beauty is shattered: her squeaky voice instantly transforms her from a glamorous leading lady into a cartoonish boor. Threatened with losing their box-office cash-cow, the studio chiefs frantically enroll her in voice and etiquette lessons, but nothing helps, and eventually they're forced to substitute the voice of the attractive and lovely-voiced Kathy Selden.
But what makes one voice attractive and another unattractive -- and how much effect does a voice have on our overall perception of attractiveness? Recent research has found that women with attractive faces also tend to have attractive voices (which may explain why Lamont's hideous voice in Singin' in the Rain is so surprising).
In general we perceive higher voices as more feminine. Faces with exaggerated feminine features are also perceived as more attractive. Can we say the same about feminine voices?
A group of researchers led by David Feinberg recorded the voices of 123 young women as they pronounced five vowel sounds: ah, ee, eh, oh, and oo. Then ten male volunteers rated each voice for attractiveness. Here are the results:
Read on »
Posted by Dave Munger at 12:17 PM • Comments (26)
June 30, 2008
Category: Research • Social • Video Games / Technology
In our discussions of violence associated with video game play, we've frequently noted that there appear to be different effects depending on the type of video game. Some games are more violent than others, and some games reward violence while others discourage it. All this has an impact in terms of real-world behavior and attitudes. Some games have positive effects.
One type of game -- one of the most popular types, in fact -- hasn't been studied nearly as much as the traditional arcade-style game: massively multiplayer online role-playing games, or MMORPGs. One of the studies of this type of game seemed to find that players weren't more aggressive because the games foster cooperation between players.
But we've also heard -- and seen, with Jim's game-play, that MMORPGs like World of Warcraft can be more engaging and distracting than other games, sucking away hours and hours in seemingly endless online quests. Even if it turns out these games don't promote violent behavior, is it possible that they have other detrimental effects?
Joshua Smyth recruited 100 college students to play one of four randomly-assigned video games free for a month. They played the games on their own time, in a campus "game laboratory" (or in an arcade for the arcade group). The only requirement was that they play the game for at least an hour a week. The arcade group could play any of the games in the arcade; one group played Gauntlet: Dark Legacy on a PlayStation 2; one group played Diablo II on a computer, and the final group played the MMORPG Dark Age of Camelot. So did the type of game had any impact on how much the games were played? You bet it did -- here are the results:
Read on »
Posted by Dave Munger at 1:13 PM • Comments (30)
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