dmunger | August 19, 2008The current issue of WIRED reveals an interesting quirk of the human perceptual system:
Can you spot what's wrong?
dmunger | August 18, 2008One of the first things I did after my 90-mile hike with Nora in the North Cascades was play some music on the car stereo. We'd been in the wilderness for seven days, and other than birdsong, we hadn't heard so much as a note for the entire time.
Matching our intuitions about music, researchers have found that music is an important influence on our memories. We associate songs with emotions, people, and places we've experienced in the past. This isn't to say that music is the only influence on memory: the photos I took, the sights I saw, and the words I wrote about my hike will also help to…
dmunger | August 14, 2008[This article was originally published in December, 2006]
As parents of a 1516-year-old, Greta and I are very interested in what causes people to behave aggressively. We know a lot about specific causes of aggression -- violent media, testosterone, guns, and personal insults can all lead to aggressive behavior in certain circumstances. But kids and others exposed to one or more of these things don't necessarily become violent. Sometimes it seems that just the presence of his sister in the room can cause Jim to act more aggressively than he would otherwise.
That's one reason we were intrigued…
dmunger | August 13, 2008Over at Sciam's Mind Matters blog, Greta and I have written a guest post about tone deafness and bad singing:
Although there have been many studies of perceptual tone deafness, or amusia, few have compared people's ability to hear differences between musical notes with their ability to produce good music. This fact is what makes the recent study by Pfordresher and Brown so interesting. They tested 79 college students on both their ability to discriminate between musical notes and their ability to sing accurately.
... and here's what they found:
The bad singers were significantly worse than…
dmunger | August 11, 2008[This article was originally published in December, 2006]
Take a look at these two images. Do they belong in the same category or different categories?
You say the same? Wrong -- they're different! The one on the right is a little blurrier.
What about these two?
These are in the same category. Sure, the one on the right is still blurrier, but now it's rotated a bit, so that puts the two objects back in the same category. My rule for categorizing is complex, involving both blurriness and rotation (I'll explain how it works later on).
How do you think you would do if you were tested on…
dmunger | August 7, 2008[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…
dmunger | August 4, 2008[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…
dmunger | July 31, 2008[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…
dmunger | July 30, 2008Cognitive 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…
dmunger | July 28, 2008One 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…
dmunger | July 25, 2008I'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.…
dmunger | July 24, 2008Several 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…
dmunger | July 21, 2008A 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…
dmunger | July 17, 2008When 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…
dmunger | July 16, 2008Bora'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.
dmunger | July 15, 2008Imagine 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…
dmunger | July 9, 2008In 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…
dmunger | July 8, 2008Last 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:
So, now, is the photo itself a work of art? Some of the arguments that were made in the original debate might be pertinent. Maybe…
dmunger | July 7, 2008Last 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…
dmunger | July 3, 2008Have 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-…