Perception
dmunger | May 10, 2006Recent research suggests that one of the reasons that as many as 97 percent of women and 68 percent of men experience food cravings is because of visual representations of food. When we picture food in our minds, our desire for the food increases. So why not just distract the visual system? One research team attempted just that, tempting volunteers with pictures of chocolate, and then distracting them with either a randomly changing visual image or an auditory task. The participants who watched the visual image experienced fewer food cravings.
I've attempted to reproduce the type of display…
dmunger | March 27, 2006Take a look at these two shapes. Which appears more "joyful"? Which appears fearful?
How about these shapes? Which is angrier? Which appears to be suffering more?
If you're like most people, the shapes that appear to be less stable (number 2 in the figures above) are also more fearful. Those that are rotated more from the vertical position (again, number 2 in the figures) are more suffering and less angry.
Assigning emotions to shapes is nothing new. In experiments as early as the 1940s, individuals have been found to consistently apply the same emotions to shapes in schematic cartoons: "…
dmunger | March 16, 2006A Witches' Bible states that "the sensitive is psychically aware of character qualities, or emotional or spiritual states, in the subject, and this awareness presents itself to him or her as visual phenomena." It's easy to dismiss such claims as pseudoscientific claptrap, yet there exist humans who, when presented with nonvisual stimuli such as tastes or smells, perceive visual imagery. I'm talking about the scientifically recognized condition, synesthesia. Synesthetes are people who perceive stimuli presented in one mode (often corresponding to one of the five senses) with a different mode.…
gmunger | February 27, 2006You can get a lot of information from a simple bar graph, but to what extent does the arrangement of the bars matter? You can find great commentary about good design, but what about a nice clean experiment? Martin H. Fischer led a team that asked participants to indicate if a given relationship was true or false, based on a variety of different bar graphs. For example, is A > B in this graph?
And what about this one?
If you are like most people, it was easier to confirm that A was larger than B in the first graph -- where the bars were oriented vertically. In addition to…
dmunger | February 20, 2006Here's a picture of our daughter Nora at about 3 months of age. She looks like she's fairly aware of the events going on around her (arguably more aware than she sometimes appears now, at age 12). However, as our knowledge of how infants begin to perceive the world around them has increased, we've learned that the world of a three-month-old literally looks different to them than the world we perceive as adults. That's because vision, which seems so obvious and instinctive, is actually an active process. When we perceive the world visually, we're not just passively "seeing" what's there, we're…
dmunger | February 16, 2006Can you tell the difference between the images below?
At first, they just look like fuzzy diagonal lines -- there doesn't appear to be a significant difference between them. But if you look at them closely, you begin to notice that the images at the top of the picture (category A) tend to have single dark bands, while the images towards the bottom have dark bands that come in pairs. The "phase angle" refers to the technique used to generate the images, and based on this angle, the images can be divided into two categories.
With a lot of work, people can be trained to quickly distinguish…
dmunger | January 31, 2006Clicking on the image below will take you to a short Quicktime movie. Make sure you have your sound turned up, because I've recorded a few sentences that play along with the movie. Your job is to determine, as quickly as possible, if each sentence is grammatically correct -- while you focus your vision on the animated display.
This demonstration replicates part of an experiment conducted by a group of researchers led by Michael P. Kaschak. The researchers showed similar animations to a group of volunteers and asked them to make similar judgments about spoken language. The question: does…
dmunger | January 25, 2006 Disney's purchase of Pixar makes it clear that computer-generated (CGI) animation appears to be the wave of the future in movies. But one difficulty with CGI animation is conveying realistic emotions. While film animators (whether they use computers or not) can use artistic license to achieve the desired effects, when "emotions" are generated exclusively by computer, it can be difficult to identify the key factors in conveying that emotion.
We've discussed avatars, for example, as one way that computers can automate human interaction. Artificial intelligence -- lifelike simulators of human…
dmunger | January 18, 2006Chad Orzel has challenged the ScienceBloggers to come up with the greatest experiments in their respective fields. While Greta and I are reluctant to say this is the greatest experiment ever (there are so many great experiments!), we both independently came up with the same one: Roger Shepard and Jacqueline Metzler's 1971 experiment on mental rotation. It's certainly our favorite, and it's difficult to overstate its importance.
The design of the experiment is simple and brilliant; yet it was not easy to execute at the time. Today researchers studying vision almost always use computers to…
dmunger | January 17, 2006Point-light displays can tell us an amazing amount about other people. Looking only at a few glowing spots corresponding to joints and set in motion, we can tell what people are doing, whether they are over- or underweight, and even identify a friend among strangers. We can also identify animals or determine the emotional state a dancer or actor is conveying. But some emotions are more difficult than others. Take a look at the following two animations (click on the image to view a quicktime movie):
Now, which emotion does each animation convey? Your choices are Anger, Joy, Sadness, Love,…
dmunger | January 12, 2006There was a fascinating article in the Washington Post last May about Dilbert creator Scott Adams' battle with focal dystonia. Though the symptoms of this disorder are involuntary muscle contractions (in Adams' case, his right pinky finger), the root of the problem is in the brain. For Adams, it has meant suspending his cartooning career more than once. The first time, he taught himself to draw with his left hand, only to see the symptoms reappear there. He's also tried grueling physical therapy regimens. His most recent effort to battle dystonia has been drawing his cartoons using a…
dmunger | December 30, 2005What is your mind doing when you think about something? For decades, the prevailing wisdom was that when you imagine, say, the scent of a flower or your lover's perfume, your mind is doing something different from when you actually smell those things. The metaphor was a computer: The hardware for sensing things was distinct from the software for thinking about things.
More recent evidence suggests that the way we understand concepts relies on the sensorimotor system. When you think of the sound of a dripping faucet, the same parts of your brain are activated as when you are actually hearing a…
dmunger | December 26, 2005How do we know when we see a beautiful body? Is it some social standard such as thinness or proportion? Do we simply think that bodies that are closest to "normal" are also most beautiful? We know that to be the case with faces, where faces that closest to "average" are generally rated as more attractive than others which deviate, and faces that combine the characteristics of several races are rated as more attractive than those typical of a particular race.
We've written before on how our perception of faces can be altered. If you look at faces that have been systematically distorted to look…
dmunger | November 10, 2005Eric Durbrow pointed me to this article in the Globe and Mail. Its lead sentence offers a surprising claim:
Parents take note: Reading to your preschoolers before bedtime doesn't mean they are likely to learn much about letters, or even how to read words.
But aren't teachers and literacy advocates constantly urging parents to read to their kids? Aren't their entreaties backed by research?
The Globe and Mail article reports on research published in Psychological Science by Mary Ann Evans and Jean Saint-Aubin. I decided to look at the original article to see if it lives up to the dramatic…
dmunger | October 24, 2005Psychologists have known for decades that people perceive music as happier when it's played faster, and in a major key (mode). Take a listen to the following sound clips I created using a synthesized flute. Each plays the same melody three times—first in a major mode, then a minor mode, then a "whole tone" middle ground. The only difference between the two clips is that the second clip is played twice as fast.
Clip 1 (slow)Clip 2 (fast)
For most people, the second clip sounds happier than the first overall, and the major mode portion sounds happiest within each clip. But what matters most—the…
dmunger | October 21, 2005I'm usually disappointed when I try to take a picture of a steep precipice—it never seems as impressive in the photo as it did when I was standing right there. Take this photo, for example. It's a nice shot of my daughter Nora, taken on our hike in the Great Smoky Mountains this past summer, but you just don't get much sense of the dizzying precipice she's standing on the edge of.
Later that summer, on Lake Powell, Utah, I finally managed to get a shot that conveyed some drama:
But even this shot doesn't really show the paralyzing terror Nora felt as she peered over the 100-foot drop-off…
dmunger | October 20, 2005If you're a perception teacher, a great way to show how the vision system adapts is to use prism glasses to shift a volunteer's vision. While various types of glasses are available (the most common is designed to allow a person to read a book lying on her back), the most effective for this demo is a pair that makes the world appear shifted about ten degrees to one side—so what was directly in front of your victim now appears ten degrees to the left (or right, depending on the particular pair of glasses). The best volunteers are athletes—quarterbacks or pitchers. Suppose the starting softball…
dmunger | October 10, 2005This weekend, robot cars competed in a challenge that most humans would find trivial: drive 132 miles in 12 hours without crashing. Yet crash, they do. The difficult part isn't so much the steering and acceleration, it's determining the difference between an obstacle you must navigate around and a benign shadow on the road; it's deciding whether that dark patch ahead is open roadway or deep water. These things are so easy for humans that we take them for granted, yet for a machine it's a task literally in its infancy.
By the time a child is 2, it can easily tell the difference between a…
dmunger | October 5, 2005The Parthenon in Nashville, Tennessee, is a full-scale reconstruction of the rather more famous monument atop the Acropolis in Athens, Greece. We visited it with our daughter Nora a few years back:
As you can see, it's a dramatic building, dominating the landscape of the otherwise ordinary city park in which it sits. So, when we're confronted with such a massive landmark, do we use it to organize the surrounding area as well? Several studies have shown that we do pay attention to the surroundings of objects in order to remember their location. If we memorize the locations of a number of…
dmunger | September 28, 2005There are two different ways we might navigate from place to place: we either remember landmarks along the way, or we note how far we go in each direction, and what turns we've made along the way. The landmark system doesn't work very well in nondescript landscapes or in the dark, and the second system—which mariners term "dead reckoning," is susceptible to increasing errors as the distance we travel increases. So in day-to-day life, walking or driving around town, which method do we use?
A team led by Florence Gaunet explored this issue using a driving simulator. The participants in the…