African nomads and Westerners show the same ability to discriminate between shapes, a new study in Psychological Science reports. Authors suggest that the brain's shape perception develops without deliberate training.
Full story
Wednesday, March 31, 2010
Sunday, March 14, 2010
Thursday, March 4, 2010
when a simple problem gets really hard!
After today's class when we were walking back to our department, Vinod and me were talking about some puzzles he used to post for PhD students at ISyE. he then asked me "what is a hard puzzle?" or better to say "is a problem hard because the solution is complicated or maybe something else is involved?"
I answered Vinod's question by bringing this example that we all know:
suppose we are training a child to learn the mathematical sum operation. To help him understand the "relationship" better we present him a story: suppose there are 3 birds sitting on a tree and 2 birds just come and sit next to them. how many birds are now on the tree? the child hopefully will answer 5. we repeat this problem with different numbers until he learns the whole concept of sum. now we switch the gear and try to teach him "subtraction" we ask him what will happen if we have 3 birds on the tree and 1 of them flies away. he will say 2 birds will remain on the tree. we repeat this experiment over and over until he learns this operation as well. now we test him on a "slightly" different problem. we tell him to suppose that there are 3 birds on the tree, we have a gun to shoot them, so we shoot and hit one of them. how many birds are now on the tree?
the first time I encountered this problem I immediately answered 2. I used the fact that since 2 problems are slightly different (actually they are exactly the same but some features are different. it's like we use 2 different kind of birds in 2 problems), the answer should be the same. but as we all know the answer is 0 since if you shoot one bird, other birds will fly away before you find a chance to shoot them.
I would call this problem "hard" and why so? before giving my reasons I would like to hear what you think.
I answered Vinod's question by bringing this example that we all know:
suppose we are training a child to learn the mathematical sum operation. To help him understand the "relationship" better we present him a story: suppose there are 3 birds sitting on a tree and 2 birds just come and sit next to them. how many birds are now on the tree? the child hopefully will answer 5. we repeat this problem with different numbers until he learns the whole concept of sum. now we switch the gear and try to teach him "subtraction" we ask him what will happen if we have 3 birds on the tree and 1 of them flies away. he will say 2 birds will remain on the tree. we repeat this experiment over and over until he learns this operation as well. now we test him on a "slightly" different problem. we tell him to suppose that there are 3 birds on the tree, we have a gun to shoot them, so we shoot and hit one of them. how many birds are now on the tree?
the first time I encountered this problem I immediately answered 2. I used the fact that since 2 problems are slightly different (actually they are exactly the same but some features are different. it's like we use 2 different kind of birds in 2 problems), the answer should be the same. but as we all know the answer is 0 since if you shoot one bird, other birds will fly away before you find a chance to shoot them.
I would call this problem "hard" and why so? before giving my reasons I would like to hear what you think.
Wednesday, March 3, 2010
Scientists extract images directly from brain
For your amusement, check this one
http://pinktentacle.com/2008/12/scientists-extract-images-directly-from-brain/
Discussed in class on 3-2
The Prof discussed the experiment whereby humans neural activity was charted by a computer as they were exposed to different 'artifacts.' In the example given, one person's perception of a knife was recorded by the computer and it was shown that the computer could tell what the person was looking at simply by the neural patterns. Researchers had discovered that different people's brains exhibited the same characteristics when processing the knife. The class seemed very interested in this and discussed this for several minutes. Some questions I had were:
1. Was the person asked to 'say' the word representing the object they saw, or just to look at it?
2. Did everybody look at the exact same knife? From the same perspective?
3. How would/should people's experience with knives play into their neuro-biological 'output'? For instance, would a chef who used knives like the one displayed on a daily basis have the same 'reaction' as a person who had little familiarity?
4. How would adults' perception of the knife differ from that of children?
In the end, the Prof explained the 'magic' behind the computer's ability to read minds, but it seemed that some of the class was still unsatisfied. (Note that the answer to number 1 is NO; I must have misunderstood.) What I gathered from his explanation was the following:
The computer detected neural activity, but the portion of the activity which actually spoke directly to the object in view was the portion connected to the visual center. That is, the computer looked for (and discerned) whatever happens in the brain when the eye falls on a particular color, depth, pattern, shape, blah, blah, blah. The information picked up by the eyes is somehow mapped and the device read and interpreted that mapping. That doesn't however, answer all of the questions. Would not a person looking at the knife from a different perspective (or angle) have a different resultant mapping? (the answer might be that the mapping is different but similar enough for the machine to detect the pattern)
What about the question of familiarity? Wouldn't the chef 'perceive' the knife a bit differently? (perhaps there were no chefs in the study)
Are not children's perceptual-cognitive representations of knives different than that of adults? That question raises the next question: is there a perceptual 'cutoff'? I guess (answering my own question) that a human is a human and if the eye captures the image, the mapping would be the same. What about a chimp's representation of the knife?
Just some quick notes so that I could say I participated in the blog and not be lying. Really, though, this class is thoroughly enjoyable to me and I love to listen to the discussions raised by the students from time to time. This blog should be a great tool. See you guys in class.
1. Was the person asked to 'say' the word representing the object they saw, or just to look at it?
2. Did everybody look at the exact same knife? From the same perspective?
3. How would/should people's experience with knives play into their neuro-biological 'output'? For instance, would a chef who used knives like the one displayed on a daily basis have the same 'reaction' as a person who had little familiarity?
4. How would adults' perception of the knife differ from that of children?
In the end, the Prof explained the 'magic' behind the computer's ability to read minds, but it seemed that some of the class was still unsatisfied. (Note that the answer to number 1 is NO; I must have misunderstood.) What I gathered from his explanation was the following:
The computer detected neural activity, but the portion of the activity which actually spoke directly to the object in view was the portion connected to the visual center. That is, the computer looked for (and discerned) whatever happens in the brain when the eye falls on a particular color, depth, pattern, shape, blah, blah, blah. The information picked up by the eyes is somehow mapped and the device read and interpreted that mapping. That doesn't however, answer all of the questions. Would not a person looking at the knife from a different perspective (or angle) have a different resultant mapping? (the answer might be that the mapping is different but similar enough for the machine to detect the pattern)
What about the question of familiarity? Wouldn't the chef 'perceive' the knife a bit differently? (perhaps there were no chefs in the study)
Are not children's perceptual-cognitive representations of knives different than that of adults? That question raises the next question: is there a perceptual 'cutoff'? I guess (answering my own question) that a human is a human and if the eye captures the image, the mapping would be the same. What about a chimp's representation of the knife?
Just some quick notes so that I could say I participated in the blog and not be lying. Really, though, this class is thoroughly enjoyable to me and I love to listen to the discussions raised by the students from time to time. This blog should be a great tool. See you guys in class.
Cognitive Science course blog
Cognitive Science is an interdisciplinary study of mind and intelligence. It lies at the intersection of computer science (specially artificial intelligence), psychology, linguistics, biology (specially neurobiology), anthropology and philosophy.
This blog is for students taking Cognitive Science course to express their views and opinions, to reflect, verbalize, share and discuss to collectively make sense of the course together.
The course webpage for this class is: http://www.cc.gatech.edu/classes/AY2010/cs6795_spring/
Subscribe to:
Posts (Atom)