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Decade of the Brain as seen on The Frontiers Decade


q Do you think humans are born with the ability to use logic to solve a problem? In your experiment with Minnie Mouse, the older babies seemed to know that the object could not simply disappear. So did they use logic to determine the trick was not magic?

A You raise a very good question: What abilities are infants born with that enable them to learn about the physical world as quickly as they do? This is the big scientific question that my field is trying to answer, and different researchers all have different answers to it. Some people believe that babies are born with some knowledge already built-in; for my part, I tend to think that, instead of having knowledge built-in, what might be built-in is a special mechanism (like a special purpose computer, say) that helps infants learn about objects. This mechanism would direct infants to attend to certain things (like contacts between objects), and to seek out general facts about the ways in which objects move and interact.

To get back to our Minnie experiment: both the younger and the older babies expected the Minnie in the arch; the difference between them was that the younger infants could not figure out why it did not appear, whereas the older ones immediately realized that we must be using two Minnies to do the event. Perhaps that explanation came more easily to the older infants because (a) they had observed things like that in their daily world or (b) as the brain matures it becomes easier for them to generate explanations for events that are not consistent with their explanations.
Renee Baillargeon
It's a Kid's World, March 1995



q Are there any general guidelines to help distinguish between "normal" forgetfulness the onset of Alzheimers in older adults? For example, does forgetting common words mean possible Alzheimers?

A Many older people have trouble remembering names, so that trouble with names (unless it is quite pronounced) is not a sign of Alzheimer's disease. Difficulty learning and remembering new information is the most common problem in early Alzheimer's disease. People who have that kind of memory loss start repeating themselves, forgetting recent conversations and the like. If that kind of difficulty starts to happen on a regular basis (daily or weekly) then it is cause for concern. However, it is important to remember that many treatable illnesses can cause similar problems. So if you are concerned about someone you know, they should have a regular medical checkup.
Marilyn Albert
Never Say Die, January 2000



q Why do some people have no memory of a traumatic or painful event? I have heard that hypnotism can surface these memories in an individual.

A A simple answer is that we do not know what may cause traumatic amnesia. But, it could be that is, at least under some conditions, due to an over-activation of stress hormone systems. Our studies with rats and mice indicate that very high doses of adrenaline impair or block memory formation. Such memories cannot be retrieved or surfaced simply because they are not formed. The evidence suggesting that hypnosis can aid memory retrieval is weak, at best. A problem with efforts to induce recall by hypnosis is that subjects simply tend to be more talkative - and what they talk about does not necessarily indicate that they have reliable memories.
James McGaugh
Pieces of Mind, January 1997



q Our class would be interested to hear how your research on memory will be used to help people, and who could it help.

A There are three ways in which I believe that the kind of research conducted in my laboratory will be useful in helping people. First, knowledge of how the brain works is important in its own right. It is important to understand the complex working of the brain in providing a basis for our learning and memory. Second, the work could lead to the development of drugs for treating disorders of memory (i.e., impaired memory) resulting from diseases and injury. Third, the work could lead to the development of prevention or treatment of traumatic memory such as that seen in the Post-Traumatic Stress Disorder.
James McGaugh
Pieces of Mind, January 1997



q Why do rapid eye movements occur during a dream?

A "Why" is a tricky question. If you mean "why" in terms of what causes them to occur, the answer appears to be that during REM sleep there is a REM control center in the brainstem which gives off periodic bursts of activity that spread over wide areas of the brain. These chaotically arising signals activate other midbrain structures that control eye movements. If the REM center on the left side of the brain happens to send out a burst, the eyes will move to the left; if the right side center fires, the eyes will move to the right.

If you're asking "why" meaning what's it for, the answer is less clear. One theory is that it's one of the way that the brainstem gives the forebrain the raw materials out of which to construct dreams; the forebrain recognizes that the eyes are moving and decides that something in their field of vision is moving, or that they're moving, and builds this information into the ongoing dream narrative. Interestingly, dreams turn out to be chock full of movement, much more than you would normally see in your waking life. Maybe this is why. But a second theory turns this idea on its head. This "scanning hypothesis" proposes that the eyes are actually following the action of the dream, much as your eyes follow the action on a movie screen. But the anatomy of the brain doesn't seem to encourage this explanation; there don't seem to be major pathways that could carry clear information about the dream imagery back down to the brainstem so that it could send signals up to the midbrain to make the appropriate movements.
Robert Stickgold
Pieces of Mind, January 1997



q Why is it so hard to remember what we have dreamed about after we wake up?

A Although we don't have a firm answer to this one, it obviously has to do with how memories are formed, and the fact that they are formed differently when you're dreaming than when you're awake. There are, unfortunately, a couple of different theories. One says that because of the altered chemical environment in the brain during REM sleep, the brain is literally unable to form new memories. The only way to remember a dream is to wake up out of the dream while it's still fresh in your mind, and then rehearse it in the wake state. According to this theory, it's during the process of rehearsal that the actual memory is formed so that you can remember it later.

The second theory says that memory formation is fine during REM sleep, but that recall is very difficult. This theory is strongly supported by those times when something happens during the day, like a dog runs out in front of a car and almost gets hit, and you suddenly say, "Oh wow, I had a dream last night with a dog running around in it." The argument here is that the memory of the dream is there in your memory (when you recall the dog dream, you see the whole dream segment with clear visual imagery, recalling your feelings, what else was going on, etc.) but until the dog appeared the next day you had no associations that would allow you to locate and recall the memory of the dream. After all, if I try to remember where I left my car keys last night, I have a strategy for searching my memory - what did I do after dinner, where did I go, when did I come home, what did I do when I came back into the house, etc. But if I want to recall my dreams from last night, where do I look for that memory? Unless we can hold onto the images in our mind when we first wake up, and then use then as a pathway to the memory of the rest of the dream, we seem to be out of luck.
Robert Stickgold
Pieces of Mind, January 1997



q What makes the dowsing rods "work"? Do you think people unconsciously loosen their hands so the rod turns?

A The term we used in our book, and also on the Scientific American Frontiers show, is IDEOMOTOR ACTION. This term was coined in the middle 1800s by the physiologist William Carpenter. He used the term to describe how our ideas of an expected movement can actually cause our muscles--unconsciously--to produce the expected movement. Carpenter used this concept to account for how the dowsing rod moves, how tables seem to move of their own accord during seances, how the pendulum moves to answer questions, and automatic writing. Later, others used the concept to explain how the ouija board works.

Dowsers used to insist that the rod was moved by some outside force acting directly on the rod. Later some dowsers argued that an outside force acted on the muscles of the dowser. The rod served mainly as a way to amplify and better detect the slight movement of the muscles that were reacting directly to the alleged force generated by the underground water. Indeed, during the early part of this century the dowsers argued with one another as to which explanation was correct. Psychologists and skeptics argued that neither explanation was correct. Instead, the rod moved because the dowsers expectations subconsciously were transmitted to his/her muscles. Today, most dowsers accept the psychological explanation that their muscles are moving the rod because of signals from their unconscious. However, they differ from the skeptics in that they believe their unconscious is in touch with special forces or psychic information that guides the rod.
Ray Hyman
Pieces of Mind, January 1997






 

Scientific American Frontiers
Fall 1990 to Spring 2000
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