Sometimes people do things that appear to be the result of psychic abilities. One example is the curious case of blindsight. Blindsight occurs when an otherwise blind person can tell you where objects are located. This sure sounds strange and incredible. In fact, the first time blindsight was reported, neurologists thought the reports were fraudulent. So, how could a blind person tell you where something was located that they could not see? The answer lies in how vision is processed in the brain.
Vision starts with light entering the eye through the pupil and then being reflected by the lens to the retina at the back of the eye. The rods and cones in the retina convert the physical light energy into electrochemical energy that the brain understands. The message is then sent by way of the optic nerve to the primary visual cortex at the back of the brain. From the primary visual cortex, the message is sent to other areas in the brain that tell us what an object is and where it is located. As a result, we actually “see” with the brain. It wouldn’t make any sense that a blind person could tell you where an object is located if their primary visual cortex was damaged. So, what other explanation could there be?
When one of our sense is damaged, the brain often compensates by heightening the remaining other senses. Maybe blind people are able to get in touch with the “psychic” part of their brain after their vision loss. Is that the answer? Well, as it turns out, blindsight isn’t the result of psychic ability. The reason is that, in addition to the primary visual cortex, visual information travels to a midbrain structure called the superior colliculus. The superior colliculus receives messages that tell us where an object is located and whether it is moving. Blind people who have damage to the primary visual cortex, but not the superior colliculus, exhibit blindsight.
So you see, blindsight has a totally natural explanation. This shows that unexplained things can have natural explanations if we continue searching for them. If we stop looking for answers because we accept paranormal explanations, then we will stop learning and progressing. Some things may continue to stump scientists but that is no reason to accept paranormal explanations. By continuing to find out more about ourselves and the world, we get closer to discovering the true nature of reality. We should never become complacent about what we think we know, whether scientific or not. Natural explanations do not make the world a less interesting place. The fact that the brain can produce blindsight with sight impaired people is amazing.
Saturday, October 10, 2009
How to Make a Pinhole Camera
Did you know that the visual image you see is upside down and inverted left to right? This is because the opening that lets light into your eye (the pupil) is very small and light can only travel in a straight line. Because light travels in a straight line, the top of an image is reflected to the bottom of your retina in the back of your eye and the bottom of the image is reflected to the top of your retina. The result is that the image on your retina is upside down (and what is left is right and vice versa). You might ask why we don’t see the world upside down and the answer is that your brain makes the image right-side up. A pinhole camera works on the same principle as how light enters your eye. If you want to see for yourself what the image on your retina looks like it is easy to make a homemade pinhole camera.
Here is what you need: An empty Pringles can, a marker, a ruler, an X-Acto knife (or utility knife), masking tape, a thumbtack, a piece of aluminum foil, and a piece of wax paper. Most of these things can be found around your house. If you don’t have one or more of these things available, it won’t cost much to buy them. The cool thing with this project is that you get to eat potato chips and do a nifty science demonstration.
Step 1: Take the lid from the empty Pringles can and punch a hole in the middle of it with the thumbtack. Then punch a hole in the metal bottom of the can. Put the lid aside.
Step 2: Draw a line around the can about two inches from the bottom. Take your X-Acto knife and cut along the line so the tube is in two pieces.
Step 3: Take the wax paper and cover the small piece of the can (the wax paper acts like a screen). Fold the wax paper over the edge and tape it to the can with the masking tape.
Step 4: Put the big piece of the can next to the small piece and tape them together. Next, take your aluminum foil and wrap it around the entire can twice (to keep light out of the tube) and then tape it to the can. Put the plastic lid back on the can. You are done!
Step 5: Go outside, close one eye, and hold the can up to your other eye. Look through the lid. You will see the image in your backyard upside down. The top of your trees will be at the bottom of the wax paper and the bottom of the trees will be at the top of it! (Note: you can only look through the Pringles can. You can’t actually take pictures like a real camera.)
For a pictorial demonstration, check out the website at www.exploratorium.edu/science_explorer/pringles_pinhole.html. The steps I listed are slightly different but that’s what worked for me when I made the Pringles can pinhole camera I show my students.
Here is what you need: An empty Pringles can, a marker, a ruler, an X-Acto knife (or utility knife), masking tape, a thumbtack, a piece of aluminum foil, and a piece of wax paper. Most of these things can be found around your house. If you don’t have one or more of these things available, it won’t cost much to buy them. The cool thing with this project is that you get to eat potato chips and do a nifty science demonstration.
Step 1: Take the lid from the empty Pringles can and punch a hole in the middle of it with the thumbtack. Then punch a hole in the metal bottom of the can. Put the lid aside.
Step 2: Draw a line around the can about two inches from the bottom. Take your X-Acto knife and cut along the line so the tube is in two pieces.
Step 3: Take the wax paper and cover the small piece of the can (the wax paper acts like a screen). Fold the wax paper over the edge and tape it to the can with the masking tape.
Step 4: Put the big piece of the can next to the small piece and tape them together. Next, take your aluminum foil and wrap it around the entire can twice (to keep light out of the tube) and then tape it to the can. Put the plastic lid back on the can. You are done!
Step 5: Go outside, close one eye, and hold the can up to your other eye. Look through the lid. You will see the image in your backyard upside down. The top of your trees will be at the bottom of the wax paper and the bottom of the trees will be at the top of it! (Note: you can only look through the Pringles can. You can’t actually take pictures like a real camera.)
For a pictorial demonstration, check out the website at www.exploratorium.edu/science_explorer/pringles_pinhole.html. The steps I listed are slightly different but that’s what worked for me when I made the Pringles can pinhole camera I show my students.
Non Sequitur
There’s a comic strip called Non Sequitur which has a strange sense of humor sort of like The Far Side. Non sequitur is Latin for “it does not follow.” Non sequiturs are common ingredients in a lot of humor. We often laugh (or sometimes cringe) when we see connections that do not make sense. The humor is in the absurdity of the situation. Non sequiturs are also fallacies of logic. They occur when logic goes awry. When we make unfounded conclusions based on certain assumptions, the conclusion is a non sequitur.
Here is an example. Say we see more births during a full moon. You might be tempted to say that the births are caused by the full moon, but is that really the case? Maybe there are seasonal variation at work. What we would need to do is track the daily birth rate over several months or years and then compare whether the birth rate when there is a full moon statistically differs from other times. This would enable us to determine whether there was a true connection between full moons and birth rates. Other non sequiturs do not lend themselves as easily to statistical analysis.
Some people claim that if the theory of evolution is true, then God cannot exist. Denying the existence of God is in direct contradiction with many people’s core beliefs so they do not accept the theory of evolution. However, this is a non sequitur. Whether the theory of evolution is true or not has nothing to do with God’s existence. The conclusion that God does not exist if evolution is true is a non sequitur. The real concern here is that the theory of evolution contradicts a literal interpretation of specific religious texts. However, it could be possible that God in his or her infinite power kickstarted evolution. Similar arguments could be made about the big bang theory. God could have inititiated the big bang. Accepting the evidence of the big bang in no way negates the existence of God.
The real motivation for making these kinds of non sequiturs is that we are uncomfortable with things that contradict one or more of our core beliefs. Instead of making these unfounded conclusions we should examine our beliefs and the available evidence and decide whether our belief system should be modified to accept new information. If we evaluate our beliefs and change or maybe even discard some of them, then we are cognitively flexible. Unfortunately, this process causes too much anxiety for many people and they fall back on what is most comfortable to them.
Each of us needs to decide what to do with scientific information. If we choose to ignore what we learn from science then we are turning our back on ourselves. We are curious creatures with the ability to discover knowledge about the world. If we discount what we find through science at the expense of long held beliefs then we have to question the validity of those beliefs. Perhaps we should accept what we learn through science and modify our belief in a God that can only work according to a literal interpretation of ancient religious texts than make a non sequitur just to make ourselves feel better.
Here is an example. Say we see more births during a full moon. You might be tempted to say that the births are caused by the full moon, but is that really the case? Maybe there are seasonal variation at work. What we would need to do is track the daily birth rate over several months or years and then compare whether the birth rate when there is a full moon statistically differs from other times. This would enable us to determine whether there was a true connection between full moons and birth rates. Other non sequiturs do not lend themselves as easily to statistical analysis.
Some people claim that if the theory of evolution is true, then God cannot exist. Denying the existence of God is in direct contradiction with many people’s core beliefs so they do not accept the theory of evolution. However, this is a non sequitur. Whether the theory of evolution is true or not has nothing to do with God’s existence. The conclusion that God does not exist if evolution is true is a non sequitur. The real concern here is that the theory of evolution contradicts a literal interpretation of specific religious texts. However, it could be possible that God in his or her infinite power kickstarted evolution. Similar arguments could be made about the big bang theory. God could have inititiated the big bang. Accepting the evidence of the big bang in no way negates the existence of God.
The real motivation for making these kinds of non sequiturs is that we are uncomfortable with things that contradict one or more of our core beliefs. Instead of making these unfounded conclusions we should examine our beliefs and the available evidence and decide whether our belief system should be modified to accept new information. If we evaluate our beliefs and change or maybe even discard some of them, then we are cognitively flexible. Unfortunately, this process causes too much anxiety for many people and they fall back on what is most comfortable to them.
Each of us needs to decide what to do with scientific information. If we choose to ignore what we learn from science then we are turning our back on ourselves. We are curious creatures with the ability to discover knowledge about the world. If we discount what we find through science at the expense of long held beliefs then we have to question the validity of those beliefs. Perhaps we should accept what we learn through science and modify our belief in a God that can only work according to a literal interpretation of ancient religious texts than make a non sequitur just to make ourselves feel better.
Dissociative Identity Disorder
You’ve probably heard stories about people who experienced such terrible traumas that they block out the experience and create alternate personalities to deal with the situation. This paradoxical disorder used to be called multiple personality disorder. It is now referred to as dissociative identity disorder (DID). Is this a real mental disorder? Can this happen to people?
Students often enter a psychology class with many preconceptions about psychology, behavior, and the mind. Much of what we know about psychology has been distilled to us through the popular press and the media. Many of my students assume that DID is real because they have heard about it in the media or other sources. The thing is that they do not have first hand experience with the disorder to know if it actually exists. The popular assumption is that when people experience trauma they either repress memories of that trauma or they dissociate from it. However, everything we know about memory indicates that we have trouble forgetting things with increased exposure. We also cannot differentiate between a real and a false memory unless we have corroborative evidence from another person. This makes the repression theory of trauma shaky.
The story of Sybil is cited often as evidence for DID. Many people are not aware that Sybil was highly prone to hypnotic suggestion. Her alternate personalities were suggested when she was under hypnosis. Sybil came up with sixteen personalities, or alters. Up until that time, most people who were diagnosed with DID showed two or three alters. A curious thing happened after Sybil’s case was reported – most people who were subsequently diagnosed with DID started manifesting ten, twelve, or more alters. Was this just a coincidence?
So, what causes DID? There are two major theories of DID. The first, called the posttraumatic model, has already been described. In this case, a person who experiences a terrible trauma dissociates, or compartmentalizes, the experience into alternate personalities as a means of coping with the intense emotional pain of the trauma. The second theory of DID is called the sociocognitive model. In this case, the diagnosis stems from decades of therapist-induced influences and increased media attention. DID then becomes a form of role playing in which the patient learns to assume different roles as a result of societal expectations and therapist encouragement. Subjective therapeutic practices such as hypnosis, guided imagery, and prompting of alters facilitate the development of DID.
We have to be careful here. Once we create a diagnosis, we begin to make it real. If a diagnosis is contained in the manual of mental disorders, then someone will be diagnosed with it. This is not to say that there are no cases of DID that were caused by posttraumatic stress. In some cases, this may certainly happen. However, we need to be aware of how social and culture factors influence our mental health. If we reduce the number of therapist-induced cases of DID, then we can begin to treat the real issues associated with traumatic experiences. DID masks the underlying problems people are struggling with that make them resort to anything to escape their pain, even fabricating false personalities as a way of escaping reality.
Students often enter a psychology class with many preconceptions about psychology, behavior, and the mind. Much of what we know about psychology has been distilled to us through the popular press and the media. Many of my students assume that DID is real because they have heard about it in the media or other sources. The thing is that they do not have first hand experience with the disorder to know if it actually exists. The popular assumption is that when people experience trauma they either repress memories of that trauma or they dissociate from it. However, everything we know about memory indicates that we have trouble forgetting things with increased exposure. We also cannot differentiate between a real and a false memory unless we have corroborative evidence from another person. This makes the repression theory of trauma shaky.
The story of Sybil is cited often as evidence for DID. Many people are not aware that Sybil was highly prone to hypnotic suggestion. Her alternate personalities were suggested when she was under hypnosis. Sybil came up with sixteen personalities, or alters. Up until that time, most people who were diagnosed with DID showed two or three alters. A curious thing happened after Sybil’s case was reported – most people who were subsequently diagnosed with DID started manifesting ten, twelve, or more alters. Was this just a coincidence?
So, what causes DID? There are two major theories of DID. The first, called the posttraumatic model, has already been described. In this case, a person who experiences a terrible trauma dissociates, or compartmentalizes, the experience into alternate personalities as a means of coping with the intense emotional pain of the trauma. The second theory of DID is called the sociocognitive model. In this case, the diagnosis stems from decades of therapist-induced influences and increased media attention. DID then becomes a form of role playing in which the patient learns to assume different roles as a result of societal expectations and therapist encouragement. Subjective therapeutic practices such as hypnosis, guided imagery, and prompting of alters facilitate the development of DID.
We have to be careful here. Once we create a diagnosis, we begin to make it real. If a diagnosis is contained in the manual of mental disorders, then someone will be diagnosed with it. This is not to say that there are no cases of DID that were caused by posttraumatic stress. In some cases, this may certainly happen. However, we need to be aware of how social and culture factors influence our mental health. If we reduce the number of therapist-induced cases of DID, then we can begin to treat the real issues associated with traumatic experiences. DID masks the underlying problems people are struggling with that make them resort to anything to escape their pain, even fabricating false personalities as a way of escaping reality.
What is Humanism?
Some people have asked what I mean when I say I am an existentialist, humanist, and a free thinker. I feel that I need to describe what this means. First, existentialism is the viewpoint that we find meaning in life through free will, choice, and personal responsibility. This is contrary to the idea that we live life for a supernatural entity that we cannot see or touch. Existentialism emphasizes the here and now.
Second, humanism is the viewpoint that we should rely on ourselves instead of making appeals to invisible supernatural entities. It is a philosophy that encourages rational thought, logic, and skepticism. Humanism, like existentialism, emphasizes the here and now. It is a philosophy of compassion which strives to find solutions to human problems such as poverty, hunger, and violence. Humanism looks for solutions to problems in the context of human life without worrying about the possibility of life after death.
Third, free thinking refers to looking at different sides to issues. Many people assume that being a free thinker means thinking that anything might exist (such as psychic ability, clairvoyance, etc.). However, being a true free thinker means entertaining the idea that things like god and the paranormal may not exist. This kind of thinking is difficult for many people to wrap their hands around because it goes contrary to core beliefs imparted to them when they were children.
You may not agree with my ideas but I hope you take the time to examine your own beliefs. I grew up Catholic, became a born again Christian, had no specific religion, became an atheist, and now am more or less agnostic. The conclusions I made about the world are based on my study of religion, philosophy, psychology, and science, along with discussions I had with family, friends, and students. I was reluctant to accept the conclusions I made about god and the paranormal at first but I have found that you can live more freely without the constraints of religion and the supernatural. You can be a moral person and have a good life without believing in weird things. That's more than I can say for a lot of religious people.
Second, humanism is the viewpoint that we should rely on ourselves instead of making appeals to invisible supernatural entities. It is a philosophy that encourages rational thought, logic, and skepticism. Humanism, like existentialism, emphasizes the here and now. It is a philosophy of compassion which strives to find solutions to human problems such as poverty, hunger, and violence. Humanism looks for solutions to problems in the context of human life without worrying about the possibility of life after death.
Third, free thinking refers to looking at different sides to issues. Many people assume that being a free thinker means thinking that anything might exist (such as psychic ability, clairvoyance, etc.). However, being a true free thinker means entertaining the idea that things like god and the paranormal may not exist. This kind of thinking is difficult for many people to wrap their hands around because it goes contrary to core beliefs imparted to them when they were children.
You may not agree with my ideas but I hope you take the time to examine your own beliefs. I grew up Catholic, became a born again Christian, had no specific religion, became an atheist, and now am more or less agnostic. The conclusions I made about the world are based on my study of religion, philosophy, psychology, and science, along with discussions I had with family, friends, and students. I was reluctant to accept the conclusions I made about god and the paranormal at first but I have found that you can live more freely without the constraints of religion and the supernatural. You can be a moral person and have a good life without believing in weird things. That's more than I can say for a lot of religious people.
Your Gut Feeling
Our view of the world and who we are as people has changed over time. One example is that the ancient Egyptians thought the heart was the organ that created the intellect. They thought the only purpose of the brain was to cool the blood. They would preserve the heart and place it in an urn next to a mummy, while the brain got tossed out as a worthless organ. The Egyptian’s belief in the heart being the source of our thoughts is how we got the expression “learning by heart.” Now we know that the brain is the source of all our thoughts, emotions, and sensations and that it also has critical life sustaining functions. Scientists, however, are now suggesting that we might have a kind of second brain, that of the stomache.
So, why would the stomache be elevated to such an important status? Isn’t its role just to digest our food and disperse nutrients to other parts of the body? Well, it has to do with how we experience anxiety. The stomache has lots or nerve connections that become activated when we become aroused. This accounts for the feeling of butterflies in our stomaches when we are nervous. It also accounts for why we say we have a gut feeling about something when we are making a decision.
A decision in which you don’t have full information or are unsure about the outcome is by definition a risky decision. The element of risk can range from something very trivial to even a matter of life or death. The way we make a decision when we have incomplete information is to base the possible outcome on probabilities of success vs. failure (or cost vs. benefit). If we were totally rational beings we could make our decisions based strictly on weighing different outcomes. We often seek out information to help us make difficult decisions. The sources of information can be other people, books, the internet, etc. Another source many people rely on when making difficult decisions is their intuition or gut feeling.
The feelings we have when we make difficult decisions inform us as to whether we are taking the correct course of action. If we feel good about something, we will probably go ahead with the action. If we don’t feel good about it, then we will probably refrain from doing whatever we are contemplating. The feeling in our gut is why the stomache is now sometimes referred to as the “second brain.” The visceral feedback we get from the stomache is an extension of the mental state we are in at a given time.
So, this is all well and good but it should be pointed out that our intuitions are not always correct. We can be prone to something called the confirmation bias. This occurs if we only pay attention to the times our gut feeling was correct and ignore the times it wasn’t. Making decisions without complete information is something most of us would like to avoid. All we can do is to discuss the problem with people we trust and try to gather as much information as possible. After that, we have to take the plunge. Our gut might be telling us that we are taking the right course of action, or it just might be reflecting our uneasiness about making a risky decision.
So, why would the stomache be elevated to such an important status? Isn’t its role just to digest our food and disperse nutrients to other parts of the body? Well, it has to do with how we experience anxiety. The stomache has lots or nerve connections that become activated when we become aroused. This accounts for the feeling of butterflies in our stomaches when we are nervous. It also accounts for why we say we have a gut feeling about something when we are making a decision.
A decision in which you don’t have full information or are unsure about the outcome is by definition a risky decision. The element of risk can range from something very trivial to even a matter of life or death. The way we make a decision when we have incomplete information is to base the possible outcome on probabilities of success vs. failure (or cost vs. benefit). If we were totally rational beings we could make our decisions based strictly on weighing different outcomes. We often seek out information to help us make difficult decisions. The sources of information can be other people, books, the internet, etc. Another source many people rely on when making difficult decisions is their intuition or gut feeling.
The feelings we have when we make difficult decisions inform us as to whether we are taking the correct course of action. If we feel good about something, we will probably go ahead with the action. If we don’t feel good about it, then we will probably refrain from doing whatever we are contemplating. The feeling in our gut is why the stomache is now sometimes referred to as the “second brain.” The visceral feedback we get from the stomache is an extension of the mental state we are in at a given time.
So, this is all well and good but it should be pointed out that our intuitions are not always correct. We can be prone to something called the confirmation bias. This occurs if we only pay attention to the times our gut feeling was correct and ignore the times it wasn’t. Making decisions without complete information is something most of us would like to avoid. All we can do is to discuss the problem with people we trust and try to gather as much information as possible. After that, we have to take the plunge. Our gut might be telling us that we are taking the right course of action, or it just might be reflecting our uneasiness about making a risky decision.
Alien Hand Syndrome
Imagine you wake up and you find your hand clenched against your throat. Your hand has you in a death grip and you struggle to free it from you. You finally pry your hand from your throat. You have feeling in the hand but it doesn't seem like it belongs to you. You might even think it's possessed. This is an extreme example of something called Alien Hand Syndrome.
Alien hand syndrome is a rare and strange problem. Normally when you do something, like pick up a glass of water, your brain sends a signal from the motor area across a bundle of fibers, called the corpus collosum, down your spinal cord and peripheral nerves, to your hand. The corpus collosum enables the two sides of your brain to communicate with each other. You can think of it like an email server. If the corpus collosum is damaged then your email server is down. This is what happens with alien hand syndrome. A stroke or aneurysm causes damage to the corpus callosum so the messages that initiate movement don’t get to your hand.
Like I said, the example of your hand choking you is an extreme one. In most cases, the alien hand will reach or grab an object, touch your face, put food in your mouth, or do something like unbutton your shirt. It is such a weird problem that is has been portrayed in movies, the most famous being Dr. Strangelove. In the movie, Dr. Strangelove’s right hand continually does offensive things and he has to beat it down with his left hand.
Unfortunately, there is no treatment for alien hand syndrome. People will often try to keep the alien hand occupied by having it hold an object. Others will go as far as tying it behind their back. Gradual recovery may occur if the person's brain trauma was not too extensive. For the rest, all they can do is try to adapt to the feeling that their hand does not belong to them and that it has a mind of its own.
Alien hand syndrome is a rare and strange problem. Normally when you do something, like pick up a glass of water, your brain sends a signal from the motor area across a bundle of fibers, called the corpus collosum, down your spinal cord and peripheral nerves, to your hand. The corpus collosum enables the two sides of your brain to communicate with each other. You can think of it like an email server. If the corpus collosum is damaged then your email server is down. This is what happens with alien hand syndrome. A stroke or aneurysm causes damage to the corpus callosum so the messages that initiate movement don’t get to your hand.
Like I said, the example of your hand choking you is an extreme one. In most cases, the alien hand will reach or grab an object, touch your face, put food in your mouth, or do something like unbutton your shirt. It is such a weird problem that is has been portrayed in movies, the most famous being Dr. Strangelove. In the movie, Dr. Strangelove’s right hand continually does offensive things and he has to beat it down with his left hand.
Unfortunately, there is no treatment for alien hand syndrome. People will often try to keep the alien hand occupied by having it hold an object. Others will go as far as tying it behind their back. Gradual recovery may occur if the person's brain trauma was not too extensive. For the rest, all they can do is try to adapt to the feeling that their hand does not belong to them and that it has a mind of its own.
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