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Sunday, July 18, 2010

Left or Right?

When you pick up an infant, is it more likely for you to hold the child in your left arm or your right?  It has been found that 70-80% of women, regardless of which hand is dominant, hold babies with their left arm. 

Dr. Karl on a Triple J podcast pointed this out.  He said that with the help of physicians, mothers were studied quietly.  After examining an infant, the doctor would return the infant to the mother to the midline of her body.  Not toward the left nor the right.  The majority would take the baby and hold the child in her left arm. 

There are many different studies that I have read.  There seems to be two ideas about why this side preference might occur.  Some state that intuitively and subconsciously moms have figured out that the baby is more calm on the left side.  Before birth the baby can hear the mother's heart beating and it is a familiar, comforting sound. After birth, the baby can hear the mother's heart beat better when being held on the left side. This conclusion has many critics and is not well supported.

Many more studies believe that the left-side preference has to do with holding the baby on the side of the body that connects to the part of the brain which is dominant for processing emotions.  A mother is then better able to read the emotions of the child and react better. 

One of these studies found that mothers who cradle the baby on the right side speak higher and louder to their child than those who hold on the left.  Some mothers go back and forth between holding right and left.  Their pitch and volume went up when holding on the right.

There have also been studies about which side people prefer when hugging or kissing.  The majority of people tilt their heads to the right when kissing, and approach another person's left side when hugging.  Some of these reports think that the left-side baby cradling preference and the left-side approach to hugging are related.

There are many, many sites with this information.  Here are a few links. 

General overview
Do you kiss to the right or left?
Hugging preference
Pitch and volume differences
Left-sided baby cradling preference studies done on great apes.

Being right-handed, I always thought that I held my children on my left hip so that I could use my right hand to do things.  According to these studies, right-handers in general feel the same as I do.  And left-handers say they cradle on the left because that is the stronger arm.  It turns out it all might come down to our subconscious knowing the best way and our conscious mind coming up with a reason.

Now you have heard something interesting.

Saturday, July 3, 2010

Can You Hear that Color?

Have you ever heard of synesthesia?  It is an accident of nature that would be fun to have.

Synesthesia is when two different senses are abnormally joined.  For instance, some synesthetes always see a certain color when they hear a certain musical note.  The most common form is colored numbers or letters, but any combination is possible.  There is a report of one man who tasted chocolate when he said his wife's name.  Another man claims that cucumbers taste pink.

Every synesthete experiences things uniquely.  For instance, one who sees an A major chord as purple, always sees it as purple.  But another might see that sound as yellow.

"I could never figure out why I was such a poor student at Math, until I received a 32 color pen for a present. FINALLY NUMBERS WERE THE RIGHT COLOR, 2 was yellow, 3 was green, 4 was orange, 5 was red, and so on. My teacher thought I was nutty, but when she invested in colored chalk, my Math scores SOARED... she just had to get the colors right. Oddly another student and I got into a fist-fight because he thought 3 should be blue, and 8 should be green... I won, and I made him cry, too..."

Estimates of the frequency of synesthesia range from 1 in 250,000 to 1 in 2,000.  Some famous people have this condition.  Most seem to be creative, such as musicians and artists.
Leonard Bernstein
Duke Ellington
Billy Joel
Stevie Wonder
Eddie Van Halen
Jimi Hendrix 
Frank Lloyd Wright
Victor Hugo 

Synesthetes tend to be:
Women: in the U.S., studies show that three times as many women as men have synesthesia; in the U.K., eight times as many women have been reported to have it. The reason for this difference is not known
Left-handed: synesthetes are more likely to be left-handed than the general population.
Neurologically normal: synesthetes are of normal (or possibly above average) intelligence, and standard neurological exams are normal.
In the same family: synesthesia appears to be inherited in some fashion; it seems to be a dominant trait and it may be on the X-chromosome.

The causes of synesthesia remain unknown. Some scientists have suggested that everyone is born synesthetic but that as the brain develops, the different areas become segregated.  It is not known why synesthetes retain these connections.  There might be a biological answer, because the condition tends to run in families.

For further reading, you might enjoy these books.
The Man Who Tasted Shapes by Richard E. Cytowi
Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia by Richard E. Cytowi

Now you have heard something interesting.