Educational Tidbits

The difference between relative versus absolute risk reported in studies

New reports often reports the relative risk or benefits between two groups (say a control group versus treatment group).   This number is usually deceptively higher than the absolute risk or benefit.

What is the difference between relative risk versus absolute risks?

KnowBreastCancer.org has a good explanation.   Suppose that 2 person out of 100 in a control non-treated group ended up with cancer.  And supposed that only 1 person out of 100 in a treatment group ended up with cancer.  Hence the relative risk would be a 50% decrease in breast cancer in the treatment group.  This is arrived at by taking the change and dividing by the initial value:  (2 – 1) / 2 = 0.5 = 50%    This is the number often reported.   Sounds pretty good right?

But consider the absolute risk.   Since the risk of cancer is 2% in the non-treated group, and the risk of cancer in the treated group is 1%, the treatment only reduced the risk from 2% to 1%.  This is only a 1% reduction in absolute risk.  Now it doesn’t sound that great.   This number is arrived at by taking the change in percentage divided by the overall percentage: (2-1)/100 = 0.01 = 1%.

Presentation by Sally Fallon-Morell also gives examples of how distorting the reports of relative risk are.  Video presentation on YouTube.

Tom Naughton is a comedian that did a bit at the Ancestral Health Symposium called “Science for Smart People” in which among the other topics talked about relative risk versus absolute risk…

Many Causes of Depression

Depression is a name given to a set of symptoms consisting of low mood and aversion to activity that can affect a person’s thoughts, behavior, feelings and physical well-being.

But there are many different causes that can produce this depressive state. Here are just a few of the many causes (listed in no particular order) with links to references…

Omega-3 deficiencies, Vitamin D deficiencies, magnesium deficiencies, vitamin B deficiencies, etc.

Mercury toxicity and mercury dental fillings.

Emotional Trauma

Stress and burnout

Low Testosterone in Men

Thyroid imbalance

Dementia associated with Depression

Calcium Toxicity or Calcium deficiency

Concussion and brain trauma

Mercury and Omega-3 comparison of Seafoods

WashingtonPost has chart linked here showing the relative mercury levels and the relative omega-3 levels of various seafoods.

You want the one with high omega-3 and low mercury.

What do teen text about?

Ever wonder what do teens text about? Find out in this infographic on Mashable.

It is possible to drink too much water

Dr. Ben Kim writes article explaining why a person can die from force drinking too much water.

Unfortunately, it was reported that someone did die in a water-drinking contest called “”Hold Your Wee For A Wii” in which she drank 2 gallon worth of water.

This is due to consuming too much water in a too short amount of time and not allowing your bladder to empty. The circulatory system gets diluted with water, reducing electrolytes level.   And the cells in the brain swell with water causing cranial pressure.

Infographics of “Evolution of Facebook Features”

Infographic of the evolution of Facebook Features by GroSocial….

Infographic about Interesting Facts About Space

Via: OnlineSchools.org

Presidents age twice as fast when in office

According to Cleveland.com, Dr. Michael Roizen speculates that “presidents get two years older for every year they’re in office” [reference]

This is probably due to stress of the job rather than living at the white house. It is well known that stress shortens the cell’s telomeres which is an indication of cellular aging.

What is the Ebbinghaus Illusion?

An example of the Ebbinghaus illusion is where the perception of the orange circles below appears to be smaller in the left diagram than in the right diagram, when in fact the two orange circles are exactly the same size.

Ebbinghaus Illusion (public domain image)

Even after you measured the size of the circles and have confirm and know cognitively that they are indeed the same size, your mind’s automatic perception system still cannot help but see the left circle as being smaller. The best that you can do is to be aware that in certain situations your perceptions can be fooled. This way, the next time you and encounter such a similar situation, your conscious mind can alert you to not trust your perception due to the fact that what you are seeing may be flawed.

There are many other visual and cognitive illusions in which our minds can be fooled. By being aware of the types of illusions will help us be aware of situations in which our minds can be fooled. The book

The Ebbinghaus illusion was named after the German psychologist Hermann Ebbinghaus who discovered it. The illusion is also called the Titchener circles.

Pupils dilate under complex mental computation

Did you know that your pupils will dilate when you are doing complex mental computation? Yes, this is according to Daniel Kahneman in his book Thinking, Fast and Slow. Examples of mental computation would be if you had to increment each of the digits of a 4-digit number by 1. Or if one is trying to hold number in one’s head.

Some psychology experiments would measure a subjects pupil dilation as an indication of the amount of thinking the subject is undergoing.