Mulubinba Moments

The Serotonin Myth

A myth is a story (either fictional or partially factual) which is used to explain a natural phenomenon or to illustrate a moral or cautionary lesson.

If you go along to your doctor complaining of depression there is a fair chance that you will hear about serotonin. Perhaps the older term "chemical imbalance in the brain" will get a mention too. The idea is that the low levels of serotonin in the brain cause the symptoms of depression. Serotonin is a neurotransmitter which means that it is a chemical that nerve cells use to message one another. If it is in short supply then the brain nerve cells that are dependent on it will not function very well. Many of those cells help to maintain happiness, so when they fail we become unhappy. And if we can just give the serotonin a boost all will be well again. It is a good story - simple, easy to understand, seemingly scientific. But it is a myth....

There is evidence that serotonin is somehow linked to depression, not the least of which is the fact that most of the drugs which help depression do appear to boost serotonin levels. However the truth of the matter is that doctors do not really fully understand the neurochemical basis of depression or indeed most of human behaviour.

Some people object to using a neurochemical model to explain human feelings and behavior because they believe it denies the reality of free will, and that idea challenges some very important ideas regarding morality, ethics and religious belief. Humans clearly do not function as puppets with the strings being pulled by chemicals such as serotonin. Free will is something we all experience and use most of the time. But of course the operation of free will is limited by biological factors. We all have the choice of eating or fasting but most of us could not voluntarily maintain a total fast for much longer than a day, mainly due to the biological drive to eat, which eventually becomes stronger than our willpower. People with drug addiction have a similar problem - while the decision to use drugs is ascribed to a weakness of willpower the biological drive is often more powerful than the will to eat!
In depression a person's ability to make choices is hampered by the biological factors of their illness, but it is far more complicated than just a low serotonin level.

However like ancient myths the serotonin myth serves some important purposes.

Explanation. Myths explain things that need explaining. Most of the explanations of ancient mythology have been superseded by scientific explanations so a modern myth has to be based on a scientific model to have any credibility. Being only partially factual does not matter to a myth.

Morality. Myths provide moral guidance. People with depression often feel guilt and feel that they have done something to deserve their situation. They are often blamed by others for not "snapping out of it". Unfortunately there is a stigma attached to mental illness. Presenting it as a chemical deficiency (like diabetes) excludes blame guilt and morality, which is a good thing.

Action. Myths provide guidance in decision making. The serotonin myth helps guide people to make a sensible decision which is to get treatment for their depression. Drugs which boost serotonin are lifesaving and even cognitive behavioral based therapies sometimes get explained in terms of the fact that these therapies will boost serotonin levels and thus help resolve the depression.

For many people ancient myths are now regarded as "wrong" because the explanations they provide have been replaced by better explanations. But such a judgement ignores the valuable role these stories served in their own time. Similarly I have no doubt that one day the serotonin explanation will be regarded as wrong. However that does not matter to us now as the serotonIn story still has much to offer in the treatment of depression.

The Blogroll Small World Experiment

Do we all know about the small world theory? The idea is that anyone in the world is only six degrees of separation away from anyone else. This concept emerged from an experiment conducted by social psychologist Stanley Milgram in 1967 using mail. In 2003 New Scientist reported on a massive experiment (conducted by Duncan Watts and colleagues at Columbia University in New York) using email which confirmed that a random target person was in most cases contacted in between 5 and 7 steps. It has occured to me that anyone with a weblog can test the theory themselves without leaving home or even actually contacting anyone!

Enter the Blogroll small world experiment!

Step 1. Find a random weblog. I used the Typepad recently updated weblogs list or www.weblogs.com
Step 2. Use the blogroll (or any list of links to other weblogs) to find other weblogs with blogrolls.
Step 3. Compile a path of links through the world of weblogs that will take you home to your own weblog (or any other target you choose). You may have to explore several different possible paths until you find the shortest path to your home weblog.

Can you get home in 6 clicks?

Just to clarify, to get from blog A to blog B, blog B must be listed on blog A's blogroll (regardless of whether the reverse is true)

For example I found this blog purely at random:
Shut Up Sheila
However I was able to get back to Mulubinba Moments as follows
Purging Poison
My Favorite (links to page named "An Agoraphobic's Brown Study")
Under the Firestar
London and the north
Mulubinba Moments

I did encounter some dead-ends:
Some blogs are not blogs, but are really information sites for things ranging from football to porn - they don't have blogrolls.
Some weblogs don't have blogrolls at all.
One weblog had a blogroll of 5 other sites, but each of those other sites linked to the same group of weblogs - a closed community.
But in all other cases I clicked to my home blog in 6 clicks or less (usually 4 or 5).

Out of 10 random blogs 5 were dead-ends for the various reasons mentioned above, out of the other 5 I was home in 4,5,6,5,4 clicks.
I also tried a French blog (Bartlebooth) and while it took me a little longer to find the path, I clicked home in 6 steps!

Have a try and let me know how you go. My initial results using a very small sample seem to confirm the 6 degrees of separation concept.

Have fun, and if anyone asks you what you are doing trawling through weblogs you can tell them you are doing scientific research!

Evolution at work

Interesting news item: Researchers welcome evolution of cane toad's predator. 23/12/2004. ABC News Online. The cane toad was introduced into Queensland about 70 years ago and has spread unchecked because of a lack of effective predators. Their skins contain a toxin and any creature with the ability to eat them will subsequently die. Many species of potential predator have become endangered including several species of snake. Now some of these species have evolved an adaptation which protects them: their heads have become smaller such that they cannot swallow the toads. As a result the population of these snakes is undergoing a recovery. Perhaps the tyrrany of the cane toad will eventually end.

Do you trust scientific research?

You may have heard about the 5-second rule. This is the theory which says it is safe to eat food that has been dropped on the floor as long as you pick it up within 5 seconds. Jillian Clarke of the Chicago High School for Agricultural Sciences and Howard University, has been awarded an Ig Nobel prize for investigating this theory.
Her findings make interesting reading. Apparently most of the floors studied were remarkably free of bacteria, and therefore food dropped onto these surfaces was safe to eat even after more than 5 seconds. However if the floor was heavily contaminated with bacteria it took much less than 5 seconds contact for the food to become contaminated. Surprisingly (for me at least) women were more likely than men to eat food that had been dropped. Unsurprisingly cookies and candy were more likely than vegetables to be eaten after contact with the floor. I have a suggestion for the next phase of this research: investigate the bacterial contamination of food and of surfaces after having been crawled upon by cockroaches.
Other interesting Ig Nobel winners include the Smith father and son team who patented the combover and The American Nudist Research Library of Kissimmee, Florida, USA, for preserving nudist history so that everyone can see it. These and more can be found at the Ig Nobel website.

Photo of alien abductee

Here is a website dedicated to preventing alien abductions (courtesy of New Scientist's Feedback column). I felt such information needs to be widely disseminated.

It's A Small World After All

It is a small world after all.
A recent New Scientist article reports on an experiment performed under the supervision of Duncan Watts of Cornell University. Participants were asked to try to get a message to a nominated target person elsewhere in the world using email, and only by contacting people they knew personally, and then asking them to relay the message to people they knew until the target was reached. Apparently in most cases the target was reached in a chain of 5 to 7 contacts.
The amazing conclusion is that email and the internet hasn't altered the degree of connectedness in the world: In the 1960s a similar result was acheived using ordinary mail.
I disagree with the conclusion.
I suspect there are 2 main factors which affect the number of degrees of separation of 2 individuals. One is the size of the community the 2 individuals belong to. For example if the community under study was a small rural village the answer might be 2 degrees of separation, especially if there was one person such as the Vicar (or local doctor or vet) that everyone knew. The other factor is the average number of people on a person's list of aquaintances. However as in the village, you only need a few people with lots of aquaintances to push the number down.
The world population is clearly much larger than it was in the 1960s, so I think the result of this experiment suggests that there are a sufficient number of people with large enough contact lists to balance the growth in population. Surely the greater availability of instant world-wide communication and travel has something to do with this.........(posted by Geoff)