Some apparently strange religious rules can have a rational basis. The Jewish and Islamic ban on eating pork was probably very sensible in an age before meat inspection. More difficult to understand is the notion found in the Bible and the Koran that a menstruating woman is “impure”.

Leviticus states this unambiguously: “and anyone who touches her will be impure until nightfall (…) and everything on which she sits is impure (…) and anyone who touches her bed will be impure until nightfall (…) If a man lies with her (…) he will be impure for 7 days.”

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Transsexuals are convinced that they were born in the body of the opposite gender and would do almost anything to change that fact. This transformation occurs step by step, by first taking on the social role of the other gender, then taking hormones and then undergoing a series of major operations, after which just 0.4 percent express regret later.

The gender team of the Vrije Universiteit Medical Centre in Amsterdam has been a pioneer in this field for many years, initially under the leadership of professor Louis Gooren and now of professor Peggy Cohen-Kettenis. This is unusual because the Bible, on which the VU is founded, states in Deuteronomy 22:5-6: “A woman must not wear men’s clothing, nor a man wear women’s clothing, for the Lord your God detests anyone who does this.”

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In the old days, when a patient started producing large quantities of urine, the doctor just stuck his finger in the urine and tasted it. If the urine tasted sweet, the patient had diabetes mellitus (= sweet flood). If the urine was not sweet, then the diagnosis was diabetes insipidus (= tasteless flood), and something was wrong with the kidneys or the brain.

Every day large quantities of blood pass through the kidney for cleaning purposes. During the cleaning process, the kidney recycles about 15 liters of fluid per day from the waste water. The kidney receives help with this from a brain hormone that inhibits the excretion of water, hence its name: “anti-diuretic hormone” (ADH). The same hormone is also known as “vasopressin” because it acts to raise the blood pressure. It is a small protein produced by the brain cells. These cells are located in the hypothalamus and transport the hormone to the rearmost part of the pituitary gland, where it enters the bloodstream.

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There was amazement all round when it was clinically proven that the effect of the most commonly used antidepressant was not significantly better than that of a placebo. But strangely enough, no one admires the effectiveness of the placebo. A placebo effect is any and all effects of a pill not caused by its specific chemical composition. For example, a red, yellow or orange pill is associated with a stimulating effect, while blue and green pills are thought to be calming.

A placebo can also have adverse effects. It can make a person nauseous or give them stomachache. People even get addicted to it, and develop withdrawal symptoms when the placebo treatment is terminated. There is thus sufficient reason to be interested in the effectiveness and the neurobiological mechanism of action of placebos. Lees verder »

The deterioration process proceeds slowly, step by step, in Alzheimer’s disease. Whatever one learned first is the last thing to disappear from memory.

Alzheimer’s disease follows a fixed route through the brain. When the typical signs of the disease, the ‘tangles’, develop in the entorhinal cortex and then a few appear in the hippocampus, those can be seen only under a microscope. No external symptoms are visible. But as the disease strongly takes hold in those areas of the brain, problems become evident in the short-term memory. One no longer remembers what happened just recently, but can recall minute details of a birthday party in primary school. When finally the Alzheimer’s disease reaches the other cerebral cortex regions, the patient becomes demented.

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Our average life expectancy has risen in the past century from 45 to almost 80 years, while, at the same time, we have to exert less and less physical effort to survive. The conclusion seems obvious: it pays to be lazy. However, nothing could be further from daily reality.

There are only a few things in this world that everyone seems to agree on, but people everywhere believe that it is bad to exercise little, and that we can only stay healthy by doing sports. The result is that, nowadays you cannot go for a peaceful walk in the woods without being overtaken by panting, sweating and clearly suffering joggers. Lees verder »

We have a ‘moral network’ in our brain made up of neurobiological building blocks that evolved step by step. First of all, we notice the emotions of other people through ‘mirror neurons’. Watching a hand movement by someone else stimulates the same brain cells to be activated when you make the movement yourself. Mirror neurons form the basis for learning by imitation.

This imitation behaviour largely functions automatically. Newborn human babies less than one hour old can already copy the movements of an adult’s mouth. Mirror neurons also work with emotions. They enable you to experience the emotions another person is feeling, and thus form the basis for empathy. Mirror neurons have been found in the prefrontal cortex, the foremost part of the brain, and in other parts of the cerebral cortex.

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During the US president George Bush’s term of office, the clock was turned back in Christian America. An ‘ex-gay movement’ arose that considers homosexuality a disease that can be cured.

Hundreds of clinics and therapists work in this field, and it is claimed, without proof, that 30 percent of those who underwent therapy were ‘healed’. In the clinics people can be treated for two weeks for 2,500 US dollars and for six weeks for 6,000 dollars. The therapists are mostly ‘former homosexuals’, who say that after a course of therapy they became real family men. A counter-movement ‘It is OK to be Gay’ points out that the therapies are based on a conditioning of the shame, stigmatisation and discrimination of homosexuals. Suicides are the result.

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Moral laws were not invented by religions but taken over by them, after they had evolved for social animals, including man. These rules promote teamwork and mutual support within a social group. They act as a social contract imposing many restrictions on the individual.

Darwin’s moral psychology (1859), consequently, was not based on an egotistical competition between individuals but on social involvement within the group. During the course of evolution, the benefit of helping each other developed from the loving care exhibited by parents towards their offspring. This was then expanded to apply to others of their kind according to the principle: do unto others, as you would have others do unto you. At a certain moment sympathising with the other became a goal in itself. Finally, this product of millions of years of evolution turned into a cornerstone of human morality that was recently, a couple of thousand years ago, incorporated in religions. It is thus rather cynical to ascertain that having a common enemy is the strongest stimulus for community spirit, a mechanism that many world leaders have exploited.

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Empathy, intuitive understanding of another’s feelings, is not an ability unique to humans.

Adherents of the ‘Intelligent Design’ movement assume that morality was granted to man by God’s grace and that Christian believers were at the front of the distribution queue. This idea was expressed by Intelligent Design adherent Henk Jochemsen in a 2005 book: “For sociobiology and evolutionary ethics, it is irrefutable that altruistic behaviour is biologically perverse and pathological, because it goes against human nature. But in most cultures and major religions, true altruistic behaviour is presented as the higher ideal.”

Anyone familiar with the work of Darwin and biologist Frans de Waal knows that this is nonsense. A dead-end idea. Lees verder »