Anti-vaccination beliefs can cause real, substantive harm, as shown by the recent outbreak of measles in the US. These developments are as shocking and distressing as their consequences are predictable. But if the consequences are so predictable, why do the beliefs persist?

It is not simply that anti-vaxxers don’t understand how vaccines work (some of them may not, but not all of them). Neither are anti-vaxxers simply resistant to all of modern medicine (I’m sure that many of them still take pain killers when they need to). So the matter is not as simple as plain stupidity. Some anti-vaxxers are not that stupid, and some stupid people are not anti-vaxxers. There is something more subtle going on.

It's no surprise to most that Germanwings Flight 9525 co-pilot Andreas Lubitz, who crashed the plane into a mountain, killing all of the passengers and crew, had been treated for suicidal tendencies. 

You're out shopping for basic goods you have bought many times. Is  choosing these products a complicated decision or a simple one? 

It could be complex: Factors like price, quality, and brand loyalty may run through your mind. Indeed, some scholars have developed complicated models of consumer decision-making, in which people accumulate substantial product knowledge, then weigh that knowledge against the opportunity to explore less-known products.

Experiments dating back to the 1960s show people have less of a reaction to viewing an unpleasant image or experiencing an electric shock when they know it’s coming than when they’re not expecting it.

Orthorexia nervosa, the “health food eating disorder”, gets its name from the Greek word ortho, meaning straight, proper or correct.

This exaggerated focus on food can be seen today in some people who follow lifestyle movements such as “raw”, “clean” and “paleo”.

American doctor Steven Bratman coined the term “orthorexia nervosa” in 1997 some time after his experience in a commune in upstate New York.

It was there he developed an unhealthy obsession with eating “proper” food:

Had a break up and finding it difficult to move on? It's an evolutionary mandate, according to a review of evolutionary psychology articles on romantic break-ups.

People are hardwired to fall out of love and move onto new romantic relationships, the authors suggest after examining the process of falling out of love and breaking up, which they call primary mate ejection, and moving on to develop a new romantic relationship, which they call secondary mate ejection.  

Filmmakers know personality disorders make for compelling viewing.

Think of attention-seeking Scarlett O'Hara in "Gone with the Wind" (1939). Or the manipulation and callous disregard for others in "Silence of the Lambs" (1991), "The Talented Mr. Ripley" (1999) and "Chopper" (2000). Then there are the fears of abandonment and emotional instability in "Fatal Attraction" (1987) and "Girl, Interrupted" (1999).

Cinema is less adept, however, at showing the ordinary joys, heartache and sometimes suicidal despair of the friends, workers or relatives we might know with personality disorders.

Narcissistic children feel superior to others, believe they are entitled to privileges and crave admiration from others.

When they don’t get the admiration they want, they may lash out aggressively.

Why do some children become narcissistic, whereas others develop more modest views of themselves? We have undertaken research into this question and we found socialization plays a significant role.

Remember the social media storm about the color of the dress? Did you see blue and black or white and gold?

It was some harmless fun that drew in millions of online commenters.

But clothes are not frivolous, flippant or foolish. In telling and talking about clothes, we reveal much about ourselves, our lives, and the experiences that we drape around our bodies. Whether bought or handmade, passed down or reconstructed, clothes help us to construct meaning as we remember those things in our lives that matter.

Cardiovascular diseases such as heart attacks and stroke, cancers, diabetes and chronic respiratory diseases such as chronic obstructive pulmonary disease and asthma are among the leading causes of death across the world.