Category Archives: Individual differences

Have a big-head

The cleverest member of the Griffin family and the one with the largest head…coincidence?

“Oh they’re so big-headed”, a phrase often used to describe someone who believes that they are very intelligent or very good at something. In other words, someone who is very arrogant which in turn means that being told you have a big head is not a positive thing. I have particularly strong feelings about the use of this phrase as I myself have a large head. I am often teased for being big-headed though I like to think this isn’t because of any arrogance on my part but more the physical stature of my skull. So is there any link between having a physically big head and the intended meaning of this phrase, that you’re intelligent or skillful and arrogant with it.

There are no studies (that I could find) which have directly found a positive correlation between IQ and head size.  Some researchers have looked at the effect of the pre-natal physical environment on subsequent IQ scores and found a significant correlation between birth weight and later IQ (Breslau et al., 1996) with birth weight relating to head size. However, this correlation has been suggested to be concealing a much larger effect at extremely low birth weights where the low weight may be symptomatic of other developmental abnormalities (Rutter et al., 1970, Education, health and behaviour (Longman, London)). This suggests that the correlation between low birth weights (and small head sizes) and low IQs is not direct and that both are related to developmental abnormalities due to things like having a mother who smoked during her pregnancy (Broman et al., 1975, Preschool IQ Prenatal and Early Developmental Correlates. New York: Lawrence Erlbau).

Maybe it is not our head size but the size of our brain that determines our intelligence and a weak link between these two has emerged though is apparent much more strongly when compared with the rest of the animal kingdom. In comparison with other animals, the brain size of humans is three times what you would expect in the average animal with animals like dolphins and other primates, which we consider intelligent, having larger than average brains. So maybe brain size is related to our intelligence though our variability in brain size (compared to the rest of the animal kingdom) is not enough to account for the variation in intelligence seen in humans. Something worth noting is that I have been using IQ and intelligence interchangeably and there is still an ongoing debate (to which I couldn’t do justice here) as to whether IQ scores are representative of intelligence.

Head size may not be related to intelligence though one group of researchers found that people with a larger head circumference were less likely to show decline in their cognitive abilities as they aged. They found no association between head circumference at birth and peoples’ scores on the cognitive function tests. This led them to suggest that brain development whilst you’re young is crucial in determining to what extent your cognitive abilities decline in old age.

In conclusion, there is very little (to no) evidence to support the statement ‘they have a big-head’ when referring to someone who believes themselves to be intelligent or skillful. The physical size of your head (unfortunately for me) has no bearing on how intelligent you turn out to be though does seem to mean that you fare better in your twilight years compared to your small-headed peers!


Have a one track mind

Is it possible for us to have a one track mind? (Attribution: tckrockz)

When we use the phrase ‘they have a one-track mind’ we mean that someone thinks entirely about one particular subject. This idiom is often used to emphasise somebody’s obsession with something be it sport, their work or even the opposite sex. However, it appears that some autistic individuals may, to a certain extent, have a one-track mind.

Autism was defined by Lorna Wing as a triad of impairments. This triad consists of social abnormalities, communicative abnormalities, and repetitive behaviour and narrow interests. This last characteristic can lead to distress at a change in routine and an unusual focus on one particular area of knowledge or a skill. Uta Frith proposed a theory of autism called the weak central coherence (WCC) theory which proposed that autistic people lack the ability to perceive the whole but instead focus on the parts (central coherence being the ability to draw together diverse information before processing it to provide higher level meaning in context).

There is a lot of evidence to support this theory which can be applied to the characteristic of narrow interests often seen in autistic people. The Embedded Figure Test is an example of such evidence with autistic individuals performing significantly better than matched controls. You are given a shape to find within a figure and your time taken to do so is measured. Autistic people are significantly faster at this suggesting that they perceive the parts of a picture more easily than the whole.

The Navon Test

The Navon Test

The Navon Test (1977) is another example of autistic people’s increased attention to local as opposed to global perception. Frith and Snowling (1983) also showed that autistic individuals have worse performance on correctly pronouncing an ambiguous word at the end of a contextually illuminating sentence. For example;
– she had a tear in her eye
– she had a tear in her dress
The scores that most autistic people got reflected the more common pronunciation rather than the use of contextual meaning. This failure to integrate the meaning of the whole sentence with the perception of individual words could explain the communicative abnormalities seen in some autistic individuals.

This WCC theory goes some way to demonstrate the presence of a one-track mind in autistic individuals with very narrow interests perhaps due to their inability to detach from the details. However, this isn’t exactly a one-track mind as even autistic individuals who do have a particularly focussed interest on something are able to pay attention to other things too. In my opinion, no one has a one-track mind; even those people who tend to have narrow interests and focus on a particular part of something still have “other tracks” in their mind. So next time you hear someone say that so and so has a one-track mind, remember, they almost certainly don’t, but maybe just give them a bit of artistic license.

A leopard can’t change its spots

"Of course the zip is stuck, why do you even bother? You know the rules!"(Many thanks to Eleanor Rule for the drawing)

“Of course the zip is stuck, why do you even bother? You know the rules!”
(Many thanks to Eleanor Rule for the drawing)

‘A leopard can’t change its spots’ is a phrase often used to suggest that someone’s personality, especially if it is bad, will not change, even if they pretend it has. This is a question of whether our personality can change over our lifetime or if it’s an unchanging structure.

Personality is widely defined as characteristics which account for consistent patterns of feeling, thinking and behaviour. These personality traits are stable over time and across different situations. These definitions suggest that there is truth behind the idiom; that a leopard cannot change its spots. However there is some evidence to suggest otherwise.

There are some extraordinary cases of personality change such as that of Phineas Gage. He was an American railroad construction foreman who, in 1848, had an accident which resulted in a large iron rod being driven through his skull, damaging most of his frontal lobe. Surprisingly, he survived this accident though he lost his inhibitions both socially and emotionally. This case changed the face of neuroscience as it was the first case to suggest that personality and behaviour were specifically localised within the brain.  However, this is a special case; can a leopard change its spots without suffering severe brain damage?

In 2003, Srivastava et al. performed a study that aimed to find out if personality altered in early and middle adulthood. McCrae and Costa’s 5 factor theory of personality states that personality traits arise from biological causes and reach full maturity in early adulthood, around about 30 years old. This implies that there is little or no change on any personality dimension after early adulthood. Haan et al. (1986) believed that social roles, life events and social environments that change during an individual’s life are factors that have an important influence on basic personality traits. Srivastava et al. found a lack of support for McCrae and Costa’s theory and in some cases, evidence that contradicted their theory. They found that the personality trait of conscientiousness showed a major change during early and middle adulthood, particularly early adulthood. This period of life is often when people are beginning jobs and entering into committed relationships, events that are linked to conscientiousness. The personality trait of agreeableness also showed a significant change later in life when adults are typically caring for children. These findings suggest that people’s personality continues to develop well into middle adulthood.

All of these results indicate that a leopard can (and does) change its spots up until middle adulthood as our personalities develop as we experience the major turning points in life. Our spots/personality then becomes more permanent across different situations and through time, that is if you don’t suffer any brain damage…

APE: Alcohol Policy and Epidemiology

Summarising and pondering public health research on alcohol

The Importance Of Knowing Actions

Using psychological research to show that every decision has a reaction.

Steps to Cloud Nine

Research based ways to lift your mood every day

The Blog

The latest news on and the WordPress community.