Theorists have long been trying to link body and personality types.
From early Greeks to the present day, theorists have been trying to link body and personality types.
There is long history of claims linking physical and psychological characteristics. Greek physician Galen suggested our personalities reflect relative levels of the four “humours” (hint: you don’t want an excess of yellow or black bile); French anthropologist Paul Broca reckoned small heads meant smaller intellects; and US psychologist William Sheldon claimed that ectomorphs – long, lean people – are more shy and reserved than their slow-witted, rounder, endomorph counterparts.
There is, however, not a lot of evidence to support these fellows’ claims. Which is not to say that physiology and psychology are independent. After I was approached by a student interested in blood type and personality, I did a little digging. I’d not heard of the idea, and it sounds a little far-fetched.
First, it’s useful to know a bit about blood types. As the New Zealand Blood Service tells us, we all have blood cells, which, depending on the proteins, carbohydrates and other chemicals on their surface, fall into two broad families – ABO and Rh(D) – that produce more than 30 recognised combinations.
The early pioneers of the notion of a blood-personality link were Japanese. A quarter-century after Austrian Karl Landsteiner was credited with identifying the A, B, and O blood groups, Professor Takeji Furukawa reported on “the study of temperament through blood type”, following it with several papers. Based on the finding that a high proportion of Taiwanese participants were identified with type O blood, Furukawa linked “rebelliousness” (inferred from their resistance to the Japanese occupation of Taiwan) to blood type O.
Though Wikipedia states that Masahiko Nomi repopularised the notion in the 1970s, no less a luminary than Raymond Cattell looked into this in the 1960s.
Cattell is important because he argued that personality isn’t made up of boxes (like extroversion or openness) that you either tick or don’t, but continuums where some people have a little, some people have a lot and most of us are somewhere in between. In research in 1964, Cattell reported that people with type-A blood were more empathic, tender-minded and interpersonally agreeable than Os, Bs, and ABs. A 1980 study found that As reported higher average levels of anxiety.
Closer to home, Mary Rogers and Ian Glendon asked Gold Coasters about their personalities. They used what is pretty commonly considered to be a best guess – that is, without statistical significance – at the structure of personality, the Big Five (openness to experience, conscientiousness, extroversion, agreeableness and neuroticism).
There have also been suggestions that things such as allergies are associated with personality and psychological characteristics. I have a particular interest in one finding: that people with allergies appear to be more susceptible to anxiety and anxiety-related disorders, given that my children both have nut allergies.
The groundbreaking Dunedin Multidisciplinary Health and Developmental Study shines a light in this area. As well as psychiatric history, among the many things that participants in the longitudinal research are “exposed” to are allergy prick tests and tests of blood serum immunoglobulin (an indicator of allergies).
This is important because a lot of previous research asks people about their anxiety and their allergies, and it’s reasonable to assume that if you’re more anxious than average, then you might worry more about health issues such as allergies.
The Dunedin group showed that 62% of participants said they have allergies, 65% showed allergic responses to at least one allergen in the prick test and 48% showed elevated immunoglobulin levels.
Self-reported allergies are associated with anxiety, but prick or blood tests tell a different story. Phew, my kids are safe. Just not from nuts.
Furukawa linked “rebelliousness”, inferred from resistance to the Japanese occupation, to blood type O.