How Blood Groups can Affect Personality Traits

Whether you are sociable or a perfectionist, a psychopath or timid, your personality trait can be explained by the principle of Personality Type Theory. This theory has been criticized quite widely in recent years with the result that, while it has not exactly fallen into disrepute, sufficient questions are being asked about the original studies to have a large question mark hanging over the validity of those original findings. Nevertheless, this is not the case in Japan where it is deemed as popular as the Western affinity for matching personalities with horoscopes. In a nutshell, according to this theory, those preoccupied hard workers tend to have a Type A personality trait whilst people who are resourceful, ingenious and idealistic tend to exhibit Type B personality traits.

Basically, this theory relates to matching personality traits with blood types and coming up with a definitive answer to the type of person you tend to be. When following this precept, the Rh factor of the blood is not a factor. Generally the evidence is portrayed as:

Type O – extrovert, sociable, ultra-self confident, enjoy being the centre of attention.

Type A – perfectionists who present a facade of total calm. These people are described as being conscientious, rather shy and

sensitive, yet the most artistic of all the categories.

Type B – individualists who tend follow their own inclinations; they can be relied on completing whatever they started; strong-

minded and dynamic.

Type AB – these people seem to be rather a conundrum: outgoing yet shy; confident yet timid; flourish when responsibilities

handed to them yet recoil in horror when they find they are responsible for too much.

This theory extends to a compatibility existing between people of differing blood groups – such as Type A having an affinity to Types A and AB; while Type B exhibits empathy for Types B and AB; Type AB with Types AB, A, B, and O; Type O is generally more at home with Types O and AB. Personality Trait Theory aims to categorize people into one of the groups presented here and, according to this principle, individuals can only belong to one group or another – they cannot be an amalgam of these classifications. Looking at my immediate family I can see a discrepancy with these concepts immediately: I have a daughter with Type A blood who is clearly a Type B personality; another family member has Type O blood but exhibits all the characteristics of Type A personality!

Type A Personalities

People exhibiting Type A personalities flourish on stress. They have been described as being intolerant, status-conscious, motivated, assertive, dynamic, highly competitive and have difficulty in relaxing. These individuals are always rushing around and tend to dislike delays. Probably the best way to describe these people is as highly driven workaholics. Friedman identified three specific symptoms relating to Type A personalities, explaining two of these symptoms as being overt and the third specifically covert. He observes Type A personalities may exhibit low self-esteem and a covert intrinsic insecurity that provides the underlying cause to the way in which their personalities ultimately developed. Friedman observed their impatience and sense of time urgency stemmed from an underlying irritation and exasperation these people experienced as an integral core of their personalities – and this resulted in an overt hostility towards the human race in general and tended to be triggered by what they perceive as inadequacies in other people. Minor occurrences could provide the trigger that gives rise to their exasperation and their lack of tolerance towards others.

The reason for dwelling on Type A personalities short-comings is because observance of their personality traits by cardiologists led to a large, double-blind trial which concluded with the evidence that Type A personalities have double the risk of contracting coronary heart disease than any other personality type. Ultimately, the success of this study has been attributed to the wide acceptance and respectability now attached to the field of health psychology seen today. Moreover, there is a co-morbidity factor associated with this highly-driven Type A personalities who fail to succeed.

Type B Personalities

Individuals in this category contrast to Type A to the extent that Type B individuals often dislike many of the characteristics of the Type A personality. If you are seeking an individual who is relaxed and easy-going then the Type B personality is clearly your sort of person. However, when you consider that each individual is sub-characterised according to a continuum, it might be less frustrating if you sought a Type B personality who occupied a less lethargic and indifferent position on the spectrum!

Type AB Personalities

As their name suggests, these individuals are neither one thing nor the other and it can be more difficult to achieve a definitive persona. Perhaps this can be explained as we delve further into the concept of Personality Type Theory. The first thing to understand is the difference between ‘Types’ and ‘Traits’: according to this theory, a personality type refers to the category into which the individual is classified; personality traits relates to a sub-genre within each specific category.

In other words, a person who has been categorized as being an introvert cannot also be categorized as being an extrovert – they are mutually exclusive. Traits in a person can be identified along a spectrum ranging from very introverted to only slightly introvert within the category of introversion. A similar perspective relates to the extrovert category. During the 1940s individuals’ personalities were classified into ‘somatotypes’ – a term employed by William Sheldon who came up with these characteristics. Basically, according to Sheldon’s model, there are three specific somatotypes:

Ectomorph Endomorph Mesomorph

Ectomorphs relate loosely to Type A of the Personality Type model; Endomorphs tend to exhibit character traits synonymous with Type AB from the Personality Type model; meanwhile, Mesomorphs exhibit more of a Type B from the Personality Type model. Sheldon’s model can only be compared very loosely to the Personality Type model, taken at its most basic. Sheldon elaborates on his somatotypes by expressing Ectomorphic characteristics as ‘cerebrotonic’; Endomorphic as ‘viscerotonic’; and Mesomorphs as ‘somatotonic’. According to Sheldon’s paradigm, endomorphs tend to be seen as chubby, overweight individuals: the archetypical ‘fat and happy’ picture typified in much literary sketches. Meanwhile, Ectomorphs are their direct opposite in terms of the pictorial body image: according to Sheldon’s model, they are skinny, with poorly defined muscle structure.

Sheldon’s Mesomorphs, meanwhile, are evidenced in the ‘Mr Muscle-man’ image which we can all envisage – six-pack and huge pectoral muscles, highly developed biceps and triceps and leg muscles that stand out on parade! Taking the Mesomorph image, however, Sheldon allies this somatotype with an individual being assertive, belligerent and active. Sheldon’s model can be described further according to a spectrum of 1 to 7 within each category, where low equates to 1; and 7 equates to very high. These classifications do get a bit more complicated at this point, but suffice to say that an American Footballer is likely to exhibit mesomorphic tendencies whilst a ballet dancer is more likely to be an ectomorph.

Sheldon’s model has long had its day and is rarely used nowadays in mainstream psychology, having been superseded by the Jungian typology and by Myers-Briggs Type Indicator – neither of which I have discussed here as it would be more appropriate devoting a separate article to these facets. Workaholics who are focused and driven continue to be labeled as ‘Type A’ personalities, while their more laid-back counterparts are deemed to be ‘Type B’ personalities. Comparisons still continue, relating personality types to blood groups – especially amongst the Japanese where this concept is particularly popular. Empirical studies in 2002 and 2003 respectively, were inconclusive to date.

Nevertheless, the Japanese continue to relate vocational prowess to blood types and, even in the marriage stakes, differences in Type A, AB and B personality traits are not immune and, when seeking a marriage partner, this concept is still taken very seriously indeed. In fact, according to a study undertaken in 1998 by Gunness, battle groups during World War II were formed in accordance with adherence to the application of Personality Type Theory. In the light of more modern research, criticism leveled at isolating the Type A personality abounds – generally in relation to over-simplistic analyses that cannot identify the diversities in human personality types based on such insubstantial evidence as blood types.

The most compelling reason to treat the concept relating to the differences in type A, AB and B personality traits comes from Duke University. Here, they have established that the only significant risk factor for Type A personalities is their inherent hostility to the shortcomings in others which results in suppressed anger that, over the course of their lifetime, can contribute to a higher incidence of coronary heart disease developing. Apart from this facet, Personality Type theory has been largely discredited by modern psychologists and superseded by more reliable and appropriate models to indicate traits and characteristics in human personalities.