An introduction to theories around personality types

The debate around personality theory is a multifaceted and complex one. We have selected just a few of the main points in that debate to present here and it must be acknowledged that this is not a comprehensive overview.  We have chosen to focus on the two broad personality types as described by Jung (1921) and later Kagan (2010) for the sake of simplicity and so have not explored the more complex issue of personality traits such as those described by Allport (1937), Eysenck (1967) and Cattell (1973)  to name but a few.  Boyle (2008) provides a good overview of trait theory here.

 

Jung

Carl Jung may be said to be the father of modern personality theory since the publication of his "Psychological Types " in 1921.  He argues that it is self-evident that there are two general attitude types, the introvert and the extravert. 
"The two types are so essentially different, presenting so striking a contrast, that their existence, even to the uninitiated in psychological matters becomes an obvious fact, when once attention has been drawn to it. Who does not know those taciturn, impenetrable, often shy natures, who form such a vivid contrast to these other open, sociable, serene maybe, or at least friendly and accessible characters, who are on good terms with all the world, or, even when disagreeing with it, still hold a relation to it by which they and it are mutually affected. Naturally, at first, one is inclined to regard such differences as mere individual idiosyncrasies. But anyone with the opportunity of gaining a fundamental knowledge of many men will soon discover that such a far-reaching contrast does not merely concern the individual case, but is a question of typical attitudes" (p 412)

The fundamental difference between the two general attitude types is seen to be their "attitude to the object" (Jung, 1921, p412) or their relationship to the world around them.  Jung gives some examples to illustrate this point.  In both cases the data received from the outside world are the same, but the reaction to the data is different:

Because it is cold out of doors, one man is persuaded to wear his overcoat, another from a desire to become hardened finds this unnecessary; one man admires the new tenor because all the world admires him, another withholds his approbation not because he dislikes him but because in his view the subject of general admiration is not thereby proved to be admirable; one submits to a given state of affairs because his experience argues nothing else to be possible, another is convinced that, although it has repeated itself a thousand times in the same way, the thousand and first will be different. The former is orientated by the objective data; the latter reserves a view, which is, as it were, interposed between himself and the objective fact (1921, p416).

Jung further argues that these two different attitude types must have some sort of biological origin.  Two children, born to the same parents and brought up in identical conditions may, nevertheless, exhibit from an early age different attitude types.  He concludes that:

Although nothing would induce me to underestimate the well-nigh incalculable importance of parental influence, this experience compels me to conclude that the decisive factor must be looked for in the disposition of the child. The fact that, in spite of the greatest possible similarity of external conditions, one child will assume this type while another that, must, of course, in the last resort he ascribed to individual disposition...As regards the particular disposition, I know not what to say, except that there are clearly individuals who have either a greater readiness and capacity for one way, or for whom it is more congenial to adapt to that way rather than the other. In the last analysis it may well be that physiological causes, inaccessible to our knowledge, play a part in this (1921, p416).

The extravert personality type, according to Jung,  may be characterised as being drawn to "the external life of people and activities" whereas an introvert will be more concerned with the "inner world of thought and feeling" (Cain 2012, p10).  You can read more about introverts here and extraverts here.

Kagan

Jerome Kagan has conducted a number of large longitudinal studies on individuals aged from 0-18 years. As a result of his observations, he classified infants into either high or low-reactives. Here he describes  high-reactive infants:

First, about 20 per cent of these infants were unusually responsive to events that were unexpected or unfamiliar. When colourful toys they had never seen before were moved slowly in front of their faces, the four-month-olds begin to thrash their limbs, arch their backs, and cry, as if this experience was too arousing for their brains. These infants, whom we call high-reactive, tended to be shy when they met unfamiliar people and afraid when they entered unfamiliar rooms or encountered unfamiliar objects during their second year of life... As adolescents, many told us they worried excessively about the future and were anxious over events that most adolescents regarded as unrealistic. For example, they didn't like talking to strangers and felt anxious when they had to go to a party where they knew few people (2010, online).

Kagan measured the physical characteristics of these high-reactive individuals when exposed to unfamiliar events and found that they were much more likely to exhibit changes such as increased blood pressure, altered breathing, sweating etc.  He argues that "high reactives seem to possess a chemistry of the amygdala that renders it more excitable than it is with most children" (2010, online)

Broadly speaking, high and low reactivity tended to correspond to introversion and extraversion.  Kagan (1994) comments that "Carl Jung's description of the introvert and extravert, written over seventy-five years ago, apply with uncanny accuracy to a proportion of our high- and low reactive adolescents." However he also notes that "The most important conclusion is that the power of an infant's temperament rests with its ability to limit what a child might become, rather than determining a particular personality." (2010, online)  Thus, "the prediction that high reactives would not become consistently extraverted and sociable was affirmed more often that the prediction that a high reactive would become extremely shy and introverted." (Zelazo 2013, p155) This can be illustrated with reference to the following image:

Predicting the exact location where a rock will land after rolling down a mountain provides an analogy. Knowledge of the location, size, and shape of the rock, analogous to a temperament, permits an observer to eliminate many places where it will not rest, but it is impossible to know its final location because one cannot know the gullies and obstacles it will strike on its way down. These events are analogous to the diverse experiences each person encounters as they grow to maturity.  (Kagan 2010, online)

In summary, then, for the purposes of this project, we have concentrated on the broad differences between extraverts, or low-reactives and introverts/ high reactives.   


Personality types and second language learning
 A considerable body of work has emerged which considers the role of personality in second language learning over the past 30 years or so. It is not proposed to provide a summary here, as Sharp (2008) and Liyanage and Bartlett (2013) both provide a helpful overview of  these recent studies.  However, one common factor appears to be the inconsistency of the results obtained by these studies.

As we have seen, even from the brief survey of the literature presented above, there are many different approaches to personality theory and trait theory, and this may, at least in part, have contributed to this inconsistency.  Kiany (1998, p117), reviewing nine studies which attempted to demonstrate a relationship between academic achievement and extraversion/introversion, found that:
In sum, and setting aside some methodological problems, out of the nine studies reviewed, two partly showed a positive relationship between extraversion and L2 proficiency, while three others, again partly, revealed a positive relationship between introversion and L2 proficiency; the remaining four did not show any clear link between EXT-INT and foreign/ second language learning.
Kezwer also reviewed eleven studies on the effect of outgoingness vs reservedness on second language learning (1987. p46) and notes wryly,
It would seem that the clearest idea to emerge from this tangle of results is that the relationship between extroversion and second language learning is a very murky one indeed.

Despite these inconsistencies, Sharp (2008, p21) suggests that there is an "intuitive belief held by teachers and educators of these [personality] issues in learning"  and Liyanage and Bartlett (2013, p606) argue that:
There seem to be good reasons for educators to revisit the personality-language learning relationship and to consider helping students to develop a personalised kitbag of strategies to fit the various contexts in which they will learn and with which they are at ease, in terms of personality.

We share that "intuitive belief" and felt that it would be helpful to test it on our own students to see if we could improve their learning experience and outcomes though better understanding of their personality type.