Monday 31 August 2009

Reliable but dumb, or smart but slapdash?

Bruce G Charlton

Why it is ‘better’ to be reliable but dumb than smart but slapdash: Are intelligence (IQ) and Conscientiousness best regarded as gifts or virtues?

Medical Hypotheses. 2009; Volume 73: 465-467



The psychological attributes of intelligence and personality are usually seen as being quite distinct in nature: higher intelligence being regarded a ‘gift’ (bestowed mostly by heredity); while personality or ‘character’ is morally evaluated by others, on the assumption that it is mostly a consequence of choice? So a teacher is more likely to praise a child for their highly Conscientious personality (high ‘C’) – an ability to take the long view, work hard with self-discipline and persevere in the face of difficulty – than for possessing high IQ. Even in science, where high intelligence is greatly valued, it is seen as being more virtuous to be a reliable and steady worker. Yet it is probable that both IQ and personality traits (such as high-C) are about-equally inherited ‘gifts’ (heritability of both likely to be in excess of 0.5). Rankings of both IQ and C are generally stable throughout life (although absolute levels of both will typically increase throughout the lifespan, with IQ peaking in late-teens and C probably peaking in middle age). Furthermore, high IQ is not just an ability to be used only as required; higher IQ also carries various behavioural predispositions – as reflected in the positive correlation with the personality trait of Openness to Experience; and characteristically ‘left-wing’ or ‘enlightened’ socio-political values among high IQ individuals. However, IQ is ‘effortless’ while high-C emerges mainly in tough situations where exceptional effort is required. So we probably tend to regard personality in moral terms because this fits with a social system that provides incentives for virtuous behaviour (including Conscientiousness). In conclusion, high IQ should probably more often be regarded in morally evaluative terms because it is associated with behavioural predispositions; while C should probably be interpreted with more emphasis on its being a gift or natural ability. In particular, people with high levels of C are very lucky in modern societies, since they are usually well-rewarded for this aptitude. This includes science, where it seems that C has been selected-for more rigorously than IQ. Indeed, those ‘gifted’ with high Conscientiousness are in some ways even luckier than the very intelligent – because there are more jobs for reliable and hard-working people (even if they are relatively ‘dumb’) than for smart people with undependable personalities.


Moral evaluations of intelligence and personality

The psychological attributes of intelligence and personality are usually seen as being quite distinct in nature: higher intelligence being regarded as a morally-neutral aptitude which is a lucky ‘gift’; while personality or ‘character’ is morally evaluated by others, on the assumption that it is mostly a consequence of choices. So a teacher is much more likely repeatedly to praise a child for exceptional self-discipline and hard work than for being of high intelligence. In other words, virtue is seen as an aspect of character/personality rather than intelligence.

General intelligence (aka. ‘g factor’ intelligence, or ‘intelligence quotient’ or IQ) [1], [2], [3] and [4] and the ‘Big Five’ personality trait of Conscientiousness [5], [6] and [7] are the two main measurable psychological factors, higher levels of which are predictive of better educational and job performance [8] and [9]. IQ is the aptitude that enables a person to think abstractly and logically, to solve a wide range of novel problems, and to learn rapidly.

The personality trait of Conscientiousness (‘C’) incorporates features such as perseverance, self-discipline, meticulousness, and long-termism. In a nutshell, Conscientiousness is the capacity to work hard at a task over the long-term despite finding the task uninteresting and despite receiving no immediate reward.

The usual conceptualization sees IQ as a gift and C as a virtue; i.e. intelligence as an ability available to be used when necessary and personality traits such as Conscientiousness as a moral disposition to make better or worse behavioural choices. The mainstream idea would be that people are not responsible for the level of their intelligence but are responsible for their behaviour. So apparently it makes sense to praise Conscientiousness as virtuous but not similarly to praise IQ.

However, I will argue that – while there are indeed practical reasons to praise good behaviour – in reality IQ has morally-relevant elements, while high-C (and other valued personality traits) should also be regarded as a gift. So, both intelligence and personality can be regarded either as gifts or as virtues, according to context.

Intelligence is regarded as a gift

Most people regard intelligence as a ‘gift’ – and highly intelligent children have sometimes been termed gifted. This interpretation is accurate, in the sense that the main known determinant of general intelligence is heredity: people inherit intelligence from their parents [1], [2], [3] and [4]. While bad experiences (such as starvation and disease in the womb or during infancy) can pull intelligence downwards, it is at present difficult or impossible significantly to raise a person’s real, underlying, long-term predictive general intelligence by any kind of environmental intervention[10]. (It may, however, be possible to raise IQ scores by practicing IQ tests and other focused interventions; but this does not cash-out into significant and prolonged general benefits in terms of education and employment).

IQ is calculated by testing groups of people at different ages, and (usually) putting their scores into rank order and organizing rankings onto a normal distribution curve with a mean average IQ of 100 and a standard deviation of 15. Using this type of calculation, intelligence scores/rankings are relatively stable throughout life – so that a child of 8 with high IQ will usually grow to become an adult with similarly high IQ, and vice versa [1], [2], [3] and [4].

Because intelligence is a gift which is substantially hereditary and stable throughout life, on the whole it is regarded as a result of ‘luck’ and something for which people should be grateful; and not, therefore, as a virtue deserving of moral approbation or praise. Indeed, people with high intelligence may be given less help than they need, and may be held to a higher standard of behaviour, precisely because they are regarded as lucky.

Higher intelligence is socially valued more highly than lower intelligence, probably because people with a higher IQ are on average more useful economically [11] (having higher economic productivity, on average); nonetheless the most intelligent people are not usually regarded as intrinsically virtuous nor especially morally praiseworthy. And although it is true that people of low intelligence may attract hurtful and insulting descriptors such as dumb, dull, slow or stupid; nonetheless, a person with these attributes is not regarded as intrinsically wicked.

Personality traits are morally evaluated

There is a contrast between IQ and personality in respect of moral evaluations. While IQ is seen as a gift there is a spontaneous tendency to regard personality as a morally distinguishing feature – as a visible marker of a person’s underlying moral nature. It is quite normal to praise the most diligent people for their high capacity for hard work, and at the same time to regard them as merely fortunate if they are also of high intelligence.

Yet it is probable that both IQ and personality traits (such as the ability to work hard) are almost-equally hereditary ‘gifts’. The heritability of IQ is generally quoted as between 0.5 and 0.8 (probably at the higher end) [1], [2], [3] and [4] and the heritability of personality is quoted as being around 0.5 [5], [6] and [7]. However, the estimate of personality heritability is certainly an underestimate due to the sub-optimal conceptualization of personality traits, and especially to the lesser precision of current personality measurement methods compared with IQ tests [4]. To the extent that these things can be observed in everyday experience, both IQ and personality are probably about-equally inherited; and the high IQ and extra-hard-working person should about-equally thank their genes rather than congratulate themselves.

Furthermore, rankings of personality, like IQ, are generally stable throughout life; so that a highly Conscientious child will probably grow into a highly Conscientious adult and vice versa (whatever their familial, educational and socially experiences may be). However, it is also important to recognize that average personality traits change through the lifespan – e.g. Conscientiousness levels increase through early adult life, while Extraversion declines [12]. The high-C personality type which enables people to work hard, be self-disciplined and pursue long-term goals is therefore, in this sense, no more ‘virtuous’ than the high IQ ability quickly to do complex verbal, mathematic and symbolic puzzles.

But Conscientiousness is often regarded as highly moral behaviour, and an exceptionally-reliable individual will probably be regarded as virtuous even when they are of low IQ. However, in contrast, a person who is low in C is likely to be feckless, distractible, slapdash, and focused on short-term rewards – even when they are very intelligent. These behaviours are regarded as moral deficiencies; and the coexistence of high IQ in some ways makes it worse, because it is often felt that clever people ‘should know better’. Of course, low-C traits are negatively evaluated probably for the obvious reason that they are not very useful socially – indeed a person of very low Conscientiousness is likely to be a poor student and troublesome employee under most circumstances.

Aside, it should be noted that low-C may also be associated with some positively-evaluated attributes; especially creativity (insofar as highly creative people tend to have very high IQ and moderately high ‘Psychoticism’ which trait includes moderately-low Conscientiousness [13]). I have previously suggested that selecting for very high-C will therefore – as an unintended side effect – tend to reduce the average level of creativity; and that this may have happened in science over the past several decades [14].

Furthermore, it has been argued that in the hunter gatherer societies of our ancestors it would probably have been advantageous for most people to have lower levels of C than seem to be optimal nowadays; in the sense that it was more important for hunter gatherers to react spontaneously and quickly to immediate stimuli; and less important for them to plan far ahead, or to be able to persevere in the unrewarding and often repetitive tasks that characterize much of formal education or agricultural and industrial employment [7].

But in modern societies, it is certainly an advantage (on average) to have higher levels of C.

Moral evaluation of personality

The evidence therefore suggests that it is likely that although the two psychological attributes of IQ and C are not highly-correlated (see Ref. [13] for review); the ability to work hard and with self-discipline and the ability of general intelligence are about-equally inherited, about-equally stable throughout life, and about-equally difficult to change either by self-determination or by the social interventions of other people. It seems that we as individuals are pretty much ‘stuck with’ the intelligence and the personalities with which we were born; and it is strange that exceptional IQ should be regarded as a gift while exceptional C is regarded as being the praiseworthy result of resolution and effort.

It might be argued that personality traits are associated with moral behaviours in a way that IQ is not. Certainly personality traits do have moral aspects. Three of the Big Five – Conscientiousness, Agreeableness and Neuroticism – have one extreme which would generally be immoral [6] and [7]. For example, it would generally be regarded as ‘bad behaviour’ to be low in Agreeableness since this would include selfishness, uncooperativeness, emotional coldness, unfriendliness, unhelpfulness. Likewise it may be regarded as socially-undesirable to be high in Neuroticism since this would include proneness to mood swings, irritability and anger.

But the reason that humans apparently spontaneously regard personality in moral terms is presumably because humans respond to incentives. Society would probably wish to encourage pro-social behaviour by praising it, on the basis that even though personality rankings cannot be much changed by whole-population interventions, at the individual level behaviour can be shaped by incentives – by rewards and punishments.

Furthermore, high-C behaviour takes more effort than low-C behaviour. Although the ability to work hard on topics that are uninteresting is mostly hereditary, and therefore a gift, hard work is still hard work, and it is still easier not to work hard! Slapdash, distractible behaviour is undemanding, takes less effort. So, unless there is system of incentives which encourages hard work, then the default position is to work less hard, or not to work at all.

However, when the same incentives are applied to the whole of a group of people varying in C; it is unreasonable and may be cruel to expect that the Conscientiousness gap between high and low individuals to disappear. Although all students might work harder, at least while the incentives were being applied, the gap between high-C and low-C students would remain, and the size of this gap might increase. Certainly, this is what has been found with IQ, when attempting to close various IQ-testing ‘gaps’. And, insofar as C is like IQ (heritable and stable), the possible size of improvement due to interventions is likely to be modest or negligible [2]. The accumulated experience of trying to improve general intelligence (in developed nations) is that it is difficult or impossible to produce sustained long-term improvements in intelligence, especially when the improvements are tested by independent outcomes such performance in employment. Improvements are often superficial results of specific training which only enhance specific types of test performance or evaluations done while under the influence of structured motivational systems [10].


Personality clearly has a moral dimension, but something similar could also be said of intelligence in the indirect sense that higher intelligence is associated with reduced levels of a range of social pathologies including crime and family breakdown [15].

Furthermore intelligence is associated with several aspects of personality and behaviour. There is a positive association between IQ and the Big Five trait of Openness to Experience – which means that more-intelligent people are more likely to seek novelty, enjoy artistic experiences, and be imaginative [7]. Furthermore, intelligence is associated positively with atheism and also with what have been termed ‘enlightened’ values such as left-wing or ‘liberal’ and anti-traditional/anti-conservative views [16]. So that IQ is associated with several morally-evaluated socio-political views which could be judged as virtuous, adaptive, mistaken or even damaging – according to one’s socio-political and religious perspective.

I do not, however, wish to press the similarity of personality and intelligence too hard since these attributes may have a somewhat distinct evolutionary rationale, and selectional basis [17]. My main point is that, although we regard intelligence and personality as different kinds of psychological attributes, in fact they are similar in several important ways.

Nonetheless, in sum, it seems that our traditional interpretations of intelligence and personality require modification. IQ is not just an ability which can be used as required; instead higher IQ is also a predisposition which on average includes a bias towards some types of behaviours and away from others. And high conscientiousness – such as the ability to take the long view, work hard and persevere in the face of difficulty – should probably be interpreted with more emphasis on its being a gift in much the same sense as high intelligence – despite the fact that IQ is ‘effortless’ while high-C emerges mainly in tough situations where exceptional diligence is required.

People with high levels of IQ are mostly very lucky, as is widely recognized; but people with high-C are very lucky too, because they are usually well-rewarded for this aptitude in modern society; and indeed rewarded in science too, where it seems that self-discipline is now selected-for more rigorously than IQ [14].

Indeed, in some ways those ‘gifted’ with high-C are even luckier than very intelligent people, because there are always going to be more jobs for reliable and hard-working people (even if they are relatively ‘dumb’) than jobs which are suitable for smart people who are undependable, short-termist and slapdash.


[1] U. Neisser et al., Intelligence: knowns and unknowns, Am Psychol 51 (1996), pp. 77–101.

[2] A.R. Jensen, The g factor: the science of mental ability, Praeger, Westport, CT, USA (1988).

[3] N.J. Mackintosh, IQ and human intelligence, Oxford University Press, Oxford (1998).

[4] I.J. Deary, Intelligence: a very short introduction, Oxford University Press, Oxford (2001).

[5] J.R. Harris, The nurture assumption: why children turn out the way they do, Bloomsbury, London (1998).

[6] G. Matthews, I.J. Deary and M.C. Whiteman, Personality traits, Cambridge University Press, Cambridge, UK (2003).

[7] D. Nettle, Personality: what makes you the way you are, Oxford University Press, Oxford, UK (2007).

[8] M.R. Barrick and M.K. Mount, The big five personality dimensions and job performance: a meta analysis, Pers Psychol 44 (1991), pp. 1–26.

[9] A.L. Duckworth and M.E.P. Seligman, Self-discipline outdoes IQ in predicting academic performance of adolescents, Psychol Sci 12 (2005), pp. 939–944.

[10] H.H. Spitz, The raising of intelligence: a selected history of attempts to raise retarded intelligence, Erlbaum, Hillsdale, NJ, USA (1986).

[11] L.S. Gottfredson, Implications of cognitive differences for schooling within diverse societies. In: C.L. Frisby and C.R. Reynolds, Editors, Comprehensive handbook of multicultural school psychology, Wiley, New York (2005), pp. 517–554.

[12] P.T. Costa and R.R. McCrae, Stability and change in personality from adolescence through adulthood. In: C.F. Halverson Jr, G.A. Kohnstamm and R.P. Martin, Editors, The developing structure of temperament and personality from infancy to adulthood, Lawrence Erlbaum Associates, Hillsdale, NJ, USA (1994), pp. 139–150.

[13] H.J. Eysenck, Genius: the natural history of creativity, Cambridge University Press, Cambridge, UK (1995).

[14] B.G. Charlton, Why are modern scientists so dull? How science selects for perseverance and sociability at the expense of intelligence and creativity, Med Hypotheses 72 (2009), pp. 237–243.

[15] R.J. Herrnstein and C. Murray, The bell curve: intelligence and class structure in American life, Forbes, New York (1994).

[16] I.J. Deary, C.D. Batty and C.R. Gale, Bright children become enlightened adults, Psychol Sci 19 (2008), pp. 1–6.

[17] L. Penke, J.J. Denissen and G.F. Miller, The evolutionary genetics of personality, Eur J Personality 21 (2007), pp. 549–587.