Contra Boris Johnson, IQ doesn’t ensure life success: Non-cognitive skills and poverty matter greatly, too

The IQs of a large enough population are calcu...
The IQs of a large enough population are calculated so that they conform S.E. Embretson & S.P.Reise: Item response theory for psychologists, 2000. #v=onepage&q&f=false to a normal distribution. (Photo credit: Wikipedia)

The Mayor of London, Boris Johnson has been criticised for statements on life success, inequality and intelligence in a wide-ranging speech. IQ, despite what Boris seems to think, incompletely predicts life outcomes: one important review concludes that ‘…the magnitude of the effects of personality traits on mortality, divorce, and occupational attainment was indistinguishable from the effects of SES and cognitive ability on these outcomes‘. Furthermore, IQ measures are not temporally-stable or immutable; IQ varies in an upward direction across succeeding generations.  The Flynn Effect suggests that ‘[t]est score increases have been continuous and approximately linear from the earliest years of testing to the present’ (wiki). Don’t be surprised by this: we’re getting taller, too. Other factors matter greatly too: these go by different names – conscientiousness, motivation, grit, resilience. Here’s an important review paper that focuses on these other non-cognitive domains (abstract below). It concludes that ‘[c]haracter skills predict later-life outcomes with the same, or greater, strength as measures of cognition‘.

Experiencing poverty or financial stress also impedes cognitive performance – and quite dramatically (see Mani et al, 2013 – abstract below). Persistent financial stress depletes cognitive function (abstract below) directly and substantially – perhaps by 13 IQ points (approximately the same as the loss of a complete night’s sleep). This brings someone of an average IQ (100) within the measurement error range of Boris’s daft point that ‘16% of our species have an IQ below 85‘ (this is merely a design feature resulting from the normalising of IQ scores: there will also be 50% of the population at or below 100 on IQ tests – because test scores are transformed to a normal (bell-curve-shaped) distribution).

This brings me to a more important point: the implications of Mani et al’s paper are that individual IQ deficits might be remediated by relieving poverty! In other words, variations in cognitive performance within and and between individuals can depend substantially on the degree of financial stress they are under. The arguments in favour of a universal income may have important support from such research. Of course, if such a poverty reduction policy were rolled out successfully, the underlying bell curve would just be restandardised and renormalised upward – so even if IQ scores were pushed up by relieving poverty traps, we would still leave have half the population with an IQ at or below 100!


Science. 2013 Aug 30;341(6149):976-80. doi: 10.1126/science.1238041.
Poverty impedes cognitive function.
Mani A, Mullainathan S, Shafir E, Zhao J.
The poor often behave in less capable ways, which can further perpetuate poverty. We hypothesize that poverty directly impedes cognitive function and present two studies that test this hypothesis. First, we experimentally induced thoughts about finances and found that this reduces cognitive performance among poor but not in well-off participants. Second, we examined the cognitive function of farmers over the planting cycle. We found that the same farmer shows diminished cognitive performance before harvest, when poor, as compared with after harvest, when rich. This cannot be explained by differences in time available, nutrition, or work effort. Nor can it be explained with stress: Although farmers do show more stress before harvest, that does not account for diminished cognitive performance. Instead, it appears that poverty itself reduces cognitive capacity. We suggest that this is because poverty-related concerns consume mental resources, leaving less for other tasks. These data provide a previously unexamined perspective and help explain a spectrum of behaviors among the poor. We discuss some implications for poverty policy.

Science. 2012 Nov 2;338(6107):682-5. doi: 10.1126/science.1222426.
Some consequences of having too little.
Shah AK, Mullainathan S, Shafir E.

Poor individuals often engage in behaviors, such as excessive borrowing, that reinforce the conditions of poverty. Some explanations for these behaviors focus on personality traits of the poor. Others emphasize environmental factors such as housing or financial access. We instead consider how certain behaviors stem simply from having less. We suggest that scarcity changes how people allocate attention: It leads them to engage more deeply in some problems while neglecting others. Across several experiments, we show that scarcity leads to attentional shifts that can help to explain behaviors such as overborrowing. We discuss how this mechanism might also explain other puzzles of poverty.

Fostering and Measuring Skills: Interventions That Improve Character and Cognition by James J. Heckman, Tim Kautz

This paper reviews the recent literature on measuring and boosting cognitive and noncognitive skills. The literature establishes that achievement tests do not adequately capture character skills – personality traits, goals, motivations, and preferences that are valued in the labor market, in school, and in many other domains. Their predictive power rivals that of cognitive skills. Reliable measures of character have been developed. All measures of character and cognition are measures of performance on some task. In order to reliably estimate skills from tasks, it is necessary to standardize for incentives, effort, and other skills when measuring any particular skill. Character is a skill, not a trait. At any age, character skills are stable across different tasks, but skills can change over the life cycle. Character is shaped by families, schools, and social environments. Skill development is a dynamic process, in which the early years lay the foundation for successful investment in later years. High-quality early childhood and elementary school programs improve character skills in a lasting and cost-effective way. Many of them beneficially affect later-life outcomes without improving cognition. There are fewer long-term evaluations of adolescent interventions, but workplace-based programs that teach character skills are promising. The common feature of successful interventions across all stages of the life cycle through adulthood is that they promote attachment and provide a secure base for exploration and learning for the child. Successful interventions emulate the mentoring environments offered by successful families.

Author: Shane O'Mara

Neuroscientist, Psychologist, Writer

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