Tag: individual differences

Myers-Briggs

People are rightly critical of the Myers–Briggs Type Indicator (MBTI). But some of the types are moderately correlated with the Big Five dimensions, which are seen as more credible in differential psychology. MBTI extraversion correlates with… wait for it… Big Five extraversion (50% shared variance). MBTI intuition correlates with openness to new experiences (40% shared variance). The opposite poles correlate as you’d expect.

Here are the key correlations (Furnham et al., 2003, p. 580, gender and linear effects of age have been partialed out):

“Neuroticism was most highly correlated with MBTI Extraversion (r = -.30, p = .001) and Introversion (r = .31, p < .001). Costa and McCrae’s Extraversion was most highly correlated with Myers-Briggs Extraversion (r = .71, p < .001) and Introversion (r=-.72, p < .001). Openness was most highly correlated with Sensing (r = -.66, p < .001) and Intuition (r = .64, p < .001). Agreeableness was most highly correlated with Thinking (r=-41, p < .001) and Feeling (r = .28, p < .001). Conscientiousness was most highly correlated with Judgment (r = .46, p<.001) and Perception (r=-.46, p < .001).”

Dichotomising is still silly, particularly for scores close to thresholds, where a light breeze might flip someone’s type from, say, I to E or vice verse. But the same can be said of any discretisation taken too seriously. Consider also clinical bands on mental health questionnaires and attachment styles on the Experience in Close Relationships Scale.

Also silly are tautologous non-explanations of the form: they behave that way because they’re E. Someone is E because they ticked a bunch of boxes saying they consider themselves extraverted! The types are defined transparently in terms of thoughts, feelings, and behaviour. They help structure self-report, but don’t explain why people are the way they are. Explanations require mechanisms.

References

Furnham, A., Moutafi, J., & Crump, J. (2003). The relationship between the revised NEO-Personality Inventory and the Myers-Briggs Type Indicator. Social Behavior and Personality, 31, 577–584.

Mill on patterns of human existence

“… it is important to give the freest scope possible to uncustomary things, in order that it may in time appear which of these are fit to be converted into customs. But independence of action, and disregard of custom are not solely deserving of encouragement for the chance they afford that better modes of action, and customs more worthy of general adoption, may be struck out; nor is it only persons of decided mental superiority who have a just claim to carry on their lives in their own way. There is no reason that all human existences should be constructed on some one, or some small number of patterns. If a person possesses any tolerable amount of common sense and experience, his own mode of laying out his existence is the best, not because it is the best in itself, but because it is his own mode. Human beings are not like sheep; and even sheep are not undistinguishably alike.”
—J. S. Mill, On Liberty

Profiles of intelligence

Johnson, W. & Bouchard, Jr., T. J. Sex Differences in Mental Abilities: g Masks the Dimensions on Which They Lie. Intelligence, 2007, 35, 23-39:

“Performance on image rotation tasks is known to predict success in fields such as airplane piloting, engineering, physical sciences, and fine arts better than does general intelligence, and especially verbal ability. What has perhaps not been recognized is that inclusion of verbal ability in assessments used to recruit individuals to those fields may actually act to impair efforts to select those with the talents most relevant to the jobs in question.”

"... we have presented evidence supporting the idealized notion of
general intelligence as a general-purpose mechanism that accesses a
toolbox made up of components that vary from individual to individual.
Though everyone clearly has most if not all of the same tools,
individuals appear to differ not only in the skill with which they use
their tools, but also in the specific tools they habitually use. For
some of the more specific tools, it would appear that using one tool
means failing to use another. [...] Performance on image rotation tasks
is known to predict success in fields such as airplane piloting,
engineering, physical sciences, and fine arts better than does general
intelligence, and especially verbal ability. What has perhaps not been
recognized is that inclusion of verbal ability in assessments used to
recruit individuals to those fields may actually act to impair efforts
to select those with the talents most relevant to the jobs in question."

Individual differences (continued)

“I am surprised that the author has used this data set. In my lab, when we collect data with such large individual differences, we refer to the data as ‘junk’. We then redesign our stimuli and/or experimental procedures, and run a new experiment. The junk data never appear in publications”

—An anonymous reviewer in 2005, commenting on research that sought to model individual differences in cognition.

From the intro to Navarro, D. J.; Griffiths, T. L.; Steyvers, M. & Lee, M. D. Modeling individual differences using Dirichlet processes. Journal of Mathematical Psychology, 2006, 50, 101-122

Psychological assessment at NSA

The Memory Hole managed to obtain all non-classified forms used at the NSA (claims NSA). Two nice finds:

If you got here via Google because you’re applying to work for NSA, probably best not to email me about the assessment, eh? (Yes, some people have.)

Gender differences in psychology

My take on this:

  1. There are gender differences in ability, but not many, and the effect size is typically small* (Hyde 2005).
  2. Brain structure development is affected by a range of factors, environmental and genetic. For instance brain structure changes as a result of learning (e.g., Maguire et al, 2000). (And the phrase “hard-wired” is annoying.)
  3. A mean difference between groups, mean(group 1) > mean(group 2), on some measure does not imply that everyone in group 1 is better than everyone in group 2. So when selecting someone for a job, say, you could (a) grab a load of people with the gender which, on average, has (very slightly—see point 1) more of the ability you want and choose someone at random, or (b) you could choose someone who has more of the ability you want, and not focus on what gender they happen to be.
  4. The designers of IQ tests hack their tests to remove gender differences, for instance the designers of the British Ability Scales (version 2) “used three strategies to test for fairness and to remove items likely to increase bias” (Hill, 2005). Blinkhorn (2005) says: “Where there are sex differences to be found, detailed study of the internal workings of the test tends to show why. That’s not based on instinct, but on my professional experience in designing gender-fair tests.”

References

Blinkhorn, S. (2005). Intelligence: a gender bender. Nature, 438, 31-32.

Hill, V. (2005). Through the Past Darkly: A Review of the British Ability Scales. Second Edition. Child and Adolescent Mental Health, 10, 87-98.

Hyde, J. S. (2005). The gender similarities hypothesis. American Psychologist, 60, 581-592.

Maguire, E. A.; Gadian, D. G.; Johnsrude, I. S.; Good, C. D.; Ashburner, J.; Frackowiak, R. S. & Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences of the United States of America, 97, 4398-4403

* Cis women are better at giving birth than cis men, with a large effect size.