sabato 1 luglio 2017

De gustibus...

De Gustibus…

Stigler Becker versus Myers Briggs why preference-based explanations are scientifically meaningful and empirically important by Bryan Caplan
Tesi: Becker e Stigler avevano torto
1. Introduction
Economists have long harbored the suspicion that using preferences to explain behavior is tautologous. But Stigler and Becker’s classic “De Gustibus Non Est Disputandum” (1977)… may have been the critical factor that transformed a diffuse suspicion into a professional consensus….
When they wrote, Stigler and Becker may well have been correct to assert that “no other approach of remotely comparable generality and power is available” 2 (1977, p. 77). But since then, empirical work in personality psychology has been extremely fruitful, reaching a solid consensus on a wide range of topics (Hogan et al., 1997; Piedmont, 1998; McCrae and Costa, 1997a).
Empirically, there is fairly strong support for the view that preferences are stable; personality changes are rare, especially after the age of 30 (McCrae and Costa, 1990).
However, the view that preferences are identical is very difficult to empirically defend. Rather, personalities differ widely along a handful of basic dimensions (Piedmont, 1998; Costa and McCrae, 1995; Johnson, 1997).
2. The explanatory power of preferences
Factor analysis on personality questionnaires— administered on a large scale to diverse populations around the world— typically recovers approximately same five highly reliable factors (Section 3)( Hogan et al., 1997; Costa and McCrae, 1995; McCrae and Costa, 1997b; Piedmont, 1998)… Five factors emerge even when researchers take a highly agnostic approach ex ante by, for instance, sampling over all humanly-applicable adjectives in the dictionary (Piedmont, 1998, pp. 20– 32)….
Behavioral genetic studies of personality normally find moderate (40– 60 percent) heritabilities for the five personality factors, showing that personality traits have a biological basis (Bergeman et al., 1993; Blum and Noble, 1997; Bouchard and Hur, 1998; Bouchard and McGue, 1990; Jang et al., 1996).
research on the genetic and environmental contributions to personality make a pure habit-formation account of personality formation difficult to defend. As mentioned above, the big five personality traits are usually found to be moderately heritable (40– 60 percent). To a fair extent, then, people would differ exogenously in temperament even if their “past consumption and personal experiences” were the identical.
3. Preferences: heterogeneous but stable
3.1. The “big five” personality traits
Enumerating thousands of ways that individuals vary is obviously not particularly helpful for empirical researchers. Much of the value-added of personality research comes from the discovery that the apparently messy universe of human traits can be reduced to a small number of basic dimensions using factor analysis (Piedmont, 1998). Eysenck’s (e.g. Eaves et al., 1989) earlier research along these lines concluded that personality could be reduced to three dimensions: extraversion, neuroticism, and psychoticism. Using less formal techniques, and building on Jung’s speculations, Myers and Briggs argued for a four-dimensional model (Briggs Myers and Myers, 1993; Bouchard and Hur, 1998; McCrae and Costa, 1989; Carlson, 1985)… It classifies respondents according to their location on the extraversion– introversion, sensing– intuition, thinking– feeling and judging– perceiving spectra. Academic personality researchers, however, now generally see a strong preponderance of evidence in favor of the five factor model (FFM), typically assessed using the revised NEO personality inventory, or NEO-PI-R. According to the FFM, there are five fundamental and largely orthogonal personality dimensions, frequently referred to as the “big five”. These are generally called openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism.
The big five factors emerge from a wide variety of data sets across gender, race, and national origin (Triadas, 1997; McCrae and Costa, 1997a),
3.1.1. Openness to experience
The openness dimension captures receptivity to novel experiences and ideas ( McCrae and Costa, 1997b).
3.1.2. Conscientiousness
Conscientiousness is a measure of motivation and diligence; as Piedmont puts it, “This dimension contrasts dependable, fastidious people with those who are lackadaisical and sloppy” (1998, p. 90).
3.1.3. Extraversion
Extraversion measures a cluster of traits, not just preference for personal interaction, but also activity level and cheerfulness (Watson and Clark, 1997).
3.1.4. Agreeableness
Agreeableness captures variation in attitudes towards other people, from compassionate and trusting on the one hand to cold and cynical on the other (Graziano and Eisenberg, 1997).
3.1.5. Neuroticism
Neuroticism indexes the propensity to experience negative emotions like anxiety, anger, and depression. Persons low in neuroticism rarely experience such feelings, while persons high in neuroticism experience them frequently.
3.2. Stability
Personality psychologists, in contrast, view the stability of personality over time as an empirical question. But they conclude that it is indeed highly— though not perfectly— stable throughout individuals’ lives.
4. Some applications of personality to economic questions
4.1. Personality, the return to education and signalling
An enormous literature within economics examines the determinants of labor earnings, but almost never considers personality as a possible independent variable. One interesting possibility to investigate, then, is whether there is any link between job performance and personality and whether this tends to bias familiar coefficient estimates.
For every occupational category that they consider, conscientiousness invariably predicts better job performance: it “appears to tap traits which are important to the accomplishment of work tasks in all jobs” (Barrick and Mount, 1991, p. 18).
A particularly noteworthy aspect of the conscientiousness— job performance link is that conscientiousness is highly correlated (0.5– 0.6) with various measures of educational achievement but uncorrelated with measured intelligence (Barrick and Mount, 1991, p. 5). Conscientious people are more successful in both school and work.
4.2. Personality, occupational choice and discrimination
Moving from job performance to occupational choice reveals a still wider scope for personality. The evidence is particularly encyclopedic for the MBTI (Macdaid et al., 1986; Briggs Myers and McCaulley, 1985), but extending these results to the closely related FFM is fairly unproblematic.
High openness is strongly over-represented in creative, theoretical fields such as writing, the arts, and pure science, and under-represented in practical, detail-oriented fields such as business, police work and manual labor (Briggs Myers and McCaulley, 1985, pp. 246– 248). High extraversion is over-represented in people-oriented fields like sales and business and under-represented in fields like accounting and library work (Briggs Myers and McCaulley, 1985, pp. 244– 246). High agreeableness is over-represented in “caring” fields like teaching, nursing, religion and counseling, and under-represented in pure science, engineering and law (Briggs et al., 1985, pp. 248– 50).
The link between personality and occupational choice also raises questions about some forms of alleged occupational discrimination, especially for gender (Filer, 1986). Stereotypes about personality and gender turn out to be fairly accurate: on both Myers– Briggs thinking– feeling and FFM agreeableness, there are large male– female gaps in the expected directions. Women are about half a standard deviation more agreeable than men;
4.3. Conscientiousness and the adverse selection puzzle
Contrary to theoretical predictions, it frequently appears as if low-risk people buy more insurance than high-risk people. In the market for life insurance, for example, consumers buy more when their risk of mortality is less.
There could be a personality trait that leads individuals to act cautiously and buy insurance, ceteris paribus. Conscientiousness is a highly plausible candidate for this role, for this factor encompasses attributes such as “thinking carefully before acting”, “scrupulously fulfilling moral obligations”, and being “organized and thorough” (Piedmont, 1998, pp. 90– 91). Individuals low in conscientiousness would seemingly be more likely to, for example, drive recklessly, and start wondering how to cope with an accident after it happens.
4.4. “Pathological” behavior and the tails of the personality distribution
Extreme or “pathological” behavior— from habitual myopia to drug addiction— is often viewed as a challenge for the economic approach, though naturally such charges have not gone unanswered (Becker and Murphy, 1988; O’Donoghue and Rabin, 1999).
Personality researchers have already developed a detailed case that even pronounced psychiatric disorders are frequently nothing more than the tails of familiar continuous personality distributions— not discrete conditions (Morey, 1997; Costa and Widiger, 1994; Costa and McCrae, 1992) The whole range of “addictive” behavior, for instance, can be captured by the trait of neuroticism;
Personality is also relevant to the large body of anomalies produced by experimental economics (Camerer, 1995; Rabin, 1998). While these experiments definitely show that the average subject behaves in a certain way, they often overlook the possibility that the propensity for anomalous behavior varies.
The average person considers himself better than average by a variety of measures. But vulnerability to such biases is still far from universal. Robins and John (1997) surprisingly report that “only about 35 percent of the subjects show a clear self-enhancement bias whereas about 50 percent are relatively accurate and about 15 percent actually show self-diminishment bias” (p. 669).
5. Conclusion: toward joint estimation
None of this means that traditional explanations using prices and income are unimportant. But empirical work that excludes measures of personality on principle is almost bound to suffer from omitted variable bias. Attributing all unexplained variation to unspecified preferences, as Stigler and Becker emphasized, systematically overstates the role of preferences. But omitting measures of personality on methodological grounds systematically understates the role of preferences.