Arguments For and Against Personality Predictors

Arguments For and Against Personality Predictors Arguments in favour Anyone seeking to measure personality has an abundance of useful psychometric instruments at their disposal, include the Minnesota Multiphasic Personality Inventory (MMPI) (e.g. Archer, 2005), the Weschler Intelligence Scale for Children (WISC) (Watkins et al, 1997), the Myers Briggs Type Indicator (MBTI) (Myers McCauley, 1985; McCrae Costa, 1989), and the, NEO Personality Inventory (revised) (Costa McCrae, 1992), and the Thematic Apperception Test (TAT) (Cramer, 1996), just to mention a few. Thus it should be simple matter to generate a reliable and valid set of scores, which can then be used to make various predictions about future behaviour. Studies have shown that the more established personality tests have acceptable levels of reliability (i.e. they measure personality consistently, both in terms of stability over time/across situations, and internally), and validity (they seem to measure personality, rather than some other psychological feature) (e.g. Costa McCrae, 1992; Wa tkins et al, 1997). Indeed, use of some of these measures is so widespread that they have become a standard part of psychological assessments in health care and recruitment, marriage counselling, and other fields (Davey, 2004; Myers, 2007). The data obtained can for example be used to make a prediction about the success of a marriage, professional abilities of a candidate for a job, or medical outcomes. For example, the MMPI is regularly used to make determinations about future behavioural problems in psychiatric patients (Arbisi et al, 2002). The NEO Personality Inventory and Myers Briggs Type Indicator have been fund to be particularly useful at predicting future behaviour. For example Moutafi et al (2003) asked 900 people to complete various psychological tests as part of an exercise conducted by a business consulting company. These tests included the MBTI and the revised version of the NEO Personality Inventory. Multiple regression analysis showed that various personality scales contained in both personality inventories reliably predict multiple dimensions of intelligence, at the 5% level of significance (Howitt Cramer, 2005). Clearly, the availability of tried and tested measurement tools suggests that it personality can be measured reasonably accurately, and hence used as the basis for making predictions. Another argument concerns the dispositional nature of personality traits. Personality has long been conceptualised as a stable and enduring feature that once developed does not change much during a person’s lifetime (Allport, 1937; Ryckman, 2004). This stability means it is possible to formulate a clear idea about the nature of a person’s personality (e.g. using a personality test) (Myers, 2007). This idea, once formed, can then be used to make predictions. To better appreciate this argument consider more volatile psychological characteristic like stress or coping (Janis, 1986). A persons stress levels can fluctuate widely over any given period of time. For example, an individual may experience high stress levels when the go to work during the day, but then feel relaxed once they return home. Similarly an individual may become highly agitated when flying in an aircraft and then subsequently experience little or no stress once they are back on the ground. Given the volat ility of stress levels it may be rather difficult for a researcher to conduct an overall and accurate assessment of a person’s anxiety. By contrast, personality shows sufficient continuity to enable a researcher develop a reliable personality profile (Engler, 2006) for any one individual. The accuracy of personality measurement is facilitated by the availability of suitable statistical tools, notably factor analysis (Tabachnick Fidell, 1996; Field, 2000). Factor analysis is a statistical method that allows one to condense a large amount of data into a small number of more manageable dimensions. In particular, a persons’ responses to a large number of items in an inventory can be reduced to a small number of basic dimensions that encapsulate the individuals’ personality. This is important given that personality is a multidimensional construct that can be described with thousands of words, phrases, and sentences, in the English language (Livesley Jackson, 1986). Consequently, personality theorists have routinely used this test to identify the basic dimensions of personality, such Goldberg’s (1993) ‘Big Five’ personality themes – agreeableness, conscientiousness, neuroticism, extraversion, and openness to experience. It is well known that renowned psychologist Hans Eysenck (Haggbloom, 2002) was one of those to first grasp the utility of factor analysis for developing accurate measures of personality. He subjected a large number of personality items to factor analyses, over several decades, yielding several dimensions: a proclivity to experience negative feelings, which he called neuroticism; an interest in social activity, labelled extraversion; and later a susceptibility to mental illness (e.g. schizophrenia), named psychoticism. These dimensions have been used to make predictions about a wide variety of behaviours, in many different situations (e.g. see review by Riggio Riggio, 2002). Furthermore, a person’s personality is a significant determinant of their behaviour in many different situations (Ryckman, 2004; Myers, 2007). This is a scientific fact, as demonstrated by the large number of studies that have used personality measures as the basis for determining various aspects of human behaviour under disparate conditions (McCrae Costa, 1990). For example, studies have shown how a defensive, unreceptive, or evasive personality can lead audiences to reject health warnings issued on a variety of topics and in a multiplicity of situations (see review by Eagly Chaiken, 1993). Empirical studies show that personality scores predict a significant amount of the variance in various behavioural scores, with the influence of chance factors falling below the five percent level (e.g. Moutafi et al, 2003). For this reason psychologists have spent a considerable amount of time and effort studying this construct. Once an accurate measurement of a persons personality have been obtained it should be fairly simple to make a significant prediction about their current or future behaviour in any given situation, using analytic procedures such as multiple regression analysis. Arguments against Psychologists cannot agree on the proper definition of personality, let alone measure it accurately and make reliable predictions. Open any relevant psychology textbook and one is confronted with several different theoretical accounts of precisely what personality means (e.g. Davey, 2004; Myers, 2007). For example, the legendary Sigmund Freud conceptualises personality as a multidimensional construct (incorporating the id, ego, and superego) that transcends the conscious, preconscious, and subconscious, and is driven by unconscious emotional problems. By contrast behaviourists, such as Burrhus Skinner, view personality as learned behaviours shaped by reinforcement and conditioning. Trait theorists like Gordon Allport conceptualise personality as stable behavioural characteristics that manifest across different situations. Thus, psychologists are far from reaching a consensus. Therefore, the idea that personality can be measured accurately is nonsensical. How can one measure a phenome non that isn’t clearly defined? Until psychologists can agree on a universal definition of personality, accurate measurement will remain an unattainable dream. At the beginning of this essay I provided a list of measurement tools for assessing personality, for example the MMPI, MBTI, and NEO personality inventory. While these instruments do appear to have some accuracy, their psychometric properties are continually the subject of doubt and criticism (e.g. McCrae Costa, 1989; Watkins et al, 1997). Reliability coefficients, while good, aren’t often high enough, and validity tests are rarely conclusive (Arbisi et al, 2002). Given these problems in the measurement of personality, accurate prediction of behaviour is bound to be impaired. For example, it is known fact that measurement error, resulting from the use unreliable and invalid measurement tools, can obscure significant relations between variables, resulting in a type II error (Baron Kenny, 1986; Howitt Cramer, 2 005). The idea that personality could be used to predict behaviour across situations rests on an important assumption – that how people respond in any given situation is necessarily predictable. The truth is that a person’s behaviour may sometimes be random with no apparent cause. This idea is echoes chaos theory (Gleick, 1987), a scientific school of thought that proposes that an event may be unpredictable due to various complexities or errors in its antecedent conditions. For example, long-term weather forecasting is often difficult because so many unstable climatic factors interact in such a complex fashion that minor changes in the nature of these interactions, and the elements which interact, could produce random, unpredictable, and escalating weather patterns. Chaos theory is applicable to the social sciences (Kiel Elliot, 1997). Different personality characteristics may interact (Howitt Cramer, 2005) in extremely complex fashions that any slight changes in the nature of these interactions or the variables involved can produce statistical and computational problems that reduce predictive power (Field, 2000). For example, any error in measurement of personality will be magnified to such an extent that it would obscure significant relationships between personality and behaviour. Baron and Kenny (1986) document this magnification in measurement error resulting from interactions between multiple variables. It means that behaviours produced by overly complex interactions between personality characteristics may to all intents and purposes be mathematically unpredictable, and hence appear random and sporadic, irrespective of the situation (Gleick, 1987). This is especially likely when trying to predict fleeting or eccentric behaviours (e.g. deliberate self-harm) often resulting from the complicated interplay between not just personality traits, but also other psychological phenomena, not to mention situational factors. There are others concerns. Psychologists can’t agree on whether personality traits are best conceptualised as stable entities that persist across situations or variable characteristics that change from one situation to the next (Davey, 2004). Which is it? Whatever view one subscribes to has measurement implications. Stable personality dispositions are generally more difficult to measure accurately, for various reasons (Leventhal et al, 1993). For example, people are less accurate at describing how they ‘generally’ behave, showing a memory bias towards positive rather than negative characteristics: in which case it would be more difficult to predict behaviour in any given situation, due to reliability and validity constraints. Finally, there is what social psychologists call the fundamental attribution error (Aronson, 1995). This refers to the tendency to overestimate the effect of personality on behaviour and underestimate the impact of the situation. Consider for example a person who has a fear of flying. They become highly stressed, agitated, and sometimes even panic stricken once a plane reaches cruising altitude. However, their anxiety disappears once the plane is back on the ground. The primary determinant of this individual’s emotional stress is situational – flying in a plane. Although personality may be important – for example, he/she may have a neurotic personality, making them more prone to stress (Riggio Riggio, 2002) – it would be a mistake to underestimate the effect of the situation (Janis, 1986; Engler, 2006). The essence of the fundamental attribution error here is thus: even if personality could be measured accurately, it may still fail to predict behaviour effectively to the extent that the behaviour in question is primarily a function of the situation rather than personality characteristics. Conclusion Can we predict a person’s response in any given situation if personality could be measured accurately? This essay presents arguments for and against. Regarding the former, psychometrically useful measures of personality abound, yielding reasonably reliable and valid personality scores that can be used for making behavioural predictions. Furthermore, analytic tools like factor analysis and the purportedly stable property of personality traits may both facilitate accurate measurement and further improve predictive power. Various empirical studies exist the support these arguments. However, there are several strong counterarguments that are difficult to refute. There is as yet in psychology no unanimous definition of personality. This raises serious questions about the psychometric attributes of any instrument that purports to measure personality. Indeed existing personality inventories are continually plagued by concerns about reliability and validity. Even without these psychom etric issues, a person’s behaviour is often heavily (if not entirely) determined by the prevailing situation, rather than their personality characteristics. Thus, even the most accurate personality measures will exhibit poor predictive power. In any case it is questionable whether human behaviour is always predictable. 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