Mapping Personality Traits onto Brain Systems: BIS, BAS, FFFS and Beyond
COLIN G. DeYOUNG
University of Minnesota, USA
This comment critiques Corr's (2010) characterization of the personality traits associated with the elements of Gray's conceptual nervous system: The behavioural inhibition system (BIS), the behavioural approach system (BAS) and the fight-flight-freeze system (FFFS). Most attention is paid to the FFFS because least is known about its manifestation in personality. Additionally, I suggest that Corr's framework for understanding automatic and controlled processing is useful for developing theories of the biological systems underlying traits that are not directly related to BIS, BAS and FFFS. Copyright © 2010 John Wiley & Sons, Ltd.
Personality has been defined as ‘an individual's unique variation on the general evolutionary design for human nature’ (McAdams & Pals, 2006, p. 204), which implies that to understand personality we must explain (1) the relevant evolved systems that are operative in every intact human brain and (2) the parameters of those systems that vary from person to person to produce personality trait differences. In relation to the first of these explanatory categories, Corr (2010) focuses on the distinction between automatic and controlled systems. In relation to the second, Corr focuses on personality traits reflecting variation in the elements of Gray's ‘conceptual nervous system’: The behavioural inhibition system (BIS), the behavioural approach system (BAS) and the fight-flight-freeze system (FFFS). I offer a critique of Corr's characterization of these systems and their associated traits, followed by a brief discussion of additional traits that are probably not primarily related to the BIS, BAS and FFFS and may primarily reflect controlled instead of automatic processes.
Of Gray's three systems, the FFFS has received the least empirical and theoretical attention in relation to personality, and the question of what states and traits are associated with the FFFS is far more open than one might assume from Corr's (2010) summary:
‘The [FFFS] is responsible for mediating reactions to all aversive stimuli, conditioned and unconditioned, and is responsible for avoidance and escape behaviours. It mediates the emotion of fear, and the associated personality factor consists of fear-proneness, timidity and avoidance’.
Note that the FFFS is not responsible for all forms of avoidance, given that Corr identifies the BIS as responsible for passive avoidance, which is likely to be more common than active avoidance in day-to-day human life. Both BIS and FFFS serve a primarily defensive function, to prevent or correct error and avoid harm. Gray and McNaughton (2000) noted that the crucial distinction between BIS and FFFS is that the FFFS controls response to threats when the only motivation is avoidance. In those cases, avoidance can be accomplished either by active avoidance (flight) or by destruction/deterrence (fight). The BIS, in contrast, controls response to threats that one is motivated to approach. The function of the BIS most generally is to detect and resolve goal conflicts, which usually take the form of approach-avoidance conflicts. (Imporantly, however, approach-approach and avoidance-avoidance conflicts also trigger BIS, and thus simultaneous activation of BAS and FFFS is not necessary to trigger BIS—nor is it sufficient, as BAS and FFFS may be strongly activated together in pursuit of a single goal, e.g. running from a bear toward a building with a sturdy door.) Activation of the BIS serves to protect an organism motivated to approach a potential reward where danger is also present. This protection is accomplished by inhibiting (slowing or even completely stopping) the relevant approach behaviour, triggering increased attention and identification of potential threats and increasing arousal of the FFFS to allow a rapid switch to flight or fight, if threat becomes too great. Even if perceived threat never becomes sufficient to trigger a switch to behaviour governed by FFFS, a strong BIS activation may prevent any further approach to the potential reward (passive avoidance), whereas a weaker activation will allow cautious approach.
The above summary suggests that ‘fear’ is a problematic label for the emotional state associated with FFFS activation and that ‘fear-proneness, timidity and avoidance’ are probably not the best characterizations of traits associated with FFFS sensitivity. McNaughton and Corr (2004) use ‘fear’ to denote a specific psychological and biological state categorically distinct from anxiety. In common usage, however, the referent of ‘fear’ is more general—and less distinct from anxiety. What most lay people mean by ‘fear’ describes emotions accompanying both the active avoidance produced by FFFS and the passive avoidance produced by BIS. We say things like, ‘I feared asking my boss for a raise’, even if, after hesitating, we were able to bring ourselves to do so rather than panicking outside the door to the boss' office and fleeing back to our desks.
Most stimuli feared by human beings occur in situations containing potential reward (the most commonly experienced fears are probably of negative evaluations by others, in work, dating, family, friendship, etc.). BIS activation and passive avoidance should therefore be a more typical referent of ‘fear’, in common usage, than FFFS activation and active avoidance. Thus, Carver and White's (1994) BIS scale is not necessarily wrong to refer to ‘fear’ in some of its items. And ‘timidity and avoidance’ are traits as likely to be associated with BIS sensitivity (and with anxiety) as with FFFS sensitivity.
‘Panic’ is probably a better specific emotional label to use as a marker of FFFS activity in personality assessment. Most people do not panic often, which highlights a problem with Corr's assertion that, except in cases of false alarm, activation of the BIS ends when ‘behavioural control reverts to FFFS-mediated avoidance/escape’. In fact, when BIS activation causes passive avoidance of some danger, one frequently neither actively flees nor fights, but rather switches to some other approach behaviour that is less threatening (cf. McGregor, Prentice, & Nash, 2009)—perhaps explaining the popularity of computer solitaire. The BIS has then resolved conflict not by activating FFFS but simply by suppressing the potentially dangerous goal, allowing a different goal to be pursued instead.
Thus far, I have said little about the ‘fight’ component of the FFFS. However, a sensitive FFFS may lead to irritability and defensive anger as well as to panic. The existence of ‘anger attacks’, which have physical symptoms similar to panic attacks but without the emotion of fear, is suggestive of the biological link between these affective states (Fava, Anderson, & Rosenbaum, 1990). A trait reflecting general FFFS sensitivity should encompass the tendency to be both panicky and irritable.
Such a trait can be found within Neuroticism. Factor analysis of 15 different facets (subtraits) of Neuroticism, within the Big Five model, provided evidence for a two-factor solution (DeYoung, Quilty, & Peterson, 2007). These factors were than characterized by their correlations with over 2000 trait items. The factor labelled ‘Withdrawal’ described people as anxious, self-conscious and depressed, whereas the factor labelled ‘Volatility’ described people as emotionally labile, irritable and easily upset. Withdrawal seems to encompass traits associated with passive avoidance and the functions of the BIS (the label ‘Withdrawal’ can refer to a withdrawal of effort from approach-oriented goals, rather than to active physical withdrawal or flight). In contrast, Volatility has promise as a possible marker of FFFS sensitivity. The existence of BIS- and FFFS-related subtraits within Neuroticism would be consistent with Gray and McNaughton's (2000) description of Neuroticism as jointly determined by the sensitivities of BIS and FFFS.
Corr's (2010) description of traits associated with BIS is unproblematic, but his assertion that the personality factor associated with BAS ‘consists of optimism, reward-orientation and impulsiveness’ requires a caveat. Although Gray initially identified impulsivity as the trait most likely to be associated with BAS sensitivity, research has since suggested that Extraversion is a better candidate (Depue & Collins, 1999; Pickering, 2004; Smillie, Pickering & Jackson, 2006). Individual differences in impulsivity are likely to reflect not only BAS sensivity, but also variation in the strength of the top-down control systems that inhibit prepotent responses. Impulsivity is therefore a compound trait resulting from the strengths of multiple systems (Depue & Collins, 1999; DeYoung, in press).
The existence of individual differences in top-down control systems highlights the need to go beyond Gray's conceptual nervous system in mapping traits onto brain systems. The Big Five model provides a reasonably comprehensive taxonomy of traits, as its five factors emerge when a large variety of descriptive adjectives or existing personality scales are factor analyzed (John, Naumann, & Soto, 2008; Markon, Krueger, & Watson, 2005). Two of the Big Five, Neuroticism and Extraversion, seem to encompass the personality traits directly influenced by the BIS, BAS and FFFS. The other three factors, Conscientiousness, Agreeableness and Openness/Intellect may reflect variation in systems that Corr (2010) describes as involving consciousness and top-down control. Based on the personality neuroscience literature, we have been developing theories regarding the brain systems that are involved in each of the Big Five (DeYoung & Gray, 2009; DeYoung, Hirsh, Shane, Papademetris, Rajeevan, & Gray, 2010). The trait that seems most directly to reflect the ability to inhibit prepotent responses is Conscientiousness. In contrast, Openness/Intellect seems to reflect individual differences in the systems that govern attention and the conscious perception and manipulation of information. Both Conscientiousness and Openness/Intellect have been linked to variation in lateral prefrontal cortex (DeYoung et al., 2010; DeYoung, Shamosh, Green, Braver, & Gray, 2009). Agreeableness, which encompasses traits related to altruism, has been linked to brain systems involved in understanding the emotional and cognitive states of others. With his exploration of the interaction of automatic and controlled processes, Corr (2010) has offered psychologists attempting to explain personality in terms of brain function a useful extension of Gray's framework that makes room for additional traits.