Murayama and Jach (M&J) suggest that one important direction for future work is that “to understand motivational states and traits, we need to develop a theory of mental computational processes that explicitly addresses how intra-individual processes translates into long-term development” (target article, sect. 5, para. 6). One route that may illuminate this future direction is to engage recent accounts of personality dynamics. Here we propose Whole Trait Theory (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2021a; Jayawickreme, Fleeson, Beck, Baumert, & Adler, Reference Jayawickreme, Fleeson, Beck, Baumert and Adler2021) as a guiding framework. Whole Trait Theory suggests that personality traits are composed of two parts: (1) An explanatory aspect which captures social-cognitive mechanisms that cause trait manifestations and (2) a descriptive aspect which captures manifestations of personality traits and states in daily life (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2021a). Whole Trait Theory suggests that the explanatory component is important to understanding meaningful intra-individual variations in behavior. In our view, this aligns with M&J's account; specifically, we argue that mental computational processes represent an example of the explanatory processes underlying trait enactments. Given these parallels, empirical work engaging Whole Trait Theory and other dynamic accounts of personality may inform future directions of research on mental computational processes.

One particularly illuminating line of research using Whole Trait Theory has examined the relation between momentary goal pursuits and trait manifestations. In a 10-day experience sampling study of extraversion, participants reported both their state extraversion and the extent to which they were trying to accomplish 18 goals related to facets of extraversion (e.g., sociable) in the last 30 minutes (McCabe & Fleeson, Reference McCabe and Fleeson2012). These momentary goal pursuits predicted nearly three quarters of the variance in state extraversion, suggesting that motivation plays a role in state manifestations of traits (McCabe & Fleeson, Reference McCabe and Fleeson2012). In subsequent research, momentary goals explained nearly half the variance in extraversion and conscientiousness trait enactments (McCabe & Fleeson, Reference McCabe and Fleeson2016). Additionally, in an experiment where participants were assigned either an extraversion or conscientiousness goal to enact for the next 45 minutes, participants reported higher state levels of that respective trait (McCabe & Fleeson, Reference McCabe and Fleeson2016). These studies demonstrate a connection between motivation and trait enactment that may elucidate how intra-individual processes transition to long-term development.

The transition from intra-individual processes to long-term development may be related to the descriptive aspect of Whole Trait Theory. The descriptive aspect is represented as density distributions of states. These density distributions refer to the unique distribution formed over time of a person's states (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2015). Characteristics of density distributions include the location of the distribution on a dimension (i.e., different people have different means; Fleeson & Noftle, Reference Fleeson and Noftle2008) and the width of the distribution (i.e., how much variability in intra-individual states; Fleeson & Gallagher, Reference Fleeson and Gallagher2009). Distributions vary from person to person; however, individual's distributions are typically stable in terms of their location (rs around 0.8) from week to week (Fleeson, Reference Fleeson2001). Additionally, as indicated in the studies by McCabe and Fleeson (Reference McCabe and Fleeson2012, Reference McCabe and Fleeson2016), density distributions are shaped by the motivations and goals of an individual, which are expressed as part of the explanatory aspect of Whole Trait Theory. Continued manifestation of trait expressions form density distributions of states.

The explanatory aspect of Whole Trait Theory includes “the set of cognitive, affective, biological, and motivational processes that influence the degree to which a person manifests the trait at any given moment” (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2021b, p. 99). The explanatory aspect, as its name suggests, explains the distributions of states; it explains the variations in behaviors, why people enact different trait contents at different times (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2021b). The manner in which people understand and react to the situation they are in leads to changes in their trait enactment and behavior; people adapt their behavior to their context. Additionally, these behaviors can be reinforced or undermined by their external environment. For example, when a person is more talkative, others may engage with them more. Additionally, state extraversion has been found to cause more state positive affect (e.g., McNiel, Lowman, & Fleeson, Reference McNiel, Lowman and Fleeson2010), which may in turn reinforce extraverted behavior. There are a host of processes that undergird the explanatory aspect of Whole Trait Theory – social-cognitive, affective, biological, interpretative, temporal – but a key process is the motivational process (Fleeson & Jayawickreme, Reference Fleeson and Jayawickreme2021b). As indicated in the goal-related research described above, momentary goal pursuits – momentary motivations – explained between half and three quarters of the variance in trait enactments (McCabe & Fleeson, Reference McCabe and Fleeson2012, Reference McCabe and Fleeson2016). The explanatory aspect is thus well-positioned to include mental computational processes as a specific subtype within the explanatory aspect of Whole Trait Theory.

Mental computational processes are described by M&J as momentary motivation manifestations. If we consider mental computational processes as part of the explanatory aspect, then we would expect that people's mental computational processes change based on their situation and on their momentary goal pursuits. Additionally, changes in mental computational processes would lead to a shift in the distributions of motivational states. To the extent to which these changes are reinforced by a person's environment, these changes would become more fixed and stable, perhaps accounting for more stable motivational traits (e.g., intrinsic motivation).

M&J lay the foundation for mental computational processes and their relation to motivation. Future research into mental computational processes could draw inspiration from research on Whole Trait Theory and other dynamic accounts of personality. Some avenues for future directions include investigating: (1) The density distributions of momentary motivational “states” and their relation to stable motivational traits, (2) how mental computational processes are reinforced or challenged by changes in people's environments, (3) the situational influences on the manifestations of mental computational processes, and (4) the role of specific goal pursuits in the selection of mental computational processes. Such research into how, when, and why mental computational processes are engaged will help to further unpack the black box of motivation.