340 III. DEvELOPMENT
items) is needed (Condon, 2014; McCrae, 
2015; Mõttus, 2016; Soto & John, 2017). 
Broad bandwidth traits such as the Big Five 
can sometimes be clumsy when predicting 
specific outcomes. A new interest in facets 
is growing. We do not know much about 
how lower-  bandwidth constructs change 
in adulthood, as only one major trajectory 
(growth curve) investigation has been pub -
lished (Bleidorn, Kandler, Riemann, Anglei -
tner, & Spinath, 2009). Many more studies 
of facet change will be required in the future.
Note that in discussing the empirical lit -
erature on personality change, we did not 
mention studies of rank-order stability at 
all. Such work is typically considered a key 
component of the body of work on personal -
ity development in adulthood (e.g., Roberts 
& DelVecchio, 2000). However, we believe 
the longitudinal correlation coefficient, or 
stability coefficient, which is the main tool 
researchers have used for evaluating rank-
order (or relative) stability, has perhaps out -
lived its usefulness. We say this because of 
two inherent flaws. First, they make use of 
only two measurement occasions at a time. 
Second, correlations conceal any individual 
differences in change. With so many extant 
datasets with multiple waves, and the avail -
ability of sophisticated modeling techniques 
that maximize use of many waves (MLM, 
latent growth), it may be time to retire the 
stability coefficient, along with the concept 
of rank-order stability.
Naturally Occurring Predictors 
of Personality Change
Earlier we discussed individual differences 
in change, noting that it is consistent with a 
fundamental tenet of lifespan developmental 
theory. However, it is important in another 
way. Evidence of variation in rate or direc -
tion of personality change opens the door 
to prediction and explanation of those indi -
vidual differences. If everyone changes at the 
same rate (or if everyone is stable), then there 
is no need to identify factors that account for 
change.
The existence of individual variation in 
personality change has spurred the rise of 
many research programs worldwide that 
have attempted to account for these individ -uals differences. What are the factors that 
predict personality change? The majority 
of these studies have focused on naturally 
occurring factors (noninterventional, non -
pharmacological), such as stressful events, 
life transitions, social roles, and changes 
in roles. This, along with a greater under -
standing of intervention-  based personality 
change, has been one of the most significant 
developments since the previous handbook 
(for intervention-  based change, see Jack -
son et al., Chapter 38, this volume; see also 
Bleidorn et al., 2019). There had been some 
early attempts around the turn of the mil -
lennium that looked at early adult (Neyer & 
Asendorpf, 2001; Robins, Caspi, & Moffitt 
2002), and older adult (Mroczek & Spiro, 
2003) relationship changes as predictors of 
subsequent trait change. Entering a roman -
tic relationship was associated with decline 
in neuroticism in the former study, whereas 
experiencing the death of spouse was asso -
ciated with increases in neuroticism in the 
latter study (but remarriage was related to 
a decline in that trait). More recently, due 
to greater availability of personality stud -
ies with multiple measurement occasions, a 
richer examination of predictors has blos -
somed.
A plurality of these investigations has fo -
cused on social and romantic relationships 
as the central predictors. For example, fol -
lowing Neyer and Asendorpf (2001), Neyer 
and Lehnart (2007) found that entering a 
romantic relationship for the first time was 
associated with decreases in neuroticism, a 
finding that was later replicated (Lehnart, 
Neyer, & Eccles, 2010). Peer relationships 
also influence personality changes (Reitz, 
Zimmermann, Hutteman, Specht, & Neyer, 
2014), and Mund and Neyer (2014) have 
found both romantic and peer relationships, 
as well as changes in those relationships, are 
associated with trait changes (see also Neyer, 
Mund, Zimmermann & Wrzus, 2014).
Work and career-  oriented predictors have 
formed another major effort at personal -
ity change prediction. Lüdtke, Roberts, 
Trautwein, and Nagy (2011) found that 
vocational career paths are associated with 
greater increases in conscientiousness and 
a less steep increase in agreeableness than 
university-  oriented career paths. Jackson, 
Thoemmes, Jonkman, Lüdtke, & Traut -