342 III. DEvELOPMENT
cesses, which means that change in one trait 
can lead to changes in others traits, feeding 
back on the first trait (Klimstra, Bleidorn, 
Asendorpf, van Aken, & Denissen, 2013). 
These correlated change models or coupled 
change models, sometimes estimated with 
autoregressive latent trajectory (ALT) or 
autoregressive crosslagged (ARCL) mod -
els (Allemand, Zimprich, & Martin, 2008; 
Bollen & Curran, 2004), can help establish 
evidence of bidirectionality, as well as other 
relevant concepts such as the “corresponsive 
principle” (Roberts & Wood, 2006) which 
holds that people’s personality traits lead 
them to seek out experiences that reinforce 
those very traits.
As we argued earlier, these ideas and bod -
ies of evidence may require us to give up 
traditional notions of causality. These tra -
ditional notions may not model reality very 
well. Discarding them is probably good, for 
psychology is far too infused with simplistic 
ideas of stimulus–  cause relationships. Both 
bidirectionality and “corresponsiveness” 
(Roberts & Wood, 2006) imply ongoing 
feedback loops in which cause and effect are 
impossible to disentangle (this is often how 
“transactional processes” are described in 
the developmental literature), as we noted 
earlier. That said, most bidirectional pro -
cesses probably have some sort of beginning, 
and thus a distal “cause.” Yet once a pro -
cess is set into motion, feedback loops take 
over, and traditional causality is very diffi -
cult to determine. This is likely how many 
developmental processes work. It is also 
very far away from the simplistic indepen -
dent variable–  dependent variable mindset 
espoused in much of the rest of psychology.
Third, the very idea of a clean separation 
between the internal (e.g., personality traits, 
genes) and external (life events, relationships) 
is false. Recent work in epigenetics (Petro -
nis, 2010) promotes the notion that genes 
and environments are entwined in compli -
cated ways. Environmental factors can acti -
vate genetic factors (e.g., methylation), but, 
importantly, genetic factors as manifested 
in phenotypic expressions (e.g., personal -
ity) can shape and select the environments 
in which we later find ourselves (Roberts et 
al., 2008; Caspi & Shiner, 2008). Extraverts 
choose to go to parties. Introverts choose to 
stay home. Contexts do not just happen to us. People are highly active agents who select 
themselves into situations, mold contexts, 
and create new environments (Bell, 1968). 
Roberts et al. (2008) echoed this view, not -
ing that people’s personality characteristics 
are “evocative,” leading to construction of 
new contexts to suit one’s gregarious or shy -
ness, whichever the case. In turn, these con -
texts often reinforce existing trait levels, as 
shown by Jackson (2011).
What does this mean for the study of pre -
dictors of personality change? These three— 
genetic factors underlying some portion of 
personality change, bidirectional processes 
between personality and context, and the 
person as an active agent—would seem to 
limit the appeal of searching for predictors 
of personality change. If a certain factor, 
say, a relationship variable, predicts person -
ality change, we are justified in then asking 
how prior personality influenced the entry 
into that relationship in the first place. We 
might also ask how relationship and person -
ality variables may influence each other in a 
transactional or bidirectional fashion. Last, 
we may question how largely that predictor 
influences personality change relative to ge -
netic factors. It would seem that the search 
for predictors is ultimately a circular task, 
due to personality effects on many contex -
tual predictors prior to the assessment of the 
“predictor.” However, we end this section 
by encouraging the continued study of per -
sonality change predictors.
Even if there are strong personality- 
based selection effects on the environments, 
groups, and relationships in which we find 
ourselves, those contexts still retain a con -
siderable degree of independence from the 
person. Yes, our profile of personality char -
acteristics may play a big role in our selection 
of whom we choose in a romantic partner -
ship, but it does not mean that we fully con -
trol what that other person does. The other 
actor is still a different organism and is part 
of an abstract “external” context. He or she 
can and will do things that are far out of our 
control, and we in turn are shaped by these 
uncontrollable circumstances. This is per -
haps best seen when individuals become par -
ents. Even though parents share a great deal 
with their children, they are independent 
beings and have the power to shape parents 
in ways they do not expect. Children evoke 