808 vIII. EMERGING  ISSuES AND  NEW  DIRECTIONS
blood pressure and mask hypertension (J. 
Schwartz et al., 2016). Both scenarios high -
light the need for ambulatory blood pressure 
monitoring, which is what the American 
Heart Association now recommends to con -
firm a diagnosis of hypertension. Another 
example, closer to the field of personality 
psychology, is that women and men may 
differ in how talkative they are in different 
laboratory contexts (Leaper & Ayres, 2007) 
but, when unobtrusively monitored over the 
day, counter to the prevalent stereotype, they 
use a similar number of words (~ 16,000; 
Mehl, Vazire, Ramirez-  Esparza, Slatcher, & 
Pennebaker, 2007).
Real‑Time  Behavior
Research methods for studying daily life 
allow researchers to understand phenomena 
the way they naturally occur, such as feel -
ings when in specific situations (Bakolis et 
al., 2018), rather than how they are remem -
bered. This aspect is particularly important 
for experiences, behavior, and situations 
that are fleeting in nature and thus difficult 
to remember accurately. A wide range of 
factors influence people’s responses to the 
question of how happy, sad, or worried they 
generally are, including recent experiences, 
salient memories, personal beliefs, and gen -
eral expectations (N. Schwarz, 2012). In 
fact, immediate momentary, retrospectively 
recalled and generalized typical experiences 
appear to be represented differently in mem -
ory (e.g., working, episodic, and semantic 
memory, respectively) and can differentially 
relate to behavior (Conner & Barrett, 2012; 
Robinson & Clore, 2002). For example, in 
a trial with an antidepressant medication, 
daily symptom reports detected improve -
ments significantly faster than did weekly 
clinical assessments (Lenderking et al., 
2008). On the other hand, Wirtz, Kruger, 
Scollon, and Diener (2003) found that stu -
dents’ remembered Spring Break experienc -
es predicted their desire to go back better 
than their actual momentary ones—  despite 
being overly positive. Together, the concep -
tual differences among global, retrospec -
tive, and momentary assessments, and their 
divergent empirical ramifications, suggest 
that personality research would benefit 
from complementing traditional trait assess -ments with (close to) real-time state mea -
surements.
Within‑Person  Effects
Research methods for studying daily life can 
help identify behavioral patterns within in -
dividuals (i.e., idiographic assessment; Ha -
maker, 2012). This approach differs from the 
field’s traditional focus on between-  person 
associations (i.e., nomothetic approach). 
Molenaar and Campbell (2009) have argued 
that between- and within-  person effects 
are conceptually and empirically indepen -
dent, and that psychology has an unfortu -
nate tradition of trying to answer within- 
person questions with between-  person (i.e., 
cross-  sectional) data. With their repeated, 
high-  frequency sampling of experiences, 
behaviors, and situations over time, ecologi -
cal sampling methods yield “intensive lon -
gitudinal data” that can be used to uncover 
contextual and temporal within-  person pro -
cesses, as well as between-  person variability 
around them (Bolger & Laurenceau, 2013; 
Wright & Zimmerman, 2019). For example, 
using 6 weeks of daily diary data, Bolger 
and Schilling (1991) found an association 
between the experience of a stressor and 
anxiety that day. This within-  person effect, 
though, was moderated by personality, with 
neurotic individuals experiencing a height -
ened emotional reactivity. Also focusing 
on within-  person dynamics, Wrzus, Wag -
ner, and Riediger (2016), assessed person– 
situation transactions in an experience sam -
pling study. They showed that personality 
traits predict change and maintenance of 
situations over time: For example, extraver -
sion predicted that participants who were 
alone at a measurement occasion were more 
likely to be with friends at the next, 2 hours 
later (i.e., situation change). In contrast, 
extraversion was not predictive when par -
ticipants already were with friends at a mea -
surement occasion and were still with them 
at the next one (i.e., maintenance of situa -
tion). Intensive-  longitudinal, within-  person 
data can uniquely contribute to understand -
ing temporal and contextual personality 
processes (Fleeson & Law, 2015; Wrzus & 
Roberts, 2017).
Taken together, these advantages provide 
a strong, multifaceted rationale for why it is 