812 vIII. EMERGING  ISSuES AND  NEW  DIRECTIONS
Electronically Activated Recorder  (EAR)
Mehl and his colleagues have developed a 
naturalistic observation methodology that 
unobtrusively samples thin slices of auditory 
behavior in vivo (Mehl, Pennebaker, Crow, 
Dabbs, & Price, 2001). The electronically 
activated recorder (EAR), an audio record -
er, intermittently records snippets of ambi -
ent sounds (e.g., 30 seconds, five times per 
hour). Participants carry the EAR device 
(initially an analog microcassette recorder, 
then a digital voice recorder, now a smart -
phone app) on them as they go about their 
days. The recorder yields a series of sound 
bites that, together, form an acoustic diary 
of participants’ days as they unfolded. The 
ambient sound recordings are then coded for 
their momentary location (e.g., at home, at 
work, at a bar), activities (e.g., eating, social -
izing, watching TV), and interactions (e.g., 
alone, with one person, in a group) (Kaplan 
et al., 2020).
The EAR method has been successfully 
used in age groups ranging from childhood 
to old age and with different healthy and 
clinical populations (Alisic, Barrett, Bowles, 
Conroy, & Mehl, 2015; Mehl, Robbins, & 
Deters, 2012). Practical recommendations 
for how to use the EAR, including infor -
mation on the ethics of unobtrusive audio 
recording and practices for protecting the 
privacy of participants and their interaction 
partners, are available at an Open Science 
Framework (OSF) EAR Repository curated 
by Megan Robbins: https://osf.io/n2ufd.  
The power of the EAR lies in collecting au -
thentic, real-life observational data relative -
ly unobtrusively. In preserving a high degree 
of naturalism at the level of the raw data, 
it resembles ethnographic methods; through 
its sampling, it protects privacy and enables 
large(r) empirical studies (Mehl, 2017).
In a series of studies, Mehl and colleagues 
have shown that (1) a broad spectrum of be -
haviors can be assessed reliably and with low 
levels of reactivity from the sampled ambient 
sounds (Mehl & Holleran, 2007); (2) these 
behaviors show large between-  person vari -
ability and good temporal stability (Mehl & 
Pennebaker, 2003); and (3) they have good 
convergent validity with measures of theo -
retically related constructs such as the Big 
Five (Mehl, Gosling, & Pennebaker, 2006), subclinical depression (Mehl, 2006), narcis -
sism (Holtzman, Vazire, & Mehl, 2010), 
and well-being (Mehl, Vazire, Holleran, & 
Clark, 2010).
A few studies speak directly to the meth -
od’s added measurement value. For exam -
ple, in a binational EAR study, American 
participants reported being more  talkative 
than their Mexican counterparts, but they 
actually spent considerably less  time talk -
ing (Ramírez-  Esparza, Mehl, Álvarez-  
Bermúdez, & Pennebaker, 2009). In another 
study, Mehl and colleagues (2007) estimat -
ed that, counter to the pervasive idea that 
women are more talkative than men, both 
sexes speak on average about 16,000 words 
per day. Furthermore, Vazire and Mehl 
(2008) used the objective time-use estimates 
that the EAR provides (e.g., percentage of 
time spent alone or laughing) to show that 
self- and informant reports predict actual 
behavior with comparable precision, but 
that each one has unique predictive validity. 
Finally, Tenney, Vazire, and Mehl (2013), 
showed that self-  knowledge, operational -
ized as the congruence between participants’ 
beliefs about how they behave and their ac -
tual EAR-  assessed behavior, was positively 
related to how friends rated their relation -
ship with them.
In summary, the strength of the EAR lies 
in its ability to (1) provide ecological, behav -
ioral criteria independent of self-  report, (2) 
assess subtle and habitual behaviors that eas -
ily escape awareness (e.g., automatic word 
use, subtle expressive behaviors; e.g., Mehl, 
Raison, Pace, Arevalo, & Cole, 2017), and 
(3) limit response bias around the measure -
ment of evaluative (i.e., prosocial or moral) 
behavior (Bollich et al., 2016). An important 
next step is to combine the EAR’s “outside” 
observer’s perspective with the person’s “in -
side” experiential (i.e., cognition, emotion) 
perspective through coupled EAR and ex -
perience sampling. Simine Vazire’s PAIRS 
study provides unique data in this regard 
(Finnigan & Vazire, 2018; Wilson, Thomp -
son, & Vazire, 2017).
Smartphone  Sensing
The diffusion of smartphones into all areas 
of our lives has opened up powerful ways 
of measuring behavior passively and objec -