838 vIII. EMERGING  ISSuES AND  NEW  DIRECTIONS
began as a methodological interest. As a 
young graduate student, my (S. V.) first paper 
received a review criticizing my use of peer 
reports to measure personality. “The best 
measure of a person’s personality is the per -
son’s self-  report,” the reviewer wrote. “Oth -
erwise, the whole enterprise of personality 
assessment seriously needs to rethink itself.” 
As a naive and idealistic graduate student, 
this struck me as a bold statement. Given the 
dearth of research on the topic, the accuracy 
of self- versus peer-  reports was (and is) an 
empirical question. Indeed, it seemed like 
the reviewer was arguing that self-  reports 
are the best measure of personality because 
concluding otherwise would have grave im -
plications for researchers. Perhaps this was a 
sign of my irreverence, but it seemed entirely 
plausible to me that personality researchers 
had been relying mainly on self-  reports due 
to convenience rather than strong empirical 
evidence of their superiority.
This is, of course, a fundamental method -
ological question: What is the best way to 
measure personality? The early days of per -
sonality psychology provided a good deal 
of fodder for investigating this question: 
thousands of self- and peer-  reports on per -
sonality trait items that could be examined 
for their factor structure, agreement, halo 
effects, and so forth. However, the investi -
gation of the accuracy of self- and peer re -
ports of personality did not become a major 
topic of research until a few decades later, 
when accuracy research became popular 
(Funder, 1995). Evaluating the accuracy of 
self- reports of personality, in particular, 
presented new methodological challenges, 
which we describe in the next section. These 
methodological challenges likely account 
for the dearth of studies examining the ac -
curacy of self-  reports: The amount of effort 
required to obtain a valid criterion measure 
is daunting. Some have recommended avoid -
ing the question altogether due to the dif -
ficulty and inherent murkiness of identify -
ing a valid non-self-  report criterion measure 
for personality, but it is hard to argue that 
this question is not worthy of gargantuan ef -
forts. Indeed, the stakes could not be high -
er for personality research. Identifying the 
circumstances under which self-  reports are 
(not) valid could impact most uses of person -ality measures in both scientific and applied 
contexts.
As important as the methodological im -
plications of self-  knowledge are, however, it 
would be a mistake to think of the accuracy 
of self-  reports as a purely methodological 
matter. As we mentioned earlier, many theo -
retical insights can be gleaned from studying 
self- knowledge. Indeed, because the capac -
ity for self-  awareness is so fundamental to 
the human experience (Robins, Chapter 26, 
this volume), understanding when people 
excel at this and when they fail is necessary 
for understanding the human mind. In this 
chapter, we review the evidence concerning 
how good we are at self-  reflection, individ -
ual differences in self-  insight, the correlates 
and consequences of self-  insight, and poten -
tial ways to improve self-  insight. Although 
this topic is as old as recorded history, there 
is surprisingly little empirical research on it. 
Thus, we also discuss unresolved questions 
and future directions in the study of self- 
knowledge.
What Do We Know When We 
Know  Ourselves?
There are entire sections of this handbook 
dedicated to delineating the different units 
of personality. In his classic article, McAd -
ams (1995; see also, McAdams, Chapter 
5, this volume) famously classified some of 
these units into three levels: Traits  (Level 1); 
goals, motives, and contextualized patterns 
(Level 2); and life stories  (Level 3). However, 
when one considers the various units of per -
sonality, there are interesting questions to be 
asked about self-  knowledge for each of these 
units.
Perhaps the cheapest form of self- 
knowledge is knowing one’s traits,  or one’s 
general tendencies with respect to behavior, 
thoughts, and feelings. Are you the kind of 
person who complains a lot, who cannot re -
sist temptation, who prefers to have a rou -
tine, who ruminates? Knowing these things 
about oneself is not trivial, but as McAdams 
argued, it barely skims the surface. We would 
not think of someone who can accurately de -
scribe their typical level of the Big Five traits 
and facets, but nothing else about themself, 