No-one can understand someone better than the person him/herself

The intuition that we have privileged and unrestricted access to ourselves – that we inevitably know who we are, how we feel, what we do, and what we think – is very compelling. Here, we review three types of evidence about the accuracy of self-perceptions of personality and conclude that the glass is neither full nor empty. First, studies comparing self-perceptions of personality to objective criteria suggest that self-perceptions are at least tethered to reality – people are not completely clueless about how they behave, but they are also far from perfect. Second, studies examining how well people’s self-perceptions agree with others’ perceptions of them suggest that people’s self-views are not completely out of synch with how they are seen by those who know them best, but they are also far from identical. Third, studies examining whether people know the impressions they make on others suggest that people do have some glimmer of insight into the fact that others see them differently than they see themselves but there is still a great deal people do not know about how others see them. The ﬁndings from all three approaches point to the conclusion that self-knowledge exists but leaves something to be desired. The status of people’s self-knowledge about their own personality has vast implications both for our conception of ourselves as rational agents and for the methods of psychological inquiry.At times I fancy, Socrates, that anybody can know himself; at other times the task appears to be very difﬁcult. – AlcibiadesHow clearly can we see ourselves? Are we our own best experts? The intuition that we have privileged and unrestricted access to ourselves – that we inevitably know who weare, how we feel, what we do, and what we think – is very compelling. After all, who knows better what it’s like to be you than you do? Certainly, our perceptions of ourown personality are vivid, but how accurate are they? Do we know, better than anybody else, what we are like?The question of whether we know ourselves better than anybody else knows us has been a prominent theme in mainstream culture, including in music (‘I’ll be your mirror⁄Reﬂect what you are ⁄In case you don’t know’; Velvet Underground, 1996), literature (‘I know you, buddy boy, know you better than you know your own self’; Nobody’s Fool, Richard Russo, 1994, p. 488), and ﬁlm (‘No, I don’t think you’re paranoid. I think you’re the opposite of a paranoid. I think you walk around with the insane delusion that people like you.’; Deconstructing Harry, Woody Allen, 1996). This preoccupation with self-knowledge (or lack thereof) is not new, indeed it has been around as long as history itself. Starting with the Oracle at Delphi, self-knowledge has been a documented interest of philosophers, including such exalted thinkers as Socrates, Plato, Descartes, Hume, and Nietzsche. Self-knowledge has also been a major theme in popular books, including the Dalai Lama’s How to See Yourself as You Really Are (2006). Finally, self-knowledge themes are still prominent in the scholarly writings of contemporary philosophers (e.g., Doris, Social and Personality Psychology Compass 4/8 (2010): 605–620, 10.1111/j.1751-9004.2010.00280.x ª 2010 The Authors Journal Compilation ª 2010 Blackwell Publishing Ltdforthcoming; Haybron, 2008; Mele, 2001; Schwitzgebel, 2008; Shoemaker, 1996; Tiberius, 2008). Despite millennia of concerted attention, however, the question remains: How well do people know themselves?To psychologists this question is, at heart, an empirical one. Indeed, Freud saw as a major aim of psychological research ‘to prove that the ego is not master in its own house’, and with not a little megalomania of his own, described this as the ‘third and most wounding blow’ to human megalomania, after Copernicus’s discovery that our planet is not at the center of the universe and Darwin’s discovery that our species is descended from other animals (1966; p. 353). Since then, many psychologists have shared Freud’s skepticism about people’s capacity for self-knowledge. For example, behaviorists have been notoriously dismissive of people’s capacity for self-insight, Nisbett and Wilson (1977) famously asserted that people are ‘telling more than they can know’ about themselves, and the literature on positive illusions and self-enhancement paints people as blissfully ignorant about their own personality traits (Brown & Dutton, 1995; Taylor & Brown, 1988).So, has psychology shown that people do not know themselves? Not exactly. To judge from our methods, the ﬁeld of social and personality psychology still has plenty of faith in self-perceptions. As Swann and Pelham point out, ‘if we are to question the selfreports of participants, much, if not most, of results of research on the self becomes suspect’. (Swann & Pelham, 2002; p. 228). Indeed, the vast majority of all social and personality research relies on self-reports (Gosling, Vazire, Srivastava, & John, 2004; Vazire, 2006) and thus would be called into question if we were to conclude that people lack self-insight. As one of us was once admonished by the ubiquitous Reviewer A, ‘the best criterion for a target’s personality is his or her self-ratings […] Otherwise, the whole enterprise of personality assessment seriously needs to re-think itself’ (personal communication, 2003). Which is the correct view? Are people hopelessly deluded about themselves, or can we trust people’s self-perceptions of their personality to be an accurate reﬂection of what they are like? In this review, we examine the evidence for one particular type of self-knowledge: people’s knowledge of their own personality. Clearly, this is only one of several types of self-knowledge (Wilson, 2002; Wilson & Dunn, 2004); we could also ask whether people are aware of their reasons or motives (Thrash, Elliot, & Schultheiss, 2007), mental states (Dijksterhuis & Nordgren, 2006), or emotions (Wilson & Gilbert, 2005). For a broader review of self-knowledge, we recommend Wilson’s (2009) excellent paper. Here, we focus our attention on self-knowledge of personality.