Scholars throughout the world have advanced the principle that society cannot survive unless individuals establish and sustain basic levels of interpersonal trust (O'Hara, 2004; Uslander, 2002; Volker, 2002; Warren, 1999). Furthermore, interpersonal trust has been regarded as a crucial facet of human functioning since the very beginning of psychology as a discipline (Erikson, 1963; Hartshorne, May, and Maller, 1929). There is a growing body of evidence demonstrating that interpersonal trust across the course of development is linked to: physical health (e.g., Barefoot, Maynard, Beckham, Brammett, Hooker, and Siegler, 1998), cognitive functioning (e.g., Harris, 2007; Imber, 1973), social functioning (e.g., Rotenberg, Boulton, and Fox, 2005; Rotter, 1980), and the development and maintenance of close relationships (e.g., Holmes and Remple, 1989). Certainly, interpersonal trust plays a crucial role for physical health and psychosocial functioning during childhood and adolescence. Furthermore, because of developmental trajectories, interpersonal trust during childhood and adolescence should affect individuals by adulthood both directly (i.e., early trust affects later trust) and indirectly (i.e., via earlier links to health and psychosocial functioning). Unfortunately, there is a dearth of research on this topic. Indeed, most contemporary psychology books on childhood, adolescence, or developmental psychology fail to include any reference to interpersonal trust at all.

The purpose of this book is to redress that oversight and establish interpersonal trust during childhood and adolescence as a priority within the discipline of psychology. The book includes a selective set of chapters that address interpersonal trust during onset of adulthood as well as late adolescence.

The recent movement in positive psychology has beckoned a call for more attention to the strengths and positive aspects of human functioning (Seligman and Csikszentmihalyi, 2000). Much of the intellectual basis for this recent movement in psychology stems from a reemergence of an interest in philosophical perspectives on what constitutes a good and moral life. Not surprisingly, scholars have long noted that prosocial tendencies (e.g., kindness, caring, helping) and trust are basic elements of persons with strong moral and good character (e.g., Aristotle, 1980; Blum, 1980; Mayeroff, 1971; Noddings, 2003; Rotter, 1980). The belief that trust and prosocial tendencies are basic elements of moral character also extends the notion that these are markers of close, interpersonal relationships. As Bukowski and Sippola (1996) noted, “particular qualities are essential for ‘morally excellent’ friendships. These qualities include: (a) a deep concern for the other for his or her own sake … (c) high levels of trust and commitment to the relationship” (p. 245). These authors further assert that there are conceptual reasons to expect ties between trust and prosocial tendencies – that, indeed, friendship requires goodness.

In his classic essay, On caring, Milton Mayeroff (1971) eloquently introduces to us the intricate links between caring, helping, trust, and interpersonal relationships.

Trust is a key ingredient in the formation and maintenance of healthy interpersonal relationships. According to Rotter (1967), trust is “an expectancy held by an individual or group that the word, promise, or written statement of another individual or group can be relied upon” (p. 651). Interpersonal trust holds a prominent place in theoretical models of development. Erikson described the key developmental task of infancy as that of learning to see others as trustworthy (Erikson, 1963). The infant's trust in the caregiver is believed to be one of the primary bases in the formation of the attachment bond (Bowlby, 1979). Trust remains important across the life-span. Building a new relationship rests, in part, upon the partners' joint ability to trust the other as they engage in a process of reciprocal disclosure of thoughts, feelings, and life experiences (Rempel, Holmes, and Zanna, 1985). Maintenance of relationships also rests upon trust; relationship disintegration frequently results from either a lack of trust (e.g., romantic jealousy) or an outright betrayal of trust (e.g., infidelity) (Collins and Read, 1990; Feeney, 2005; Mikulincer, 1998). Given the significance of trust in the life-course of the individual, continued empirical research charting the developmental progression of interpersonal trust is necessary.

Interpersonal trust has been viewed as a crucial aspect of social functioning that originates in infant–caregiver interactions and affects psychosocial functioning across the life-span (Armsden and Greenberg, 1987; Erikson, 1963; Waters, Vaughn, Posada, and Kondo-Ikemura, 1995). Researchers have found that children's interpersonal trust is associated with various aspects of their psychosocial functioning. Specifically, trustworthiness in children has been found to be associated with, and longitudinally predictive of, the number of their friendships (Rotenberg, McDougall, Boulton, Vaillancourt, Fox, and Hymel, 2004) and their adjustment to school (Betts and Rotenberg, 2007; Betts, Rotenberg, and Trueman, 2009; Rotenberg, Michalik, Eisenberg, and Betts, 2008). Children's trust beliefs have been found to be associated with honesty (Wright and Kirmani, 1977), lack of depression (Lester and Gatto, 1990), academic achievement (Imber, 1973), and lack of loneliness (Rotenberg, MacDonald, and King, 2004). Rotenberg, Boulton, and Fox (2005) found that the trust beliefs of elementary school children were negatively associated with, and longitudinally predictive of, internalized maladjustment (loneliness, depression, and anxiety). Also, a curvilinear relationship was found whereby children with very high and those with very low trust beliefs were at additional risk for internalized maladjustment. Some researchers (see Chapter 2) have highlighted that interpersonal trust during childhood is dyadic and reciprocal in nature, but there is a scarcity of research addressing this hypothesis.

The notion that trust is crucial to psychosocial functioning has been advanced since the beginning of contemporary psychology (see Simpson, 2007). Erikson (1963) proposed that trust is formed during infancy and affects psychosocial functioning during the life-course. Similarly, attachment theorists propose that infants' trust is a product of their interactions with caregivers that, via its role in a cognitive model (the internal working model [IWM]), affects subsequent social functioning (Armsden and Greenberg, 1987; Bridges, 2003; Waters, Vaughn, Posada, and Kondo-Ikemura, 1995). Researchers have emphasized the role that trust plays in relationships with parents and peers across childhood and adolescence (see Bernath and Feshbach, 1995; Harris, 2007). Also, trust has been regarded as a critical facet of romantic relationships during adulthood (e.g., Holmes and Rempel, 1989; Mikulincer, 1998; Miller and Rempel, 2004).

A major problem confronting a researcher is how to conceptualize and assess interpersonal trust. This type of problem is frequently encountered in the discipline of psychology, where researchers examine constructs that correspond to commonly understood terms or concepts: ones that tap into individuals' naïve notions of psychosocial functioning. As a consequence, the conceptualization of trust is a very thorny problem, because a researcher's conceptualization may not match those commonly held by a social community, thus appearing to be disconnected from social reality. Researchers might attempt to avoid such problems by assessing individuals' perceptions or reports of trust per se. Unfortunately, this method is very limited because the meaning of the measure is unclear.

After reviewing the literature, both academic and nonacademic (e.g., popular media), it has become obvious to me that loneliness is an inherent part of the human condition. Most likely, every person experiences loneliness at some time during the course of his or her life, at least in a transient form. Moreover, loneliness appears to be a cross-cultural phenomena, one identified and examined in an array of countries: Australia (e.g., Renshaw & Brown, 1992), Canada (e.g., Boivin, Hymel, & Bukowski, 1995), Belgium (e.g., Marcoen & Brumagne, 1985), Israel (Margalit & Ben-Dov, in press), and the United States (Cassidy & Asher, 1992). The universality of loneliness may well arise, as Baumeister and Leary's (1995) theory implies, from the universal need for belongingness – the need to establish stable social bonds with others who care. In that context, loneliness is the cognitive and affective reaction to the threat to social bonds. Indeed, loneliness has been regarded in the literature as comprising two related components: (a) a cognitive component, comprising the discrepancy between desired social relationships and actual social relationships, either quantitatively or qualitatively, and (b) an affective component, comprising the negative emotional experiences of disorientation, lostness, and loneliness (see Peplau & Perlman, 1982; Rotenberg, 1994). The chapters in this book are guided by this conceptualization of loneliness, although they vary considerably in the emphasis placed on the two components.

Research supports the conclusion that a stable pattern of loneliness poses a serious threat to an individual's mental health and psychosocial functioning (see McWhirter, 1990).