There is little question as to whether or not spiritual intelligence develops over the human lifespan. As will be demonstrated, both theory and empirical evidence support the development of spirituality, and it can be inferred from this literature that spiritual intelligence is also developing over the lifespan, underlying aspects and components of spirituality.

Although many theorists and researchers suggest that spiritual development does not begin until the years of adolescence and young adulthood (e.g., Helminiak, 1987; Parks, 1986, 2000), some argue that such development begins in childhood. Fowler’s (1981) theory of faith development proposes that spiritual development begins at birth, mirroring Piaget’s (1963) theory of development up until the years of childhood, when faith is characterized by a belief in universal justice, reciprocity, and anthropomorphic deities. Although little empirical evidence has been offered to support Fowler’s (1981) theory, it would require an early development of existential thinking and meaning production.

Unfortunately, empirical research on childhood spirituality is quite lacking (Benson, Roehlkepartain, & Rude, 2003). Between 1969 and 1977, British biologist Hardy (1977) collected over 4000 reports of spiritual experiences. Of these reports, Robinson (1977) investigated the experiences that occurred in childhood, finding that 23% occurred before the age of five, with the remainder occurring between the ages of five and fifteen. Others (e.g., Hoffman, 1992, 1998; Maxwell & Tschudin, 1990; Nye, 1998) have collected similar reports of childhood spiritual experiences, demonstrating that “children are capable of having genuine spiritual experiences of divine presence, oneness and interrelatedness, energy pulsating in living and nonliving objects, self as not physical, a sense of continuity between life and death, and much more” (Piechowski, 2001, p. 2). Some of these experiences have been observed in gifted children (Lovecky, 1998; Morelock, 1995; Piechowski, 1998).

Piechowski (2001) noted common themes in these reported experiences, including states of oneness and timelessness as well as a sense of self beyond physical reality (and in some cases beyond this lifetime). Such experiences are highly suggestive of emerging abilities of transcendental awareness and conscious state expansion. In fact, in many of these reports, children described their own techniques for entering higher states of consciousness (Piechowski, 2001). Hay and Nye (1998) identified children aged six to ten years who could describe such strategies, which included mental and physical withdrawal, focusing on breathing, silent gazing, prayer, and contemplating or questioning one’s origins and the origins of the world. Not only are these techniques suggestive of conscious state expansion, but they also involve some level of critical existential thinking.

Gackenbach (1992) maintains that the whole range of higher states of consciousness can be experienced by children, in some cases at an adult level. In fact, she suggests that this evidence may be indicative of consciousness savants (children who are exceptionally skilled at entering higher states; Gackenbach, 1992), which would be more specifically supportive of Gardner’s (1983) second criterion for intelligence. Hay and Nye (1998) have further proposed that children have a natural spiritual inclination, expressed as relational consciousness, which is described as an intentional and natural means of relating to the world, to all things animate and inanimate, to the divine, to others, and to the self. Evans and Wellman (2006) note that research indicates a childhood potential for existential reasoning which is contingent on the development of theory of mind. Although research is limited, it suggests that aspects of spiritual intelligence are emerging in childhood.

Research and theory are far more extensive on the development of spirituality in adolescence and early adulthood. Fowler (1981) proposed a stage of adolescence marked by conformity to faith, during which previously-established belief systems dominate. According to Parks (1986, 2000), between the ages of 17 and 30, individuals develop in their meaning-making abilities, becoming more aware of their conception of reality and shifting towards virtuous behaviours. Helminiak (1987) described a five-stage model of spiritual development, which begins with externally-based and conformist meaning-making in adolescence.

Many authors have argued that adolescence is the time when most individuals first encounter issues of an existential nature, including purpose and meaning (e.g., Chessick, 1996; Damon, Menon, & Bronk, 2003; Ellsworth, 1999; Fitzgerald, 2005; Fry, 1998; Hacker, 1994). It has been suggested that this occurs due to a combination of two events: (1) the development of abstract reasoning during adolescence (Batten & Oltjenbruns, 1999; Piaget, 1963); and (2) personal identity formation (Erikson, 1968) and the related need to define one’s self in adolescence, which may mirror an existential crisis (Fitzgerald, 2005; Scharfstein, 1978; Schlesing, 2005).

Cook and Oltjenbruns (1982) found evidence of significant development in such existential skills between the junior high level and the high school level, noting major differences in the complexity and depth of questions regarding death. Hill and Foster (1996) have suggested that the specific development of hypothetico-deductive reasoning in adolescence also contributes to existential reasoning abilities; and life crises such as sibling bereavement appear to act as a source of further spiritual development (Batten & Oltjenbruns, 1999). In female adolescents in particular, a yearning for meaning may serve as an additional spiritual catalyst (Bruce & Cockreham, 2004). Lavoie and de Vries (2004) found that existential contemplation appears to be present in adolescents and young adults, but remains unresolved in the context of identity development.

Fowler’s (1981) model of faith development describes young adulthood as a time of personal responsibility for existential attitudes. According to Helminiak’s (1987) model, early adulthood is characterized by a conscientious stage, which involves a restructuring of one’s life based on one’s own personal existential views. The two final stages of his model, compassionate and cosmic, deal with the development of more realistic perspectives of one’s self and reality, with self-actualization as a potential outcome (Helminiak, 1987). Alexander et al. (1990) have proposed a theory which accounts for peak or spiritual experiences across the lifespan, suggesting that such experiences describe postrepresentational stages of human development beyond Piaget’s (1963) formal operations stage. Hamel et al. (2003) have also outlined the development of transcendent-actualization, which describes an individual’s growth towards a transpersonal self. A model of existential development has been proposed by Adams (2006), which describes a move towards a greater understanding of one’s existence.

Jung (1964) contended that around midlife, individuals typically begin to turn inward and explore the more spiritual aspects of the self, which culminates and leads to higher levels of self-realization. Wink and Dillon (2002) conducted a longitudinal study of spiritual development, finding an increase in spirituality from late-middle adulthood to older adulthood. Men also displayed a high level of stability in their level of spirituality from middle to late adulthood, while women displayed more fluctuation around middle age (Wink & Dillon, 2002). Fowler’s (1981) model describes a fifth stage of development which reflects a mid-life crisis, characterized by the realization of religious paradoxes and the meaning behind spiritual symbols. His final stage involves some form of enlightenment or “universalizing” faith (Fowler, 1981).

The majority of the literature on spiritual development has focused on individuals in the late stages of life. Erikson’s (1982) theory of ego development originally described later adulthood as a time to attain a sense of integrity, wisdom, and satisfaction with one’s life. Some have suggested that the evolution of one’s identity continues beyond this stage, into a period of gerotranscendence, which is characterized by a resolution of one’s past and the preparation for death (Tornstam, 1989, 2005). In fact, Erikson’s wife recently updated her husband’s original theory to include gerotranscendence as a ninth stage of development (Erikson & Erikson, 1996). According to J. Erikson (1996), the challenge at this stage is the decline in physical and mental abilities often experienced in old age, the resolution of which leads to death acceptance.

Tornstam (1989, 2005) adds that gerotranscendence is further characterized by the following: a redefinition of the perception of such things as time, space, objects, life, and death, which would require a high level of critical existential thinking; an increased sense of affinity with past and future generations, which would require personal meaning production; the transcendence of the ego, of the self, of the physical body, and of material or superfluous interests, requiring a high level of transcendental awareness; and an increase in time spent meditating on life, which may involve methods of conscious state expansion. Essentially, Tornstam (1989, 2005) is describing a phase of human life which involves development towards transcendence, a more “cosmic” outlook, and a reformulation of existential thoughts, which undoubtedly require a moderate to high level of spiritual intelligence. Nevertheless, a factor analysis by Bruyneel, Marcoen, and Soenens (2005) revealed that gerotranscendence is more significantly related to level of spirituality than to age, suggesting that one need not be in the later stages of human development to reach such levels of transcendence or death acceptance.

Gerotranscendence has also been related to increased levels of meaning in old age (Bram, Bramsen, Tilberg, Ploeg, & Deeg, 2006). Other studies have revealed similar correlations between indicators of successful aging (e.g., psychological health, physical health) and measures of personal meaning in the elderly (e.g., Fry, 2000; Reker, 1997; Reker et al., 1987; Zika & Chamberlain, 1992). In particular, Reker et al. (1987) observed that life purpose and future meaning were positively related to perceived psychological and physical well-being in older adults (rs = .21 to .59), while indicators of an existential vacuum were negatively related to well-being (rs = -.14 to -.49). Fry (2000) also observed a significant relationship between psychological well-being and both will to meaning and life purpose in the elderly (rs = .42 to .57). Although these findings are supportive of the adaptive nature of personal meaning, they also speak to a highly developed ability in old age to derive personal meaning from one’s life.

When viewed chronologically, the literature is highly supportive of the development of spiritual intelligence across the lifespan. Childhood appears to be spotted with spiritual experiences, some of which actually result from developing abilities of conscious state expansion, transcendental awareness, and premature existential thinking. During adolescence and young adulthood, we see an expansion of all spiritual capacities, resulting in part from identity formation and the emergence of abstract reasoning. Development continues throughout adulthood, as abilities deepen and contribute to the awareness of a transpersonal or transcendent self following self-actualization. Finally, in later adulthood, we see abilities peak in many individuals as death approaches.

This is not to say, however, that abilities cannot peak in earlier stages of human development. As suggested by Noble (2000, 2001) and Vaughan (2002), spiritual experiences throughout the lifespan contribute to the individual development of spiritual intelligence. Although the research has demonstrated that both traumatic events and existential crises contribute to such development (e.g., DeCarvalho, 2000; Decker, 1993; Van Kamm, 1969), the catalysts are by no means exclusively negative. Deslauriers (2000) has stressed the critical role of dreamwork in the development of both emotional and spiritual capacities, including metaphoric thinking, increased empathy, and better understanding of the mind-body connection. He adds that dreams provide an effective medium for spiritual forms of self-actualization and the attainment of meaning, whether that meaning is produced immediately or following contemplation (Deslauriers, 2000). It is maintained that dreamwork is one of many positive experiences which may contribute to the development of spiritual intelligence.

Evidence, although limited, also suggests the existence of individuals (both children and adults) who are gifted and/or highly skilled in their spiritual abilities (Emmons, 2000a; Gackenbach, 1992; Holmes et al., 1993; Lehmann et al., 2001; Lovecky, 1998; Morelock, 1995; Piechowski, 1998). Gardner (1997, 1999) himself suggested that examples of individuals with a high spiritual intelligence are easy to find, noting philosophers, theologians, and religious/ spiritual leaders throughout history. Whether or not true end-states actually exist remains unknown, as too little is understood about their full potential. Furthermore, modern and developed societies tend not to foster spiritual or existential abilities. As such, it would be premature to attempt to define, in detail, the end-state performances of each of the abilities. Nevertheless, general notions of end-states have been suggested.