Introduction

Although various forms of self-knowledge and self-awareness are thought to be present in human infants (Neisser, 1988; Stern, 1985), the question of selfawareness in nonhuman primates has been overshadowed by discussion of their capacity for mirror self-recognition (Gallup, 1977a, 1985; Suarez & Gallup, 1981). Evidence for mirror self-recognition (MSR) via passing the mark test and/or examining body parts not visible without a mirror have been obtained for each great ape species (Gallup, 1970; Hyatt & Hopkins, SAAH15; Miles, SAAH16; Patterson & Cohn, SAAH17; Suarez & Gallup, 1981). In contrast, evidence for MSR in monkeys is much more questionable (Anderson, SAAH21; Gallup, SAAH3): Self-examination using the mirror is typically absent, and mark-directed behaviors during the mark test are infrequent and different in form than that seem in the apes (e.g., Itakura, 1987; Thompson & Boatright-Horowitz, SAAH22).

The rationale for using the mark test in the assessment of self-recognition is that the individual must have a mental representation of the self that he or she understands to be reflected in the mirror (Gallup, 1988). The presence of the mark is a violation of that internal representation, and therefore is a novelty to which the individual's behavior is directed.

Macaques may have failed to provide evidence for MSR for reasons other than a failure to have an internal representation of the self. First, few subjects have been used in the tests of self-recognition, ranging from one (Gallup, 1977a) to four (Gallup, 1970) of any particular species.

Introduction

Darwin's conjecture that morality is an epiphenomenon of intelligence is consistent with increasing evidence that self-awareness depends upon cognitive and affective capacities present in only a few species. The connection between self-awareness and morality, of course, is that conscience is a manifestation of self-awareness. If we follow Darwin's lead and compare the manifestations of self-awareness and their development in species closely related to humans, we may be able to begin to trace the evolution of self-awareness. In order to compare kinds and degrees of self-awareness, of course, we need a system for classifying the phenomenon and a method for diagnosing its manifestations. Ideally the classification system will allow us to identify a broad range of selfrelated phenomena so that we can compare many species and thereby reconstruct the evolutionary history of self-awareness and self-knowledge.

This volume grew out of a 1991 conference on self-awareness in monkeys, apes, and humans at Sonoma State University in Rohnert Park, California. A major goal of the conference was to bring together investigators who espoused opposing viewpoints on a variety of issues relating to self-awareness.

Psychoneuroimmunology contends that important relationships exist among behavior, the psychosocial environment, prior experience, and the immune system. These relationships are reflected, for example, in increased morbidity and mortality among the recently bereaved. The rapidly growing number of studies supporting psychosocial/immune relationships in the field of psychoneuroimmunology generally support the biopsychosocial model proposed by Engel (1977) many years ago. This model focused on the role of behavioral and psychosocial factors in the disease process. In spite of the many observations relating psychosocial factors to either disease processes or immunity (see Ader, Felten, & Cohen, 1991, for recent reviews of this rapidly progressing field), there remain questions and doubts regarding the role of these factors by many in the medical community (Angell, 1985). Much of the difficulty in drawing clear relationships between behavior and health outcome is related to the problems inherent in the study of human populations. Appropriate animal models can often resolve some of these dilemmas. This chapter focuses primarily on studies in nonhuman primates that have a particular relevance for loss and ensuing grief in humans. The reader is referred to chapter 11 in this volume by Irwin and Pike, which considers studies of immune function associated with loss in humans, and chapter 10, by Kim and Jacobs, which covers neuroendocrine function in humans during the bereavement process.

Although the relationship between bereavement and increased morbidity and mortality has been well documented (W. Stroebe & Stroebe, 1987; see also this volume), the biological mechanism(s) by which this experience leads to increased risk for medical illness is not clear.