Irritability in infants is more than aversive and stressful to parents; it is associated with a variety of developmental problems. Furthermore, although infant irritability does not appear to be a direct contributor to insecure attachment, infant irritability does interact with other maternal stressors such as low social support and low-SES to contribute to an increased risk of insecure attachment (Crockenberg, 1981; van den Boom, 1994). Insecure attachment, in turn, is associated with a variety of negative outcomes (see Belsky and Cassidy, 1994). Of particular concern from a mental health perspective is mounting evidence of links between early insecure attachment and various forms of psychopathology, including conduct disorder, anxiety, and dissociation (see Greenberg, in press). Given these negative outcomes, attempts to better understand infant irritability and to intervene with irritable infants are crucial The proposed study was designed to address the following four questions: (1) Can we successfully intervene with irritable, low- SES infants to reduce infant irritability and to decrease the risk of insecure attachment? (2) Are there changes in patterns of EEG activity among irritable infants associated with intervention? (3) Is change in maternal sensitivity associated with change in maternal "state of mind with regard to attachment"? (4) How do infant irritability, caregiving experiences, and attachment interact to predict toddler behavioral inhibition and internalizing/externalizing behavior? This study will replicate and extend van den Boom's (1994) intervention study which revealed striking effects from a relatively minor intervention. Seventy-five irritable low-SES infants and mothers will participate in three home-based interventions between 6 and 9 months, and 75 irritable low-SES infants and mothers will serve as a control group. Home observations of maternal and infant behavior will be made at 6m (pre-intervention) and 9m (immediate post-intervention). Longer- term intervention effectiveness will be examined with assessments of attachment (12 and 18m), maternal and child behavior (18 and 24m), child behavior problems (CBCL at 24m), and behavioral inhibition (24m). Two additions in the proposed study will permit examination of a series of important questions: Infant EEG will be measured at 6, 12, and 24m, permitting examination of physiological changes associated with intervention. Maternal Attachment Interviews (at 6 and 12m) will permit examination of several important questions.