insecure-resistant/ambivalent attachment: A pattern of attachment in which an infant’s anxiety and uncertainty are evident, as when the infant becomes very upset at separation from the caregiver, such infants both resist and seek contact on reunion.

insecure-avoidant attachment: A pattern of attachment in which an infant avoids connection with the caregiver, as when the infant seems not to care about the caregiver’s presence, departure, or return.

still-face technique: An experimental practice in which an adult keeps his or her face unmoving and expressionless in face-to-face interaction with an infant.

social smile: A smile evoked by a human face, normally first evident in full-term infants about 6 weeks after birth.

self-awareness: A person’s realization that he or she is a distinct individual whose body, mind, and actions are separate from those of other people.

stranger wariness: An infant’s expression of concern—a quiet stare while clinging to a familiar person, or a look of fear—when a stranger appears.

attachment: According to Ainsworth, “an affectional tie” that an infant forms with a caregiver—a tie that binds them together in space and endures over time.

secure attachment: A relationship in which an infant obtains both comfort and confidence from the presence of his or her caregiver.

temperament: Inborn differences between one person and another in emotions, activity, and self-regulation. It is measured by the person’s typical responses to the environment.

synchrony: A coordinated, rapid, and smooth exchange of responses between a caregiver and an infant.

separation anxiety: Distress when a familiar caregiver leaves; most obvious between 9 and 14 months.

disorganized attachment: A type of attachment that is marked by an infant’s inconsistent reactions to the caregiver’s departure and return.

allocare: Literally, “other-care”; the care of children by people other than the biological parents.

social learning: The acquisition of behavior patterns by observing the behavior of others.

working model: In cognitive theory, a set of assumptions that the individual uses to organize perceptions and experiences. For example, a person might assume that other people are trustworthy and be surprised if someone lies, cheats, or betrays a confidence.

proximal parenting: Caregiving practices that involve being physically close to the baby, with frequent holding and touching.

autonomy versus shame and doubt: Erikson’s second crisis of psychosocial development. Toddlers either succeed or fail in gaining a sense of self-rule over their actions and their bodies.

trust versus mistrust: Erikson’s first crisis of psychosocial development. Infants learn basic trust if the world is a secure place where their basic needs (for food, comfort, attention, and so on) are met.

distal parenting: Caregiving practices that keep some distance from a baby, such as providing toys, food, and face-to-face communication with minimal holding and touching.

social referencing: Seeking information about how to react to an unfamiliar or ambiguous object or event by observing someone else’s expressions and reactions. That other person becomes a social reference.

strange situation: A laboratory procedure for measuring attachment by evoking infants’ reactions to the stress of various adults’ comings and goings in an unfamiliar playroom.