Final answer:
Infants and toddlers gain trust primarily by having caregivers who provide an organized routine and who are responsive to their needs, promoting a predictable and safe environment supportive of secure attachment and autonomy.
Step-by-step explanation:
An infant or small toddler would MOST likely gain trust in an individual who provides an organized, routine environment. According to Erikson, the establishment of trust is the essential phase of development in infancy, where infants see the world as a safe, predictable place if their needs are consistently met by responsive caregivers. Providing a routine environment helps infants develop a sense of predictability and security. Ainsworth and Bell's attachment theories also support that infants develop a secure attachment through caregivers who are sensitive and responsive to their needs, as demonstrated by the consistent distress when caregivers leave and happiness upon their return. In line with developing autonomy, toddlers who are allowed to make choices and act on their surroundings with a supportive caregiver promote independence and are less likely to experience shame and doubt. Ensuring that infants and toddlers have an opportunity to establish such autonomy within a structured environment contributes to trust and secure attachment formation.