Attachment refers to the affectional bond between two people, especially the bond formed between infants and their caregivers. This bond is important for survival as it ensures close proximity and helps infants feel secure. Psychologists have identified phases of attachment development from birth to one year, including an indiscriminate phase and specific attachment phase. The "Strange Situation" experiment studied how infants respond to separation from and reunion with caregivers, identifying secure, anxious-avoidant, and anxious-resistant attachment styles based on the infant's behaviors. Long-term effects of early attachments may influence relationships later in life.