Difficulties in
understanding that
objects outside of their
field of vision still exist; object permanence
Preoperational
Ages 2-7 years
Usually believes that everyone
thinks, sees, and believes as they do
(egocentrism); have the ability to think
representationally/symbolically; able
to use basic language.
Concrete
Operational
Ages 7-11 years
Are able to understand that an object's size and shape do not directly relate to the quantity or
amount that it can hold; can personify objects in thoughts and speech
Formal Operational
Mary Ainsworth
Infant Psychology:
Attachment Types
Experiment: "The Strange Situation"
A baby and its mother are brought into a room with toys. After a few minutes, a stranger comes in, and after a few minutes
more, then mother leaves. Shortly thereafter, the mother returns. The baby is observed for the duration of all this time, to
judge and categorize their attachment types based on their reactions to each and every stimuli (the new room, the stranger,
their mother leaving and returning, the toys)