Aresearcher hides the baby's toy under a cloth in location a as the baby watches. the baby finds it easily. the researcher again hides the toy as the baby watches, again in location a. the baby finds it easily. then the researcher hides the toy under a cloth in location b. although the baby saw the toy hidden in location b, the baby still looks in location a. this cognitive error is claimed to demonstrate . the child is egocentric. b. the baby lacks cognitive flexibility. c. the child has developed "theory of mind"d. the child has not yet fully developed object permanence.

d. The child has not yet fully developed object permanence.                                

Explanation:

Object permanence: In psychology, the term object permanence is being used in the theory of cognitive development which was proposed by Jean Piaget.

According to Piaget, the object permanence occurs at the sensorimotor stage that starts from the birth of a child and lasts through two years of age.

Object permanence is defined as a child's understanding that an object continues to exist even though the object cannot be perceived i.e, heard, sensed, toughed, seen, etc.

In the question above, the cognitive error is claimed to demonstrate that the child has not yet fully developed object permanence.

answer; the above statement is (true);