A-not-B error
Encyclopedia
A-not-B error is a phenomenon uncovered by the work of Jean Piaget
in his theory of cognitive development
of children. The A-not-B error is a particular error made by infants during substage 4 of their sensorimotor stage.
A typical task goes like this: An experimenter hides an attractive toy under box "A" within the baby's reach. The baby searches for the toy, looks under box "A", and finds the toy. This activity is usually repeated several times (always with the researcher hiding the toy under box "A"). Then, in the critical trial, the experimenter moves the toy under box "B", also within easy reach of the baby. Babies of 10 months or younger typically make the perseverance error, meaning they look under box "A" even though they saw the researcher move the toy under box "B", and box "B" is just as easy to reach. This demonstrates a lack of, or incomplete, schema
of object permanence
. Children of 12 months or older typically do not make this error.
Smith and Thelen used a dynamic systems theory approach to the A-not-B task. They found that various components of the activity (strength of memory trace, salience of targets, waiting time, stance) combine in the "B"-trial (where the object is hidden in the "B" location rather than "A") so the child either correctly or incorrectly searches for the toy. They experimentally manipulated the task to see if they could make 10-month-old babies (who typically make the perseverative error of searching at "A") perform like 12-month-old babies (who typically search correctly). Changing the stance of the baby (sitting or standing) was one manipulation they found could make the 10-month-old search correctly. Just standing instead of sitting for the "B"-trial made the prior experience of searching in location "A" less salient to the child, who then searched correctly. The researchers concluded that the length of wait time was one of the crucial elements of the task that is influenced by age.
Jean Piaget
Jean Piaget was a French-speaking Swiss developmental psychologist and philosopher known for his epistemological studies with children. His theory of cognitive development and epistemological view are together called "genetic epistemology"....
in his theory of cognitive development
Theory of cognitive development
Piaget's theory of cognitive development is a comprehensive theory about the nature and development of human intelligence first developed by Jean Piaget. It is primarily known as a developmental stage theory, but in fact, it deals with the nature of knowledge itself and how humans come gradually to...
of children. The A-not-B error is a particular error made by infants during substage 4 of their sensorimotor stage.
A typical task goes like this: An experimenter hides an attractive toy under box "A" within the baby's reach. The baby searches for the toy, looks under box "A", and finds the toy. This activity is usually repeated several times (always with the researcher hiding the toy under box "A"). Then, in the critical trial, the experimenter moves the toy under box "B", also within easy reach of the baby. Babies of 10 months or younger typically make the perseverance error, meaning they look under box "A" even though they saw the researcher move the toy under box "B", and box "B" is just as easy to reach. This demonstrates a lack of, or incomplete, schema
Schema (psychology)
A schema , in psychology and cognitive science, describes any of several concepts including:* An organized pattern of thought or behavior.* A structured cluster of pre-conceived ideas....
of object permanence
Object permanence
Object permanence is the understanding that objects continue to exist even when they cannot be seen, heard, or touched. It is acquired by human infants between 8 and 12 months of age via the process of logical induction to help them develop secondary schemes in their sensori-motor coordination...
. Children of 12 months or older typically do not make this error.
Competing explanations
Traditionally, this phenomenon has been explained as the child seeing an image and remembering where it was, rather than where it is. Other accounts deal with the development of planning, reaching, and deciding things. There are also behaviorist accounts that explain the behavior in terms of reinforcement. This account argues that the repeated trials with hiding the toy in box "A" is reinforcing that specific behavior, so that the child still reaches for box "A" because the action has been reinforced before. However, this account does not explain the shift in behavior that occurs around 12 months.Smith and Thelen used a dynamic systems theory approach to the A-not-B task. They found that various components of the activity (strength of memory trace, salience of targets, waiting time, stance) combine in the "B"-trial (where the object is hidden in the "B" location rather than "A") so the child either correctly or incorrectly searches for the toy. They experimentally manipulated the task to see if they could make 10-month-old babies (who typically make the perseverative error of searching at "A") perform like 12-month-old babies (who typically search correctly). Changing the stance of the baby (sitting or standing) was one manipulation they found could make the 10-month-old search correctly. Just standing instead of sitting for the "B"-trial made the prior experience of searching in location "A" less salient to the child, who then searched correctly. The researchers concluded that the length of wait time was one of the crucial elements of the task that is influenced by age.