Editing Object permanence (section)

==Early research==
Developmental psychologist Jean Piaget conducted experiments that collected behavioral tests on infants. Piaget studied object permanence by observing infants' reactions when a favorite object or toy was presented and then was covered with a blanket or removed from sight. Object permanence is considered to be one of the earliest methods for evaluating [[working memory]].<ref name=Lowe>{{cite journal|last1=Lowe|first1=Jean|author2=Peggy MacLean |author3=Michele Shaffer |author4=Kristi Watterberg |title=Early Working Memory in Children Born With Extremely Low Birth Weight: Assessed by Object Permanence|journal=Journal of Child|year=2009|volume=24|issue=4|pages=410–415|doi=10.1177/0883073808324533|pmid=19339284|pmc=3071030|id={{ProQuest|621922851}}}}</ref> An infant that has started to develop object permanence might reach for the toy or try to grab the blanket off the toy. Infants that have not yet developed this might appear confused.<ref name=Ellis-Christensen>{{cite web|last=Ellis-Christensen|first=Tricia|title=What Is Object Permanence?|url=http://www.wisegeek.com/what-is-object-permanence.htm|publisher=Conjecture Corporation|access-date=2011-11-21}}</ref> Piaget interpreted these behavioral signs as evidence of a belief that the object had ceased to exist. Reactions of most infants that had already started developing object permanence were of frustration because they knew it existed, but did not know where it was. However, the reaction of infants that had not yet started developing object permanence was more oblivious. If an infant searched for the object, it was assumed that they believed it continued to exist.<ref name="Santrock"/>

Piaget concluded that some infants are too young to understand object permanence. A lack of object permanence can lead to [[A-not-B error]]s, where children reach for a thing at a place where it should not be. Older infants are less likely to make the A-not-B error because they are able to understand the concept of object permanence more than younger infants. However, researchers have found that A-not-B errors do not always show up consistently.<ref name=Sophian>{{cite journal |doi=10.1037/0012-1649.21.6.932 |journal=Developmental Psychology |title=Infants' understanding of visible displacements |last1=Sophian |first1=C. |last2=Yengo |first2=L. |volume=21 |year=1985 |pages=932–941 | issue=6}}</ref> They concluded that this type of error might be due to a failure in memory or the fact that infants usually tend to repeat a previous motor behavior.<ref name="Santrock"/>