Goldfarb

• 30 Romanian Orphans split into two equal groups
• Group 1

  Was fostered by 4 months of age ( before beginning of critical period )

  By 12 years of age they performed an IQ test and averaged 96 which is a normal IQ
• Group 2

  Group remained in the orphanage for the remainder of the time

  Maternal Deprivation exists in only this group

  By 12 years of age they performed an IQ test and averaged 68 which is below the cut off point for what is considered an intellectual disability
• Goldfarb attempts to establish cause and effect however confounding variables such as bad education and genes were not controlled for