▁by ▁the ▁network . ▁However , ▁McC los key ▁and ▁C ohen ▁noted ▁the ▁network ▁was ▁no ▁longer ▁able ▁to ▁properly ▁answer ▁the ▁ones ▁addition ▁problems ▁even ▁after ▁one ▁learning ▁trial ▁of ▁the ▁tw os ▁addition ▁problems . ▁The ▁output ▁pattern ▁produced ▁in ▁response ▁to ▁the ▁ones ▁facts ▁often ▁res emble d ▁an ▁output ▁pattern ▁for ▁an ▁incorrect ▁number ▁more ▁closely ▁than ▁the ▁output ▁pattern ▁for ▁a ▁correct ▁number . ▁This ▁is ▁considered ▁to ▁be ▁a ▁dr astic ▁amount ▁of ▁error . ▁Furthermore , ▁the ▁problems ▁ 2 + 1 ▁and ▁ 2 + 1 , ▁which ▁were ▁included ▁in ▁both ▁training ▁sets , ▁even ▁showed ▁dram atic ▁dis ruption ▁during ▁the ▁first ▁learning ▁tri als ▁of ▁the ▁tw os ▁facts . ▁▁ ▁Ex periment ▁ 2 : ▁Rep lication ▁of ▁Bar nes ▁and ▁Under wood ▁( 1 9 5 9 ) ▁study ▁ ▁In ▁their ▁second ▁connection ist ▁model , ▁McC los key ▁and ▁C ohen ▁attempted ▁to ▁rep licate ▁the ▁study ▁on ▁retro active ▁inter ference ▁in ▁humans ▁by ▁Bar nes ▁and ▁Under wood ▁( 1 9 5 9 ). ▁They ▁trained ▁the ▁model ▁on ▁A - B ▁and ▁A - C ▁lists ▁and ▁used ▁a ▁context ▁pattern ▁in ▁the ▁input ▁vector ▁( input ▁pattern ), ▁to ▁differenti ate ▁between ▁the ▁lists . ▁Specifically ▁the ▁network ▁was ▁trained ▁to ▁respond s ▁with ▁the ▁right ▁B ▁response ▁when ▁shown ▁the ▁A ▁stim ulus ▁and ▁A - B ▁context ▁pattern ▁and ▁to ▁respond ▁with ▁the ▁correct ▁C ▁response ▁when ▁shown ▁the ▁A ▁stim