. ▁The ▁Music ▁Per ception ▁review ▁by ▁Ian ▁Cross ▁and ▁the ▁article ▁by ▁Sch ellen berg ▁provide ▁introdu ctions ▁to ▁the ▁theory . ▁ ▁Basic ▁mel od ic ▁structures ▁ ▁General ▁claims ▁The ▁Analysis ▁and ▁C ogn ition ▁of ▁Basic ▁Mel od ic ▁Struct ures : ▁The ▁Imp lication - Real ization ▁Model ▁begins ▁with ▁two ▁general ▁claims . ▁The ▁first ▁is ▁given ▁by ▁" two ▁universal ▁formal ▁hypoth eses " ▁describing ▁what ▁listen ers ▁expect . ▁The ▁process ▁of ▁mel ody ▁per ception ▁is ▁based ▁on ▁" the ▁real ization ▁or ▁den ial " ▁of ▁these ▁hypoth eses ▁( 1 9 9 0 , ▁ 3 ): ▁▁ ▁A ▁+ ▁A ▁→ ▁A ▁ ▁A ▁+ ▁B ▁→ ▁C ▁ ▁Here , ▁A , ▁B , ▁and ▁C ▁are ▁mel od ic ▁items ▁of ▁either ▁form , ▁interval ▁patterns , ▁or ▁pitch es . ▁A ▁+ ▁A ▁→ ▁A ▁indicates ▁that ▁hearing ▁two ▁similar ▁items ▁yields ▁an ▁expectation ▁of ▁repet ition ▁of ▁the ▁item . ▁A ▁+ ▁B ▁→ ▁C , ▁on ▁the ▁other ▁hand , ▁indicates ▁that ▁hearing ▁two ▁different ▁items ▁yields ▁an ▁expected ▁change ▁in ▁the ▁imp lied ▁item . ▁ ▁The ▁second ▁claim ▁is ▁that ▁the ▁" forms " ▁above ▁function ▁to ▁provide ▁either ▁closure ▁or ▁non closure . ▁N arm our ▁goes ▁on ▁to ▁describe ▁the ▁five ▁mel od ic ▁arch et ypes ▁of ▁his ▁theory : ▁▁ ▁process ▁[ P ] ▁or ▁iteration ▁( dup lication ) ▁[ D ] ▁( A ▁+ ▁A ▁without ▁closure )