▁of ▁a ▁class ▁of ▁models ▁known ▁as ▁hierarchy ▁of ▁effects ▁models ▁or ▁hier arch ical ▁models , ▁all ▁of ▁which ▁imply ▁that ▁consum ers ▁move ▁through ▁a ▁series ▁of ▁steps ▁or ▁stages ▁when ▁they ▁make ▁purchase ▁dec isions . ▁These ▁models ▁are ▁linear , ▁sequ ential ▁models ▁built ▁on ▁an ▁assumption ▁that ▁consum ers ▁move ▁through ▁a ▁series ▁of ▁cogn itive ▁( th inking ) ▁and ▁affect ive ▁( fe eling ) ▁stages ▁cul min ating ▁in ▁a ▁behaviour al ▁stage ▁( do ing ▁e . g . ▁purchase ▁or ▁trial ) ▁stage . ▁ ▁The ▁steps ▁proposed ▁by ▁the ▁A ID A ▁model ▁are ▁as ▁follows : ▁▁ ▁Att ention ▁– ▁The ▁consumer ▁becomes ▁aware ▁of ▁a ▁category , ▁product ▁or ▁brand ▁( us ually ▁through ▁advert ising ) ▁ ↓ ▁ ▁Interest ▁ ▁– ▁The ▁consumer ▁becomes ▁interested ▁by ▁learning ▁about ▁brand ▁benefits ▁& ▁how ▁the ▁brand ▁fits ▁with ▁l ifest yle ▁ ↓ ▁ ▁Des ire ▁ ▁– ▁ ▁The ▁consumer ▁develop s ▁a ▁favor able ▁disposition ▁towards ▁the ▁brand ▁ ↓ ▁ ▁Action ▁– ▁The ▁consumer ▁forms ▁a ▁purchase ▁intention , ▁sh ops ▁around , ▁eng ages ▁in ▁trial ▁or ▁makes ▁a ▁purchase ▁ ▁Some ▁of ▁the ▁contemporary ▁variants ▁of ▁the ▁model ▁replace ▁attention ▁with ▁aw aren ess . ▁The ▁common ▁thread ▁among ▁all ▁hier arch ical ▁models ▁is ▁that ▁advert ising ▁oper ates ▁as ▁a ▁stim ulus ▁( S ) ▁and ▁the ▁purchase ▁decision ▁is ▁a ▁response ▁( R ). ▁In ▁other ▁words , ▁the ▁A ID A