Thesupermarketisdesignedtolurecustomersintospendingasmuchtimeaspossiblewithinitsdoors.Thereasonforthisissimple:Thelongeryoustayinthestore,themorestuffyou'llsee,andthemorestuffyousee,themoreyou'llbuy.Andsupermarketscontainalotofstuff.Theaveragesupermarket,accordingtotheFoodMarketingInstitute,carriessome44,00differentitems,andmanycarrytensofthousandsmore.Thesheervolumeofavailablechoiceisenoughtosendshoppersintoastateofinformationoverload.Accordingtobrain-scanexperiments,thedemandsofsomuchdecision-makingquicklybecometoomuchforus.Afterabout40minutesofshopping,mostpeoplestopstrugglingtoberationallyselective,andinsteadbeginshoppingemotionally-whichisthepointatwhichweaccumulatethe50percentofstuffinourcartthatweneverintendedbuying.