Memoryisoneofthemoststudiedfieldsinpsychology.Afterthemid-1950s,manypsychologistsusedtheviewpointofinformationprocessingtoexplainmemory.Accordingtothememoryprocess,fromtheinputtotheextractionofinformation,theelapsedtimeintervalisdifferent,andtheencodingmethodisdifferent.Generally,memoryisdividedintothreesystemsorthreestages,namelysensorymemory,short-termmemoryandlong-termmemory.Figure1.
1.Sensorymemory,whenthestimulusstopsacting,thesensationdoesnotdisappearimmediately,anditmaintainsitsimpressioninashortperiodoftime.Forexample,whenwelookatthelight,whenthelightisturnedoff,wemaintainitsimpressionforashortperiodoftime.Thiskindofafterimageinvisiononlystoresinstantaneousmemory,whichissensorymemory,alsocalledinstantaneousmemory,andsomepeoplecallitsensoryregistration.Thisisthebeginningofthememoryprocess.
2.Short-termmemory(STM)isthecoreoftheinformationprocessingsystem.Theinformationencodedinthesensorymemoryisentered,andthegeneralshort-termmemoryisthenfurtherprocessed,andthenentersthelong-termmemorythatcanbestoredforalongtime.Informationisgenerallyonlykeptfor20-30secondsinshort-termmemory,butifitisrepeated,itcanbekept.Retellingensuresthatitsdelaydisappears.Whatisstoredinshort-termmemoryistheinformationbeingused,whichplaysaveryimportantroleinmentalactivities.First,short-termmemoryplaystheroleofconsciousness,allowingustoknowwhatwearereceivingandwhatwearedoing.Secondly,short-termmemoryallowsustointegratealotofinformationfromthesensestoformacompleteimage.Third,short-termmemoryactsasatemporaryregisterwhenthinkingandsolvingproblems.Forexample,whendoingcalculationproblems,beforedoingthenextstep,thecalculationresultsoftheprevioussteparetemporarilystoredforthefinaluse.Finally,short-termmemorypreservescurrentstrategiesandwishes.Allthisallowsustotakeavarietyofcomplexactionsuntilwereachthefinalgoal.Becauseofthediscoveryoftheseimportantfunctionsofshort-termmemory,ithasbeenrenamedasworkingmemoryinmostcurrentstudies.
3.Long-termmemory(LTM)isthelong-termmemoryofinformationaftersufficientprocessing.Long-termmemoryislikeahugelibrary,whichholdsvariousfacts,appearancesandknowledgethatwecanuseinthefuture.Thecapacityoflong-termmemoryisanastronomicalnumber,almostunlimited.Inlong-termmemory,informationmaybekeptforever.Short-termmemorywaswidelystudiedonlyafterthe1960s.SincetheGermanpsychologistEbbinghausfirstsystematicallystudiedmemoryinthe19thcentury,long-termmemoryhasalwaysbeenthefocusofpsychologists.