Time perception - Wikipedia

The study of time perception or chronoception is a field within psychology, cognitive linguistics and neuroscience that refers to the subjective experience, ... Timeperception FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Perceptionofevents'positionintime Thestudyoftimeperceptionorchronoceptionisafieldwithinpsychology,cognitivelinguistics[1]andneurosciencethatreferstothesubjectiveexperience,orsense,oftime,whichismeasuredbysomeone'sownperceptionofthedurationoftheindefiniteandunfoldingofevents.[2][3]Theperceivedtimeintervalbetweentwosuccessiveeventsisreferredtoasperceivedduration.Thoughdirectlyexperiencingorunderstandinganotherperson'sperceptionoftimeisnotpossible,perceptioncanbeobjectivelystudiedandinferredthroughanumberofscientificexperiments.Sometemporalillusionshelptoexposetheunderlyingneuralmechanismsoftimeperception. Pioneeringwork,emphasizingspecies-specificdifferences,wasconductedbyKarlErnstvonBaer.[4] Contents 1Theories 2Philosophicalperspectives 3Neuroscientificperspectives 4Ecologicalperspectives 4.1Timeperceptioninvertebrates 4.1.1Examplesinfish 4.1.2Examplesinbirds 4.1.3Examplesinmammals 4.2Timeperceptionininvertebrates 5Typesoftemporalillusions 5.1Kappaeffect 5.2Eyemovementsand"Chronostasis" 5.3Flash-lageffect 5.4Oddballeffect 5.5Reversaloftemporalorderjudgment 6Physiologicalassociations 6.1Tachypsychia 6.2Effectsofemotionalstates 6.2.1Awe 6.2.2Fear 6.3Changeswithage 6.3.1Proportionaltorealtime 6.3.2Proportionaltosubjectivetime 6.4Effectsofdrugsontimeperception 6.5Effectsofbodytemperature 7Applications 7.1SocialNetworks 8Seealso 9References 10Furtherreading 11Externallinks Theories[edit] Timeperceptionistypicallycategorizedinthreedistinctranges,becausedifferentrangesofdurationareprocessedindifferentareasofthebrain:[5] Sub-secondtimingormillisecondtiming Intervaltimingorseconds-to-minutestiming Circadiantiming Therearemanytheoriesandcomputationalmodelsfortimeperceptionmechanismsinthebrain.WilliamJ.Friedman(1993)contrastedtwotheoriesofthesenseoftime:[6][7][8] Thestrengthmodeloftimememory.Thispositsamemorytracethatpersistsovertime,bywhichonemightjudgetheageofamemory(andthereforehowlongagotheeventrememberedoccurred)fromthestrengthofthetrace.Thisconflictswiththefactthatmemoriesofrecenteventsmayfademorequicklythanmoredistantmemories. Theinferencemodelsuggeststhetimeofaneventisinferredfrominformationaboutrelationsbetweentheeventinquestionandothereventswhosedateortimeisknown. Anotherhypothesisinvolvesthebrain'ssubconscioustallyingof"pulses"duringaspecificinterval,formingabiologicalstopwatch.Thistheoryproposesthatthebraincanrunmultiplebiologicalstopwatchesindependentlydependingonthetypeoftasksbeingtracked.Thesourceandnatureofthepulsesisunclear.[9]Theyareasyetametaphorwhosecorrespondencetobrainanatomyorphysiologyisunknown.[10] Philosophicalperspectives[edit] Mainarticle:Speciouspresent Thespeciouspresentisthetimedurationwhereinastateofconsciousnessisexperiencedasbeinginthepresent.[11]ThetermwasfirstintroducedbythephilosopherE.R.Clayin1882(E.RobertKelly),[12][13]andwasfurtherdevelopedbyWilliamJames.[13]Jamesdefinedthespeciouspresenttobe"theprototypeofallconceivedtimes...theshortdurationofwhichweareimmediatelyandincessantlysensible".In"ScientificThought"(1930),C.D.Broadfurtherelaboratedontheconceptofthespeciouspresentandconsideredthatthespeciouspresentmaybeconsideredasthetemporalequivalentofasensorydatum.[13]AversionoftheconceptwasusedbyEdmundHusserlinhisworksanddiscussedfurtherbyFranciscoVarelabasedonthewritingsofHusserl,Heidegger,andMerleau-Ponty.[14] Neuroscientificperspectives[edit] Althoughtheperceptionoftimeisnotassociatedwithaspecificsensorysystem,psychologistsandneuroscientistssuggestthathumansdohaveasystem,orseveralcomplementarysystems,governingtheperceptionoftime.[15]Timeperceptionishandledbyahighlydistributedsysteminvolvingthecerebralcortex,cerebellumandbasalganglia.[16]Oneparticularcomponent,thesuprachiasmaticnucleus,isresponsibleforthecircadian(ordaily)rhythm,whileothercellclustersappeartobecapableofshorter(ultradian)timekeeping.Thereissomeevidencethatveryshort(millisecond)durationsareprocessedbydedicatedneuronsinearlysensorypartsofthebrain.[17][18] WarrenMeckdevisedaphysiologicalmodelformeasuringthepassageoftime.Hefoundtherepresentationoftimetobegeneratedbytheoscillatoryactivityofcellsintheuppercortex.Thefrequencyofthesecells'activityisdetectedbycellsinthedorsalstriatumatthebaseoftheforebrain.Hismodelseparatedexplicittimingandimplicittiming.Explicittimingisusedinestimatingthedurationofastimulus.Implicittimingisusedtogaugetheamountoftimeseparatingonefromanimpendingeventthatisexpectedtooccurinthenearfuture.Thesetwoestimationsoftimedonotinvolvethesameneuroanatomicalareas.Forexample,implicittimingoftenoccurstoachieveamotortask,involvingthecerebellum,leftparietalcortex,andleftpremotorcortex.Explicittimingofteninvolvesthesupplementarymotorareaandtherightprefrontalcortex.[10] Twovisualstimuli,insidesomeone'sfieldofview,canbesuccessfullyregardedassimultaneousuptofivemilliseconds.[19][20][21] Inthepopularessay"BrainTime",DavidEaglemanexplainsthatdifferenttypesofsensoryinformation(auditory,tactile,visual,etc.)areprocessedatdifferentspeedsbydifferentneuralarchitectures.Thebrainmustlearnhowtoovercomethesespeeddisparitiesifitistocreateatemporallyunifiedrepresentationoftheexternalworld: ifthevisualbrainwantstogeteventscorrecttimewise,itmayhaveonlyonechoice:waitfortheslowestinformationtoarrive.Toaccomplishthis,itmustwaitaboutatenthofasecond.Intheearlydaysoftelevisionbroadcasting,engineersworriedabouttheproblemofkeepingaudioandvideosignalssynchronized.Thentheyaccidentallydiscoveredthattheyhadaroundahundredmillisecondsofslop:Aslongasthesignalsarrivedwithinthiswindow,viewers'brainswouldautomaticallyresynchronizethesignals".Hegoesontosaythat"Thisbriefwaitingperiodallowsthevisualsystemtodiscountthevariousdelaysimposedbytheearlystages;however,ithasthedisadvantageofpushingperceptionintothepast.Thereisadistinctsurvivaladvantagetooperatingasclosetothepresentaspossible;ananimaldoesnotwanttolivetoofarinthepast.Therefore,thetenth-of-a-secondwindowmaybethesmallestdelaythatallowshigherareasofthebraintoaccountforthedelayscreatedinthefirststagesofthesystemwhilestilloperatingneartheborderofthepresent.Thiswindowofdelaymeansthatawarenessisretroactive,incorporatingdatafromawindowoftimeafteraneventanddeliveringadelayedinterpretationofwhathappened."[22] Experimentshaveshownthatratscansuccessfullyestimateatimeintervalofapproximately40seconds,despitehavingtheircortexentirelyremoved.[23]Thissuggeststhattimeestimationmaybealowlevelprocess.[24] Ecologicalperspectives[edit] Inrecenthistory,ecologistsandpsychologistshavebeeninterestedinwhetherandhowtimeisperceivedbynon-humananimals,aswellaswhichfunctionalpurposesareservedbytheabilitytoperceivetime.Studieshavedemonstratedthatmanyspeciesofanimals,includingbothvertebratesandinvertebrates,havecognitiveabilitiesthatallowthemtoestimateandcomparetimeintervalsanddurationsinasimilarwaytohumans.[25] Thereisempiricalevidencethatmetabolicratehasanimpactonanimals'abilitytoperceivetime.[26]Ingeneral,itistruewithinandacrosstaxathatanimalsofsmallersize(suchasflies),whichhaveafastmetabolicrate,experiencetimemoreslowlythananimalsoflargersize,whichhaveaslowmetabolicrate.[27][28]Researcherssupposethatthiscouldbethereasonwhysmall-bodiedanimalsaregenerallybetteratperceivingtimeonasmallscale,andwhytheyaremoreagilethanlargeranimals.[29] Timeperceptioninvertebrates[edit] Examplesinfish[edit] Inalabexperiment,goldfishwereconditionedtoreceivealightstimulusfollowedshortlybyanaversiveelectricshock,withaconstanttimeintervalbetweenthetwostimuli.Testsubjectsshowedanincreaseingeneralactivityaroundthetimeoftheelectricshock.Thisresponsepersistedinfurthertrialsinwhichthelightstimuluswaskeptbuttheelectricshockwasremoved.[30]Thissuggeststhatgoldfishareabletoperceivetimeintervalsandtoinitiateanavoidanceresponseatthetimewhentheyexpectthedistressingstimulustohappen. Intwoseparatestudies,goldenshinersanddwarfinangasdemonstratedtheabilitytoassociatetheavailabilityoffoodsourcestospecificlocationsandtimesofday,calledtime-placelearning.[31][32]Incontrast,whentestedfortime-placelearningbasedonpredationrisk,inangaswereunabletoassociatespatiotemporalpatternstothepresenceorabsenceofpredators. Examplesinbirds[edit] Whenpresentedwiththechoicebetweenobtainingfoodatregularintervals(withafixeddelaybetweenfeedings)oratstochasticintervals(withavariabledelaybetweenfeedings),starlingscandiscriminatebetweenthetwotypesofintervalsandconsistentlyprefergettingfoodatvariableintervals.Thisistruewhetherthetotalamountoffoodisthesameforbothoptionsorifthetotalamountoffoodisunpredictableinthevariableoption.Thissuggeststhatstarlingshaveaninclinationforrisk-pronebehavior.[33] Pigeonsareabletodiscriminatebetweendifferenttimesofdayandshowtime-placelearning.[34]Aftertraining,labsubjectsweresuccessfullyabletopeckspecifickeysatdifferenttimesofday(morningorafternoon)inexchangeforfood,evenaftertheirsleep/wakecyclewasartificiallyshifted.Thissuggeststhattodiscriminatebetweendifferenttimesofday,pigeonscanuseaninternaltimer(orcircadiantimer)thatisindependentofexternalcues.[35]However,amorerecentstudyontime-placelearninginpigeonssuggeststhatforasimilartask,testsubjectswillswitchtoanon-circadiantimingmechanismwhenpossibletosaveenergyresources.[36]Experimentaltestsrevealedthatpigeonsarealsoabletodiscriminatebetweencuesofvariousdurations(ontheorderofseconds),butthattheyarelessaccuratewhentimingauditorycuesthanwhentimingvisualcues.[37] Examplesinmammals[edit] Astudyonprivatelyowneddogsrevealedthatdogsareabletoperceivedurationsrangingfromminutestoseveralhoursdifferently.Dogsreactedwithincreasingintensitytothereturnoftheirownerswhentheywereleftaloneforlongerdurations,regardlessoftheowners'behavior.[38] Afterbeingtrainedwithfoodreinforcement,femalewildboarsareabletocorrectlyestimatetimeintervalsofdaysbyaskingforfoodattheendofeachinterval,buttheyareunabletoaccuratelyestimatetimeintervalsofminuteswiththesametrainingmethod.[39] Whentrainedwithpositivereinforcement,ratscanlearntorespondtoasignalofacertainduration,butnottosignalsofshorterorlongerdurations,whichdemonstratesthattheycandiscriminatebetweendifferentdurations.[40]Ratshavedemonstratedtime-placelearning,andcanalsolearntoinfercorrecttimingforaspecifictaskbyfollowinganorderofevents,suggestingthattheymightbeabletouseanordinaltimingmechanism.[41]Likepigeons,ratsarethoughttohavetheabilitytouseacircadiantimingmechanismfordiscriminatingtimeofday.[42] Timeperceptionininvertebrates[edit] Foragerhoneybeeflyingbacktothehivewithpollenandnectar. Whenreturningtothehivewithnectar,foragerhoneybeesneedtoknowthecurrentratioofnectar-collectingtonectar-processingratesinthecolony.Todoso,theyestimatethetimeittakesthemtofindafood-storerbee,whichwillunloadtheforageandstoreit.Thelongerittakesthemtofindone,thebusierthefood-storerbeesare;andthereforethehigherthenectar-collectingrateofthecolony.[43]Foragerbeesalsoassessthequalityofnectarbycomparingthelengthoftimeittakestounloadtheforage:alongerunloadingtimeindicateshigherqualitynectar.Theycomparetheirownunloadingtimetotheunloadingtimeofotherforagerspresentinthehive,andadjusttheirrecruitingbehavioraccordingly.Forinstance,honeybeesreducethedurationoftheirwaggledanceiftheyjudgetheirownyieldtobeinferior.[44]Scientistshavedemonstratedthatanesthesiadisruptsthecircadianclockandimpairsthetimeperceptionofhoneybees,asobservedinhumans.[45]Experimentsrevealedthata6-hour-longgeneralanesthesiasignificantlydelayedthestartoftheforagingbehaviourofhoneybeesifinducedduringdaytime,butnotifinducedduringnighttime.[46] Bumblebeescanbesuccessfullytrainedtorespondtoastimulusafteracertaintimeintervalhaselapsed(usuallyseveralsecondsafterthestartsignal).Studieshaveshownthattheycanalsolearntosimultaneouslytimemultipleintervaldurations.[47] Inasinglestudy,coloniesfromthreespeciesofantsfromthegenusMyrmicaweretrainedtoassociatefeedingsessionswithdifferenttimes.Thetrainingslastedseveraldays,whereeachdaythefeedingtimewasdelayedby20minutescomparedtothepreviousday.Inallthreespecies,attheendofthetraining,mostindividualswerepresentatthefeedingspotatthecorrectexpectedtimes,suggestingthatantsareabletoestimatethetimerunning,keepinmemorytheexpectedfeedingtimeandtoactanticipatively.[48] Typesoftemporalillusions[edit] Atemporalillusionisadistortionintheperceptionoftime.Forexample: estimatingtimeintervals,e.g.,"Whendidyoulastseeyourprimarycarephysician?"; estimatingtimeduration,e.g.,"Howlongwereyouwaitingatthedoctor'soffice?";and judgingthesimultaneityofevents(seebelowforexamples). Maintypesoftemporalillusions Telescopingeffect:Peopletendtorecallrecenteventsasoccurringfurtherbackintimethantheyactuallydid(backwardtelescoping)anddistanteventsasoccurringmorerecentlythantheyactuallydid(forwardtelescoping).[49] Vierordt'slaw:Shorterintervalstendtobeoverestimatedwhilelongerintervalstendtobeunderestimated Timeintervalsassociatedwithmorechangesmaybeperceivedaslongerthanintervalswithfewerchanges Perceivedtemporallengthofagiventaskmayshortenwithgreatermotivation Perceivedtemporallengthofagiventaskmaystretchwhenbrokenuporinterrupted Auditorystimulimayappeartolastlongerthanvisualstimuli[50][51][52][53] Timedurationsmayappearlongerwithgreaterstimulusintensity(e.g.,auditoryloudnessorpitch) Simultaneityjudgmentscanbemanipulatedbyrepeatedexposuretonon-simultaneousstimuli Kappaeffect[edit] TheKappaeffectorperceptualtimedilation[54]isaformoftemporalillusionverifiablebyexperiment,[55]whereinthetemporaldurationbetweenasequenceofconsecutivestimuliisthoughttoberelativelylongerorshorterthanitsactualelapsedtime,duetothespatial/auditory/tactileseparationbetweeneachconsecutivestimuli.Thekappaeffectcanbedisplayedwhenconsideringajourneymadeintwopartsthateachtakeanequalamountoftime.Whenmentallycomparingthesetwosub-journeys,thepartthatcoversmoredistancemayappeartotakelongerthanthepartcoveringlessdistance,eventhoughtheytakeanequalamountoftime. Eyemovementsand"Chronostasis"[edit] Theperceptionofspaceandtimeundergoesdistortionsduringrapidsaccadiceyemovements.[56] Chronostasisisatypeoftemporalillusioninwhichthefirstimpressionfollowingtheintroductionofaneweventortaskdemandtothebrainappearstobeextendedintime.[57]Forexample,chronostasistemporarilyoccurswhenfixatingonatargetstimulus,immediatelyfollowingasaccade(e.g.,quickeyemovement).Thiselicitsanoverestimationinthetemporaldurationforwhichthattargetstimulus(i.e.,postsaccadicstimulus)wasperceived.Thiseffectcanextendapparentdurationsbyupto500msandisconsistentwiththeideathatthevisualsystemmodelseventspriortoperception.[58]Themostwell-knownversionofthisillusionisknownasthestopped-clockillusion,whereinasubject'sfirstimpressionofthesecond-handmovementofananalogclock,subsequenttoone'sdirectedattention(i.e.,saccade)totheclock,istheperceptionofaslower-than-normalsecond-handmovementrate(thesecondshandoftheclockmayseeminglytemporarilyfreezeinplaceafterinitiallylookingatit).[59][60][61][62] Theoccurrenceofchronostasisextendsbeyondthevisualdomainintotheauditoryandtactiledomains.[63]Intheauditorydomain,chronostasisanddurationoverestimationoccurwhenobservingauditorystimuli.Onecommonexampleisafrequentoccurrencewhenmakingtelephonecalls.If,whilelisteningtothephone'sdialtone,researchsubjectsmovethephonefromoneeartotheother,thelengthoftimebetweenringsappearslonger.[64]Inthetactiledomain,chronostasishaspersistedinresearchsubjectsastheyreachforandgraspobjects.Aftergraspinganewobject,subjectsoverestimatethetimeinwhichtheirhandhasbeenincontactwiththisobject.[60] Flash-lageffect[edit] Mainarticle:Flashlagillusion Inanexperiment,participantsweretoldtostareatan"x"symbolonacomputerscreenwherebyamovingbluedoughnut-likeringrepeatedlycircledthefixed"x"point.[65][66][67]Occasionally,theringwoulddisplayawhiteflashforasplitsecondthatphysicallyoverlappedthering'sinterior.However,whenaskedwhatwasperceived,participantsrespondedthattheysawthewhiteflashlaggingbehindthecenterofthemovingring.Inotherwords,despitetherealitythatthetworetinalimageswereactuallyspatiallyaligned,theflashedobjectwasusuallyobservedtotrailacontinuouslymovingobjectinspace—aphenomenonreferredtoastheflash-lageffect. Thefirstproposedexplanation,calledthe"motionextrapolation"hypothesis,isthatthevisualsystemextrapolatesthepositionofmovingobjectsbutnotflashingobjectswhenaccountingforneuraldelays(i.e.,thelagtimebetweentheretinalimageandtheobserver'sperceptionoftheflashingobject).ThesecondproposedexplanationbyDavidEaglemanandSejnowski,calledthe"latencydifference"hypothesis,isthatthevisualsystemprocessesmovingobjectsatafasterratethanflashedobjects.Intheattempttodisprovethefirsthypothesis,DavidEaglemanconductedanexperimentinwhichthemovingringsuddenlyreversesdirectiontospinintheotherwayastheflashedobjectbrieflyappears.Ifthefirsthypothesiswerecorrect,wewouldexpectthat,immediatelyfollowingreversal,themovingobjectwouldbeobservedaslaggingbehindtheflashedobject.However,theexperimentrevealedtheopposite—immediatelyfollowingreversal,theflashedobjectwasobservedaslaggingbehindthemovingobject.Thisexperimentalresultsupportsthe"latencydifference"hypothesis.Arecentstudytriestoreconcilethesedifferentapproachesbytreatingperceptionasaninferencemechanismaimingatdescribingwhatishappeningatthepresenttime.[68] Oddballeffect[edit] Humanstypicallyoverestimatetheperceiveddurationoftheinitialandfinaleventinastreamofidenticalevents.[69] Thisoddballeffectmayserveanevolutionarilyadapted"alerting"functionandisconsistentwithreportsoftimeslowingdowninthreateningsituations.Theeffectseemstobestrongestforimagesthatareexpandinginsizeontheretina,inotherwords,thatare"looming"orapproachingtheviewer,[70][71][72]andtheeffectcanbeeradicatedforoddballsthatarecontractingorperceivedtoberecedingfromtheviewer.[71]Theeffectisalsoreduced[70]orreversed[72]withastaticoddballpresentedamongastreamofexpandingstimuli. Initialstudiessuggestedthatthisoddball-induced"subjectivetimedilation"expandedtheperceiveddurationofoddballstimuliby30–50%[70]butsubsequentresearchhasreportedmoremodestexpansionofaround10%[72][73][74][75]orless.[76]Thedirectionoftheeffect,whethertheviewerperceivesanincreaseoradecreaseinduration,alsoseemstobedependentuponthestimulusused.[76] Reversaloftemporalorderjudgment[edit] Numerousexperimentalfindingssuggestthattemporalorderjudgmentsofactionsprecedingeffectscanbereversedunderspecialcircumstances.Experimentshaveshownthatsensorysimultaneityjudgmentscanbemanipulatedbyrepeatedexposuretonon-simultaneousstimuli.InanexperimentconductedbyDavidEagleman,atemporalorderjudgmentreversalwasinducedinsubjectsbyexposingthemtodelayedmotorconsequences.Intheexperiment,subjectsplayedvariousformsofvideogames.Unknowntothesubjects,theexperimentersintroducedafixeddelaybetweenthemousemovementsandthesubsequentsensoryfeedback.Forexample,asubjectmaynotseeamovementregisteronthescreenuntil150millisecondsaftertheyhadmovedthemouse.Participantsplayingthegamequicklyadaptedtothedelayandfeltasthoughtherewaslessdelaybetweentheirmousemovementandthesensoryfeedback.Shortlyaftertheexperimentersremovedthedelay,thesubjectscommonlyfeltasthoughtheeffectonthescreenhappenedjustbeforetheycommandedit.Thisworkaddresseshowtheperceivedtimingofeffectsismodulatedbyexpectations,andtheextenttowhichsuchpredictionsarequicklymodifiable.[77] InanexperimentconductedbyHaggardandcolleaguesin2002,participantspressedabuttonthattriggeredaflashoflightatadistance,afteraslightdelayof100milliseconds.[78]Byrepeatedlyengaginginthisact,participantshadadaptedtothedelay(i.e.,theyexperiencedagradualshorteningintheperceivedtimeintervalbetweenpressingthebuttonandseeingtheflashoflight).Theexperimentersthenshowedtheflashoflightinstantlyafterthebuttonwaspressed.Inresponse,subjectsoftenthoughtthattheflash(theeffect)hadoccurredbeforethebuttonwaspressed(thecause).Additionally,whentheexperimentersslightlyreducedthedelay,andshortenedthespatialdistancebetweenthebuttonandtheflashoflight,participantshadoftenclaimedagaintohaveexperiencedtheeffectbeforethecause. Severalexperimentsalsosuggestthattemporalorderjudgmentofapairoftactilestimulideliveredinrapidsuccession,onetoeachhand,isnoticeablyimpaired(i.e.,misreported)bycrossingthehandsoverthemidline.However,congenitallyblindsubjectsshowednotraceoftemporalorderjudgmentreversalaftercrossingthearms.Theseresultssuggestthattactilesignalstakeninbythecongenitallyblindareorderedintimewithoutbeingreferredtoavisuospatialrepresentation.Unlikethecongenitallyblindsubjects,thetemporalorderjudgmentsofthelate-onsetblindsubjectswereimpairedwhencrossingthearmstoasimilarextentasnon-blindsubjects.Theseresultssuggestthattheassociationsbetweentactilesignalsandvisuospatialrepresentationismaintainedonceitisaccomplishedduringinfancy.Someresearchstudieshavealsofoundthatthesubjectsshowedreduceddeficitintactiletemporalorderjudgmentswhenthearmswerecrossedbehindtheirbackthanwhentheywerecrossedinfront.[79][80][81] Physiologicalassociations[edit] Tachypsychia[edit] Tachypsychiaisaneurologicalconditionthatalterstheperceptionoftime,usuallyinducedbyphysicalexertion,druguse,oratraumaticevent.Forsomeoneaffectedbytachypsychia,timeperceivedbytheindividualeitherlengthens,makingeventsappeartoslowdown,[82]orcontracts,withobjectsappearingasmovinginaspeedingblur.[83][84] Effectsofemotionalstates[edit] Awe[edit] Researchhassuggestedthefeelingofawehastheabilitytoexpandone'sperceptionsoftimeavailability.Awecanbecharacterizedasanexperienceofimmenseperceptualvastnessthatcoincideswithanincreaseinfocus.Consequently,itisconceivablethatone'stemporalperceptionwouldslowdownwhenexperiencingawe.[85]Theperceptionoftimecandifferaspeoplechoosebetweensavoringmomentsanddeferringgratification.[86] Fear[edit] Possiblyrelatedtotheoddballeffect,researchsuggeststhattimeseemstoslowdownforapersonduringdangerousevents(suchasacaraccident,arobbery,orwhenapersonperceivesapotentialpredatorormate),orwhenapersonskydivesorbungeejumps,wherethey'recapableofcomplexthoughtsinwhatwouldnormallybetheblinkofaneye(SeeFight-or-flightresponse).[87]Thisreportedslowingintemporalperceptionmayhavebeenevolutionarilyadvantageousbecauseitmayhaveenhancedone'sabilitytointelligiblymakequickdecisionsinmomentsthatwereofcriticalimportancetooursurvival.[88]However,eventhoughobserverscommonlyreportthattimeseemstohavemovedinslowmotionduringtheseevents,itisunclearwhetherthisisafunctionofincreasedtimeresolutionduringtheevent,orinsteadanillusioncreatedbytherememberingofanemotionallysalientevent.[89] Astrongtimedilationeffecthasbeenreportedforperceptionofobjectsthatwerelooming,butnotofthoseretreating,fromtheviewer,suggestingthattheexpandingdiscs—whichmimicanapproachingobject—elicitself-referentialprocesseswhichacttosignalthepresenceofapossibledanger.[90]Anxiouspeople,orthoseingreatfear,experiencegreater"timedilation"inresponsetothesamethreatstimuliduetohigherlevelsofepinephrine,whichincreasesbrainactivity(anadrenalinerush).[91]Insuchcircumstances,anillusionoftimedilationcouldassistaneffectiveescape.[92][93]Whenexposedtoathreat,three-year-oldchildrenwereobservedtoexhibitasimilartendencytooverestimateelapsedtime.[10][94] Researchsuggeststhattheeffectappearsonlyatthepointofretrospectiveassessment,ratherthanoccurringsimultaneouslywitheventsastheyhappened.[95]Perceptualabilitiesweretestedduringafrighteningexperience—afreefall—bymeasuringpeople'ssensitivitytoflickeringstimuli.Theresultsshowedthatthesubjects'temporalresolutionwasnotimprovedasthefrighteningeventwasoccurring.Eventsappeartohavetakenlongeronlyinretrospect,possiblybecausememorieswerebeingmoredenselypackedduringthefrighteningsituation.[95] Otherresearchers[96][97]suggestthatadditionalvariablescouldleadtoadifferentstateofconsciousnessinwhichalteredtimeperceptiondoesoccurduringanevent.Researchdoesdemonstratethatvisualsensoryprocessing[98]increasesinscenariosinvolvingactionpreparation.Participantsdemonstratedahigherdetectionrateofrapidlypresentedsymbolswhenpreparingtomove,ascomparedtoacontrolwithoutmovement. Peopleshownextractsfromfilmsknowntoinducefearoftenoverestimatedtheelapsedtimeofasubsequentlypresentedvisualstimulus,whereaspeopleshownemotionallyneutralclips(weatherforecastsandstockmarketupdates)orthoseknowntoevokefeelingsofsadnessshowednodifference.Itisarguedthatfearpromptsastateofarousalintheamygdala,whichincreasestherateofahypothesized"internalclock".Thiscouldbetheresultofanevolveddefensivemechanismtriggeredbyathreateningsituation.[99]Individualsexperiencingsuddenorsurprisingevents,realorimagined(e.g.,witnessingacrime,orbelievingoneisseeingaghost),mayoverestimatethedurationoftheevent.[86] Changeswithage[edit] Psychologistshavefoundthatthesubjectiveperceptionofthepassingoftimetendstospeedupwithincreasingageinhumans.Thisoftencausespeopletoincreasinglyunderestimateagivenintervaloftimeastheyage.Thisfactcanlikelybeattributedtoavarietyofage-relatedchangesintheagingbrain,suchastheloweringindopaminergiclevelswitholderage;however,thedetailsarestillbeingdebated.[100][101][102] Veryyoungchildrenliterally"liveintime"beforegaininganawarenessofitspassing.Achildwillfirstexperiencethepassingoftimewhenheorshecansubjectivelyperceiveandreflectontheunfoldingofacollectionofevents.Achild'sawarenessoftimedevelopsduringchildhood,whenthechild'sattentionandshort-termmemorycapacitiesform—thisdevelopmentalprocessisthoughttobedependentontheslowmaturationoftheprefrontalcortexandhippocampus.[10][103] Thecommonexplanationisthatmostexternalandinternalexperiencesarenewforyoungchildrenbutrepetitiveforadults.Childrenhavetobeextremelyengaged(i.e.dedicatemanyneuralresourcesorsignificantbrainpower)inthepresentmomentbecausetheymustconstantlyreconfiguretheirmentalmodelsoftheworldtoassimilateitandmanagebehaviourproperly. Adults,however,mayrarelyneedtostepoutsidementalhabitsandexternalroutines.Whenanadultfrequentlyexperiencesthesamestimuli,suchstimulimayseem"invisible"asaresultofhavingalreadybeensufficientlymappedbythebrain.Thisphenomenonisknownasneuraladaptation.Thus,thebrainwillrecordfewerdenselyrichmemoriesduringthesefrequentperiodsofdisengagementfromthepresentmoment.[clarify][104]Consequently,thesubjectiveperceptionisoftenthattimepassesbyatafasterratewithage. Proportionaltorealtime[edit] LetSbesubjectivetime,Rberealtime,anddefinebothtobezeroatbirth. Onemodelproposesthatthepassageofsubjectivetimerelativetoactualtimeisinverselyproportionaltorealtime:[105] d S d R = K R {\displaystyle{\frac{dS}{dR}}={\frac{K}{R}}} Whensolved, S 2 − S 1 = K ( log ⁡ R 2 − log ⁡ R 1 ) = K log ⁡ ( R 2 / R 1 ) {\displaystyleS_{2}-S_{1}=K(\log{R_{2}}-\log{R_{1}})=K\log{\left({R_{2}}/{R_{1}}\right)}} . Onedaywouldbeapproximately1/4,000ofthelifeofan11-year-old,butapproximately1/20,000ofthelifeofa55-year-old.Thishelpstoexplainwhyarandom,ordinarydaymaythereforeappearlongerforayoungchildthananadult.Soayearwouldbeexperiencedbya55-year-oldaspassingapproximately5timesmorequicklythanayearexperiencedbyan11-year-old.Iflong-termtimeperceptionisbasedsolelyontheproportionalityofaperson'sage,thenthefollowingfourperiodsinlifewouldappeartobequantitativelyequal:ages5–10(1x),ages10–20(2x),ages20–40(4x),age40–80(8x),astheendageistwicethestartage.However,thisdoesnotworkforages0–10,whichcorrespondstoages10–∞.[105][106] Proportionaltosubjectivetime[edit] Lemlichpositsthatthepassageofsubjectivetimerelativetoactualtimeisinverselyproportionaltototalsubjectivetime,ratherthanthetotalrealtime:[105] d S d R = K S {\displaystyle{\frac{dS}{dR}}={\frac{K}{S}}} Whenmathematicallysolved, S 2 = 2 K R + C {\displaystyleS^{2}=2KR+C} Itavoidstheissueofinfinitesubjectivetimepassingfromrealage0to1year,astheasymptotecanbeintegratedinanimproperintegral.UsingtheinitialconditionsS=0whenR=0andS>0, S = 2 K R {\displaystyleS={\sqrt{2KR}}} d S d R = K 2 R {\displaystyle{\frac{dS}{dR}}={\sqrt{\frac{K}{2R}}}} Thismeansthattimeappearstopassinproportiontothesquarerootoftheperceiver'srealage,ratherthandirectlyproportional.Underthismodel,a55-year-oldwouldsubjectivelyexperiencetimepassing2¼timesmorequicklythanan11-year-old,ratherthan5timesundertheprevious.Thismeansthefollowingperiodsinlifewouldappeartobequantitativelyequal:ages0–1,1–4,4–9,9–16,16–25,25–36,36–49,49–64,64–81,81–100,100–121.[105][107] Inastudy,participantsconsistentlyprovidedanswersthatfitthismodelwhenaskedabouttimeperceptionat1/4oftheirage,butwerelessconsistentfor1/2oftheirage.Theiranswerssuggestthatthismodelismoreaccuratethanthepreviousone.[105] Aconsequenceofthismodelisthatthefractionofsubjectiveliferemainingisalwayslessthanthefractionofrealliferemaining,butitisalwaysmorethanonehalfofrealliferemaining.[105]Thiscanbeseenfor 0 < S < S f {\displaystyle0