Perception visuelle du mouvement humain dans les interactions lors de tâches locomotrices

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https://hal.inria.fr/tel-01944500v2

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To cite this version:

Sean Lynch. Perception visuelle du mouvement humain dans les interactions lors de tâches locomotri-

ces. Education. Université Rennes 2, 2018. Français. �NNT : 2018REN20046�. �tel-01944500v2�

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T ^HESE ^DE ^DOCTORAT ^DE

L ’UN IVERS ITE RENNES 2 C ÔMUE U ^N ÎVERS ÎTE B ^RETAGNE L Ô ÎRE E COLE D OCTORALE N ° 603

Educa t ion , Langages , In terac t ion , Cogn i t ion , C l in ique Spéc ia l i té : STAPS

V isua l percept ion of human movement dur ing wa lk ing task interact ions

Percep t ion v isue l le du mouvemen t huma in dans les in terac t ions lors de tâches locomo tr ices

Thèse présentée et soutenue à Un ivers ité Rennes, le 24 Octobre 2018 Un ité de recherche : Laborato ire M2S - EA 7470

Par Sean LYNCH

Rappor teurs avan t soutenance :

V ic tor ia INTER RANTE Pro fesseure , Un ive rs i ty o f M inneso ta

N ico las BENGU IGU I Pro fesseur , Un ivers i té de Caen-No rmand ie

Compos it ion du Jury :

V ic to r ia INTER RANTE

Pro fesseu re , Un ive rs i ty o f M inneso ta N ico las BENGU IGU I

Pro fesseu r , Un ive rs i té de Caen-No rmand ie G i l les MONTAGNE

Pro fesseu r , A ix-Ma rse i l le Un ive rs i té Isabe l le S IEGLER

Pro fesseu re , Un ive rs i té Pa r is-Sud

D i rec teu r de thèse R icha rd KULPA

Ma î tre de Con fé rence HDR, Un ive rs i té Rennes 2

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UNIVERSITÉ RENNES 2 – HAUTE BRETAGNE Un ité de Recherche 7470

Eco le Doctora le – Educat ion, Langues, Interact ion, Cogn it ion, C l in ique Sous le sceau de l’Université Bretagne Loire

VISUAL PERCEPTION OF HUMAN MOVEMENT DURING WALKING TASK INTERACTIONS

Thèse de Doctorat D isc ip l ine : STAPS

Vo lume

Présentée par Sean LYNCH

D irecteur de thèse : R ichard KULPA Co-d irectr ice de thèse : Anne-Hé lène OLIVIER

Soutenue le 24 Octobre 2018

Jury :

V ictor ia INTERRANTE Professeure, Un ivers ity of M innesota (Rapporteure) N ico las BENGUIGUI Professeur, Un ivers ité de Caen-Normand ie

(Rapporteur)

G i l les MONTAGNE Professeur, A ix-Marse i l le Un ivers ité (Exam inateur) Isabe l le SIEGLER Professeur, Un ivers ité Par is-Sud (Exam inatr ice) R ichard KULPA Ma ître de Conférence HDR, Un ivers ité Rennes 2 (D irecteur de thèse)

Anne-Hé lène OLIVIER Ma ître de Conférence, Un ivers ité Rennes 2

(Co-direct r ice de thèse)

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Inlov ing memo ryo f myfather .

Iameterna l lygrate fu lfo ryourgu idanceandpat ience ,

youa lwaysencouraged myl i fecho icesandfo r metolead myownpath . Youwere mybestfr iend ,

I m issyou .

Pau lLynch

(1972-2018)

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Introduct ion

F igure1-C ityl i fe ,acrowdo fpeop lewa lk ingin mu lt ip led irect ionsandcomp let ing severa lfo rmso finteract ion .

Wh i lelocomot ioncanbecons ideredane lementa rytaskthatiscomp letedseam less ly

w ithoutconsc iousthought ,thep rocess ingw ith inthecentra lnervoussystemisfa rfrom

atrest . Nav igat ionthroughanyg ivenenv ironmentcaninvo lvethestepp ingover ,on ,

a roundobstac les ,o racomb inat iono fa l l ,w iththepurposeo ftranspo rt ingthebody ,

sa fe ly ,towa rdsagoa l[W inter1991] .Success fu lnav igat ionisthentheab i l itytoo r ientate

thebodyandinteractw iththeenv ironment ,e itheravo id ingo rintercept ing mob i leo r

ﬁxedobstac les ,o ravo id inganobstac letointerceptanother( i .e . ,c ircumvent ingan

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Thetasko fintercept ioncanbethoughto fasathes iso rsc ient iﬁcpub l icat ion ,the we l l-re ferredbott leneckdeduct ion ,thein it ia lstagesa reb roadandnumerous wh i le app roach inganend-goa landafocuspo int . Fo rexamp le ,naturesp redato randp rey , thein it ia linteract ionisinachang ingenv ironmento fmu lt ip leposs ib i l it iesw iththep rey increas ingtheposs ib i l it iesthroughevas ivetact ics ,theend-goa lfo rthep redato rw i l lbe thecaptureo fthep rey .Avo idanceisthentheinverseo fsuch ,thein it ia lstageso fthe taska rep redeﬁned ,andeachbehav ioura ladaptat ionb roadensthescopeo fposs ib i l it ies . Intermso flocomot ion ,wh i lewa lk ingdownabusystreet(F igure1) ,ataskcanbetonot co l l idew ithothers ,thebehav ioura lresponsesfo rsuchmayinc lude :tostopcomp lete ly , changed irect ion ,o rad justyourcurrentspeed .Ineachtask ,percept ionisrequ iredfo r in fo rmat iongather ing(whereisthebodyinre ferencetothecurrentenv ironment) ,and act ionisrequ ired(neuromuscu la rcoo rd inat ionando rgan isat iono fthebody) .Fo rm ing apercept ion-act ioncoup ledloopo faperce iverandthe irenv ironment[Wa rren2006] , one mustperce iveino rdertoactandactino rdertoperce ive[G ibson1979] .

Interact ionssuchasco l l is ionavo idanceconst itutethebas icsynerg ieso fda i lyl iv ing ,

coo rd inat ingone ’s movementw ithanother . G iventh is ,human movementisthusnot

on lya im lessd isp lacementw ith inanenv ironment .Instead ,itisdensew ithperce ivab le

in fo rmat ionfo ract ion . Nav igat ingsta irwe l ls[ Wa rren1984] ,pass ingthroughdoo rways

[ C ine l l i2008b] ,andgo inga roundotherwa lkersandobstac lesa l ike[ O l iv ier2012] . The

ident iﬁcat iono funder ly ing mechan isms ,wh ichistheperceptua lcuesrequ iredfo rco r-

rect movementpercept ion ,wou lda l lowfo rs ign iﬁcantp rogresstobe madeinhuman

soc ia lbehav iour . Cons ider ,fo rexamp le ,as imp leinteract ionw ithanotherwa lkero r

a mo redynam icandcomp lexspo rt ingtask ;thev isua lsystemispa rt icu la r lysens it ive

inextract ingcuesfromhuman movement(F igure2) . Fo rexamp le ,emot iona lstates ,

intent ,genderanddecept ivemot ion[ Montepa re1987,Runeson1983a] ,o fwh ich ,these

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cuescanbeextractedfromabstractin fo rmat ionrep resentat ionssuchaspo intl ight d isp lays[T ro je2002] . Loca lcuessuchasgazecantrans ferin fo rmat ion , wheregazehas beencha racter isedasafacto ro fsoc ia linteract ion[K le inke1986]andcons ideredafo rm o fnonverba lcommun icat ion ,throughemot iona la rousa lfromp rev iousexper ienceso r commun icat iveintent ion[Sen ju2009] .Byperce iv inganotherwa lker ,ahumanisab leto determ inefutureoutcomes ,interp ret ingtheintent ionsandant ic ipatethefo rthcom ing eventw ithposs ib leadapt ionstothe ircurrentstate .

F igure2-Twoexamp leenv ironmentso fpercept ion-act ioncoup l ing .Le ft)natura lc ity scenew ithfourposs ib lefo rmso finteract ion ,ant i-c lockw isefromtop- le ft :fo l low ing , accompan iedwa lk ing ,intercept ing(meet ing) ,andco l l is ionavo idance . R ight)Anex- amp leo fsuccess fu lintercept ion(p layerbe ingtack led)andateammatefo l low ingin suppo rt .

Toth isend ,th isthes isa imsatanswer ingthefo l low ingquest ions : whata rethev isua l

cuesanind iv idua lperce ivesfromthe movemento fothers? Whata rethe mode lsfo r

determ in ingfuturep red ictedcross ingd istances? Whata retheinterp retat ion mechan-

ismsinvo lved?Inwo rk ingtowa rdsanswer ingthesequest ions ,thethes iscons istedo f

threestud ies . Theﬁrststudyfocusedonthev isua lcues ,name lythenatureo fv isua l

in fo rmat ion ,whetherthein fo rmat ionisextractedfromag loba lrep resentat iono f mo-

t iono rloca lcuesw ith intheg loba lrep resentat ion . Thesecondstudythenfocusedon

thepatho fthev irtua lwa lker ,whetherfutureoutcomesa reextrapo latedrect i l inea r lyo r

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s imp leintroducto ryone-on-onepa rad igmo fo rthogona lco l l is ionavo idancewasstud ied . Toaddressthesequest ionsand ma inta incontro lo ftheenv ironmentthewo rkshere in wereper fo rmedus ingv irtua lrea l ity . Theuseo fv irtua lrea l ityisava l idatedtoo lfo r app l iedpsycho logyasita l lowsustoman ipu latefin itedeta i lso fag ivenenv ironmentand w ithdrawconc lus ionso feffectfromthose man ipu lat ions .Fo rexamp le ,psychophys ics , acatch ingtasko faba l linfl ightunderva r iousgrav itat iona lfo rces[Bosco2012]and angu la racce lerat ions[Bennett2016] .

Thethes isisstructuredinthefo l low ing manner : Chapter1rev iewsthecurrentl it-

erature ,spec iﬁca l ly ,focus ingontheo ret ica lfoundat ions ,perce iv ingtheenv ironment ,

interact ingw iththeenv ironmentandthecoup l ingo fcomputersc iencetechno log iesfo r

percept ion-act ioninvest igat ions . Therea fter ,theob ject ivesa resumma r isedinmo rede-

ta i lbe fo rep resent ingthethreechaptersthatre fertothestud iesinvo lvedinthethes is .

Chapter3istheﬁrstwo rkcomp letedinre lat iontothethes is ,focus ingonthenatureo f

v isua lin fo rmat ion ,spec iﬁca l ly ,invest igat ingwhetherthein fo rmat ionisextractedfrom

g loba ld isp lacemento rloca l mot ioncues . Chapter4be ingthesecond wo rko fthe

thes isandfocusedonthepathconstra intso fthev irtua lwa lker ,w iththev irtua lwa lker

ma inta in ingaconstanttangent ia lve loc ityandfo l low ingacurv i l inea ro rrect i l inea rpath .

Chapter5istheﬁna lstudyo fthethes is ,focus ingonthesoc ia laspectso ftheinter-

act ion ,name ly ,gazebehav iouro fthev irtua lwa lker . F ina l ly ,agenera lconc lus iono f

thethreestud iesandfutureperspect ives . Anadd it iona lstudyonthenatureo fv isua l

in fo rmat ioninamo redynam icsett ingo farugbyattacker-de fenderdyadisava i lab lein

annexeA ,wh ichp resentsaposs ib leﬁe ldo fapp l icat ionfromchapter3 .

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Chapter1 Background

"Theenv ironmento fan ima lsandmeniswhattheyperce ive . Theenv iron- mentisnotthesameasthephys ica lwo r ld ,i fonemeansbythatthewo r ld descr ibedbyphys ics ."

—G ibson ,JamesJ . . TheEco log ica lApp roachtoV isua lPercept ion

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1 .1 V isua lcontro lo flocomot ion

A l ll iv ingo rgan ismsmustadapttothe irenv ironmentino rdertosurv iveandrep roduce , evo lut ionbe ingaby-p roducto fﬁne-tun ingfo rsuchgoa ls . Thebodyisadaptedtoand byitsenv ironment ;thep resentat iono fnutr it ionbytheenv ironmentandthemechan ics to movetowa rdsthesourceo fnutr it ionbytheo rgan ism . Evenw ith inth isexamp le , movementrequ iresregu lat ion ,theab i l itytodetecttheenv ironmentandtointeractw ith it ,thatis ,perce iveandacttoﬁndfood[ Bruce2003] .Itisthere fo rethatpercept ionand act iona recoup led ,inthatmovementisrequ iredtoperce ive ,andpercept ionisrequ ired fo r movement .

Percept ionisthepsycho log ica lphenomenonconnect ingustothesens it ivewo r ldthrough oursenses .Itinvo lvestheuseo fourﬁvesenses :hea r ing ,s ight ,sme l l ,touchandtaste , eacho fwh ichisexp ressedinapercept iveway ;aud ito ry ,v isua l ,o l facto ry ,tact i leand gustato rypercept ion . Eachsenseisusedfo rdetect ingandinterp ret ingtheva r ious fo rmso fenergyanditschangesfromtheenv ironment ,suchasl ight ,soundandneura l act ivat ion[Bruce2003] . However ,itisnoton lytheinterp retat iono fthesesystems ,but theant ic ipat iono ftheconsequenceso fthes imu latedact ionsa lsoconstra inpercept ion [ Berthoz1997] .

Anyl iv ingo rgan ismnav igat ingthe irrespect iveenv ironmentmustperce ivetheenv iron-

mentaswe l lasbeawa reo fitscurrentstate ,answer ingthefundamenta lquest ionso f

whereoneis ,howoneiso r ientated ,wherea reob jectsinre lat iontoone ,wherea re

ob jectsinre lat iontoeachanother ,a retheseaﬀo rdab lefo ract ion ,andwhatact ion

isnecessa ry[ Ma rsha l l2001] . Thev isua lsystem ,wh i lenottheso lesourceo fin fo rma-

t ionisap r iv i legedchanne lthatan ima ls(b irds ,rept i les ,ﬁshetc .)usetoexp lo reand

interactw iththe irenv ironment[ Prevost2002,Pat la2004,S i lva2018] ,p rov id ingsevera l

sourceso fimpo rtantin fo rmat ion ,inc lud ingtheident iﬁcat ionandloca l isat iono fob-

jects[ Schne ider1969,M ishk in1982] ,focusfo rﬁne moto rsk i l lso ramb iencefo rwho le

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V isua lcontro lo flocomot ion

body movements[T reva rthen1968] ,andfa randnea rspacev is ion[ Prev ic1990] . W ith thevastin fo rmat ionandtheeﬃc ientp rocess ingrate ,v is ioncansuppo rtsevera l ma jo r ro lesdur inglocomot ion ,answer ingthefundamenta lquest ionso f Ma rsha l l[2001] :the detect iono fhaza rds ,these lect iono frequ iredmanoeuvres ,thep repa rat ionandexecu- t iono fchosenmanoeuvres ,andfurtherad justments ,i fnecessa ry ,throughant ic ipat ion [ T res i l ian2012] .

Theeyes ,theper iphera lo rganso fv is ionandap r ima rysenso ryoutposto ftheb ra in , funct ioninacomp lementa ryandcon jugate manner ,detect ingl ightthatisre fracted fromob jectsintheenv ironmento ftheopt ica rray[ W i l l iams1999] . W ithl ightrays pass ingthroughatranspa rentlens ,rep l icat inganinvertedfo rmo ftheenv ironmentto thel ight-sens it iveret ina ,wh ichinturntrans latesl ightraysintonerves igna lsv iarecept- o rs ,ho r izonta lce l ls ,b ipo la rce l ls ,amacr inece l lsandgang l ionce l ls[W i l l iams1999] . The foveaisthenasma l lera reao ftheret inathata l lowsthemax ima lreso lut iono ftheenv ir- onmentthroughfixat ion[Zek i1993] ;there fo rethehumanocu lomoto rsystemupdates po intso finterestthroughfixat ionsandthedenseconcentrat iono fneura lrecepto rs (F igure1 .1) . Thev isua lsystemisthenp r inc ipa l lyfo rv isua lpercept ion ,trans fo rm ing , o rgan is ingandinterp ret ingl ighttotheb ra in . Wherein fo rmat ionisobta inedthrough fixat ions ,saccadesandpursu it movementso ftheeyes .

F igure1 .1-Cross-sect iona lv iewd isp lay ingtheanatomyo ftheeye .

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1 .1 .1 Percept iontheor ies

Themode l l ingandinterp retat iono fv isua lin fo rmat ionrequ ireatheo ret ica lframewo rkto

exp la inthere lat ionbetweenpercept ionandact ion . Thetheo ryo fm indisatheo ret ica l

framewo rk ,wh ichcons iderstheab i l itytoattr ibutementa lstatesandintentso fonese l f

andtheintent ionso fothers ,essent ia lcomponentso fsoc ia linteract ions . Thetheo r ies

o fthem inddatebackasea r lyasthe18

^th

centuryfromthewo rkso fKantand Wundt

where Kant ’sph i losophy wasas ign iﬁcantinﬂuenceonthephenomeno logyandthe

wo rkso fHusser l ,He idegger ,Sa rtre ,and Mer leau-Ponty ,and Wundtfound ingtheﬁrst

exper imenta lpsycho logylabin1879[Kau fer2015] .Ab r ie ftaxonomyo fthedeve lopment

o fthetheo r ieso fthem indisg iveninF igure1 .2 . Oneo ftheea r l ierd ist inct ionscou ldbe

thefunct iona l istso re l im inat iv istsasoneb ranchandstructura l istso rrep resentat iona l ists

o fpsycho logyasasecondb ranchfromthetheo ryo fm ind[Chemero2011,Fodo r1988] .

Structura l istssuggestastateo frep resentat ion ,intent iono rsemant icsasessent ia lfo r

cogn it ivesc iences ,whereasfunct iona l istsd isputesemant icnot ionsfo rrep resentat ion .

A lternat ive ly ,funct iona l istspostu lateneuro log ica l ,behav ioura lo rsyntact iceventsthat

fo rmu late menta lstates . Cont inu ingfromthefunct iona l istb ranch ,thev iewsthat

a rere ferredtoasfunct iona l istcomefromthe Amer icanp ragmat istso rnatura l ists

[ Fodo r1990] : Cha r lesSandersPe irce , W i l l iamJames ,andJohn Dewey[ Dewey1896,

He ft2001,Rockwe l l2005,Chemero2011] . Therea fter ,twofurtherb ranchesextended

fromfunct iona l istsconcernstheva r ietybehav iour ism ,inc lud ingtheeco log ica lapp roach

fromthewo rkso fG i lbertRy le ,R icha rdRoty ,StephenSt ich ,Dan ie lDewet ,andJames

G ibson .A l lthoseunderthefunct iona l istb ranch ,ant irep resentat iona l ists ,be l ievementa l

actsa reunderstandab lethroughthe irfunct ions( i .e . , w ithoutappea ltothoughto r

fee l ing)asopposedtoa m irro ro fnature( i .e . ,astateo frep resentat ion) .

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V isua lcontro lo flocomot ion

F igure1 .2-Taxonomyo fthetheo r ieso fthe m ind ,adaptedfrom[Chemero2011] .

Incontrast ,structura l istsbe l ieveintent ion ,semant icso rrep resentat ionsa reessent ia l

fo rcogn it ionw iththetrad it iona lv iewthatmenta lactsfo l lowedthestructureo f :ﬁrst ,

phys ica lst imu lat iono frecepto rs(e .g . ,v isua lst imu lat ion) ,then ,al inea rser ieso fmenta l

actsre latedtothest imu lusbe fo re ,ﬁna l ly ,abehav ioura lresponse[T itchener1895] .Un-

derthestructura l istb rancha retwosub-b ranches ,computat iona landrep resentat iona l ,

thelaterinaccred itat iontoJerryFodo r . Therep resentat iona ltheo ryo fthe m ind

[ Fodo r1981]comm itstoﬁvehypotheses :1)p ropos it iona latt itudestates(e .g . ,be l ie fs

anddes ires)a rere lat iona l .2)Amongstthesere lat ionsa re menta lrep resentat ions .3)

menta lrep resentat ionshavefo rma landsemant icsymbo l isat ion .4)menta lrep resenta-

t ionshavecausa lro lesasaresu lto fthe irfo rma lp ropert ies .5)p ropos it iona latt itudes

inher itthe irsemant icp ropert iesfromthoseo fthementa lrep resentat ionsthatfunct ion

asthe irob jects[Fodo r1981,Chemero2011] . There fo re ,cogn it ivesc iencetheo r iesthat

semant ica l lyeva luateinterna lent it iesa reava r ietyo fthestructura l istsrep resentat iona l

theo ryo f m indastheysha rethesehypothesesincommon . Then ,ab ranchfromthe

structura l iststheo ryo f m indwou ldbethecomputat iona ltheo ryo f m ind ,computa-

t ion(andcogn it ion)be ingtheru le-governedp rocess ingo fin fo rmat ion .Systemsw ith in

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ferredasa rt ific ia linte l l igence[ Hauge land1985] .Inh isbook ,surfinguncerta inty ,C la rk p rov idesanexce l lentexamp lewhend iscuss ingDennett ’sSL ICEmach ine .C la rkre lates the mach ineasarep resentat iona l mode l ,furtherexp ress ingthedev iceinre lat ionto act ionandembod imentinh isbooko fsurfinguncerta inty ,wherehed iscussescogn it ion asp red ict ivep rocess ing[C la rk2015] .

F ina l ly ,asexp ressedbythedashedconnect iono ftheeco log ica landembod iedtheo r ies ,

wecanseetheeventua lemergenceo fp lura l ism(theacceptancethatsevera lcontend ing

theo r iesa renecessa ryfo rexp lanat ion) . Theo ret ica lp lura l ismisthenthetheo rythat

a l lowssevera lincompat ib letheo r iestogu ideeachotherfo rp rogress ion ,eachident i-

fy ingandreso lv ingfa ls iﬁedaspectso feachtheo ry[ Feyerabend1963,Feyerabend1965,

Chemero2011] .Suchover lapscanbenotedfromthewo rko fDennett[ Dennett1969] ,

andSt ich[St ich1983] ;a rgu ingthatcogn it ionistheru le-governed man ipu lat ionina

log ica l mannerbutw ithsemant icinterp retat ion ,d iﬃcu lt iesbotha rguedcogn it ionwas

thenafo rmo fnonrep resentat iona l menta lgymnast ics[Dennett1969,St ich1983] .It

isthere fo rethatthesehavenotbeenexp l ic it lyh igh l ightedinthetaxonomyasthey

res ideunderbothfunct iona l ismandcomputat iona lcatego r ies . Anotherexamp lein-

c ludesthedynam ica lapp roach[Temp rado2001,Newe l l1994] ,wh ichcons iders muscu-

loske leta l ,env ironmenta landtaskconstra intsw iththepercept ionandact ioncoup l ing

fo ro rgan isedcoo rd inat iono fact ion(F igure1 .3) . Thesedynam ica lsystemsa rethen

s ituat inganagentw ith inanenv ironment ,whereithasbeena rguedthat mean ingo r

cogn it ioncannotbeapp l iedw ithoutaccount ingfo ragentsbe ingspat ia l lylocated( i .e . ,

s ituated)andhavein fo rmat ionfromtheloca l isat iono fthemse lvesatag iveninstant

[ Ba rw ise1981,Perry1983] . Theconcepto fbe ings ituatedisa lsousedinthedeﬁn i-

t iono frobot icsandthe irinteract ionsw iththerea lwo r ldasopposedtothe menta l

gymnast icso frep resentat iona ltheo r ies[Brooks1991,Brooks1999] . Return ingtothe

examp lefrom C la rkandh isre ferenceto Dennett ’sSL ICE[C la rk2015] ;theo r ig ina l

dev ice wasp redeterm inedrep resentat ions , C la rk ment ionsthatanadaptat ion wh ich

a l lowsact ionwou ldthenbeaRobo-SL ICEbuttheeﬀect iveinteract iono fcurrenten-

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V isua lcontro lo flocomot ion

v ironmentswou ldrequ ireaS ituatedRobo-SL ICE[C la rk2015] . Deve lop ingfrombe ing s ituatedcameembod imentandtheembod iedcogn it ivesc iences ,inco rpo rat ingwo rks inrobot ics ,s imu latedevo lut ion ,deve lopmenta lpsycho logy ,percept ion , moto rcontro l , cogn it ivea rte factsandphenomeno logy[Chemero2011] . However ,asperthewo rkso f Dennett[Dennett1969]andSt ich[ St ich1983] ,s ituatedandembod iedsystemswh i le rep resentat iona lo rcogn it ivebasedhaveusedtheeco log ica lapp roachtoreducethe cogn it iono frep resentat ions ,suchasact ion-o r ientated[C la rk1997] .F ina l ly ,thewo rks o fChemero ,whofocusesh isbook"rad ica lembod iedcogn it ion"onchang ingthed irect pathwayo fembod imentfromcomputat iona ltoeco log ica l[Chemero2011] .Inh isbook hedeﬁnesrad ica lembod iedcogn it ivesc ienceasthestudyo fpercept ion ,cogn it ion ,and act ionasembod iedphenomenon ,us inganexp lanato rytoo lotherthan menta lrep res- entat ions . Thesetheo r iescomb ine ,inpa rt ,essenceso fthe ircounterpa rttheo r iesto exp la intheother . Both DennettandSt ichfoundedinthefunct iona l iststr ingwh i le exp la in ingspec iﬁcmean ingstobesemant ica l lyo rgan ised . Mostrecentwo rkshavecon- s ideredthedynam ica lapp roachthatrega rdsl im itat ionso fcurrentab i l ity .Fo rexamp le , therangeo fmot ionanddegreefo rfreedomath ingejo intsl im itsthenumbero fposs ib le outcomes .

F igure1 .3-Mode lo fpercept ionandact ionfo rneuro-muscu loske leta lo rgan isat iona fter

cons ider ings ituatedconstra ints .Adaptedfrom[Temp rado2001,Newe l l1994] .

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Currentdebatecont inuesasto whethersenso ryin fo rmat ionis mean ing less whenit

a rr ivestotheeyeandlatertrans latedinto mean ing fu lin fo rmat ionthroughcogn it ive

p rocess ingo rwhetherthein fo rmat ionbe ingrece ivedisa lreadymean ing fu l(F igure1 .4) .

Theﬁrst ,ind irect ,otherw isere ferredtoasthetop-down ,cogn it iveandcomputat iona l

theo ryo fm inda rguesthatamb iguousst imu lat iono fthesensesfromin fo rmat ioncues

requ iresp rogress ivedeve lopmentintoapercept ,wh ichisident iﬁedandp rocessedby

the m ind[He lmho ltz1925,Ma rr1982,Ne isser2014] . Thelatter ,d irect ,andotherw ise

re ferredtoasthebottom-upo reco log ica lapp roachisthea lternat ive[Bernste in1967,

G ibson1979] . Them indisnotre jectedfromthetheo ry .However ,percept ionandact ion

a red irect lycoup ledw iththeenv ironment ;whatisbe ingperce ivedismean ing fu l ,andany

act ionismean ing fu l ,them indneedsnotinterp reta l lthein fo rmat ion .Instead ,itre l ies

onb io log ica landneurophys io log ica lp rocess ingo ftheb ra in .Coup l ingv is iontoawho le

systemratherthanas ing lechanne l ,theenv ironmentbe ingperce ivedw iththeeyes-

in-the-head-on-the-body-rest ing-on-the-groundastheheadandbody movew ith inan

env ironmentkeep ingtheeyesre lat ivetoasur face[G ibson1979] .Fo rtherema indero f

thethes is ,wew i l lfocusontheeco log ica lapp roach . Thefo l low ingsect ionsw i l ld iscuss

thetenetso ftheeco log ica lapp roachandp resentcurrentev idenceo fhowperce ived

inva r iantscanexp ressbehav ioura lresponses .

(26)

V isua lcontro lo flocomot ion

F igure1 .4-Av isua lconcept iono find irectandd irecttheo r ieso fpercept ionandact ion , adaptedfrom[W i l l iams1999] .A) .Ind irectapp roachwheremean ing lessdataisentered totheb ra in ,there initisinterp retedandg ivenamean ingfo rapp rop r iatedec is ionmak ing anda mean ing fu lact ion . B) . D irectapp roach ,in fo rmat ionisa lreadyrece ived w ith mean inganda mean ing fu lact ioniscomp letedw ithoutthenecess ityo finterp retat ion anddec is ion mak ing .

1 .1 .2 Eco log ica ltheoryo fpercept ionandact ion

Wh i letherootso feco log ica ld irectpercept ioncanbefoundp r io rtothewo rkso fJames

G ibson ,th issect ionw i l lfocusp r ima r i lyonh iswo rksandtheeﬀectstherea fterthathave

inﬂuencedthedeve lopmento feco log ica lpsycho logyasitiscurrent lyknown . Theb irth

andgrowtho fG ibson ’stheo rycanbefoundinthreema jo rbooksexpand ingmo rethan

35yea rso fh iswo rk[G ibson1950,G ibson1966,G ibson1979] .Succ inct ly ,theb irthand

thusthein it ia lbook[G ibson1950] ,hebeganw ithh iswo rkondepthpercept ionwh i le

wo rk ingw itha ircra ftp i lotsdur ingthesecondwo r ldwa r .Rad ica l lychang ingh isv iewson

v isua lpercept ion ,a lreadysuggest ingthatdepthandspaceshou ldinsteadbeemphas ised

bysur faceso ftheenv ironment[Bruce2003] . Th isemphas iso ftheenv ironmentwas

mo resuccess fu l lyexp ressedanddeta i ledratherextens ive lyinh isﬁna lbookwherea lmost

(27)

re ferr ingtotheenv ironmenthere ferredtothecurrentands ituatedsurround ingso f an ima lsando rgan ismsinwh ichtheyperce iveandbehave . F ina l ly ,w ithh islastbook andw ide lyaccepted ,G ibsondeve lopedthree ma inp r inc ip les[G ibson1979,Bruce2003, Chemero2011,Kau fer2015] :

1 .Percept ionisd irect.In fo rmat ionisperce ivedfromtheenv ironmentis mean- ing fu l ,wecanactw ithoutthefurthernecess itytop rocessthein fo rmat ion .In c la im ingso ,percept ionisthennoto fmenta lgymnast icsthroughrep resentat ions andcomputat iona lcogn it ion ,instead ,itisant irep resentat iona l ist .

2 .Percept ionisforact ion . Percept ionistogenerateandcontro lact ion . We perce ivetheenv ironmentino rdertobeab letoactw ithit .Itisfromth isp r inc ip le thepercept ion-act ioncoup l ingis mostre lated .

3 .Percept ionisofaffordances.Fo l low ingfromthefirsttwop r inc ip les ,itbecomes ev identthatd irectpercept ionisfo ract ion ,that mustbegu idedbyin fo rmat ion o faso rt .Affo rdancesa rew ide lyd iscussedfo rthe irinterp retat ion ;there fo rethey a red iscussedlaterino rdertoexp resstheimp ress iontakenfo rth iswo rk .

Theeco log ica lapp roachd iﬀeredfromp rev ioustheo r iesinthatitcoup ledtheo rgan ism

totheenv ironment ,andtheywerenottwosepa ratesystems ,rathertheywerecon-

s ideredasone . Percept ionthroughtheopt ica la rrayd irect lytrans ferr ingin fo rmat ion

o finva r iantsandva r iantso ftheenv ironments ;sur faces ,structures ,layoutsandevents .

Aﬀo rdancesa rethentheact ioncapab i l it iesread i lyava i lab leands izeab letotheact ing

agent .Eachtrans fero fin fo rmat ionbetweenthecurrents ituatedenv ironmentandthe

current lyava i lab leaﬀo rdancesa reframedependentasre levantp ropert iesbetweenthe

twoa recoup led ;thecurrentpos it iono ftheagentw ith intheenv ironmentandthecur-

rentmuscu loske leta lo rgan isat iono ftheagentinre ferencetotheenv ironmentconstra in

eachotherasasynergy[Turvey1986,W i l l iams1999,Kug ler2015] .

(28)

V isua lcontro lo flocomot ion

Thepercept ionandact ioncoup l ingin fersthatfroml im itedinva r iantso ftheopt ica l flow ,coup ledw iththepa rameterso ftheact ionab lesystemfo rmsacontro lsystem . Thatin fo rmat ionfromtheopt ica lflowcand irect lyinfluencethecontro lo f move- mentinadapt ivebehav iour ,contro l led movemento fadapt ivebehav iour ,inturn ,a l- tersthein fo rmat ionfromtheopt icflow[Kug ler2015] . W i l l iam Wa rren wentonto deve lopth iscoup l ingasbehav ioura llawsinthedynam icso fpercept ionandact ion [ Wa rren1988a,Wa rren1990,Wa rren2006] ;interact ionsbetweenbothagentandenv ir- onmento fphys ica l ,in fo rmat iona landtaskconstra ints(goa l-o r iented)fo rmbehav ioura l dynam ics(F igure1 .5) .

F igure1 .5- Thepercept ionandact ionloop w iththecons iderat iono fbehav ioura l

dynam ics .Adaptedfrom[Wa rren2006]

(29)

1 .1 .3 Opt icarrayandinvar iants

F igure1 .6-Amb ientopt ica rrayo faroomfromtwopo intso fobservat ion . Thechange o fopt ica rraycanbeb roughtbylocomoto r movemento ftheobserver ,froms itt ingto stand ingandv iceversa .F rom[G ibson1979]

Re lat ingthep ropert ieso ftheenv ironment w iththed istr ibut iono fsurround ingen-

ergyd istr ibut ionspercept ionisthenspec iﬁctosenso ryin fo rmat ion[W i l l iams1999] .

One ma jo rsourceo fin fo rmat ioncom ingfromeco log ica lopt ica lenergy[G ibson1961] ,

l ightreach ingtheeyea fterthereﬂect ionfromsur faces(notp lanes)andob jects(at-

tachedanddetached) ,eachw iththe irdeﬁn ingtexturesfo rm ingc lutteredenv ironments

[ W i l l iams1999,Bruce2003] .Cons ider ingthenumerouse lementso fas ituatedenv iron-

ment ,thereﬂectedﬂowo fl ightva r iesacco rd ingtothesur faces ,textures ,andcon-

nect ionso fsur faces . Wh i lecerta inﬂowsa reuna lteredandma inta inthe iro rderedﬂow ,

othersa reperturbedandva ry ;ﬂowsthata reuna ltereda reo ftenre ferredtoasinva r iants

wh i leperturbat ionsandchangeso ftheenv ironmenta reva r iants . Thecomb inat iono f

va r iantsandinva r iantssuppo rtsthepercept iono fmot iono fexterna lo rgan ismsaswe l l

asourown[W i l l iams1999] . Todescr ibetheamb ientopt ica rrayinfurtherdeta i l ,an

(30)

V isua lcontro lo flocomot ion

image(F igure1 .6)fromtheth irdbook[ G ibson1979] .Astat icsceneo foneobserverin twopos it ions :thefirst ,seatedpos it ion ,h igh l ightshowtheamb ientopt ica lraysa rr ive andp resentthecurrents ituatedenv ironmenttotheobserver ,thesecond ,isfrommo- t ionbytheobserver ,wheretheenv ironmenthasnotchanged ,buttheperspect iveo f theinva r iantso ftheroomhaved ifferentl ightraysreflectedfromthem . Add it iona l ly , toexp ressthein fo rmat ionp rov idedfromtexturedsur facesandthe irpotent ia linflu- encesondepthpercept ion ,animagefrom[Bruce2003] ,show ingexamp leso fa rt ific ia l gradat iong ivestheimp ress iono farecess ioninthed istance(F igure1 .7) .

F igure1 .7-Examp leso ftexturedgradat ionandanimp ress iono fd istance . F rom [ Bruce2003]

Prev ious ly ment ioned ,the mot ioncausedbyanobserverchangestheperspect iveand

indo ingsothel ighta rraysthata rr ivetotheobserver . G ibson wentontofurther

exp la inth isintermso ftheopt ica rrayandw ith initre lat iv ity :asanobserveractsand

movesthroughanenv ironment ,a l lsur facesandtextureso fva ry ingd istancesp resent

re lat ive mot ionandthelayouto fsuchobstac les . Opt icﬂowisnotﬁxatedasun id irec-

t iona l ly( i .e . ,ﬂowisnotso le lyinoned irect ion) ,rather ,itisdependentonthed irect ion

o f movement( i .e . , mov ingfo rwa rdso rbackwa rds) . The mostcommon lyre ferenced

examp leisfromh isea r lyyea rso fapp l iedwo rkinaerop lanep i lotsandﬂy ingoveran

a irstr ipo r ,ava r iat iono fopt icﬂowasthes idev iewfroma mov ingtra in(F igure1 .8) .

Ashedescr ibedopt icﬂow ,andthein fo rmat ionitp rov ided[G ibson1979] :

(31)

Theﬂowo ftheamb ientopt ica rrayind icates mot ionintheenv ironmentand nonﬂowind icatesastas isw ith inthes ituatedenv ironment .

Outflow ,astheflowexpandsfrominfrontandpasttheobserver ,ind icatesap- p roachwh i leinflow ,asi fcom ingfrombeh indtheobserverind icatesabackwa rd mot ion .

Acentra l isedpo intintheoutﬂow ,thefocuso fexpans ion ,ind icatesthecurrent attent ionandhead ingo f mot ion .

Changesinthepos it iono fthefocuso fexpans ionind icatesachangeind irect ion .

F igure1 .8-Arep resentat iono ftheopt ica rrayexpans iono ftheho r izon( focusonthe ho r izon) ,inth iscasefromthep i lot ’sﬁe ldo fv iew( le ft) ,from[G ibson1979] . Opt icﬂow fromthev iewo fs itt inginatra in(r ight) ,from[ Bruce2003] .

Thecoup l ingbetweenpercept ionandact ionandthenot ionthatchangesintheopt ic

ﬂowcaninﬂuencemoto rcontro lhasp rev ious lybeendemonstrated[Lee1975] .Us inga

purpose-bu i ltroomthata l lowedacontro l ledmovemento fthewa l lso ftheroomback-

wa rdsandfo rwa rdsinducedrespect iveswayo fch i ldrenandadu ltsats low movements

o fthewa l ls .F romth isexamp le ,theﬁnd ingsp resentedacaseo fhowinva r iants(and

va r iants)w ith intheopt icﬂowcaninﬂuence moto rcontro l . Wh i le ,genera l ly ,deta i ls

o fstructurescanva ryw ide lyoverspaceandt ime ,spec iﬁcp ropert iesrema ininva r iant ,

thatispers istencew ith intheopt icﬂow . Asintheaboveexamp le ,intheabsenceo f

inva r iantandon lysubt leﬂuctuat ionso ftheopt icﬂowleadtom im icryo fwa l lbehav iour

bytheobserver . Further ,inva r iantsa rein fo rmat ionthatanobserver mayattuneto

(32)

V isua lcontro lo flocomot ion

spec i fysometh ing . There fo re ,exper imenta lapp roachesineco log ica lpsycho logyshou ld fo l lowthreesteps[ Bootsma1994] :

1 .Inva r iantso ftheopt icﬂowshou ldbeexp ressedasa mathemat ica lfo rmu la 2 . Thesens it iv itytotheident iﬁedinva r iantsshou ldbeana lysed

3 . Theapp l icab i l ityanduseo ftheinva r iantshou lda lsobeana lysed

Cons iderhowco l l is ionavo idancebehav iourscanbetr iggeredw ithl im itedv isua lin fo rm- at ionandinva r iantsintheopt icflow . Asexp la inedbyV ick iBruce ,anobstac leinan env ironmentvo ido fanyadd it iona lv isua lcuesotherthanitse l f ,vo ido ftexturedpat- ternsfo rd istanceands izein fo rmat ion ,the mot iono fitse l fissuffic ienttotr iggeran avo idancebehav iourbytheobserver[Bruce2003] . Fo rexamp le ,i ftheobstac lewere toapp roachtheobserverd irect lyin- front ,theimageo ftheob jectwou ldexpandon theret inao ftheobserver . Whenthetra jecto ryisd irectedtowa rdstheobserver ,the twos ideso ftheobstac lewou ldexpandatthesamerate .I ftheobstac leweretopass perpend icu la rtotheobserverandnotapp roach ,thetwoedgeso ftheobstac lewou ld notincreaseins ize ,butrather ,theywou ldtrans lateacrossthefie ldo fv iew . Th is in fo rmat ioncanbeusedsepa rate lyo rasacomb inat iono fthetwointhep red ict iono f co l l is ioncoursetra jecto r ies .Insuchadep ict ion ,g loba l mot ioncues( i .e . ,expans ion o fthes ideso rtrans lat iono ffixedlengths ides)o fag ivenobstac lewou ldbedeemed suffic ientfo rdeterm in ingat imetointeract ionandalocat ionfromtheobserver .

1 .1 .3 .1 Tau

Whenthetra jecto ryisd irectedtowa rdstheobserver ,anopt ica lva r iab lethatcanbe

usedinthedeterm inat iono ft ime-to-contact( i .e . ,thet imerema in ingbe fo reaco l l is ion

w iththeobserverwou ldoccur)wou ldbeTau(τ) ,o r ig ina l lydeve lopeddur ingab rak ing

task[Lee1976] . Taudemonstratesthechangeso fhowagapisc los ing ,andthegap

isdeﬁnedasc los ingasLeere ferstoanact ion-gapthatispurpose fu lact ionsenta i l ing

(33)

dur ingthedeve lopmento fgenera ltautheo ry[Lee1998] ,a fteritsin it ia lt ime-to-co l l is ion concept ion[Lee1976]andfurtherdeve lopmento ft imetonea restapp roach[ Lee1985] . Fo rafu l lrev iewo fh iswo rkandadvancedunderstand ing ,itisrecommendedtov is ith is labo rato ry ’swebpagepercept ion- in-act ionandtoread[ Lee2011] .

F igure1 .9-S imp l iﬁedv isua l isat iono fLee ’stau ,theopt ica lexpans iono fasur face(R) asitapp roachestheeyeo ftheobserver .F rom[Chemero2011] .

Tauisd irect lyre latedtotherateo fchangeinthev isua lang leo fanob ject( inthe absenceo fp r io rknow ledgeo ftheob jectss ize ,d istanceo rve loc ity) ,wh ichinturnis re latedtothet ime-to-contact . Bestv isua l isedastwotr iang lesinvert ingatthelens o ftheeye(F igure1 .9) ,whereasur face(R)isapp roach inganobserverataconstant ve loc ity(V) .Atag ivent ime(t) ,sur faceRisad istanceaway(Z(t)) ,wheresur face Risp ro jectedatap ropo rt iona ls izeontheret ina(r(t)) . Asthed istancebetweenthe observerandsur faceRdecreasesthep ro jectedr(t)increasesatV(t) :

τ= r(t)

v(t)

(34)

V isua lcontro lo flocomot ion

Tauisexp ressedasarat ioo fanyg ivend istanceatanyinstanto fapo intfromthe centreo fexpand ingopt ica lpattern . Know ingthed istanceo ftheasarat ioandits rateo fapp roachtauisequa ltoZ(t)/V ,wherei fVisconstant ,taucanbes imp l iﬁed asthet imerema in ingunt i lcontact[Lee1976,Bruce2003,Chemero2011] . Tauisan opt ica lva r iab lethatisd irect lyava i lab leontheret inao ftheeye , wh i leitdoesnot p rov ideabso luted istanceso rca lcu latedve loc it iesitisd irect lyperce ivab leandrequ ires nofurthercomputat ion .

Leeandco l leaguesobservedmanyan ima lsinthedeve lopmento ftautheo ry ,onenotab le studybe ingthato fgannetseab irds[Lee1981] .Fo rthoseunawa re ,gannetsa reseab irds thatfly30mabovesealeve landd ive(a lmost)vert ica l lyintotheseatocatchafish nea rthesur face .AsnotedbyLeeandRedd ish[1981] ,thegannets ma inta inedaw ide w ingspanfo rgreatercontro lo fsteer ingwh i lep lummet ingatspeedso f87km/h ,on ly tostream l inethe irw ingsw iththe irbodyasecondfromthesur faceo fthewater .In suchaninstancetheve loc ityisnotconstant ,duetograv itat iona lfo rces ,andthere fo re tauatanyinstantd idnotspec i fyat imetocontact . However ,w ith inthe irwo rk ,Lee andRedd ishder ivedanexp ress ionfo rt imetocontactinre lat iontothewatersur face andsuccess fu l lyfittedacurvefromth isexp ress ionthatre latedtotheactua lt imeto contactanddurat iono fthed ive .

Anotherinterest ingpub l icat ionstudy ingthetheo ryo ftauwastheman ipu lat iono fthe opt ica lva r iab le wh i leattempt ingtograsptau[Save lsbergh1991] .Inth ispa rt icu la r studypa rt ic ipantswererequ iredtoregu latethe irhandaperturesacco rd ingtod iﬀerent s izedba l lsthatwou ldapp roachthem . Theenv ironmentwasdes ignedtol im ita l lv isua l in fo rmat ion(e .g . ,texture ,d istance ,ho r izon) ,pa rt ic ipants wereinada rkroomand interactedw ithaba l lthatwasl itup .Itwasrepo rtedthatpa rt ic ipantssuccess fu l ly ad justedthe irhandaperturestocatchd iﬀerents izedba l ls .

However ,ithasbeena rguedthattauisnotsens it ivetoacce lerat ion ,on lyp rov ides

in fo rmat iono fanob jectinre ferencetotheeyeandnottothehandcatch ingaba l l

(35)

andthattauisnotobservab lefo rsma l lerob jects ;hav ingagreaterro leinla rgeob- jectsaso r ig ina l lydev ised ,theopt ica lexpans iono fca rs[ Andersen2007,T res i l ian1999b, T res i l ian2012] . F ina l ly , wh i letauisuse fu linthedeterm inat iono ft imetoco l l is ion , anotherl im itat ionisthatitdoesnotdetectfutureco l l is ionevents[Andersen2001] .

1 .1 .3 .2 Bear ingAng le

As ment ionedabove ,tauhasl im itat ionsinthathuman movementandinteract ions occuronsevera lp lanes .Taup rov idesin fo rmat ionconcern ingt im ing ;however ,d istances andfutureco l l is ioneventsa readd it iona l lyfundamenta lfo reﬀect iveco l l is ionavo idance tasks[Cutt ing1995] . Wheretheyexp la ined ,basedontheder ivat iveo fbea r ingang le , whetheranobserverw i l lpassinfront ,beh indo rco l l idew ithanobstac leo ranother wa lker(F igure1 .10) . Thebea r ingang leder ivat iveincomb inat ionw itht ime-to-contact hasbeenev idencedinav is ion-based mode lfo rcrowds imu lat ions ,steer ingwa lkersfo r co l l is ionavo idanceus ingthesecontro llaws[Ondře j2010] .

F igure1 .10-Thechangeo rnon-changeingaze-movementang lesfo rano rthogona l

co l l is ionavo idancetask . Theang le w i l lincrease whentheobserver w i l linfronto f

anotherwa lker ,rema inconstanti faco l l is ionw i l loccur ,anddecreasewhentheobserver

passesbeh ind .F rom[Cutt ing1995] .

(36)

V isua lcontro lo flocomot ion

Ap rospect ivestrategythathasga inedincreas ingattent ionintherecentyea rsisthe constantbea r ingang lestrategy . Or ig ina l lybe inginsp iredfromthebehav ioura l wo rkon steer ing[Fa jen2004,Fa jen2007] ,thestrategyfo l lowsagoa lo fattract ionbyanobserver wh i leinteract ing w ithanobstac le mov inga longaho r izonta lp lane . Theconstant bea r ingistheang lebetweentheintendedgoa ld irect ionandtheobstac leitse l f ;i fthe constantbea r ingang lerema insinva r iantandequa ltozerothenbothobserverand obstac le w i l lintercept . A lternat ive ly ,aninva r iantabso luteang legreaterthanzero ensuresco l l is ionavo idancebylead ingtheintersect iono rpass ingsecond(F igure1 .11) . Onestrategyw ith intheconstantbea r ingang lestrategyisacontro llawl ink ingtherate o fbea r ingang lechangetoarequ iredacce lerat ionino rdertosuccess fu l lyper fo rmthe task[Cha rdenon2004,Bast in2006a,Bast in2006b] .

F igure1 .11-Mode l ledso lut ionso fintercept ionus ingaconstantbea r ingstrategy :A) , Aso lut ionthatresu ltsintheobserverintercept ingtheobstac leasbea r ingang leisnea r zero . B) ,Resu ltintheobserverpass ingbeh indtheobstac leastheconstantbea r ing ang leisgreaterthanzero . C) ,Theobserverw i l lpassinfronto ftheobstac leasthe constantbea r ingang leislessthanzero .F rom[Fa jen2007] .

Theconstantbea r ingang lestrategyhasbeenrepo rtedasarobustapp roachfo rwho le

bodyd isp lacements[Fa jen2004] ,wh icha l lowsagentsanab i l itytoadapttochangeso f

thetasko renv ironmenta lconstra intsea r lyoninexper imenta lcond it ionso ratlater

stages[Cha rdenon2005] .Inth isinstance ,theconstantbea r ingang lehasbeenrepo rted

toaccountfo rcont inuedd isp lacementadaptat ionsdur ingcurv i l inea rba l lﬂ ightpaths

(37)

curv i l inea rtra jecto r iesa reimpeded ,asopposedtotrad it iona lho r izonta lo rrect i l inea r exper imenta lcond it ions[Berthe lon1993,Cra ig2006] . Wherethewo rkbyBast ineta l . , [ 2006b]p resentedacont inua ladaptat iono facce lerat iontonu l lthebea r ingang le .

1 .1 .4 Aﬀordances

"Anaﬀo rdancecutsacrossthed ichotomyo fsub ject ive-ob ject iveandhe lps ustounderstanditsinadequacy .Itisequa l lyafacto ftheenv ironment andafacto fbehav io r .Itisbothphys ica landpsych ica l ,yetne ither . An aﬀo rdancepo intsbothways ,totheenv ironmentandtotheobserver ."

—G ibson ,JamesJ . . TheEco log ica lApp roachtoV isua lPercept ion

As ment ionedinthep rev ioussect ion ,affo rdancesa rew ide lyd iscussedfo rthe irinter- p retat ion . G ibson ’stheo ryo feco log ica lpercept ionwou ldhavep remature lyw i ltedand fadedi fnotfo rtherep lyo fTurvey ,Shawand Macein1981 ;the irpaperp rov idesa systemat icexp lanat iono faffo rdances[Turvey1981] . Thea imhereistoh igh l ightp re- v iouswo rksthathavecons ideredtheexp lanat ionso faffo rdancesthroughthere lat ion o fo rgan ismandenv ironment . Thenot iono fanaffo rdancetracesbackto Gesta lt psycho log ists[Koffka2013] :

"Top r im it ivemaneachth ingsayswhatitisandwhatheoughttodow ith it. . .afru itsays’Eatme ’ ;watersays’Dr inkme ’ ;thundersays’Fea rme ’ ."

—Koﬀka ,Kurt .Pr inc ip leso fGesta ltpsycho logy

Aﬀo rdances ,wh icha reo ftenexp ressedasoppo rtun it iesfo ract ionwereacentra ltheme

o f G ibson ’sconceptandbecamea ma jo rthemeo fthe wo rkconductedbyE leano r

G ibson .Inherpub l icat iono fperce iv ingtheaﬀo rdances :apo rtra ito ftwopsycho log ists ,

(38)

V isua lcontro lo flocomot ion

shement ionshowshefirm lybe l ievesaffo rdancesa relea rnedthroughperceptua llea rn ing ; theaffo rdanceo fth ings ,layoutandanyth inganin fantencounters .Interact ions ,then ,o f thenea renv ironmentfromreach ing ,hand l ing ,s itt ing ,craw l ingand(eventua l ly)wa lk ing o fmoto rsk i l ldeve lopmentisthelea rn ingo fwhatthewo r ldaffo rds[G ibson2001] .Pr io r torev iew ingp rev iouswo rksconcern ingaffo rdances ,herea resevera lkeyfeaturesas h igh l ightedby[Fa jen2009] :

Affordancesarerea l . Affo rdancescanbed irect lyperce ivedbyano rgan ismand neednotbeconce ivedbycogn it ivep rocess ing ;suffic ientin fo rmat ionisava i lab le betweentheacto randtheenv ironment .

Affordancesarean ima lspec ific . Affo rdancesa redefinedbytheact ioncapab i l- it ieso fthean ima l :abookaffo rdsl i ft ingandread ingtoahumanwh i leaffo rd ing c l imbab letoa mouse .

Aﬀordancescapturetherec iproc ityofpercept ionandact ion . G ibsonrecog- n isedpercept ionasawho lesystem ,thatisanagentinanenv ironmentthatcan beactedupon ;aﬀo rdancescaptureth isrec ip roc ityastheydescr ibehowan ima ls canactw iththeenv ironment .

Aﬀordancesa l lowforprospect ivecontro l . Thepercept iono faﬀo rdancesa l- lowsfo rtheo rgan isedcontro lo ffutureeventsasandwhentheyoccur . Th is isd iscussedfurtherintheexamp les w ith inthel iterature ;twoexamp les wou ld bethelawso fcontro l[Wa rren1998]andthebehav ioura ldynam icso fsteer ing [ Fa jen2003] .

Aﬀordancesare mean ingfu l . Asopposedtostructura l istph i losophy ,aﬀo rdances donotrequ ireh igher-o rderp rocess ing ,theythemse lvesa reinherent lymean ing fu l anddescr ibewhatcanandcannotbedone( i .e . ,canbeboundtothelawso f contro l) .

Aﬀordancesaredynam ic . AsG ibsonstated ,onemustmoveino rdertoperce ive

andperce iveino rderto move . There fo re ,oppo rtun it iesfo ract ioncomeandgo

w iththe movementthroughanenv ironment .Fo rexamp le ,acha irunderadesk

aﬀo rdstobepu l ledfromunderthedesk ,therea fter ,thecha iraﬀo rdss itt ing .

(39)

Awe l l-knownando ftenc itedwo rkinre lat iontoaffo rdancesisthewo rko f Wa rren andsta irc l imb ing[Wa rren1984] . W ith inthebu i ld-upo fth iswo rk ,he ment ionsthe determ inat iono fapaththataffo rdslocomot iondependsupontheana lys iso fre levant p ropert ieso ftheenv ironmentw iththere levantp ropert ieso fthean ima landitsact ion system :sur facer ig id ityinre lat iontobody mass ,andpathw idthinre lat iontobody d imens ionsfo rexamp le .Hecont inuesbyimp ly ingabody-sca ledmetr icfo rsuchana lys is . The wo rko fthepaperitse l fcons istedo fthreeexper iments ;aperceptua lstudyo f whetherastep wasc l imbab leo rnot ,theenergyexpend iturere latedtothes izeo f thestep ,andcho icetasko fp re ferenceandrat ingo fthesta irs . Theresu ltso fth is studyev idencedtheco rrespondencebetweeno rgan ismandenv ironment ;judgementso f c l imbab leo rnotd iffereddepend ingonthehe ighto fthepa rt ic ipant[Wa rren1984] . Itwasrepo rtedtheaffo rdab i l ityo fsta irc l imb ingcou ldbeaccomp l ishedthroughthe rat ioo fstand ingeyehe ightandleglength . S im i la r ly ,asrepo rtedea r l ierinth iswo rk , adec l ineinthefrequencyo fjump ingthroughanaperturewasrepo rtedwhenaper- turesweresma l lerthan1 .3×thew idtho fafrog ’shead[Ing le1977 ] .Interest ing ly ,the thresho ldo f1 .3× shou lderw idthhasa lsobeenrepo rtedfo rcom fo rtab lepassageo f humanstravers inganaperture[Wa rren1987] . Add it iona l ly ,ithasbeenrepo rtedthat thethresho ldfo rpassagethroughanaperturew ithoutshou lderrotat ionisadaptedw ith changestothebody(e .g . ,theca rry ingo fala rgerthanshou lderw idthob ject) ,o rwhen theapertureiso ftwopo leso rtwohumans[Hackney2014b,Hackney2015b] .

Aﬀo rdances ,asbecom ingev ident lyc lea rer ,a reapp l icab letonumeroustasks ;the

c l imb ingo fsta irs[Wa rren1984] ,frogsandhumanstravers ingapertures[ Ing le1977 ,

Wa rren1987,Hackney2014b,Hackney2015b] ,theaﬀo rdanceso fgaps izesintheﬂoo r

[ J iang1994] ,andsur facesthataﬀo rds itt ingdepend ingoneyehe ighto ftheperce iver

[ Ma rk1990] . Aninterp retat ionsuggestedthataﬀo rdancesa red irect lyre latedtothe

requ irementso fthetask ,aswe l lasthebodyandtheenv ironment[Proﬃtt2013] . Th is

suggest ion(F igure1 .12)sha ress im i la r it iestothedynam ica lapp roach(F igure1 .3) .

(40)

V isua lcontro lo flocomot ion

F igure1 .12-Anadaptat iono fG ibson ’sconcept iono faffo rdances ,extend ingfromjust agentandenv ironment ,thedemandso fthetask ,o rpurpose ,add it iona l lyinfluences affo rdances .Adaptedfrom[Proffitt2013] .

S incetheconcept ion ,therea retwonotab leissueswo rthment ion ing :theﬁrstasinpa rt

exp ressedbytheexamp lesabove ,intheent iretyo fthewo r ldthatweexper ience ,con-

s ider inga l ltheposs ib i l it iesfo ract ion ,weon lycomp letespec iﬁcact ions[Kau fer2015] .

Fo rexamp le ,wh i leanofficecha iraffo rdss itt ingonandadeskaffo rdssuppo rt ingacom-

puterthataﬀo rdswr it ingathes is ,thecha iranddeska lsoaﬀo rdc l imb ingandstand ing

on . Thefo rmerisaregu la r itywh i lethelatterisra re . Duetothenumerousposs ib le

aﬀo rdancesava i lab leatag iven momentandtheinteract ionw ithon lyonehasledto

thed iscuss iono ffurtherspec iﬁcat ionandc la r ityo faﬀo rdances ;name ly ,descr ib ingthe

extenttowh ichaﬀo rdancesa reinv it ing[W ithagen2012,Kau fer2015,W ithagen2017] .

Aseconddeve lopmentwasthataﬀo rdancesshou ldtakeintoaccounttheva r iab i l ityo f

human movement[F ranchak2014] . Argu ingthatcons ider ingaﬀo rdancesw ithcr it ica l

po intswastoimp lythataﬀo rdancesa react ionab lecatego r ies ,anact ionisposs ib le

unt i lacr it ica lpo intis metandthenisnolongeract ionab le . Rather ,cons ider inghu-

man movementva r iab i l ity ,aﬀo rdanceshavetobeexp ressedasp robab i l ist icfunct ions

(F igure1 .13) .Asoneo fthep r ima rytenetso ftheeco log ica ltheo ryo fpercept ionand

(41)

demonstratethatwh i leaﬀo rdancescangenera l lybeacceptedasre lat ionsh ipsbetween theagentandtheenv ironment ,theycanbeinterp retedinanumbero fa lternat iveways . Inthecontexto fthethes is ,wew i l linterp retaﬀo rdancesasgenera loppo rtun it iesfo r act ionbytheagent-env ironmentre lat ionsh ip .

F igure1 .13-A) .Aﬀo rdancesexp ressedasact ionab lecatego r ies ,act ionab lebe ingpos- s ib leo fnotdependento facr it ica lpo int . B) .Aﬀo rdancesexp ressedasp robab i l ist ic funct ions ,arangeo ftasksuccessva r iab i l itybetweenact ionab leo rnottoa l lowfo r va r iat ionso fhuman movement .F rom[F ranchak2014]

1 .1 .5 Exper imenta l methods

Theapp l icat ionand man ipu lat ionthroughpsycho-phys icswasano r ig ina linterestfo r

thestudyo fv isua lpercept ionandinteract ionsw iththeenv ironment . Wh i le ,psycho-

phys icswasa lreadyapp l iedincogn it ivestud iesfo rind irectpercept ionva l idat ions ,a fter

therad ica lapp roachfo reco log ica lpercept ions[G ibson1979] ,psycho-phys icsbecame

increas ing lyimpo rtantinthecontro landunderstand ingo finva r iantsintheopt icﬂow

[ Bootsma1994] .

(42)

V isua lcontro lo flocomot ion

Methodstostudyv isua lpercept ionby meanso fpsycho-phys ics man ipu lat ionhavead- vancedthroughtheyea rs .JamesG ibson ment ionedhowheused methodso fshadow p ro ject ioninh isea r lywo rkfo rdepthpercept ion[G ibson1979] ,E leano rG ibsondeve loped wo rko faphys ica lp lat fo rmandtranspa rentsur facefo rtheinv is ib lec l iﬀ[G ibson2001] . S im i la r ly , manystud ieshavebeenconductedinthep resenceo fphys ica lscenesthat were manua l ly man ipu latedfo rtest ingv isua lpercept ionandaﬀo rdances[Wa rren1984, Wa rren1987,Save lsbergh1991,J iang1994] .Current ly ,amo refavouredtoo lfo rexper i- mentat ionisv irtua lrea l ity[Pan2018] . Th issect ionw i l lcovertheuseo fmot ioncapture , v ideoreco rd ingandv irtua lrea l ityw itheyetrack ingandocc lus iontechn iquesfo rthe coup l ingo fv isua lpercept ionandact ion .

1 .1 .5 .1 V ideo

V ideosa l lowapp l iedpsycho log isttop resentsevera limageso fadynam icscene ,paus-

ingatinstancesp r io r ,dur ingo rd irect lya fteranact ion . Th istechn iquea l lowedthe

observertobeg inimmers ingthemse lvestothescene mo reeas i lythanstat ics l ides

[ W i l l iams1999] .Inbothapp roaches ,pa rt ic ipantsa regenera l lyrequ iredtoobservethe

scene ,wherethe ireyesa retracked ,o rtheya rerequestedtoverba l lyrepo rtbackwhat

theya relook ingatandwhattheya reth ink ing .Add it iona l ly ,v ideotechn iquesa l lowfo r

eventocc lus ionandtempo ra locc lus ion ;eventocc lus ionre ferstotheremova lo freg iona l

spec iﬁcloca lmot ioncueswhereastempo ra locc lus ionre ferstothepaus ingo rremova l

o fv ideost imu l i(F igure1 .14) .Inv isua lpercept ionandact ioninspo rts[W i l l iams1999] ,

readersa rerecommendedtoread[Abernethy1985]fo rastudyus ingeventocc lus ionand

thatrepo rtsasystemat icdec l ineintaskper fo rmancew iththeremova lo fspat ia lcues

wherealoca lcuethats ign iﬁcant lyimpedesper fo rmanceisin ferredtobeimpo rtantfo r

v isua lpercept ion . Tempo ra locc lus ionisthentostopo rremovea l lst imu l i ,fo rexamp le ,

asanattackerinrugbyrunstowa rdsade fender[Jackson2006] . W ith inth isstudy ,a

cr it ica lpo into fchangeind irect ionbytheattackerwasse lectedasatempo ra lre ference

(43)

po int ,occ lus ionso fthev ideobe ingcut-oﬀwerethensetp r io r ,a fteranddur ingth is instant . Wh i letheapp l icat iono fv ideotechn iqueshavep rovenins ight fu linthedeve l- opmentandunderstand ingo fv isua lpercept ion ,neverthe less ,theapp l icat iono fv ideo footageuncoup lespercept ionfromact ion ,suchuncoup l ingcanleadtob iasedresu lts [ D icks2010a] .Furthermo re ,anotherl im itat iono fv ideo-basedexper imenta l methodsis the monoscop icv iewin2D ,whereitisa rguedthatasenseo fimmers ionanddepth percept ionisenhancedthroughstereoscop icst imu lusin3D .Itwasfurthersuggested that3Dmayleadtoegocentr icspat ia lre ferenc ing(se l f-centred) ,whereas2Dmaylead toa l locentr ic(wo r ld-centred)[Kober2012] .

F igure1 .14-Twoexamp leso focc lus iontechn iques :le ft ,iseventocc lus iono fasoccer p layerdr ibb l ingaba l l[W i l l iams1999] ,andr ight ,isatempo ra locc lus iono farugby attackerper fo rm ingadecept iveo rnon-decept ive mot ion[Jackson2006] .

1 .1 .5 .2 Mot ioncapture

Mot ioncaptur ingfo rv isua lpercept ionstud ieshasthree ma incomponentso fapp l ica-

t ion . Thereco rd ingo fnatura landunconstra inedwho lebodybehav ioursinresponseto

p resentedst imu l iwhereanenv ironmentisp roducedw ithphys ica lst imu l i ,asment ioned

above ,andthepa rt ic ipantsa rerequ iredtonav igatetheenv ironment . Suchexamp les

wou ldinc ludeaperturetravers ingandapp roach ing mannequ insonara i l ,captur ingthe

who lebodybehav ioura lresponseso fthepa rt ic ipanttova ry ingrateso fapp roachbythe

mannequ inandthep resenceo fanaperture[C ine l l i2007,C ine l l i2008b] .

(44)

V isua lcontro lo flocomot ion

Further , mot ioncaptureisusedasastepp ingtoo lfo rthep resentat iono fst imu l i .Fo r examp le ,thev isua lst imu l icanbereducedtoapo intl ightd isp lay[Runeson1983b] . Pa rt ic ipants wereab letoident i fyb io log ica l mot ionon-screenanddetectdecept ive mot ionfromal im itednumbero fwh itedotsonspec iﬁcanatom ica llandma rksd isp layed onab lackbackground(F igure1 .15) . Further , mot ioncapturecanbeusedasan inputo fv irtua lcha racteran imat ion ,p rov id inga mo rerea l ist ic mot ionthancomputed a lgo r ithms . Thecaptured mot ioncanthenbeusedaspa rto fapercept ionandact ion studyw ithocc lus iont imepa rad igms[Brau lt2012] .

F ina l ly ,rea l-t ime mot iontrack inga l lowsfo r adapt iveandrespons iveenv ironments ; avata rscanbeembod iedo r wo rktowa rdssuchrea l ist icinteract ions . Fo rexamp le , v irtua lcha racterscanbep rogrammedtofo l lowthepa rt ic ipantsthroughgazeandhead rotat ions[Nummenmaa2009,Na rang2016] .

F igure1 .15-Anexamp lepo intl ightd isp layo fawa lker

(45)

1 .1 .5 .3 V irtua lrea l ity

"V irtua lrea l ityisasc ient iﬁcandtechn ica ldoma inthatusescomputersc i- enceandbehav ioura linter facestos imu lateinav irtua lwo r ldthebehav iour o f3Dent it ieswh ichinteractinrea lt imew itheachotherandw ithoneo r mo reusersinpseudo-natura limmers ionv iasenso r imoto rchanne ls ."

—B .Arna ld i ,P .Fuchs ,andJ .T isseau . T ra itédelaréa l itév irtue l le

V irtua lrea l ityisatoo lthatp rov idesanab i l itytodecoup lenatura lco-va ry ingva r i- ab les ,increas ingthecontro land man ipu lat iono fexper imenta lset-ups[Arna ld i2003] . Intherecentyea rs ,v irtua lrea l ityhasbeenread i lyava i lab lefo rconsumers ,thanksto techno log ica limp rovementsandcostreduct ions . V irtua lrea l ityoppo rtun it iesinc lude head-mountedd isp laysandcomputer-ass istedv irtua lenv ironments(CAVE) ,wherea userisimmersedinav irtua l wo r ld(F igure1 .16) . Theapp l icat iono fv irtua lrea l ity hasp rovenanove landpower fu ltoo lfo reco log ica l percept ionandact ionresea rch [ Loom is1999,Ta rr2002] .

F igure1 .16-Twoexamp leso fimmers ivetechno log ies :le ft ,apa rt ic ipantus ingahead

mountedd isp layfrom[Brau lt2012] ,andr ight ,apa rt ic ipantfromthestudyw ith inthe

append ixo fth isthes isus ingaCAVEenv ironment .

(46)

V isua lcontro lo flocomot ion

Ab r ie fandsucc incth isto ryinthedeve lopmento fv irtua lrea l ityandtheconceptso f immers ionfindsitsrootsw ithIvanSuther land ,p red ict ingtheimmers ivev irtua lwo r ld andhead-mountedd isp lays[Suther land1965,Suther land1968] .A lthoughthefirstHMD datesback muchea r l ier ,itisthep red ict iono fSuther landwheretherootsa re mo re grounder[S later2016] . Thesystemsa remostcommon lyknownbetterresemb lethev ir- tua linter faceenv ironmentwo rkstat ion ;afu l lv irtua lrea l itysystemw ithheadtrack ing , w idefie ldo fv iew ,aud io ,bodyinco rpo rat ionw ithtrackedg lovesthata l lowedv irtua l interact ionsthroughhapt ics[ F isher1987,S later2016] .Later ,immers iveCAVEsystems weredeve loped[Cruz-Ne ira1992,Cruz-Ne ira1993] .Independento fthesystem ,ane f- fect ivev irtua lrea l itysystemsurroundstheuserina3Dwo r ld ,wheretheuser ’sheadis trackedino rderfo rthep ro jectedimagestobeupdatedinre lat iontotheuser ’shead pos it ionando r ientat ion . Further ,usersshou ldhavetheab i l itytointeractw iththe env ironmentthroughthetrack ingo ftheuser ’sbody ,trackedhandhe lddev ices ,g loves , ajoyst icko ra mouse[S later2016,O l iv ier2017] .

Immers iondescr ibesthetechn ica lcapab i l it ieso fasystem ,thephys icso fthesystem , thatp rov ideanimmers iveexper ienceasdeﬁnedbythreecomponents :1)3Dstereo v is ion ,2)surroundv is ion ,theexterna lwo r ldisexc ludedfromcurrentv isua lpercept ion , inc lud inga fterheadrotat ions ,3)dynam iccontro lo fv iewpo int ,theuser ’sheadpos it ion shou ldbetrackedtoupdatethep ro jectedd isp layinrea lt ime[Pan2018] .Asub ject ive co rre latefromimmers ionisthesenseo fp resence ;whentheuserperce ivesthev irtua l wo r ldinanatura l waytheperceptua lsystemin fersthat whatisbe ingperce ivedis thecurrentactua lsurround ings[S later1997,S later2016] . Thesub ject ivei l lus iono f p resenceisthenthe"senseo fbe ingthere" ,be ingw ith inthev irtua lwo r ld[P imente l1993, Ba rﬁe ld1995,S later2016] .

Adeta i ledrev iewo fv irtua lrea l itywasrecent lycomp leted[Pan2018] ,there in ,severa l

interest ingandadd it iona l lycomp rehens ivecommenta r iesd iscusstheapp l icat ions(and

l im itat ions)o fv irtua lrea l ityfo rsoc ia linteract ions[ delaRosa2018,Ku l ik2018] .V irtua l

rea l ityperm itstheab i l ityto max im iseexper imenta lcontro lo fthev isua lenv ironment ,

(47)

whereoneva r iab le maybea lteredatat imetotestitsinﬂuence .Soc ia lfeatureso fa v irtua lavata rwou ldbeap r imeexamp le ,chang ingthep igmentat iontoinvest igaterac ia l b iases ,o rthegender[S later2014] ,o r ,chang ingtheappea ranceanddens it ieso fcrowds [ Bruneau2015] .Anotherexamp lewou ldbethecontro lo ftheinteract ives ituat ion ,how theuserinteractsw iththev irtua lenv ironment[C ir io2013,O l iv ier2017]o rthebehav iour o fthev irtua lcha racter[Gr i l lon2009,Hu2016] .

Thestudyo fpercept ionandact ionthroughimmers ivetechno log ies(F igure1 .17)is

notw ithoutitsdrawbacks[F ink2007,Pan2018,Ku l ik2018] :va r iancesbetweenrea l-

ityandv irtua lrea l ityhavebeenrepo rtedfo rdepthpercept ion[ Loom is2003] , wh ich

isnotnecessa r i lyre latedtoarestr ictedﬁe ldo fv iewfromhead-mountedd isp lays

[ Creem-Regehr2005] .Systemat icspat ia lest imat ionsmaybearesu lto fnotbe ingab le

toseeone ’sownbodyinv irtua lrea l ity[Ph i l l ips2010] .A lternat ive ly ,thememo ryo fthe

rea lenv ironment ,whenbothv irtua landrea lenv ironmentsa reident ica l ,ver id ica ld is-

tancepercept ionsseemsposs ib le[Interrante2008 ] .Further ,therateo fopt icﬂowfrom

fo rwa rdgaze-dr ivenspeedhasa lsobeenrepo rtedtobeunderest imated[ Banton2005] .

Add it iona l ly ,v irtua lrea l itycanp roduceundes ireda rte factso fthep ro jectedenv ironment :

m ismatch ingl imblocat ions ,latencyinmovement ,o rincongruentcues[delaRosa2018] .

Neverthe less ,desp itetheposs ib leva r iancesanddrawbacks ,v irtua lrea l ityhasbeenva l-

idatedfo rtherep roduc ib i l ityo fstereotypedwa lk ingtra jecto r ies[ C ir io2013]thatcanbe

foundinrea l ity[ H icheur2007] ,desp iteinteract ive methodssuchasa mouse ,keyboa rd

o rjoyst ick[O l iv ier2017] . Wherein[ O l iv ier2017]s im i la rco l l is ionavo idancebehav iours

wereobservedwhennav igat ingw ithajoyst ick ,add it iona l ly ,thenot iono fpersona lspace

is ma inta ined[ Gér in-La jo ie2008,Arge laguet-Sanz2015] .

(48)

V isua lcontro lo flocomot ion

F igure1 .17-Anadaptat iono fthepercept ionact ionloopthatcons idersimmers ive techno log iesapa rto ftheloop

1 .1 .5 .4 Eye-track ing

Thev isua lsystemp laysav ita lro leinthep ick-upo fin fo rmat ion ,throughﬁxat ions ,sac-

cadesandpursu itmovementso ftheeyesobserversa recapab leo fnegot iat ingcomp lex

andc lutteredenv ironments[Ma r igo ld2007,S i lva2018] . Asev idencedbytheopt ica l

inva r iantsp rev ious ly ment ioned ,soc ia linteract ionscanthenbegu idedand mode l led

basedonv is ionandopt ica lva r iab les[Ondře j2010,Fa jen2007] . There fo re ,eye-track ing

canp rov ideagoodind icat iono fwherev isua lin fo rmat ionisobta inedfo r moto rcon-

tro l[Pat la1997,Wa rren1998] . S im i la r lytov ideo ,throughtheapp l icat iono fg lasses ,

v isua lcuescanbeident iﬁedandtestedthrougheventocc lus ion ,tempo ra locc lus ion

andw itheye-track ingeventident iﬁcat ion(F igure1 .18) . Eventocc lus ion(andd isto r-

t ion[Rushton2001,Wa rren2001])andtempo ra locc lus iona res im i la rpa rad igmstothose

exp la inedw ith inv ideo methods ,there fo re ,th issect ionw i l lfocusoneye-track ing .

Perception visuelle du mouvement humain dans les interactions lors de tâches locomotrices

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To cite this version:

Sean Lynch. Perception visuelle du mouvement humain dans les interactions lors de tâches locomotri-

ces. Education. Université Rennes 2, 2018. Français. �NNT : 2018REN20046�. �tel-01944500v2�

T HESE DE DOCTORAT DE

L ’UN IVERS ITE RENNES 2 C OMUE U N IVERS ITE B RETAGNE L O IRE E COLE D OCTORALE N ° 603

Educa t ion , Langages , In terac t ion , Cogn i t ion , C l in ique Spéc ia l i té : STAPS

V isua l percept ion of human movement dur ing wa lk ing task interact ions

Percep t ion v isue l le du mouvemen t huma in dans les in terac t ions lors de tâches locomo tr ices

Thèse présentée et soutenue à Un ivers ité Rennes, le 24 Octobre 2018 Un ité de recherche : Laborato ire M2S - EA 7470

Par Sean LYNCH

Rappor teurs avan t soutenance :

V ic tor ia INTER RANTE Pro fesseure , Un ive rs i ty o f M inneso ta

N ico las BENGU IGU I Pro fesseur , Un ivers i té de Caen-No rmand ie

Compos it ion du Jury :

V ic to r ia INTER RANTE

Pro fesseu re , Un ive rs i ty o f M inneso ta N ico las BENGU IGU I

Pro fesseu r , Un ive rs i té de Caen-No rmand ie G i l les MONTAGNE

Pro fesseu r , A ix-Ma rse i l le Un ive rs i té Isabe l le S IEGLER

Pro fesseu re , Un ive rs i té Pa r is-Sud

D i rec teu r de thèse R icha rd KULPA

Ma î tre de Con fé rence HDR, Un ive rs i té Rennes 2

UNIVERSITÉ RENNES 2 – HAUTE BRETAGNE Un ité de Recherche 7470

Eco le Doctora le – Educat ion, Langues, Interact ion, Cogn it ion, C l in ique Sous le sceau de l’Université Bretagne Loire

VISUAL PERCEPTION OF HUMAN MOVEMENT DURING WALKING TASK INTERACTIONS

Thèse de Doctorat D isc ip l ine : STAPS

Vo lume

Présentée par Sean LYNCH

D irecteur de thèse : R ichard KULPA Co-d irectr ice de thèse : Anne-Hé lène OLIVIER

Soutenue le 24 Octobre 2018

Jury :

V ictor ia INTERRANTE Professeure, Un ivers ity of M innesota (Rapporteure) N ico las BENGUIGUI Professeur, Un ivers ité de Caen-Normand ie

(Rapporteur)

G i l les MONTAGNE Professeur, A ix-Marse i l le Un ivers ité (Exam inateur) Isabe l le SIEGLER Professeur, Un ivers ité Par is-Sud (Exam inatr ice) R ichard KULPA Ma ître de Conférence HDR, Un ivers ité Rennes 2 (D irecteur de thèse)

Anne-Hé lène OLIVIER Ma ître de Conférence, Un ivers ité Rennes 2

(Co-direct r ice de thèse)

Inlov ing memo ryo f myfather .

Iameterna l lygrate fu lfo ryourgu idanceandpat ience ,

youa lwaysencouraged myl i fecho icesandfo r metolead myownpath . Youwere mybestfr iend ,

I m issyou .

Pau lLynch

(1972-2018)

Contents

Introduct ion 1

1 Background 5

1 .1 V isua lcontro lo flocomot ion... 6

1 .1 .1 Percept iontheo r ies... 8

1 .1 .2 Eco log ica ltheo ryo fpercept ionandact ion ... 13

1 .1 .3 Opt ica rrayandinva r iants ... 16

1 .1 .3 .1 Tau... 19

1 .1 .3 .2 Bea r ingAng le ... 22

1 .1 .4 Aﬀo rdances... 24

1 .1 .5 Exper imenta l methods... 28

1 .1 .5 .1 V ideo... 29

1 .1 .5 .2 Mot ioncapture ... 30

1 .1 .5 .3 V irtua lrea l ity... 32

1 .1 .5 .4 Eye-track ing... 35

1 .2 Interact ionsw iththeEnv ironment... 38

1 .2 .1 Percept iono f mot ion... 39

1 .2 .1 .1 Percept iono fd irect ion... 44

1 .2 .1 .2 Percept iono fspeed... 48

1 .2 .1 .3 Mot ioncues... 49

1 .2 .2 Persona lspace ... 52

1 .2 .3 Co l l is ionAvo idance... 57

1 .2 .3 .1 Co l l is ionavo idancecha racter ist ics... 58

1 .2 .3 .2 Pass iveobstac le... 61

2 Ob ject ives 81 3 Co l l is ionavo idancebehav iourbetween wa lkers : g loba landloca l mot ion

cues 87

3 .1 Ob ject iveandcontr ibut ions... 89

3 .2 Method ... 90

3 .2 .1 Pa rt ic ipants... 90

3 .2 .2 Appa ratus... 91

3 .2 .3 Exper imenta lsetup... 92

3 .2 .4 Cond it ions... 93

3 .2 .5 Task... 95

T ^HESE ^DE ^DOCTORAT ^DE

L ’UN IVERS ITE RENNES 2 C ÔMUE U ^N ÎVERS ÎTE B ^RETAGNE L Ô ÎRE E COLE D OCTORALE N ° 603