Visual Guidance of Goal-Oriented Locomotor ...

Ecological Psychology

ISSN: 1040-7413 (Print) 1532-6969 (Online) Journal homepage: http://www.tandfonline.com/loi/heco20

Visual Guidance of Goal-Oriented Locomotor Displacements: the Example of Ball Interception Tasks Gilles Montagne & Michel Laurent To cite this article: Gilles Montagne & Michel Laurent (1998) Visual Guidance of Goal-Oriented Locomotor Displacements: the Example of Ball Interception Tasks, Ecological Psychology, 10:1, 25-37, DOI: 10.1207/s15326969eco1001_2 To link to this article: http://dx.doi.org/10.1207/s15326969eco1001_2

Published online: 08 Jun 2010.

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Visual Guidance of Goal-Oriented Locomotor Displacements: The Example of Ball Interception Tasks GiPles Montagne and Michel Lawent Facult@da Sscieflces du Sport, Malset'lle, France

Alain h e y Ecole Nmmale Supdrkxre, CIlchan,Fwtce

riMldecreases linearlywirh distance, such informationis not very useful for visually guiding &.oriented displacements in action space. hbeowr, hecause the ball's optical expansian pattern cannot be perceived in the actionspaee either, inbmatbn that includes this component must be ruled out. Oivm the previous1~mentioned limitations of the human perceptual syarem, be fonaal models that have been proposed involve monocular infoxmation W on the optical patems &placement generated by the moving ball. Following Chapman's (196@ original model, only Tadd (1981) and Bmncado (1955) twk aninterestin the information likely tobe used in this typeof task,More recently, Michaelsand Oudejans's (1992) w z k triagered a new wave of research rhat spinked oEa large debate(e.g., DannemiUW et aI.. 1996;Mclhtk SchafSr, &Kaiser. 1995a). The h t part of this reofew presents the m perceptual strategies pxoposed so far: optical acceleration cancelladon (OAC) and h e s t optical trajectory (LMI'). The curcent state of the debate heween the advocates of these two senrregies is then discussed. A few final remarks wilI ammpt to reframe rKe debate relative m theoretical approaches of perception and action.

Chapman (1968)w s the first to propose rhat one of the potensid sources of hfomation in mobile interception tab dving riae to a locoraotor displacement was the ue~lopticalacceletationofthe ball. Thisiofotmationis thoughtm aUow the subject out such a task to position himself in the right place at the right time. The player wing this atmtegglhas ody t~ cam1 the optical acce1erauion of the ball by producing the appwptiare lowmotor dispiacemmt. Bmcario (1985) oritidzed the OAC t h q b e w e it ignores the resistance of the air and, using &mulations, showed that if air resiktance is taken hto account, substantially Metent ball trajectories are obtained. However, it seems that this argument need not be regarded as ia.rralidacingChapman's ti9681 perceptual straw. Indeed, the aAC s t r a w rqrtires the s&@ct to adapt his ~ o O ~ ~ displacement O E O ~ patrem online, based on information that +s the "state of the actor-envitonmenr systemn CBootsrna, Fayt, ZaaL &Laurent, 1997). In theresearchconducted to h e , optical acceleratim is denoted dl~)/&&fichae~s & Oudejans, 1992) pr dZ (tan a)ldt (e.g.., McLwd &Dimes, 1993), depending on whether the model is based on p h e or angular geomeap (Figure1; Equation 1).

lf the optieal acceleration is positive, the player knows the ball will lend behind him; if it is negative, he haws it wilI land in front of him. An optical accderation

of zero @quation2) infom him that he wlll be located in the right place at the right time (&cure 2).

Conmp~ to what Flgyre 2 might suggest, the OAC smtegy does more than just allow the player to cham a &en mQde of action Warren, 198&), that is, m e forward, tdcward, or not at all. Once the actionhas begun, (hemcegy also allow him to c m l his action onhe to get to the MtpIace ar the right the. By zeroing

LINEAR OFFICAL TRAJECTORY

y PICURE 4 (A) O p d qwnci&a "m~lwd'm the LOT smtqy: o p t i d r r a j e b ~ projection angle (y),vntic.1 angle (a)subtendedar the obaervawo painrb the ball's hvmntPaenv locadon and h e h d o 1 m l mdbaimodr~gk (B)subtended at r k o h t i o n pdru by dx

and the lateral angle (R) subtended ar the observation point by the ban's launching point (or any other fixed point in the enviranmant),and its current Iocation must stay pmportional (Equation 3; b a d on McBeaxh et al., 1995a; Figure 4).

tan~=tana/tanfl=C,

(3)

This perceprual suategy requires keeping the optical uajectoq projection angle consrant via the cancellation of the curvature of the ball's optical path, which is achieved by moving in the appropriateway. Consequently, using the LOT strategy has repercussions onboth the shape and the kinematic properties of the loc~nomr displacementsproduced. "Extreme"values for angle ly, rhat is, ones rhat approach 0" or 906,force the player ta produce hi&-velocity locombtor displacements with u a j e c d e s that have very highcurvature, to keep a and 8 proportional. According

Points of merit Two a r l i n e a i k r p W i o n . r m ~ s . Both of these perceprual smwgies (LOTand OAC) are qiite elegant in the ,sensethat they a nor based on ha teJI k l e d g e @cheehe.ptopertiq.ofthe t o - b e - i n ~ ~ c e p t e d ~Its mtrafectoq;, d the pkym qbukthe state & w a u t ~ - e n'. t~preh (&o@~.etal.,1997). Thrs gives thefH.Homeomdprndictive C a E e s . b y &onot supply qwntitai tive inbmtion (expressed.&meWd ot innirtsic unia ofmemr&bur simply ~ f l &ephyer wherhet the m e beingma.& isthe right &or rhe taskat hand. ifthe player &@s in .& use one of chea p r & , ~ a l s~tegies,he d e not irt?oiar in advancewhere orwhen the ball d lland;heissimplp using an4'onlineadaptation scrategf (Eepet, Bwt~rna,. Mesae, &.EaLker, W),that w3blead &.:to &e &ht placeat rhe right The ,at@@@tg$atlitBgainst h e stmte$esh@e m&p been @tifainadh: fietd,ob~ations.(Ad&, 1995; Chodaph, tifbon,'&T&ii 1995;Jacobs, 1995). Chodosh et:aL,for example, viewd videoof I'Bhitll m~hes:bprohsiona~ baseball games. Conrrary'to what is assumed in onttne.adap.adon&ategies, the play@ w&re&a& bed 9be stationargat the me hey cahse in conrtadx wifh rlie ball, Thiswgeeaq tbat highlyskilledplayqn @:a mtegy Ghat a h % chun t6 predetermine:&e place and t h e of.landing(Saxkzg, l%FB?a,l$%Tb).ia&e&au aa .anline adapra& strategy, Hewever, some aspects afthe work of Chodosh er ai. r* d a r , &en?&tb~imiciagthe iatmst &the r d € spresented. Some informat@n,.su&as Lhestx@ple f r q u ~ thenatlrre q ~ ofthe he u#wtoriesi or the criterion used to determine .&at the act%@.st@ionar)tat eonwr, ip mr repod. No~over,the LOT strategy is flexible, insofar as the o p t i d u&crory linearlzatibn ir involva $ independent of the .optical trajectW pm&tio& an& "chosen" fMcBeath e d . , 1R95b)..M8fllgliniDg the b e e of the Ogt&L@jjectocy d g i ~ r i s to e Ioc~tordisplacement pgtkems that d i t k and cpne~enttyw$! y&t in difterrentdocities at eontact, as a herion ofidre artgt~fhosen,~eLeo~ SndBenes el9961 v a b d optical trajec@ry@.+@on repom w3@that .are w.mp~&lewith che Re of an oplihb adapra&n.s@te@. They analyzedthe l o c o m q t o r d i s p h c m e n t p prodpced ~ byaplaw*hh for a &en landiog poinf, che rhe'a hunch angle and velocity varied (is.,the plaid hid a variable k t o f c i m e t o p teehe landirgpint). Tne resultsdhopped &t in every case the (playerw not. sranding sdU':5 thebalh l,andhgpoint but had

THE OUTFISWER J?ROBLEM 31 chosen a displacement pattern that mabledhim to arrive at the contact point ar

the same dme as the b d . The secondmaforcrltichof online adaptadon strategiescobcems rhe faotthat chey require permanent visual anchoring on the ball. However, Aeld obsewatiom have proven tkrt this is mt always the case (Chcdosh et at. 1995;Jacobs,1995). Mc8eah et aL (199%) saessed rhan until an analysis is coaduoted to detennine therainfmalsamplingftequencytequiredfmmahrainingaliaeardiqlacernent,my statements on thls subject should be aeated with cawion. Points of Dhapement

The issues rhar oppose the advocatebofthe two perceptual saategb hinge on (a) potentialimpztmentationproblems,(b)the respective scopes of the two strategies, and (c) the inrerptetation of the results. ImpIetnentation of tkealrategiea. Different pammeters are controlled in the wtosaamgies described. QAC is basedonthe control ofa temporal parameter. LOT is based on the cancellation of the curvature ofthe o p d d disDkcement and thus on the conaol of a spatiotempod pa-ter (~anne&eree&, 19%). The question of how these two strategies are implemented adds hel to the debate. MJBeathet a!. (1995a), for instatice,speakofthe possible limitationsofthe human visual Vtem for peneiving optical acceleration. Various studies have, in fact, questioned human sensitivityto optid acceleration (e.g.,Todd, 1981). Aceording toBabletand Dannemiller (1993),Todd's (1981) resub are due to theuseofopticaI acwlerationratesthat are &low the detecdon dueshold. They showed that assoon as the acceleration gets high enough-that is, when the optieal velacity ratio is a b e the threshold (estimated ar 20% by the authors), as it b in virtual& d l trajectories not destined tosaikethe actor bemen t h e w t i o n o f t h e balI'slandinpphcebasedon tNsMomaationgetsmudrbe~er.MotOntythevettiai1 ~ the actor% not on a collision come acceleration exceeds the threshold as s o a as with the ball, but also the threshdd is passed earlier when the remaining distance to wvet is Large. Moreover, T & (1995) showed that it was indeed possible to implement the OAC saategyeven when thecMlstraintsthat limit human performancearecodered (includinga u l t y -thrg optidaocekration).Note, finally, that variouspercepdsystems(visual, vestibular,proprioeeptive, etc.) may wnaibute joindy to detecting vertical optical accehtion (Stofhegen & Ridm, 1988; Oudejans, 1996). Gnceming the LOT strategy, it seems that the human visual system is fhx able to detect optical curvame WaLhoven,Snippe, &To& 1992). In their study, Werkhoven et al. (19921show that the visual system is more sensitive to changes of direcrion than to the changes of optical velocity. Although no etudy has shown that the degree dsensitMty to the optical curvatureis s&cient to m& the LOT

sttareg.y operational Qannemimec et

a,l!%),,the

resub of W~khovenet aL

(1992)lead w mthiak thatthe,actar% able to implement# h eLIOTstia@gy catc't2ingwi&.loeomotot*la-D.

inbaII

THE (XTTmsIDER PROBLEM

33

TABLE -- I

Summary Table of the Vanw BaperimentalShuHes Aimed at D e h m M qZhe Visual Guidance StrategiesTmplemant~d in Bdll CatchingTasks Requiringa bminobr Displacglnent

Favor om

Favor OAC

E m OAC

Ase the Two Strategies Complementary?

Oudejans srres+ that the verdral optical ecceletatibn ha #I1 rhe features of

an Wvatient En the hetbwmsenae af the f e w . Hcmewr, when the .mle$t@rgof tlw b$l &du@ a &@~tt+laptic Coqonent, &e invaflit.ntis w.sufAcient to ,ip.@i@the stat~~ofche mtem,.and rhe actor hrrs tause motherinn;triant (based

in chis case on the panem of horizonral displacement; Chapman, I%!@)., -Pusso& h g severad invatiaatsm access the relevant properw of the:act~t-e'iivitron-

mtnt'sysremdeprives che perceptual 8preimss&its &e paislmonious~ch9racrer. %et&%essityt@ We ouoit1~1i8tit#m8jr~~simp'tyr&t.the(tegpxqj itvlbility of the reSe.ar&emm .fprmake within one mthematieel tom& the generic inmtanc, &ch wuld be used whatever rbe aajeaory. The samedoes hold m e 'of &e .staceglr prowed! by .M&!eaah et al. (1995a), to eht? e* '&t n@y rnrrim@i&g a ~ M ' m a phM1dlt to be insuf&&fitfor@&gaqeg to b e cwepE ,state of t h e a c t o t - e n v k ~ wdys* in whiqh c& r e o o k .@s,omeorher invarimt (su&.a,s varti~alopdml acceletatbn) is needed. Mekth,et al/1'99@ seem to* to chisstate by m a l d y ,espousing the f n r n e w d of cue t h e q (Gregorgl 1966):.Anyway,,no inregated percep~ua1s~rategp,.ab!e to lead independe~d'y&smrheconsnaih.~ thehpztor to rhe tighrphceat the I$&@@, @&+ f w d & &g 'M~seover,the srraregie* p r o p u d ao Ilaz W T and QAC)do no,t accounr 'hr the way whieh idawatiw is,inregrated to c o n d displacement (see M.ichd6rBeek, 1995, fcjr a disemsioa). 1n rhis respct, the nark of Boq@rg@ and: oollaborqors (Peper et al., 1994; BGatsma, 1958;1Bootsg.aet:;d., 1'9971is ~ n ofe the :first anrmpe tQ pmpw e mimy model af the r e l a t i ~ , ~ l i ~ ~ n perception and action. Eor the task of catctiing a ball consmind on a sin& ,axis,.htsmaet.aI. (1997) p r ~ e adsmfqaiming at (a) optically accejising: tfie rekvancproperly of tke.a@tor.+3ivkotrments j t s q (i.e., the rdquired speed offhehad) and (b) inregrating the infinmarionfor scow ofthe w & e n t &t %@elorationwutd dedepe adupon& gap &.meathereqrdred~peedand the e m n t . apced),. Fhe strategy fowdliuxl by boa^ et~d, rembles rhe strategies of wntiawus a m i presentedinfhb revia. The seror b sure to be at & &$,t p& the dght *e by m d n g m(nr&t on bagis. in&t t l w a- ~ to &:relevantmW of &e- a o m r * u i r o ~ ~srstenz ~~~ 'Mo.Ww, tb its credit, them&! m t e d by 'Bootsioaet al, o@m anintegrating mechanism of rhe info~nta*to 090.troI the mmment.. Th.e h e oftbe generaliza&x~fthistyaeofmadel to all rhe interceptivetasks hgs robe addtwd For dEe & w r r i e w & ~ & ~ l a ~ ~ ~ w ~I&o n , I&-t pqetp &'the a m - i r o r u n e n t w k @u@d to to thesole

amre re.

quired#;hheditDcrlonhtlisp~df+~~~m~~@. b i t &t f'gi!ure lormabtion *.have to (a) identify the rnertc f t is

invwkqt qsed,,@$link&invarisntarith, the re1evant~pertyaf~e acacpwwir q n m r wstem, and Cc) desuibe the mcdakityofthis~&n of theinformation townaol~edisp~acement.In,.&ecune~scaretifthearc, cbequegtioslofthevtsed remains arnmredl ,guidgnc.eoflwwaomr&-nts ~

~

ACKNOWLEDGMENT

We ha& William Mare, C h Mchaak, Jim Danndler, and Tim Babler for rfie'u helpful comments on the manuscr@t

Juwhs,T.M, Lawrewe. M.D., Hcmg, K,Oiordamo, N.,1s.. &Gbrdano, N., SI.(1996). On archhg &Ids: TTahnical common*. Wmce 273,256457.