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Control Mechanisms Influencing Reversible Figure Perception
66
J. RadJ.10v'. T. RacUl.-Vei.a
XDetitute
o~
Pby.iol.ogy. Czeobo.10vak Academy
o~
Soienoe ••
Prasue, Czeobo.l.ovaki,a 5' FT' Uai.Ds a pby.ioal.l.7 identioal. rever.i.b1e ~i.gure it· va. £oUDd tbat the ~reqaenoe o~ rever.al.. iD a tbree-cU.eneioDal. iDterpretatiOD v.a .bout two tt.e. lover tbaD iD the two~eD8io Dal. 0Ae.
Reveraibl.e ~i.surea (l.,2,1,4) o~er the po.aibi1ity o~ objeotive ana17aia o£ .ubjeotive a.peot. o~ vi.ua1 peroeption. the que.tion v_ iDve.tipted iD the pre.ent paper vhether the time pattern &Dd rate o£ ~i.gure rever.al.. were ~£erent iD tbree aDd twocU8elUJioDa1 peroeptual. apaoe de:rined b7 _&De o£ pr.vioue .zp.rimenta1 inetruotiOD siven to the aubjeot.. A .peoial. r.v.raibl.. :risure o.Uecl -:tr_- or Maob' a trunoat.d pyra-ide ha. been _.d. :U 0_ b. iDterpret.d either .. • tbree~neiona1 oono.v.OODV.Z or a twocU.enaiODa1 ODe, iD both c •••• with .pontaDeoue al.t.rnation ~ the two poaaib1. perc.ptua1 ver.iOAe. 12 .ubjeot. vere e-.p107.d, l.l. vere hich .obo01 .tudeDt., l. teohDi.oa1 ••ai.t_t (9 ~eaa1 •• , , -.!.e.), naiv. _ to the pur1.. "vereib1e 1'isare oa11ecl -:rra-- uaecl iD e:q»epo.e ~ the ezpW~t &Dd palcl ri.aeAte. 1'or ~1r aervice•• ~ .ubjeot' •
ac.
wee 20,7' ! 0,9'. aD 1IIJIa01aterecl chair iD aD aoou.U~ elda1clM . . . .darkecl ....."".. (~ Z 2a Z l.,518), ~.... iD :f'rOIlt ~ tbee tbe iU·wtnaCecl pattenl fd tbe -:rr.-(n.. l.). :It v_ • 2, Z 2, _ clraw1Dc, tbe _tral. equare ~ 8 Z 8 oa, Oo.poeM fd b1aok J.i.Dee ..... pbotGP'llPhioa1l.7 OIl a whi.te truaepareot cel.l.uJ.qi.cl 1'i1a blaDUt 1Ib£ob wee 1'izatecl OD a :JO z :JO _ s1a• • •creen _triz. 'DIe .creen v_ iUlmiDatecl ~rOl8 tile baoJl:, vi_i.Ds cl:I..taoce 01' the .creen w_ U, - 120 ca, the desree 01' 11l.lmiDation va. adaptecl iD auch a V&7 tbat the atiau.-aD . . .
~
eabjeot _t iD :trOllt fd a
~
boa _
67 lat~on pattern could be vell v~s~ble, but t~t ~t vould not botber the observer by ~ts light ~tena~ty nor after so.e tena of .~utes. Subjeots vere keeping ~ the~ banda a tvo-pos~t~ona1 .v~tch, composed of a boz 11 cm long, 8 om v~de, upon v~oh v.s
f~zated tbe vert~oa1 lit~ok 65 om long. DUferent vere used for each ser~e of ezperLments.
~truot~ODa
Before the f~st ezper~ent tbey got t~s ~truot~on: - You can .ee ~ front of you a f~e, v~ch ~s rever.~ble, ~t . .ana you can seete~ther as a -tunel-, t~s ~s a oonoave ~terpretat~on, or a~-formft, vh~oh ~s a oonvez ~terpretat~on. XD tbe former oa.e put the stiok on the wright .~de, ~ the latter put it on tbe left
.~de.
"During tbe ezplanation tbe ezper:L.enter ahoved tbe contours by a pencil, for better understanding. After so. . s~ tr~ lasting appro~. . tely Z minutes, the
ment~oned
ezper~nt started. Eleotr~oal .ignal. from the svitoh vere recorded on an adapted tape-recorder ~ a frequency modulated mode,
transformed in electrical pu1.e. &Dd fed or LAB 8z ).
~to
a oomputer LINC
After Z veeke the ezperiment. oont~ued. Thi. time .ubjeots got a ~ttle bit ~erent ~truct~on:" You are going to .ee tbe . . . . figure, the "fr. . . - but now you oan see ~ t in a tvoform a • • f~gure-groUDd-figure or .~~ a -.poo1-
dimena~oD&l
or • "fly". You are suppo.ed to .v~tch the .t~ok a. the other time, aooording to your subjeot~ve ~terpretat~on of the rever.al•• " ~e
proceeding. &Dd tbe prooe •• ing vere identioa1 as in tbe ezperi••nts.
prev~oua
.0_
In so. . oase vere fir.t done. ezperiaents vith tvod1menaional and then v~tb tbreecUaena~ona1 interpretat:Lona to ezolude
effect of
praot~oe
Stat~.t~cal
or bab~tuat~on. analy.i. of re.ult. abow. that nu.ber of rever.als
per 1 min ~. ~ oa.e of tbre~e~siOD&1 peroept~on lover (13,99
! 1,74) (M! .),
z,49). z)
tban ~ o . . e of' tvodimen.~oD&l one .1gn1f'ioant.
(zZ,z4 !
~ ~ferenoe ~• • tat~stically
~ elaboration
of lug. M. Xndra.
of' data on LINC v_ done in ool1aboratiOD
68 A thr•• t.otor · ana1y.~. ot varianoe va. perfor. .d. Faotor A oorre.pou. to the durat~oJ1 et i.Dterva1, during vhich va. the pattern .een e~ther a. ooncave or oonvex i.D the thr •• ~eD8iona1 vay ot .eeing, re.p. a. a ".po01" or "t1y" i.D the tvodimens~ona1 vay of' .eeing. Faotor B oharaoter~zed the c~ouastanoe vhether the i.Dterpretat~ on vas a thr.e~"D8iona1 or tvodim8D8~ona1. Faotor C de.or~bed i.Dt.ri.D~v~dua1 ~f'.r.noe. of' .ubjeot •• Ana1y.~. ot var~anc. .hoved that a11 tactor. v.re .ignif'~oant a1ready at 1 ~ 1.ve1. 'lbe i.Dterval.. oorr•• poDd.:Lng i.D the exper~nt v~th thre.~D8~ona1 i.Dterpretat~on, to the convex torm of' .e.ing, v.r. 10ng.r, than i.Dterva1., oorre.p~ to the oonoave one. When the . . . . pattern va. oOD8~dered a. tvod1Jle D8~ona1 - the i.Dterva1. oorre.po~ to the "f'1y" vere 10nser then tho.e, oorre.ponding to the ·.po01". U.o the hi.tosr-.,
to thr••dimensiona1 or tvoa • • • en on lI'~. 2 •
oorre.po~
~"D8:1ona1 i.Dt~tat~on
.....
I
v.re
~terent
...
..
..
j ':.
.'
...
'.
,
."..... , , •
I
... • .....
"
--
I
e_
I
J
S
......... .,
,
•
0
...
..
IS_
~
. :
,
I
...... , , • • •
J
.'........ S
1
,
•
0
15_
'lbe i.Dterval. hi.tosr.... obaraotar~zi.ng the convex variant (1et't ap.t~.) and the ooncave one (right ap.t~.) re.p. the -.po01- and -t1y- variant (1ett and right dOVD8t~.). Dc. 2
69 '!be shape
o~
interval. hi.atocraa ooul.cl be
o~ten
deaoribecl . .
saa-a cl1atribution. '!ber. v . . not IUIY aooel.eration o~ interval.a cluriaa .zper~ta. a~, the reaul.ta ~ tile prea.nt .zpert.enta incl1o.t. tbat the .pparent re......u. o~ a pbyaioal.l.y iclentioal. re .....aibl.e patt.rn are alaoat 2 tj,. .a al._.r, vban tile pattern ia ~t. . appr_ priat. inatruotiOll oooaiderecl . . . thre.cl1-.Ilaional., tIIaD vben oonaicl. .ecl . . tvocU . .Dai.onal. ODe. 1he .ubJ.ota clo not real.i_ ~ cli1'1'ereno•• 'DIe reaul.ta cl••onatrat. tbat oopi,tl.... p r _. . . . reaponaibl.. ~or tbree~naional. ...iaual. peroeption require oonalderabl.,. .ore tt.., clue probabl.y to • gre.tar nu.ber o~ at.pa in tile nearonal. alcoritlDNa in...ol....ecl. 'DIe baalo .ode (thre. or. tv~nai~ ~ pero.ptiOll oan be oontrol.ecl by a auitabl.e .ltp8rilHnt.l. 1netruction ~0Z'IIiDs a .ental. oopi,ti.... structur. re ••mbl.iDc • oo-.p1.a dat. proo.aaiaa prosra-. :ID
BltKlpC" l.. Racl1l.ova. J' Racl1l.-V.iaa, T., Ipuncla, J.: A.ot. W.rY. Sup., U. 297 (l.97 ) 2. Racl1l.ova. J •• Racl1l.-V.iaa. T •• lpUDda. J •• ZIldr•• K.I j.Ot. IlerY. Sup •• Al. 54 (l.975 a) ,. Racl11ova. J •• Racl1l.-Vei.a, T •• lpUDda. J •• ZIldra. K.I Biok;Tbernatilt V., Driaohel. 11•• J)ett.ar p •• Bcl8 •• Gaat.... ftaoher Varl.as. J.na. 267 (1975 b) 4. Bacl1l.o...a, J •• Racl1l.-V.i.a, T.: j.Ot. Werv. Sup •• (1917) (in press)
4
J. RadJ.10v'. T. RacUl.-Vei.a
XDetitute
o~
Pby.iol.ogy. Czeobo.10vak Academy
o~
Soienoe ••
Prasue, Czeobo.l.ovaki,a 5' FT' Uai.Ds a pby.ioal.l.7 identioal. rever.i.b1e ~i.gure it· va. £oUDd tbat the ~reqaenoe o~ rever.al.. iD a tbree-cU.eneioDal. iDterpretatiOD v.a .bout two tt.e. lover tbaD iD the two~eD8io Dal. 0Ae.
Reveraibl.e ~i.surea (l.,2,1,4) o~er the po.aibi1ity o~ objeotive ana17aia o£ .ubjeotive a.peot. o~ vi.ua1 peroeption. the que.tion v_ iDve.tipted iD the pre.ent paper vhether the time pattern &Dd rate o£ ~i.gure rever.al.. were ~£erent iD tbree aDd twocU8elUJioDa1 peroeptual. apaoe de:rined b7 _&De o£ pr.vioue .zp.rimenta1 inetruotiOD siven to the aubjeot.. A .peoial. r.v.raibl.. :risure o.Uecl -:tr_- or Maob' a trunoat.d pyra-ide ha. been _.d. :U 0_ b. iDterpret.d either .. • tbree~neiona1 oono.v.OODV.Z or a twocU.enaiODa1 ODe, iD both c •••• with .pontaDeoue al.t.rnation ~ the two poaaib1. perc.ptua1 ver.iOAe. 12 .ubjeot. vere e-.p107.d, l.l. vere hich .obo01 .tudeDt., l. teohDi.oa1 ••ai.t_t (9 ~eaa1 •• , , -.!.e.), naiv. _ to the pur1.. "vereib1e 1'isare oa11ecl -:rra-- uaecl iD e:q»epo.e ~ the ezpW~t &Dd palcl ri.aeAte. 1'or ~1r aervice•• ~ .ubjeot' •
ac.
wee 20,7' ! 0,9'. aD 1IIJIa01aterecl chair iD aD aoou.U~ elda1clM . . . .darkecl ....."".. (~ Z 2a Z l.,518), ~.... iD :f'rOIlt ~ tbee tbe iU·wtnaCecl pattenl fd tbe -:rr.-(n.. l.). :It v_ • 2, Z 2, _ clraw1Dc, tbe _tral. equare ~ 8 Z 8 oa, Oo.poeM fd b1aok J.i.Dee ..... pbotGP'llPhioa1l.7 OIl a whi.te truaepareot cel.l.uJ.qi.cl 1'i1a blaDUt 1Ib£ob wee 1'izatecl OD a :JO z :JO _ s1a• • •creen _triz. 'DIe .creen v_ iUlmiDatecl ~rOl8 tile baoJl:, vi_i.Ds cl:I..taoce 01' the .creen w_ U, - 120 ca, the desree 01' 11l.lmiDation va. adaptecl iD auch a V&7 tbat the atiau.-aD . . .
~
eabjeot _t iD :trOllt fd a
~
boa _
67 lat~on pattern could be vell v~s~ble, but t~t ~t vould not botber the observer by ~ts light ~tena~ty nor after so.e tena of .~utes. Subjeots vere keeping ~ the~ banda a tvo-pos~t~ona1 .v~tch, composed of a boz 11 cm long, 8 om v~de, upon v~oh v.s
f~zated tbe vert~oa1 lit~ok 65 om long. DUferent vere used for each ser~e of ezperLments.
~truot~ODa
Before the f~st ezper~ent tbey got t~s ~truot~on: - You can .ee ~ front of you a f~e, v~ch ~s rever.~ble, ~t . .ana you can seete~ther as a -tunel-, t~s ~s a oonoave ~terpretat~on, or a~-formft, vh~oh ~s a oonvez ~terpretat~on. XD tbe former oa.e put the stiok on the wright .~de, ~ the latter put it on tbe left
.~de.
"During tbe ezplanation tbe ezper:L.enter ahoved tbe contours by a pencil, for better understanding. After so. . s~ tr~ lasting appro~. . tely Z minutes, the
ment~oned
ezper~nt started. Eleotr~oal .ignal. from the svitoh vere recorded on an adapted tape-recorder ~ a frequency modulated mode,
transformed in electrical pu1.e. &Dd fed or LAB 8z ).
~to
a oomputer LINC
After Z veeke the ezperiment. oont~ued. Thi. time .ubjeots got a ~ttle bit ~erent ~truct~on:" You are going to .ee tbe . . . . figure, the "fr. . . - but now you oan see ~ t in a tvoform a • • f~gure-groUDd-figure or .~~ a -.poo1-
dimena~oD&l
or • "fly". You are suppo.ed to .v~tch the .t~ok a. the other time, aooording to your subjeot~ve ~terpretat~on of the rever.al•• " ~e
proceeding. &Dd tbe prooe •• ing vere identioa1 as in tbe ezperi••nts.
prev~oua
.0_
In so. . oase vere fir.t done. ezperiaents vith tvod1menaional and then v~tb tbreecUaena~ona1 interpretat:Lona to ezolude
effect of
praot~oe
Stat~.t~cal
or bab~tuat~on. analy.i. of re.ult. abow. that nu.ber of rever.als
per 1 min ~. ~ oa.e of tbre~e~siOD&1 peroept~on lover (13,99
! 1,74) (M! .),
z,49). z)
tban ~ o . . e of' tvodimen.~oD&l one .1gn1f'ioant.
(zZ,z4 !
~ ~ferenoe ~• • tat~stically
~ elaboration
of lug. M. Xndra.
of' data on LINC v_ done in ool1aboratiOD
68 A thr•• t.otor · ana1y.~. ot varianoe va. perfor. .d. Faotor A oorre.pou. to the durat~oJ1 et i.Dterva1, during vhich va. the pattern .een e~ther a. ooncave or oonvex i.D the thr •• ~eD8iona1 vay ot .eeing, re.p. a. a ".po01" or "t1y" i.D the tvodimens~ona1 vay of' .eeing. Faotor B oharaoter~zed the c~ouastanoe vhether the i.Dterpretat~ on vas a thr.e~"D8iona1 or tvodim8D8~ona1. Faotor C de.or~bed i.Dt.ri.D~v~dua1 ~f'.r.noe. of' .ubjeot •• Ana1y.~. ot var~anc. .hoved that a11 tactor. v.re .ignif'~oant a1ready at 1 ~ 1.ve1. 'lbe i.Dterval.. oorr•• poDd.:Lng i.D the exper~nt v~th thre.~D8~ona1 i.Dterpretat~on, to the convex torm of' .e.ing, v.r. 10ng.r, than i.Dterva1., oorre.p~ to the oonoave one. When the . . . . pattern va. oOD8~dered a. tvod1Jle D8~ona1 - the i.Dterva1. oorre.po~ to the "f'1y" vere 10nser then tho.e, oorre.ponding to the ·.po01". U.o the hi.tosr-.,
to thr••dimensiona1 or tvoa • • • en on lI'~. 2 •
oorre.po~
~"D8:1ona1 i.Dt~tat~on
.....
I
v.re
~terent
...
..
..
j ':.
.'
...
'.
,
."..... , , •
I
... • .....
"
--
I
e_
I
J
S
......... .,
,
•
0
...
..
IS_
~
. :
,
I
...... , , • • •
J
.'........ S
1
,
•
0
15_
'lbe i.Dterval. hi.tosr.... obaraotar~zi.ng the convex variant (1et't ap.t~.) and the ooncave one (right ap.t~.) re.p. the -.po01- and -t1y- variant (1ett and right dOVD8t~.). Dc. 2
69 '!be shape
o~
interval. hi.atocraa ooul.cl be
o~ten
deaoribecl . .
saa-a cl1atribution. '!ber. v . . not IUIY aooel.eration o~ interval.a cluriaa .zper~ta. a~, the reaul.ta ~ tile prea.nt .zpert.enta incl1o.t. tbat the .pparent re......u. o~ a pbyaioal.l.y iclentioal. re .....aibl.e patt.rn are alaoat 2 tj,. .a al._.r, vban tile pattern ia ~t. . appr_ priat. inatruotiOll oooaiderecl . . . thre.cl1-.Ilaional., tIIaD vben oonaicl. .ecl . . tvocU . .Dai.onal. ODe. 1he .ubJ.ota clo not real.i_ ~ cli1'1'ereno•• 'DIe reaul.ta cl••onatrat. tbat oopi,tl.... p r _. . . . reaponaibl.. ~or tbree~naional. ...iaual. peroeption require oonalderabl.,. .ore tt.., clue probabl.y to • gre.tar nu.ber o~ at.pa in tile nearonal. alcoritlDNa in...ol....ecl. 'DIe baalo .ode (thre. or. tv~nai~ ~ pero.ptiOll oan be oontrol.ecl by a auitabl.e .ltp8rilHnt.l. 1netruction ~0Z'IIiDs a .ental. oopi,ti.... structur. re ••mbl.iDc • oo-.p1.a dat. proo.aaiaa prosra-. :ID
BltKlpC" l.. Racl1l.ova. J' Racl1l.-V.iaa, T., Ipuncla, J.: A.ot. W.rY. Sup., U. 297 (l.97 ) 2. Racl1l.ova. J •• Racl1l.-V.iaa. T •• lpUDda. J •• ZIldr•• K.I j.Ot. IlerY. Sup •• Al. 54 (l.975 a) ,. Racl11ova. J •• Racl1l.-Vei.a, T •• lpUDda. J •• ZIldra. K.I Biok;Tbernatilt V., Driaohel. 11•• J)ett.ar p •• Bcl8 •• Gaat.... ftaoher Varl.as. J.na. 267 (1975 b) 4. Bacl1l.o...a, J •• Racl1l.-V.i.a, T.: j.Ot. Werv. Sup •• (1917) (in press)
4