2-A-02 奥行きと遮蔽縁の知覚における観察者の頭部の動きの影響(2002年度 日本基礎心理学会第21回大会優秀発表賞)

The Japanese Psychonomic Society

NII-Electronic Library Service The JapanesePsychonomic Society

TheILtpangseJt)urnatofPs)/chonomicSa'ence

20e3,VoL 22,No.1,37-38

Prizewinner's

Summary2-A-02

The

The occluding edge

is

an

important

factor

for

spe-cifying a

depth

order,

Gibson

etal.

(1969)

and

Kap-lan

(1969)

have

reported thattheoccluding edge can

determine

the relative distance

between

two

sur-faces.Intheirexperiments therewas a translationof

the$urfaces

but

an observer didnot move theirhead.

Normally

however,

we _perceive the oceluding edge

with movement of our head. Inthe _present study we examined

the

_perception of

depth

and theoccluding

edge

by

using

dynarnic

patterns which were linked

tothe head mevements of an observer.

We

investi-gated whether the appearanee or

disappearance

of the eccluding edge, or the active

head

movement, was necessary

for

deterrnination

of the depth of

the

surfaces.

Method

Observers

Five observers _participatedinthis

ex-perlment.

Apparatusandpatterns

The

position of each

observer's head was measured with a 3-D digital

effect

of

head

movement

on

depth

and

occluding

edge

_perception

Tomoko

NAwATAi},

Yasushi

NAKANo2>,

and

Naoe

MAsuDA*

Keio Ubeiversity*

In

the present study we examined how _perceptions of

depth

and the oecluding edge

in

the

optical tunnel were affected

by

head

movement of an observer, The optical tunnel was di$played

en a

CRT

and was observed under active and passive conditions. The results

indicated

_thatthere

were

little

_perceptual

differences

between active and passive conditions.

In

theactive condLtion a

pattern was linked toan obserVer's head movement.

In

addition,

in

the passive condition an observer saw aseries of transforrnationsof the patternsimilar totheperception of the _pattern in

the

active condition.

But

in

a second passive condition the _pattern moved laterallyat a uniform velocity and thc

_perceptual

outcorne was differentfrom theothers.

The

results suggest that

if

the available optical information isdetecteclthen an observer's

_perception

i$the same under either active or _passive conditions,

Key

words: eccluding edge, depth _perception,head movement, optical tunnel

i)

_Present

_address:

_Food

_Safety

_{and Consumer}

Affairs

Bureau,

Ministry

of Agriculture,

estry and

Fishcries

of

Japan,

1-2-1 gaseki, Chiyoda-ku, Tokyo 1OO-8950

2} _{Present address: Research}

_Center

_for

_Advanced

Science and Technology,

University

of

Tokyo,

4-6-1 Kornaba,

Meguro-ku,

Tokyo 153-8904

*

_Department

_of

_Psychology,

_Keio

_University,

15u45

Mita

Minato-ku,

Tokyo 108-8345

tracking system

(FASTRAK,

Polhemus), and allof

theoptica] _patternswere _generated

by

using a

com-puter graphics software

(LightWave3D

version 7,O,

NewTek).

The

patterns which were displayed on a

CRT simulated thc "optical _tunnel"

(Gibson

et aL.

1955)with

the

viewpoint

(the

positionof thecamera) shifted laterally,

The

_patterns either included or

excluded theocduding edge.

Procedure The pattern was observed under

ac-tiveand _passive conditions.

In

theactive condition,

the pattern on the

CRT

display

was

linked

to an

observer's head movement and was transformed in

proportion tothe ]ateralmotion of theirhead,

Each

observer was asked tomove thechinrest

iaterally

so

thatthepatterncould beseen. Activeobservation of

the _pattern occurred under either ef two further

experimental conditions: a consistent condition, and a contradictory condition.

In

the consistent

condi-tionthe

depth

order

indicated

by the dynamic

occlu-sion was consistent with that indicatedby the

mo-tion

parallax,

In

the

contradictory condition

how-ever, the

depth

order specified by thedynamic

occlu-sion was intheopposite directiontothatspecified by

the motion _parallax.Inthe _passiveobservation

con-ditionan ebserver's

head

was

fixed,

and they viewed

a series of transformations of the pattern. Passive

observation of the_pattern also occurred under either

of two further experimental conditions: a

The Japanese Psychonomic Society

NII-Electronic Library Service The JapanesePsychonomic Society

38

The

Japanese

Journal

of Psychonomic

Science

Vol.22,

No.

1

Table

The

mean rate of a _perceived shape1in each observation conditien.

Active Passive

Observers'

report

Consistent Contradictory Replay

UniformiVelocity

With Without With

occlusion occlusion occlusionWithoutocclusion

With Without With Without

occlusion occlusion occlusion occlusion

Seriesof apertures

TunnelConcave

ConvexFlat

surface

O,02O.30O,35O,30O.04o,ooO.14O,35O,44O,07O,04O.26O.31O.36O.03O.OlO.10O,37O.47O.05O.02O.29O.36e.33o.ooo.ooO.08O.36O.56o,ooO.03o,4eO,24O,32o,oo

O.03O,11O.45O.41o.oo

Total 1,OO 1,OO 1,eo 1.00

1,OO

1.00

1.00

1,OO

Assges'sonved o= p=tn,: dlR 201510 5 o

-5-10-15-20

O 10 20 30

Time

(s)

Figure 1. An exarnple of an observer's head

movernent, The areas shown with

half-tone

dots

indicate

the

locatiens

of the occluding

edge.

uniform-velocity condition the ebservers were

re-quircdtosce _thepatternas itmoved from side toside

with a uniform yelocity.

In

thereplay condition the

pattern was displayed inthe same manner as itwas

in

the active censistent condition.

The observers were required toorally report the

shape of the

patterns

thatwere

displayed

by

answer-ing multiple choice questionswhich used the

follow-ing

descriptive

phrases:a series of apertures; a

tun-nel; concave; convex; and a

flat

surface.

All

of thc

optical _patterns were viewed

binocularly.

Results

and

Discussion

Table 1Iiststhemean rate of theperceivcd shapes

foreach ebservation condition,

When

the pattern

included theoccluding edge and was viewed inthe

passive uniform-velocity condition the observers

tended toperceive

it

as a tunnel,

In

theother

condi-tionshowever, the pattern was perccivcd as either

concave or convex. There were _perceptual

differ-ences

between

the passive observation colldition with a uniform velocity and the other observation

conditions. Moreover, some partieipants performed

typical

head

moverncnts

<observed

as a series of

lateral

head

movements) around the occluding edge,

which are illustrated

in

Figure

1,

The

results indi-cated that active head movcmcnts may _play an

irn-portant relc in detectionof the occluding edge, and

are effective

gn

the perception of

depth,

Conse-quently, when thc optical

information

is

picked up

then an observer's _pcrccption isthe same ineither

passive or active observation conditions.

References

Gibson,

J.

J.

Kaplan, G,A.,Reynolds, H.N. &

ler,

K.

1969

The

change

from

visible toinvisible:

A

study of optical transitions.

I]kercoption

&

physics,

5,

113-116.

Gibson,

J.

J.

Purdy,

J.

& Lawrence, L 1955 A

od of controlling stimulation

for

thestudy of space

perception:the optical tunnel.

Iburnat

of

ExpenL

mental Rsycholog;y,,50, 1-14.

Kaplan,

G.A,

1969

Kinetic disruption optical

ture:

The

perception of

depth

at an edge.

tion& RsychQPhysics,6,193-198,