Time perception is influenced by the subjective area size of a brief stimulus(Summary of Awarded Presentation at the 25th Annual Meeting)

(1)

The Japanese Psychonomic Society

NII-Electronic Library Service

The JapanesePsychonomic Society

TheJapaneseJbTirnat of i]s.vchonomic Science

2007,N,o].25,No.2,277-278

Summary

ofAwarded

PresentationIP37

Time

_perception

is

area

size

influenced

by

the

of

a

brief

stimulussubjective

Fuminori

ONo*

and

Jun-ichiro

KAwAHARA**

luntendo

University*,IVdtionatInstitute

of

Advanced

industrialScience and Technology**

Ono

and Kawahara

(2006)

have reported that when theapparent size of a visual object in_the

Ebbinghaus

illusionwas overestimated

its

_perceived duration was longer_than when

it$

size was underestimated,

Because

the time estimation task and the sizeestimation task were _presented consecutively

in

theirstudy, the_participantsmight

have

estimated thearea size

during

thetime

estimation task.Inthe _presentstudy the timeestimatjon and $ize estimation taskswere conducted

inseparatc

blocks.

This

_procedure was used todetermine whether theeffectof apparent visual size

on the _perceived

_duration

was because

the

subjective area size was altered by the

_illusion,

or

whether itwas an artefact caused by the_participantsengaging in

the

sizeestimation task.

The

results

indicated

that the _perceived duration of apparent]y largestimuli was longer than thatof

apparently small stimuli, even

if

the _participantswere not engaged

in

thesizeestimation task,and revealed that time _pcrception is

influenced

by

_subjective _area _size,

Key words: _time _perception,subjective area size, Ebbinghaus

illusion

The

perceived

duration

of events isaffected by_the

non-temporal attributes of stimuli, such as the

num-ber

of components. size,or complexity. Presenting a

large

quantity of stimuli to an observcr tends _to result

in

an overestimated duration. Although

previ-ous studies have suggested that _time _perception

_is

infiuenced by the _physicalattributes oi stimuli, itis

not known whether _time _perception _is_infiuenced_by

differences

in

the subjective appearance of physi-cally identicalstimuli.

Recently we

investigated

(Ono

&

Kawahara,

₂₀₀₆₎

the effect of subjcctive size on time perception. Our study combined the visual area-size effect on time

perception

{Thomas

&

Cantor,

1975)

and the

Ebbing-haus illusionfigure. In the

Ebbinghaus

illusion

figure,

a central circle which

is

surrounded by large

inducers appears tobesmaller than a central circle of

the same sizewhich issurrounded by small inducers.

We

measured the _perceived

duration

of

the

visual

circles when the apparent area sizeof the circles was altered by the Ebbinghaus illusion.

_Our

re$ults

indi-cated that theperceived duration of the apparently

largecircles was longerthan thatof apparently small

* _Department _of

_{Neurophysiology,}

_School

of

Medicine, Juntendo University, 2-1-1 Hongo,

Bunkyo-ku,

Tokyo

113-8421

circles, even though the actual area size remained

lnvanant,

Inthe

Ono

&

Kawahara

(2006)

study however, the

time estimation task and thc size estimation task

were presented consecutively.

The

_participants

thereforecould have estimated the central area size

during the time estimation task. Ifthiswere thecase, the observed effect of apparent size on _perceived

duration

might have been due to contamination by

the size estimation,

Consequently

in

_the _present

study we ran the time estimation and size cstimation

tasks in separate

blocks,

_If_the variations of the

perceived

duration

were due toerrors of size

estima-tion rather than of time _perception, then the per-ceived duration of the subjectively

large

condition would

be

the same as thatof the subjectively small condition,

Alternatively,

_if_the apparent area size

infiuenced

time perception, even when _the

partici-pants were not engaged inthe size estimation task,

the_percejved duration of _thesubjectively

large

con-ditionwould

be

longer

than thatof thesubjectively small conclition.

Method

Participants

Twenty

experimentally naive

stu-dents

from

Hiroshima

University

volunteered as

$ub-jects,

and received either a course credit or _pay.

(2)

The Japanese Psychonomic Society

NII-Electronic Library Service

TheJapanesePsychonomic Society

278

The

_Japanese

_Journa]

of Psych

Stimuli

The

stimuli wcre black circles _presented on a _gray

background,

There

wcre two conditions: subjectively small and subjectively large.Four

sur-rounding

induccr

circles were displayed on thelefL right, top,and bottom, of the central circ]e. The

diameter

of theinduccr circles was

4 degrees

in

the subjectively small condition, and 1 degree in the

subjectively

large

conditjon.

In

both

conditions the

diameter of thecentra] circle was 2degrees.

Procedure

The

experimcnt included training,

time estimation, and size estimation

block$.

In

the

training block only the central circle was displayed

for

one of

four

durations

(l

OO,

200,3eO,or 400 ms)

in

a random order.

The

participants categorizcd the

duration

by_pressingone of fourkeys

<1

for

short and

4 iorIong).

After

60

training trialsthe _participants

performed

120 time estimation trials.

In

each of the

trials onc of two types

(the

subjectiv･ely large or

small condition) of surrounding circles was

ran-domly displayed for 1500ms and a central circle

appeared

for

either

150

or

350

ms. The _participants

categorized the displayed duration of the central circle

by

pressing one of four keys. After the time

estimation

block

(120

trials),the _participantswere

given

instructions

for

thesize cstimation task. The participant,swere not told toestimate the area size of

the circle until they were _givcn this instruction.In the size cstimation

block

{40

trials),the same se-quence of events as inthetimc esLimation

block

was

presented again, and then eight types of variously

sized comparison circles were displayed. From the

eight alternatives the _participantsselected a circle whose area was perceived as

identica]

tothecentral circle by pressing one of eight

keys

{1-8).

Results

and

Discussion

The mean of the time estimation and size

estima-tion

for

each subjective sizccondition is_presentedin

Tab}e 1. An analysis of variance

(ANOVA),

with

Subjective

Size

{subjectively

small or subjective]y

large)and Duration

(150

or 350 ms) as within-subject variables, revealed significant main effects of both variables: SubjectiveSizc,F{1,19)=5.97,P<.05; and

Duration,

F(1,

19)=504.82,p<,OOI.

The

lnteraction

onornlcScience Vol.25,No. 2

Table

1

The mean of the time and sizeestimation tasks.

The standard deviation is

in

parentheses.

Tirneestimation

Size

estimation

Subjec-tively

small

Subjcc-tively

large

Subjec-tively

small Subjec-tivcly large 150ms 1.53C25) 1.54{,24) 2.86(.55) 3.80C89)

350ms

3.14C29)

3,26C27>

2.90(.80)

3.91C82)

betwccn thevariables was significant,

F(1,

19)=5,99,

p<.05.

It

isjmportant tonote that themain effect of

Subjective

Size

indicated that the time _perception

was infiuenced by the subjective area size.

An

ANOVA

with SubjectiveSizeand Duration as

with-in-subject

variables revealed asignificant main effect

oi _the SubjectiveSizecondition, F{1,19)=35.80,p<

,OO1,

The

main effect of the

display

duration,

and the

interaction

between

Subjective

Size

and Duration,

were not significant, F(1,19)=O.32,

p7:.57.

The analysis of SubjectiveSizesuggested thatthe

appar-ent area sizeoi thecentral circle was changed due to the

Ebbinghaus

Musion.

In conclusion, the present study examined the

effect of theEbbinghaus illusionon time _perception

(Ono

&

Kawahara,

2006)

by

running thetime estima-tion and sizc estimation tasks

in

separate

blocks.

There

were

two

major results. First,the novel

find-ing

frorn

Ono

&

Kawahara

_<2006}

was clearly

rep]i-cated, confirrning that the _perceived duratjon of

ap-parently

large

stimuli was

longer

than thatof

appar-ently srnall stimuli. Second, theresult eliminated the

possibilitythat theirfindingwas an artifact caused

by

running the sizc estirnation

task

consecutively

with the time estimation task:the effect was

repro-duced even when _participantswere not engaged

in

the size estimation task.

References

Ono,

F.& Kawahara,

J.

2006

The

effect of subjective

area size on time perception. The

joPanese

.lburnal

of

Rsychonomic

Science,

25,

1 19-120.

Thomas,

E,

A,

C,

&

Cantor, N.E.1975

On

theduality

of simultaneous time and size perception.