recent (e.g. Terry, 1993), used an experimental paradigm similar to that of the .... Bruce, 1986), or in the intentional learning condition (Winograd, 1981). In.
M E M O R Y , 1 9 9 7 , 5 (5 ), 5 4 5 ±5 6 8
E n c o d in g A c tiv ity a n d F a c e R e c o g n itio n C hristia n C o in a n d G u y T ibe rg h ie n Institu t d e S cie n ce s C o g n itiv es, L y o n, F ra n c e
A s er ie s o f st ud ies c o nd u cte d o ve r th e p a st 2 0 y e ar s h av e e x plo re d th e ef fe c ts o f va r io u s ta sk s o n r e co g nitio n m e m o ry f o r f ac e s. M e m o ry f o r f ac e s a pp e ar s b e tte r w he n th e s tu dy ta sk in v olv es ju d g e m e nts a bo u t a n a b s tra ct tra it ra the r tha n a ph y si ca l f e atu r e . T h e v a riou s si tu a tion s in w h ich th e se r es u lts w e re ob tain ed r aise im po rta nt m e th o do lo g ic a l q u es tio ns re g a r ding the lea r ning c o nd itio n s, w he th e r in c id e nta l o r in te n tio na l, a n d th e d u r atio n o f e x po su r e to th e s tim u lu s d u ring th e st ud y p ha s e. W e c on si d er h er e tw o a lter n ativ e e xp la n a tio n s f o r the r ep o rted r es ults . O ne co n ce r ns d ep th of p ro c es si ng a n d th e o th e r th e o pp o si tion b e tw e e n co m p o ne n t a n d h o list ic pr o c e ss in g . P o s s ib le st r a te g ie s f o r im p r o vin g f a c e r e c o g n ition pe r fo rm a n c e a re c o n s id e re d.
INTRODUCTION W e c an rea d e x pre ssion fro m a fa ce pre se nte d w ithin 2 0 m s (S im p so n & C ra n d all, 1 97 2 ) an d re co g n ise form er sch o o lm a te s at ab o ut a 9 0% rec o gn itio n rate 3 5 y ea rs a fte r g rad u a tio n (B a h rick , B a h ric k , & W ittlin ge r, 1 97 5 ). In th e p ast 2 0 y ea rs, n u m e ro us stu d ies h a ve e x plo re d th e influ en c e of e n co d ing in struc tio n s o n fac ia l re co g nition . M o st o f the stu die s e xa m in e d h e re , inc lud in g th e m o st rec e n t (e .g . T e rry, 19 9 3 ), u se d an e x pe rim en ta l pa rad ig m sim ila r to th at o f the p io n e erin g stu dy rep o rted b y B o w e r a nd K arlin (1 9 74 ). S tud ie s e m p lo y in g a du lts (e.g . B o w e r & K arlin , 1 97 4 ; C lifford & P rior, 19 8 0 ; M cK e lv ie , 1 9 91 ; P atter son & B a dd e ley , 1 97 7 ; S p o re r, 19 9 1 ; W e lls & T u rtle , 19 8 8 ; W in og ra d , 1 98 1 ) sh ow th a t th e re qu ire m e nt fo r pe rso na lity trait ju d ge m e n ts, su ch a s lik e ab ility , y ie ld h ig he r re co g n itio n ra te s th a t ju d ge m e n t a b ou t siz e o f a fea ture o r g e n de r. S im ilar p attern s o f re su lts h av e be e n o b tain ed w ith ch ildre n (7 to 1 4 y ea rs o ld : C are y , D ia m o n d , & W o od s, 1 9 8 0), w ith o ld e r su b je c ts (5 0 to 7 0 y ea rs
R e q u es t s f o r re p r in t s s h o u ld b e s e n t t o C h ris ti a n C o in , In st itu t d e S c ie n c e s C o g n itiv e s , U n i v e rs ite C la u d e B e rn a rd , 8 a v en u e R o c k e fe lle r, 6 9 3 7 3 L y o n c eÂd e x 0 8 , F ra n c e . T h i s w o rk w a s c o m p l et e d w h ile th e fir st a u t h o r w a s o n a p o s t d o c to ra l fe ll o w s h ip a t t h e M a s s a c h u s ett s In s titu t e o f T e c h n o lo g y , C am b rid g e, M A . P a rts o f th is w o rk w e re s u p p o rte d b y a F u lb rig h t g ra n t to t h e firs t au th o r. W e w o u l d l ik e to t h a n k A l a n H e in a n d a n a n o n y m o u s rev ie w e r fo r h el p fu l c o m m en ts o n a n e a rlie r d ra ft o f t h i s a rti c le , a n d W e n d y M c K e n z ie a n d D a v id J a m e s fo r th e ir re a d i n g o f th e E n g li sh v e rs io n o f th is a rti c le .
Ó
1 9 9 7 P s y c h o lo g y P re s s L td
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o ld : W a rrin g ton & A ck ro y d, 1 9 7 5 ) a nd w ith am ne sic K o rsak o ff p a tien ts (B ib er e t al., 1 9 81 ). T h is p ap e r w ill rev iew a n d ev a lu a te th e v ariou s pro ce d u re s e m p lo y ed in th ese stu d ies. T he re a re fou r c ateg o ries o f en c od in g in stru ction s fo r th e stu d y ph a se of th e e x pe rim e n ts re vie w ed h e re : 1 . S tan d a rd in stru c tio n s in w h ich su b je cts a re to ld o n ly th at a reten tion te st fo llo w s the stud y p ha se . 2 . In stru c tio n s to a tten d to p h y sic a l ch a rac teristic s v iew e d d ire c tly (e .g . fa cia l fe atu res a n d a c ce sso rie s lik e gla sses), or inf erred (e.g . g en d er, rac e, w eig ht a n d he igh t). 3 . In stru c tio n s to re g ard glo ba l asp e cts o f th e fa ce (e .g . e x pre ssion , sh ap e ), p e rso na lity tra its (e .g . lik e ab ility an d inte llige n c e). T h ese in stru ction s a re so m etim e s re la ted to id e ntifyin g a ctiv ities o f the fig ure (e .g . p rofe ssio n, h o bb y ), o r to relig iou s o r p o litic al pre fere n ce . 4 . In stru c tio n s to c h oo se th e m o st d istin ctiv e fac ia l fe atu re a m o n g a set of fa cia l fe atu res. T ak e n tog e th e r, th e re su lts sh o w th at ju dg e m e n ts o f p erso n ality tra its y ie ld b e tte r re co g n itio n pe rform an c e th an tho se o f p h ysic al traits. T h e da ta p ro vid ed in T a b le 1 a lso d e m o n stra te th at in fe re ntial jud g e m e n ts im pro v e distin g u isha b ility (d ¢ ) a m o ng th e m . T h e de c isio n c riterio n ( b ), ap p ea rs u n affe c te d b y th e e n co d in g c o nd itio n s (se e a lso S h a piro & P e nro d , 1 9 8 6) a lth o u gh th e d a ta su p p ortin g th is c on c lu sio n is sp arse . T he fa c es se arc he d for th eir m o st d istin ctiv e p h y sica l fea tu re a m o n g a se t de sign a ted b y th e ex p e rim e n ter w e re b etter re m e m be red tha n th o se ju d ge d w ith re sp ec t to a sing le p h y sica l fe atu re (C ou rtois & M u e l le r, 1 9 7 9 ; S p o re r , 1 9 9 1 ; W i n o g r a d , 1 9 8 1 ). F in a ll y , re c o g n i tio n p e rfo rm an c e w as n ot differe n t fo llo w in g ju d g em en ts ab o ut pe rso n ality tra its th an a fte r ju d ge m en ts ab o u t th e m ost d istin ctive fac ial fea tu re (D aw & P a rk in , 1 9 8 1; D e ffe n b ac h e r, L e u , & B ro w n , 1 9 8 1; P a rkin & G oo d w in, 1 98 3 ; P ark in & H a y w ard , 1 9 83 ; W in og ra d , 1 98 1 ).
METHODOLOGICAL ASPECTS B e fo re a tte m p ting an e x am in atio n of th e p ro po se d e xp lan a tio n s fo r th ese re su lts it is im p o rta nt to n o te th e differ en c es in th e m e th o do lo g ie s th at u n d erlie th em . In so m e p ro c ed u res sub jec ts w ere to ld th at a re co g n itio n test w o uld fo llo w th e stu d y p h ase . In o th e r e x pe rim e n ts this in fo rm a tio n w a s n o t g ive n . A d ditio n a lly , e x po su re d u ratio n o f th e ta rg et fa c e v arie s a m o n g th e stud ie s. P ossib le c o nse q u en c es of suc h v a ria tio n s m ust b e a na lyse d . In pa rtic u la r, th e su bje c ts c o uld a d o pt a p artic u lar en c od in g strateg y w he n th ey kn o w th at a te st w o u ld f o l lo w . A lte rn a ti v e ly t h e ir n o rm a l s tr a te g y m ig h t b e u n a l te r e d b y th e in stru c tio n s. F ina lly, if d iffe re n t ju d ge m en ts ha v e d iffe re nt p roc essin g tim e s
TABLE 1 Face Recognition Performance as a Function of Encoding Instructions H i ts
d¢
FA
F
B ib e r e t a l. (1 9 8 1 )
.6 5 < .8 1
Ð
Ð
Ð
B lo o m & M u d d (1 9 9 1 )
.5 6 < .7 6
Ð
Ð
Ð
B o w er & K a rli n (1 9 7 4 ; E x p . I)
.6 0 < .8 1
Ð
Ð
Ð
B o w er & K a rli n (1 9 7 4 ; E x p I I)
.5 6 < .7 6
Ð
Ð
Ð
.8 0 < .8 8
Ð
Ð
Ð
C o u rt o i s & M u e ll e r ( 1 9 7 9 )
.6 9 < .8 4
.2 1 > .1 2
1 .5 < 2 .4
2 .1 ± 2 .7
D evine & M alpass (19 85 )
Ð
Ð
.8 6 > .8 0
Ð
Ð
Ð
Ð
.5 4 < .6 5
.2 9 > .2 1
.6 6 < .7 5
.5 5 < .6 4
.2 8 > .2 1
.6 6 < .7 6
.4 2 < .5 0
Ð
Ð
Ð
M c K e lv ie (1 9 7 8 )
.8 3 < .8 8
Ð
Ð
Ð
M c K e lv ie (1 9 8 5 )
.8 2 < .8 7
Ð
Ð
Ð
M c K e lv ie (1 9 9 1 )
.6 6 < .9 0
Ð
Ð
Ð
.5 8 < .6 6
.2 0 = .1 9
1 .1 < 1 .4
1 .7 = 1 .4
M u e ll er e t a l. (1 9 7 8 ; E x p . II )
.4 8 < .6 7
.2 5 = .2 3
.6 9 < 1 .2
1 .5 = 1 .2
M u e ll er e t a l. (1 9 7 9 )
.6 3 = .6 9
.2 2 > .1 5
1 .2 < 1 .7
1 .8 = 2 .7
M u e ll er & W h e rry (1 9 8 0 )
.5 2 < .7 8
.1 6 ± .1 5
1 .2 ± 1 .9
3 .0 ± 1 .5
P a t te rs o n & B ad d e le y (1 9 7 7 )
.7 6 < .8 2
Ð
1 .5 < 1 .9
Ð
.7 5 < .8 6
.2 1 = .2 2
1 .5 < 1 .9
1 .0 = 0 .9
S p o rer (1 9 9 1 )
.5 6 < .6 6
.3 0 ± .2 6
.6 9 < .7 7
S t rin g e r (1 9 8 7 )
.5 1 < .6 7
Ð
Ð
.4 6 < .5 5
.2 6 < .3 4
Ð
Ð
.7 4 < .8 1
.1 6 = .1 6
2 .4 = 2 .7
5 .1 = 4 .4
T e rry (1 9 9 3 ; E x p . II)
.6 5 < .7 0
.2 4 > .2 0
1 .4 > 1 .8
3 .0 = 3 .3
W a rri n g to n & A c k ro y d (1 9 7 5 )
.8 0 < .8 6
Ð
Ð
Ð
W e l ls & H ry c iw (1 9 8 4 )
.2 5 < .5 5
Ð
Ð
Ð
W e l ls & T u rtle (1 9 8 8 )
.5 4 < .7 8
Ð
Ð
Ð
W i n o g ra d (1 9 7 6 )
.6 6 < .7 5
Ð
Ð
W i n o g ra d (1 9 8 1 ; E x p . I)
.6 4 < .7 3
.2 5 > .1 6
1 .0 < 1 .6
W i n o g ra d (1 9 8 1 ; E x p . II )
.7 0 < .7 6
Ð
.8 5 < .8 8
C a re y e t a l. (1 9 8 0 )
a
P
G a o n a c ’ h & G ib o in (1 9 7 7 ; E x p . I)
.8 5 < .9 2
G a o n a c ’ h & G ib o in (1 9 7 7 ; E x p . II)
.7 8 < .8 7
L i g h t e t a l . (1 9 7 9 ; E x p . I)
d
L i g h t e t a l . (1 9 7 9 ; E x p . II) M a y e s e t al . (1 9 8 0 )
d
a
M u e ll er e t a l. (1 9 7 8 ; E x p . I)
S m i th & W in o g ra d (1 9 7 8 )
S t rn a d & M u e lle r (1 9 7 7 )
f
h
i
T e rry (1 9 9 3 ; E x p . I)
F
c c
g
c
c
P
F
b
A u th o r(s )
P
F
b
P
Ð Ð Ð
e e
b
Ð Ð
Ð Ð
Ð e e
Ð Ð
F = ju d g e m e n t a b o u t a fa c i al fe a t u re ; P = ju d g e m en t a b o u t p e rs o n a lity tra it . D a s h e s in d i c at e n o d at a a v a ila b le . T h e d iffe re n c es a re s ig n if ic a n t a t th e .0 5 l ev e l a t le a s t; < in fe rio r; > s u p e rio r; = n o s ig n i fic a n t d i ffe re n c e; ± n o d i ffe re n c e m en ti o n e d . a
b
D a ta e s tim a t ed a s a c c u ra te ly as p o ss ib le fro m a f ig u re in th e o ri g i n a l a rti c le . T h e s e n s i tiv it y is c
e x p re s s ed b y th e A ¢ es t im a te . H i ts p lu s F a ls e P o s it iv e s. e
d
D a ta o b ta in e d fro m t y p ic a l an d u n u su a l
f
fa c e s. T h e s e n s it iv ity is e x p re s s ed b y th e A g e s ti m a te . D a ta o b t a in ed fro m tw o g ro u p s o f s u b j e ct s (5 g
h
a n d 1 5 s e c o n d s e x p o s u re d u ra ti o n ). S i g n ifi c a n t a t t h e .1 0 l e v e l. D a ta o b ta i n e d fro m tw o g ro u p s o f s u b je c ts (1 8 ±5 2 y ea rs o l d an d 5 0 ±8 0 y e a rs o ld ).
i
D a t a o b ta i n e d fro m tw o g ro u p s o f s u b je c ts
(in c id e n t a l an d in te n t io n a l le a rn in g ).
547
548
COIN AND TIBERGHIEN
a n d ex p o su re d ura tion is co n stan t, th e e ffec ts of ex p osu re d ura tio n m a y b e c o nfo u n d ed w ith th e ty p e of e nc o din g in stru ctio n .
Control Group, Incidental Learning, and Intentional Learning S tu die s d esig n ed to ex a m in e th e effe cts o f en c o din g instru ctio ns on fac ial r e c o g n iti o n v a ry i n th e ju d g e m e n ts r e q u ir e d . T h i s h a s t w o i m p o rta n t c o nse q u en c es. F irs t, th e y relate o n ly to a lim ited se t o f strate g ie s fo r fa ce e n co d in g em p lo y e d o utside la b ora tory settin g s. N o rm ally fac e e n co d in g is c o nd u c te d sp on ta n eo u sly a n d is fre e of im p o se d ju d g e m e nts (a t le a st o f th e k ind d iscu sse d he re). S e co n d , c om p ariso n b etw e en stud ies is diffic u lt b ec a u se o f th e la ck o f a c o m m o n ba sis, in ad d itio n to u na v oid ab ly v a ryin g p roc e du re s b e tw e e n e x pe rim e n ts. F o r e xa m p le , it is d ifficu lt to dra w a p ara lle l b etw ee n re co g n itio n p e rfo rm an c e o bta ine d a fte r ju d ge m en ts a b ou t sex an d ab o ut lik ea b ility (e .g . B o w er & K arlin , 19 7 4 ), an d th o se o bta in e d a fter ju d g em e nts ab o u t w eig h t a nd in te llig e nc e (e .g . M u e lle r, B ailis, & G old stein , 1 9 79 ). In th e se stu die s, th re e ty p es o f lea rnin g w e re use d : 1 . S tan d a rd in te n tio n al lea rn in g in w h ich su b je c ts a re in stru c te d o nly to e x am in e th e stim u li d urin g the stu d y ph a se. T he y a re w a rne d a b ou t th e su b se qu e n t test p h ase . 2 . N o n-sta n da rd inte n tio n al le arn ing in w h ich su b jec ts m ak e jud g e m e nts d u rin g the stud y p ha se . T h e y are w a rn ed a bo u t th e sub se qu e n t tes t p h ase . 3 . In cid en ta l le a rn in g in w hic h su bje cts m a ke ju d ge m e n ts w ith o u t kn o w ing a b ou t the su bse q u en t rec o gn itio n te st. In o rd er to asse ss th e effe cts of d iffere n t e nc o din g in stru c tio n s w ith reg a rd to 1 th e sta n da rd lea rn in g p ara d igm (ba sic lev e l), th e le a rn in g fa c to r m us t n o t b e c o nfo u n d ed w ith the ty p e o f jud g e m e n t fac to r m a de du rin g the in sp ec tio n p h a se (e .g . D e v in e & M a lp ass, 19 8 5 ; S po rer , 1 9 91 ). In th ese e xp e rim en ts th e le arn in g d u rin g the insp e ctio n p h ase is in ten tio na l fo r o ne g rou p , a n d in cid en ta l w ith ju d ge m en ts to b e m a de fo r th e oth e r g ro u p . T h u s, it is n o t p ossib le to co m p a re th e effec t o f stan d ard in te n tio n al lea rn ing re co g n itio n w ith the e ffe c t of in te n tio n a l le arn ing w ith ju d ge m en ts. H o w ev e r, B o w er a n d K arlin (1 9 74 ) sh o w e d th a t fa c ia l rec o g nitio n w a s su pe rio r fo llo w in g ju d g e m e nts a b ou t th e h o n esty o f a fac e th a n after ju d ge m en ts a b ou t its ge n de r, b oth in an in cid en ta l le arn in g co n d itio n (E x p erim e n t 1 ; se e also C a re y et a l., 1 98 0 ; P a tte rso n & 1
T h e b a s ic le v e l co n s id e re d h e re i s t h e c o n d itio n w h e re t h e s u b je c t d o e s n o t m a k e ju d g e m e n ts
d u rin g th e s tu d y p h a s e a n d is n o tifi e d o f th e s u b s e q u e n t t e st p h a s e . P e rh a p s it w o u ld b e p re fe ra b le fo r t h e b a s ic l ev e l to b e th e c o n d itio n o f in c id e n t a l le a rn in g in w h i c h n o ju d g e m e n ts a re m a d e . H o w e v er, i t m u st b e a d m i tte d th a t it i s d if fic u l t to c re a te su c h a c o n d it io n .
FACE RECOGNITION
549
B a d d e le y , 1 9 7 7 ; T e rry , 1 9 9 3 ) a n d in a n in te n tio n a l le a rn i n g c o n d itio n (E x p er im en t 2 ; see S p o rer, 1 99 1 ; W e lls & T u rtle, 1 9 88 ). T h e sa m e p attern o f resu lts w a s ob ta in e d b y Strn a d a nd M u elle r (19 7 7 ) w h e re in cid en tal an d inte ntio n al lea rn in g co n d itio n s w e re co m bin ed w ith in th e sam e ex p erim en t. Ju dg e m en ts ba se d on th e m os t d istin c tiv e fe atu re do n o t le ad to b etter rec o g n itio n pe rform an c e th a n jud g e m e n ts ab o ut th e infe rred c h ara cte r o f the fac e in th e in cid en ta l le a rn in g c o n dition (D aw & P a rk in , 1 9 8 1; V ale ntin e & B ru c e, 1 9 8 6), o r in th e inte ntio n al le arn in g c o n ditio n (W in o gr ad , 19 8 1 ). In c on c lusio n , th e sim ila rity o f th e re sults o b ta in e d w ith in ten tion a l a nd inc ide n tal c on d itio n s se e m s c le a rly d em on stra te d . T o n o tify sub jec ts o f th e su b seq u e nt m n e sic te st d o es n o t h a ve a n e ffec t o n rec o g nitio n p erfo rm a nc e . O n th e oth er h a nd , in fo rm in g su b jec ts ab o ut th e re co g n itio n te st c o uld y ie ld an e ffec t o f e nc o din g in stru c tio n s th at is h ard to in terp re t. W e ca n no t b e ab so lu te ly su re th at su bje cts d id n o t u se the ir u su a l e n co d in g strate gy w h a te v er the instru c tio ns g ive n . In the sa m e w a y th at sub je cts c an n o t h e lp sem an tica lly ide n tify ing a w ritte n w o rd (S tro o p effe ct, S tro o p , 1 9 3 5 ), o r th at o n e h as diffic u lty h ea ring sp e ec h a s sim p le so u nd s (F o do r, 19 8 3 ), ask in g sub jec ts to m ak e a jud g e m e n t a b ou t a fa c ia l fe a tu re do e s n ot a ssure u s th a t a jud g e m e n t a b o ut p erso n a lity tra its is n ot a lso m a d e. T o e n sure tha t sub je cts ac tu ally u se d an h olistic e nc o din g strate gy , D effe n ba c he r e t al. (1 9 8 1) ask ed th e m to g iv e a n o pin io n a b o ut the d ifficu lty o f m e m o risin g th e ov e rall stru ctu re o f th e fa ce . S im ilarly , in o the r stud ie s, inste ad o f a b in a ry ju d ge m e n t (e .g . like ab le vs. un like a b le ), su bje cts w ere a ske d to m a k e the ir jud g em e n t on a 4 -p o in t sc ale (B ibe r e t al., 1 9 81 ) or o n a 7 -po in t sc ale (W e lls & H ry c iw , 19 8 4 ). In this w ay o ne ca n ho p e to h a ve a m ore e ffec tiv e c o ntrib ution b y su b jec ts. T o say w he the r a n o se is sh o rt o r lo n g c o u ld h ard ly h o ld th e su b je c ts’ atten tion . In o rde r to o ffset th is d isad v a nta g e, S p o rer (1 99 1 ) alte rn a te d w ithin a sessio n th e fe atu re o n w h ic h ju d g em en ts w e re m ad e . F o r ex a m p le, su bje cts w ere a ske d a bo u t no se siz e at item 1, a bo u t th e g ap b etw ee n the ey e s a t item 2 , e tc . H o w e v e r the se p re ca u tio ns a re n ot en tire ly sa tisfy in g . T he m o st dire ct c o n tro l w a s ob tain e d b y B lo o m a n d M u dd (19 9 1 ). T h e y m ea su red tog e the r tim e insp e c tio n, ey e m o ve m en ts an d p u p il d ia m e ter. T h ey fo un d tha t a s m o re e y e m o v e m e nts w ere re co rd ed , m ore fe a tu re s w e re pro c esse d . H o w e v er th is rec o rd in g is use fu l o n ly if w e co n sid e r, as B lo o m an d M u d d d id, th at pe rso n ality tra it ju d g em en ts req u ire the ex a m in atio n o f n um ero u s p hy sica l fea ture s an d c an n ot b e d o ne at first g lan c e. In sum m a ry , it is d ifficu lt to o b tain a n e q u iv a le n ce b etw ee n the e nc o din g req u este d a n d th e en co d ing m ad e . T a k ing into ac co u n t stu d ies w h ere no jud g e m e n ts w e re m a d e d u rin g e nc o din g , th e da ta sh o w c on sisten tly th at m em o ry fo r fa ce s is in v aria b ly su pe rio r o r eq u ally fo llo w in g n o ju dg e m e n ts (sta n da rd inte n tio n al e n co d in g ) c om p are d w ith fo llow in g jud g em e n ts ab o u t a fac ia l fe atu re (see T ab le 2 ). M ore o v er, fac ia l re co g n itio n is sup e rio r o r e qu a l follow in g jud g e m e n ts ab o ut a p erso n a lity trait c o m p a red w ith re co g n itio n a fte r n o ju d g e m e nts, a n d a fte r a jud g e m e n t a bo u t a fa cial fea tu re . So w e co u ld state th at ju d ge m e n ts a b ou t a
550
COIN AND TIBERGHIEN TABLE 2 Face Recognition Performance as a Function of Three Different Instructions H i ts
A u t h o r (s )
F ea tu r e
S ta n d a rd
P e r s o n a li ty
B i b e r e t a l . (1 9 8 1 )
.6 5
