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Use of Nac Eye Mark by Radiologists
Theoretical and Applied Aspects of Eye Movement Research A.G. Gale and F. Johnson (Editors) 0 Elsevier Science Publishers B.V. (North-Holland), 1984
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USE OF NAC EYE MARK BY RADIOLOGISTS
Jean Paul PAPIN*
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P i e r r e ( J ) METGES**
- Ren6 (R)
AMALBERTI*
Centre d'Etudes e t de Recherches de M6decine Aeronautique 5 b i s Avenue de l a Porte de S&vres 75731 PARIS CEDEX 15 ** Hapita1 d' I n s t r u c t i o n des Armees BEGIN. Service de Radiologie 69 Avenue de PARIS 94160 ST MANDE
SUMMARY Three experiments j o i n t l y conducted by a department o f research on v i s u a l perception and a h o s p i t a l radiology department are described and discussed. A gaze d i r e c t i o n recording device, the NAC EYE Mark recorder was used t o characterize t y p i c a l visual behaviors o f r a d i o l o g i s t s and non r a d i o l o g i s t physicians during lung radiography (Exp. 1) and abdomen echography (Exp. 2 ) . Only very general behaviors were evidenced. The s i g n i f i c a n c e o f doctor/ p a t i e n t r e l a t i o n s h i p s was a l s o analysed i n Exp. 2. These same common v i s u a l behaviors were evidenced and comnented t o young physicians (Exp. 3) viewing lung radiographs. While emphasizing the a t t r a c t i v e nature o f the f i l m s the discussion underlines the d i f f i c u l t i e s inherent t o the i n t e r p r e t a t i o n o f such documents : the NAC records gaze s h i f t s and pauses, b u t i s unable t o e x p l a i n t h e i r causes. .
INTRODUCTION Often, when you l o o k a t someone examining a p i c t u r e , you can guess the course, t h e d i f f i c u l t i e s o r the easiness o f analysis o n l y by observance o f eye movements. I n f a c t , eyes are often p r e f e r e n t i a l means t o p i c k up information. Their m o b i l i t y seams t o witness, on a f i r s t analysis, a c o n t r o l l e d and l o g i c a l search, t i e d t o the way t o perform the c u r r e n t task. If such i n t u i t i v e analysis was good, v i s u a l behavior would be h i g h l y ident i c a l f o r one operator repeating many times the same task. It would even be possible t o f i n d i d e n t i c a l features i n visual behavior between two operators performing the same task. O f course, i f you want t o argue t h i s f a c t , you need an o b j e c t i v e means t o record eye movements. To v e r i f y t h i s hypothesis i n radiology, we used an oculometer diqolay c a l l e d NAC Eye Mark Recorder. This d i s p l a y allows continuous recording ,on a movie o r video support, the scene t a k i n g place i n f r o n t o f t h e operator. An i & i c a t o r (such as an arrow) superimposes gaze d i r e c t i o n on the general scene. I n a f i r s t step, we studied a s t a t i c model o f radiography: the lung r a d i o graph. I t was i n 1981 ( 1). I
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USE OF NAC EYE MARK I N CHEST RADIOGRAPHY
I n the f i r s t experiment, we used a r e l a t i v e l y w e l l known model f o r the desc r i p t i o n o f radiologists'eye movements : chest radiography. Some importantlandmarks o f t h i s work can be b r i e f l y reviewed. I n 1963 Lewellyn Thomas (9) showed the h i g h l y i n d i v i d u a l features o f radiol o g i s t s ' v i s u a l behavior. I n 1969 Kundel & Wright (7), and i n 1972 Kundel & L a f o l e t t e (8) emphasized the importance o f t h e context (knowledge of the patient's c l i n i c a l history).
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Carmody e t al. i n 1981 (5) showed t h e g r e a t importance o f compasture scanning s t r a t e g y t o d i f f e r e n t i a t e modules f r o m anatomical s t r u c t u r e s and Gale & W o r t h i n g t o n (1983 ( 6 ) ) showed t h a t t h e r e i s n o t i e between t h e v i s u a l behav i o r recommended i n handbooks o f r a d i o l o g y and t h e r e a l i t y o f v i s u a l search. C o n s i d e r i n g such r e s u l t s , a comparative s t u d y between two groups o f subj e c t s ( t e n non s p e c i a l i s t p h y s i c i a n s and e l e v e n c o n f i r m e d r a d i o l o g i s t s ) was conducted.
r-1. ~ d t l r o h Each s u b j e c t had t o s u c c e s s i v e l y i n t e r p r e t t h r e e l u n g r a d i o g r a p h s (one normal and two p a t h o l o g i c a l p i c t u r e s ) w i t h o u t t h e h e l p o f a medical document. D u r i n g these i n t e r p r e t a t i o n s , gaze d i r e c t i o n was r e c o r d e d on i d r o tape. To make an o b j e c t i v e a n a l y s i s o f gaze d i r e c t i o n , we s e l e c t e d anumh o f marks : q u a l i t y (zone) o f l o c a t i o n , duration o f location, c h r o n o l o g y o f t h e change o f l o c a t i o n , general o r g a n i s a t i o n o f v i s u a l search.
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7 - 2 . RUULZA The r e s u l t s a n a l y s i s shows t h a t each group can be d e s c r i b e d by t y p i c a l f e a t u r e s which a r e : 1-2.1. F o r t h e non r a d i o l o g i s t s , mean d u r a t i o n o f l u n g r a d i o g r a p h i n t e r p r e t a t i o n i s q u i t e c o n s t a n t ( 2 ' ? 20") f o r normal and p a t h o l o g i c a l p i c tures. 100 100 Mean d u r a t i o n o f l o c a t i o n i s a l s o q u i t e c o n s t a n t (53 ). Physicians k 10 e x p l o r e d many t i m e s t h e same area and never saw t h e s o f t p a r t s . E x p l o r a t i o n p a t h s o f t e n r u n f r o m t o p t o bottom t o p e r i p h e r y and up t h r o u g h t h e imediast i n u m . Passage f r o m one s i t e t o another i s g e n e r a l l y done by p r o x i m i t y c r i t e r i o n . T h i s group made many i n t e r p r e t a t i o n e r r o r s ( 5 ) .
1-2.2. F o r t h e r a d i o l o g i s t s , d u r a t i o n o f l u n g r a d i o g r a p h e x p l o r a t i o n i s s h o r t e r ( 1 ' 5 " 5 l o " ) and d u r a t i o n o f l o c a t i o n i s l o n g e r (961°0 2 151°0 ) . T h i s group e x p l o r e d a l l t h e areas, g e n e r a l l y o n l y once and s p e n t more t i m e o b s e r v i n g t h e c e n t r a l p a r t o f t h e l u n g which i s used as a v i s u a l p i v o t . V i s u a l p i v o t i s t r a n s f e r e d on c o n f l i c t u a l l o c a t i o n o f t h e p i c t u r e each t i m e t h e r e i s a problem, and as l o n g as t h i s problem i s n o t s o l v e d . T h i s group d i d n o t make i n t e r p r e t a t i o n e r r o r s . 1-3. VAcuhnion
We found t h e same r e s u l t s as t h o s e r e p o r t e d i n t h e b i b l i o g r a p h y : S t r i c t l y speaking, t h e r e i s no common v i s u a l b e h a v i o r between t h e members o f each group and, o f course, between t h e two groups. Nevertheless, t h e r e i s a way t o e x p l o r e a p i c t u r e which i s used by s p e c i a l i s t s (and n o t by non s p e c i a l i s t s ) . T h i s way can be c h a r a c t e r i z e d by : a complete checking o f areas, - a l o n g pause on each l o c a t i o n , a use o f p r e c i s e l o c a t i o n ( g e n e r a l l y t h e upper p a r t o f mediastinum) as a v i s u a l p i v o t , - a g l o b a l a n a l y s i s a t t h e b e g i n n i n g and a t t h e end o f t h e v i s u a l search. The r o l e o f g l o b a l a n a l y s i s has a l r e a d y been evidenced i n o t h e r v i s u a l t a s k s ( h e l i c o p t e r f l y i n g i n 1980, Papin e t a1 ( l o ) . Indeed, a l o n g qaze l o c a t i o n on t h e c e n t e r p a r t o f a p i c t u r e can evidence an unusual mark e v e n i f i t i s i n t h e p e r i p h e r a l v i s u a l f i e l d . Today, t h e r e i s
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no valuable explanation o f information processing i n t h i s case. F i n a l l y , we can argue the f a c t t h a t there i s a common visual behavior, f o r t h e s p e c i a l i s t s and another one f o r the non s p e c i a l i s t s . They seem t o be " r u l e s o f reading", independant o f the nature o f the negative. We s h a l l c a l l such c h a r a c t e r i s t i o "higher features o f v i s u a l behavior". The f i n a l i n t e r e s t would be t o search i n f u t u r e experiments how these general behav i o r s become mentally operational as specialised knowledge i s acquired. I n other words are they consequences o r i n v e r s e l y conditions f o r the acquis i t i o n o f s k i l l e d i n t e r p r e t a t i o n ? Depending on the answer, they could be taught a t a more o r l e s s advanced stage o f studies t o be e f f i c i e n t . I t would a1 so be possible t o have a b e t t e r understanding o f the i n t e l l e c t u a l mechanisms used by the i n t e r p r e t i n g s p e c i a l i s t . I1
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USE OF NAC EYE MARK I N ABDOMINAL ECHOGRAPHY
One o f the NAC eye Mark p r o p e r t i e s i s the great m o b i l i t y o f the apparatus ; another i s t o provide a continuous movie o f gaze d i r e c t i o n . Consequently, we use the display, combined w i t h gestural and manual recording, t o study the echograph work s t a t i o n . The i n t e r e s t o f the method,in a d d i t i o n t o permit q u a l i f y i n g the v i s u a l behavior, i s t o know the consequences o f two new facts : p i c t u r e analysis i n dynamic s i t u a t i o n (dynamic search o f the good picture) , - d i r e c t presence o f the p a t i e n t (problem o f the d o c t o r / p a t i e n t r e l a tionship).
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rr-I.
Methods
Three physicians examined two p a t i e n t s ( h o s p i t a l i z e d i n the same h o s p i t a l ) . Physicians had r e s p e c t i v e l y 4,4 and 9 monthsexperience i n l i v e r echograp h i c techniques. Each one had t o examine both p a t i e n t s . A few medical documents were a v a i l a b l e t o them. The f i r s t p a t i e n t had h e p a t i t i s without echographic signs. The second p a t i e n t had l i t h i a s i s w i t h echographic signs. The morphology o f the two p a t i e n t s was s i m i l a r . The echographic examination was conducted i n three steps : 1 - Greeting o f the p a t i e n t , medical examination, complementary quest i o n s , and s h o r t explanation o f echographic techniques. 2 Examination w i t h use o f a mechanic, handheld transducer. This transducer permits r a p i d anatomic e x p l o r a t i o n w i t h d e t e c t i o n o f i n d i c a t o r p o i n t s (as vena cava). Pictures are continuously monit o r e d using a TV monitor. 3 An analysis o f selected p i c t u r e s w i t h the help o f frequency and l o c a t i o n probes, used i n r e a l time ( B Mode) follows the second p a r t . I t i s the r e a l i n t e r p r e t a t i o n p a r t o f the examination. Analysis o f gaze d i r e c t i o n recordings was made w i t h the same c r i t e r i a as i n lung radiography. Simply, we added the duration o f each p a r t o f the examination. Voice recordings and gesturd recordings allowed completimof the understanf o r the doctor/patient r e l a t i o n s h i p . ding o f v i s u a l behavior, essential
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rr-2. RUU Result analysis f i r s t shows t h a t visual behavior g r e a t l y varies between physicians and f o r t h e same physicians, between p a t i e n t s : e.g., time o f the examination varies from simple t o double. Nevertheless, the three echographs f i n d the r e l e v a n t echographic informat i o n about the p a t i e n t ' s i l l n e s s and i t i s possible t o i s o l a t e a few common v i s u a l features :
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The p a t i e n t ' s face i s observed f r o m 3 t o 5 % o f t h e o v e r a l l examin a t i o n time. TV m o n i t o r and t r a n s d u c e r a r e watched f r o m 65 t o 80 %. D u r i n g t h e c o n s t r u c t i o n o f images (phase 2) gaze f o l l o w s t h e d i f f e r e n t changes on t h e TV m o n i t o r . From t i m e t o time, gaze s t o p s on a p o s s i b l e r e l e v a n t i n f o r m a t i o n and does n o t e x p l o r e t h e o t h e r p a r t s o f t h e p i c t u r e ; t h e n e x t image i s i m m e d i a t l y w a t c h e d t o conf i r m o r t o i n v a l i d a t e c u r r e n t r e l e v a n t i n f o r m a t i o n . Such t e c h n i q u e r e c a l l s t h e p i v o t v i s u a l b e h a v i o r observed i n l u n g r a d i o g r a p h explorations. When good images a r e s e l e c t e d , gaze f i x e s t h e c e n t e r p a r t o f t h e TV screen and s t a y s on i t . I n case o f d p a t h o l o g i c a l case, e x a m i n a t i o n i s l o n g e r and p - > echographic images a r e made. The mean checking t i m e o f imar 5 also longer.
11-3.
~hCUAbiOn
For t h e p s y c h o l o g i s t , common f e a t u r e s we f i n d a r e maybe h i g h e r f e a t u r e 5 o f b e h a v i o r as i n l u n g r a d i o g r a p h y . N e t h e r t h e l e s s , t h e i r b a n a l i t y (. . f o l l o w i n g t h e image c o n s t r u c t i o n , f i x i n c l t h e TV image, e t c . . . ) r a i s e g r e a t i n t e r e s t i n i n t e r p r e t a t i o n o f such phenomenon. The f a c t t h a t gaze d i r e c t i o n i s f i x e d on t h e c e n t e r p a r t o f TV d u r i n g a l l t h e i n t e r p r e t a t i o n can reduce t h e i n t e r e s t t i e d t o NAC Eye Mark d i s p l a y . T h i s i s a g r e a t problem i n u s i n g t h e NAC Eye Mark and evidences t h e f a c t t h a t v i s u a l b e h a v i o r i s o n l y p a r t o f t h e general b e h a v i o r which i s a l s o a p a r t o f knowledge. Consequently, i n f o r m a t i o n p r o c e s s i n g can o c c u r w i t h o u t eye movement. F o r t h e c l i n i c i a n , t h e s t u d y o f v o i c e communication and p s t u r a l b e h a v i o r , combined t o v i s u a l b e h a v i o r shows t h a t d o c t o r / p a t i e n t r e l a t i o n s h i p s a r e v e r y poor. P a t i e n t a n x i e t y i n c r e a s e s w i t h t h e poor knowledge o f t h e t e c h n i q u e . A g r e a t e f f o r t must be q u i c k l y made t o improve t h e t e c h n i q u e and t o humanize r e l a t i o n s h i p s . F i n a l l y , reproach can be made t o t h i s d i s p l a y system f r o m an ergonomic s t a n d p o i n t ( b u t t o n s , d i s t a n c e o f t h e TV m o n i t o r ) .
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USE OF NAC EYE MARK I N PEDAGOGY
Because o f t h e n a t u r e o f t h e NAC Eye Mark r e c o r d i n g s ( v i d e o t a p e ) , i t seems t e m p t i n g t o use these as a pedagogical means. Such approach has a l r e a d y been used i n o t h e r branches o f i n s t r u c t i o n : I n s p o r t , i n 1981, Bayless ( 4 ) and R i p p o l l and c o l l ( 1 1 ) . I n f l y i n g , i n 1981 a l s o , Spady and c o l l ( 1 2 ) . I n r a d i o l o g y , as i n s p o r t o r f l y i n g , t r a i n i n g i s a b i g problem. On one hand, much t i m e i s needed t o t r a i n a good s p e c i a l i s t . On t h e o t h e r hand, i t i s o f t e n necessary t o g i v e s u f f i c i e n t t r a i n i n g i n a s h o r t time t o a l l o w d a i l y p r a c t i s e f o r t h e g e n e r a l i s t (case o f l u n g r a d i o g r a p h y ) . The numbers o f i n t e r p r e t a t i o n e r r o r s show t h a t such an approach i s f a r f r o m b e i n g mastered. 111-1. MeAhods
To s i m p l i f i y i n t e r p r e t a t i o n we used a g a i n a r e l a t i v e l y w e l l known model o f radiography : t h e 10 x 10 cm r a d i o p h o t o g r a p h ( a s y s t e m a t i c c o n t r o l s i z e o f l u n g r a d i o graph) * I t i s a complex s o r t i n g t a s k t h a t young p h y s i c i a n s never s t u d y i n t h e i r n o r mal e d u c a t i o n course. Consequently, s p e c i a l t r a i n i n g i s g i v e n i n a one y e a r (Aviation m i l i t a r y a p p l i e d s e s s i o n ( " B r e v e t de Mgdecine Agronautique") M e d i c i n e l i c e n s e ) f o r young m i l i t a r y p h y s i c i a n s . To conduct t h i s e x p e r i m e n t a l approach, we s e l e c t 40 radiophotographs i n two b o b i n s o f 20 exposures, w i t h t h e h e l p o f t h e r a d i o l o g y department o f
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the BEGIN M i l i t a r y Hospital (PARIS) and o f the radiology department o f CPEMPN headed by Doctor PUECH (Centre P r i n c i p a l d'Expertise Mgdicale du Personnel Navigant - PARIS). Each bobi n incl udes : - 5 obvious pathological lungs, 5 pathological lungs more d i f f i c u l t t o diagnose,
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10 normal lungs. The viewing order o f p i c t u r e s i s c o n t r o l l e d by a random table. Special f i l m s and one normal f i l m (100 radiophotographs) are examined by f o u r r a d i o l o g i s t s . D i r e c t i o n o f gaze o f three o f them i s recorded on videotape. Then, these recordings are analyzed w i t h the respective readers ( r a d i o l o g i s t s ) and a psychologist t o assess visual behavior features. The f o u r t h r a d i o l o g i s t i s o n l y interviewed and n o t recorded. He allows us t o v e r i f y the hypothesis b u i l t on the three o t h e r s p e c i a l i s t s ' v i s u a l behav i or. Subsequently, two d i d a c t i v e movies are made. The same process i s used f o r both : 1 - Two r a d i o l o g i s t ' s gaze recordings appear successively f o r one o r many negatives 2 comments are made s h o r t l y t o emphasize each idea 3 drawings give a t the end o f the sequence a summarizing idea o f behavior used by experts 4 - the t h i r d r a d i o l o g i s t ' s gaze recording o f t h i s p o i n t appears a l a s t time t o i l l u s t r a t e the drawing. Durations o f movies are r e s p e c t i v e l y 7'30" and 10'. I n the same time, a t the beginning o f the school year, a f i r s t t e s t i s proposed t o 24 young m i l i t a r y medical students. Notation judges f i r s t the good o r the bad s o r t i n g . I n a d d i t i o n , i t penal i z e s neglects, always serious i n a s o r t i n g task, and minimizes excess c o n t r o l requests. Such n o t a t i o n i s kept f o r the two t e s t s ( a t the beginning and a t the end o f the school year ). A t the end o f the f i r s t t e s t , subjects are divided i n t o two groups w i t h i d e n t i c a l means and standard deviation. The f i r s t group ( c o n t r o l group) has a normal teaching course. The second group (experimental group) has the same teaching course r e i n f o r c e d by presentation o f the movies. A second i n t e r p r e t a t i o n t e s t i s performed a t the end o f the school year t o judge progress, i f any.
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711-2. R Q h d Means o f the two groups stay q u i t e the same f o r the two t e s t s (Student t e s t N.S. a t 05). There i s no b e t t e r performance f o r the experimental group. I n addition, t h e r e i s a great i n s t a b i l i t y i n t h e i n d i v i d u a l scores ; the best subjects lower t h e i r mean and the worst subjects improve t h e i r mean. The end r e s u l t i s t h a t everybody has a comparable mean score a t the end o f the school year Only the standard d e v i a t i o n d i f f e r s between the two groups w i t h a tendency t o reduction for the experimental group (but no s t a t i s t i c a l s i g n i f i c a n c e ) . Duration o f i n t e r p r e t a t i o n i s very long : 20' f o r the c o n t r o l group, 18' f o r the experimental group. These times are double t h a t o f s p e c i a l i s t s ( 9 ' f 30")
222-3. V h c u s b i a n The c o n s t r u c t i o n o f t h i s experiment permits study o f two d i f f e r e n t problems : the v a l i d i t y and the t r a n s m i s s i b i l i t y o f higher features found i n
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t h e f i r s t l u n g r a d i o g r a p h experiment - t h e i n t e r e s t o f i n t r o d u c t i o n o f v i s u a l b e h a v i o r movies i n t e a c h i n g courses. 111-3.1. The v a l i d i t y and t h e t r a n s m i s s i b i l i t y o f h i g h e r f e a t u r e s We found a g a i n t h e h i g h e r f e a t u r e showed i n t h e f i r s t experiment. No more b u t no l e s s . T h i s f a c t a t t e s t s t h e e f f e c t i v e n e s s o f such v i s u a l b e h a v i o r s . The knowledge o f these h i g h e r f e a t u r e s does n o t appear as a s u f f i c i e n t c o n d i t i o n f o r good i n t e r p r e t a t i o n . Probably, we should have g r e a t e r r e t r o s p e c t i v e t o have a p r o p e r view o f t h e m a t t e r . S u r e l y , we were t o o a m b i t i o u s b e l i e v i n g t h a t many y e a r s o f p r a c t i s e would be l e a r n t i n 6 months. 111-3.2.
The i n t e r e s t o f v i d e o l e a r n i n g
I t must be emphasized t h a t s t u d e n t s welcomed t h e method w i t h enthusiasm. T h i s method uses a v e r y a t t r a c t i v e media : t h e movie, and c o n s t i t u t e s a p r i v i l i g e d means o f communication and s e l f t e a c h i n g ( c a s s e t t e s ) . Up t o a p o i n t , w e i g h t o f v e r b a l comments must decrease p r o g r e s s i v e l y t o l e t t h e drawings a l t e r n a t i n g w i t h l a r g e sequences o f NAC. So, accustomed by an Image S o c i e t y , where TV m o n i t o r s appear everywhere, i t would be p o s s i b l e t o make o n e ' s own judgement on t h e q u a l i t y o f v i s u a l s t r a t e g i e s shown. I n t h i s case, t h e NAC would be used f o r i t s t e a c h i n g p r o p e r t i e s ( f i l m o f v i s u a l b e h a v i o r w i t h o u t subsequent d i g i t p r o c e s s i n g ; t h e d i f f i c u l t i e s i n h e r e n t t o t h i s l a s t phase would t h e n be avoided ( p r o c e s s i n g technique, etc.. .) . CONCLUSION F o r t h e l a s t t h r e e years, o u r team which pursues t h e same o b j e c t i v e s , focused i t s i n t e r e s t on t h r e e complementary aspects : - t h e d e s c r i p t i o n o f v i s u a l b e h a v i o r s which d i f f e r e n t i a t e e x p e r t s and b e g i n n e r s (1981-( 1)) : how v i s u a l b e h a v i o r s become o r g a n i z e d as a f u n c t i o n o f experience ? - t h e t e a c h i n g o f these b e h a v i o r s ( 1 9 8 3 - ( 3 ) ) : i s i t p o s s i b l e t o speed t h i s l e a r n i n g and reduce t h e number o f e r r o r s by t e a c h i n g p r e c e d e n t l y i s o l a t e d v i s u a l behaviors ? - f i n a l l y , t h e s t u d y o f v i s u a l b e h a v i o r s i n new r a d i o l o g y t e c h n i q u e s t o assess t h e i n f l u e n c e o f t h e image dynamics e s p e c i a l l y echography ( s u c c e s s i o n o f images on TV screen) and t h e r o l e p l a y e d by t h e p a t i e n t ' s presence ( 1982- ( 2 ) ) These s t u d i e s have v a r i o i l s degrees o f i n t e r e s t f o r s e v e r a l s p e c i a l t i e s : - c l i n i c a n s , r a d i o l o g i s t s , p h y s i c i a n s hope t o draw o u t r u l e s o f " e f f i c i e n t r e a d i n g " and t h u s d i m i n i s h t h e number o f i n t e r p r e t a t i o n e r r o r s ( n e a r l y 30% a c c o r d i n t t o YERUSHALMI (13)), - r e s e a r c h e r s and p s y c h o l o g i s t s hope t o g e n e r a l i z e t h e r e s u l t s o b t a i n e d w i t h complex images and t o have a b e t t e r u n d e r s t a n d i n g o f r e l a t i o n s h i p s which e x i s t between v i s u a l b e h a v i o r and i n t e l l e c t u a l mechanisms i n v o l v e d i n image a n a l y s i s . Consequently, r e s u l t s observed i n these t h r e e experiments must be analysed as a f u n c t i o n o f t h e s p e c i a l t y o f t h e c l i n i c i a n o r p s y c h o l o g i s t : F o r c l i n i c i a n s t h e NAC seems t o o f f e r d r a m a t i c new ways t o evidence v i s u a l b e h a v i o r s . I t p e r m i t s i s o l a t i n g a few s p e c i f i c t r a i t s o f a p o p u l a t i o n h a v i n g t h e same l e v e l o f e x p e r i e n c e and can t h e r e f o r e suggest some a d v i c e o r remarks t h a t c o n t r i b u t e t o t h e e f f o r t t o d i m i n i s h t h e number o f i n t e r p r e t a t i o n e r r o r s . These v i s u a l b e h a v i o r s c o u l d be t a u g h t t o s t u d e n t r a d i o l o g i s t s more capable o f i n c o r p o r a t i n g t h e observed b e h a v i o r i n t o t h e i r knowledge. T h i s s p e c i a l course would complement t h e r e g u l a r t e a c h i n g
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program. Another way r a d i o l o g i s t s can use t h e NAC EYE MARK recorder i s t o v i s u a l i z e t h e i r own v i s u a l behavior i n order t o become aware and analyse t h e i r mistakes, p a r t i c u l a r l y as f a r as t h e d o c t o r / p a t i e n t r e l a t i o n s h i p i s concerned, since t h e number o f times when t h e r a d i o l o g i s t looks a t h i s p a t i e n t dons an a f f e c t i v e and human meaning. F o r psychologists, t h e r a d i o l o g i s t s ' experience i s a consequence o f l e a r n i n g and t r a i n i n g . General behavior ( v i s u a l , gestural, verbal .) i s o n l y a d i r e c t observable consequence o f t h e use o f knowledge. Likewise, v i s u a l behavior i s one expression o f t h e general behavior and no more. Nac Eye Mark today represents one o f t h e b e t t e r t o o l s t o o b j e c t i v e l y study v i s u a l behavior. I n most r a d i o l o g y tasks, numbers o f eye movements and t h e i r amplitudes a r e s u f f i c i e n t t o emphasize t h e way t o p i c k up i n f o r m a t i o n and t o i s o l a t e a l a r g e p a r t o f the needed i n f o r m a t i o n ( d i r e c t e d search). L i m i t s o f t h e Nac appear f o r the understanding o f t h e p i c k up o f i n f o r m a t i o n when gaze stays many times on t h e same p o i n t . Then, i t i s impossible t o know what i s e x a c t l y shown : a d e t a i l , a general ( t i m e t o t h i n k ) s i g h t t o t h e negative o r nothing ! L i m i t s o f t h e Nac a l s o appear i f you want t o q u a l i f y t h e i n f o r m a t i o n process i n g and t h e f i n a l d e c i s i o n made by r a d i o l o g i s t s . I n t h i s case, Nac Recordings can o n l y by used as o b j e c t i v e and common documents which c o n s t i t u t e t h e base o f o t h e r psychological techniques o f c o g n i t i v e e x p l o r a t i o n .
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P A P I N J.P., METGES P., HERNANDEZ C. : L ' e x p l o r a t i o n v i s u e l l e de r a d i o graphies du thorax. Rapport CERMA 81-12 (LCBA), j u i l l e t 1981.
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PAPIN J.P., FAVRE Y., METGES P. : Analyse de l a tache du medecin "echog r a p h i s t e " . Rapport CERMA 83-04 (LCBA), a v r i l 1983.
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P A P I N J.P., METGES P., AMALBERTI R., DELAFONTAINE S. : Experience de pedagogic a u d i o v i s u e l l e a p a r t i r de l ' e n r e g i s t r e m e n t de l a d i r e c t i o n du regard en r a d i o l o g i e . Rapport CERMA, 1983 I n press.
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GALE A.G., WORTHINGTON B.S. : The u t i l i t y o f scanning s t r a t e g i e s i n r a d i o l o g y i n Eye movements and psychological f u n c t i o n s . I n t e r n a t i o n a l wiews Laurence Erlbaum, 1983.
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KUNOEL H.L., WRIGHT D.J. : The i n f l u e n c e o f p r i o r knowledge on v i s u a l search s t r a t e g i e s d u r i n g the viewing o f chest radiographs, Radiology, 93, 1969, 315-20.
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KUNDEL H.L., LAFOLLETTE P.S. : Visual search p a t t e r n s and experience w i t h r a d i o l o g i c a l images, Radiology, 103, 1972, 523-528.
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LLEWELLYN, THOMAS E., LANSDOWNE E.L. : Visual search p a t t e r n s of r a d i o l o g i s t s i n t r a i n i n g , Radiology, 81, 1963, 288-92.
BAYLESS M.A. : E f f e c t o f exposure t o p r o t o t y p i e s k i l l and experience i n i d e n t i f i c a t i o n o f performance e r r o r . Perceptual and motor s k i l l s , 52, ( 2 ) , 1981, 667-70.
CARMODY D.P., NODINE C.F., KUNDEL H.L. : F i n d i n g lung nodules w i t h and w i t h o u t comparative v i s u a l scanning. Perception and psychophysics, 29, ( 6 ) , 1981, 594-98.
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10 - PAPIN J.P., NAUREILS P., WIATZ A. : Analyse de la direction du regard d'un pilote d'alouette I11 effectuant une serie de vols tactiques en vision monoculaire et avec champ visuel reduit. Rapport CERMA, 80-18, (LCBA) , septembre 1980. 11 - RIPOLL H.,
BARD C., PAILLARD J., GROSGEORGE B. : Caracteristiques de la centration de l'oeil et de la tete sur la cible et son r6le dans l'execution du tir en basket-ball. New paths to sport learning and excellence. ISSP 5th World Sport Psychology Congress, 1982, 32-36.
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- YERUSHALMY J.
SPADY A., JONES D., COATES G., KIRBY R. : The effectiveness of using real time eye scanning information for pilot training. 26th Annual meeting - Proceedings of the human factors society - 1982. : The statistical assessment of the variability in observer perception and description o f roentgenographie pulmonary shadows. Radiologic clinics o f North America, I, 381-90.
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USE OF NAC EYE MARK BY RADIOLOGISTS
Jean Paul PAPIN*
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P i e r r e ( J ) METGES**
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AMALBERTI*
Centre d'Etudes e t de Recherches de M6decine Aeronautique 5 b i s Avenue de l a Porte de S&vres 75731 PARIS CEDEX 15 ** Hapita1 d' I n s t r u c t i o n des Armees BEGIN. Service de Radiologie 69 Avenue de PARIS 94160 ST MANDE
SUMMARY Three experiments j o i n t l y conducted by a department o f research on v i s u a l perception and a h o s p i t a l radiology department are described and discussed. A gaze d i r e c t i o n recording device, the NAC EYE Mark recorder was used t o characterize t y p i c a l visual behaviors o f r a d i o l o g i s t s and non r a d i o l o g i s t physicians during lung radiography (Exp. 1) and abdomen echography (Exp. 2 ) . Only very general behaviors were evidenced. The s i g n i f i c a n c e o f doctor/ p a t i e n t r e l a t i o n s h i p s was a l s o analysed i n Exp. 2. These same common v i s u a l behaviors were evidenced and comnented t o young physicians (Exp. 3) viewing lung radiographs. While emphasizing the a t t r a c t i v e nature o f the f i l m s the discussion underlines the d i f f i c u l t i e s inherent t o the i n t e r p r e t a t i o n o f such documents : the NAC records gaze s h i f t s and pauses, b u t i s unable t o e x p l a i n t h e i r causes. .
INTRODUCTION Often, when you l o o k a t someone examining a p i c t u r e , you can guess the course, t h e d i f f i c u l t i e s o r the easiness o f analysis o n l y by observance o f eye movements. I n f a c t , eyes are often p r e f e r e n t i a l means t o p i c k up information. Their m o b i l i t y seams t o witness, on a f i r s t analysis, a c o n t r o l l e d and l o g i c a l search, t i e d t o the way t o perform the c u r r e n t task. If such i n t u i t i v e analysis was good, v i s u a l behavior would be h i g h l y ident i c a l f o r one operator repeating many times the same task. It would even be possible t o f i n d i d e n t i c a l features i n visual behavior between two operators performing the same task. O f course, i f you want t o argue t h i s f a c t , you need an o b j e c t i v e means t o record eye movements. To v e r i f y t h i s hypothesis i n radiology, we used an oculometer diqolay c a l l e d NAC Eye Mark Recorder. This d i s p l a y allows continuous recording ,on a movie o r video support, the scene t a k i n g place i n f r o n t o f t h e operator. An i & i c a t o r (such as an arrow) superimposes gaze d i r e c t i o n on the general scene. I n a f i r s t step, we studied a s t a t i c model o f radiography: the lung r a d i o graph. I t was i n 1981 ( 1). I
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USE OF NAC EYE MARK I N CHEST RADIOGRAPHY
I n the f i r s t experiment, we used a r e l a t i v e l y w e l l known model f o r the desc r i p t i o n o f radiologists'eye movements : chest radiography. Some importantlandmarks o f t h i s work can be b r i e f l y reviewed. I n 1963 Lewellyn Thomas (9) showed the h i g h l y i n d i v i d u a l features o f radiol o g i s t s ' v i s u a l behavior. I n 1969 Kundel & Wright (7), and i n 1972 Kundel & L a f o l e t t e (8) emphasized the importance o f t h e context (knowledge of the patient's c l i n i c a l history).
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Carmody e t al. i n 1981 (5) showed t h e g r e a t importance o f compasture scanning s t r a t e g y t o d i f f e r e n t i a t e modules f r o m anatomical s t r u c t u r e s and Gale & W o r t h i n g t o n (1983 ( 6 ) ) showed t h a t t h e r e i s n o t i e between t h e v i s u a l behav i o r recommended i n handbooks o f r a d i o l o g y and t h e r e a l i t y o f v i s u a l search. C o n s i d e r i n g such r e s u l t s , a comparative s t u d y between two groups o f subj e c t s ( t e n non s p e c i a l i s t p h y s i c i a n s and e l e v e n c o n f i r m e d r a d i o l o g i s t s ) was conducted.
r-1. ~ d t l r o h Each s u b j e c t had t o s u c c e s s i v e l y i n t e r p r e t t h r e e l u n g r a d i o g r a p h s (one normal and two p a t h o l o g i c a l p i c t u r e s ) w i t h o u t t h e h e l p o f a medical document. D u r i n g these i n t e r p r e t a t i o n s , gaze d i r e c t i o n was r e c o r d e d on i d r o tape. To make an o b j e c t i v e a n a l y s i s o f gaze d i r e c t i o n , we s e l e c t e d anumh o f marks : q u a l i t y (zone) o f l o c a t i o n , duration o f location, c h r o n o l o g y o f t h e change o f l o c a t i o n , general o r g a n i s a t i o n o f v i s u a l search.
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7 - 2 . RUULZA The r e s u l t s a n a l y s i s shows t h a t each group can be d e s c r i b e d by t y p i c a l f e a t u r e s which a r e : 1-2.1. F o r t h e non r a d i o l o g i s t s , mean d u r a t i o n o f l u n g r a d i o g r a p h i n t e r p r e t a t i o n i s q u i t e c o n s t a n t ( 2 ' ? 20") f o r normal and p a t h o l o g i c a l p i c tures. 100 100 Mean d u r a t i o n o f l o c a t i o n i s a l s o q u i t e c o n s t a n t (53 ). Physicians k 10 e x p l o r e d many t i m e s t h e same area and never saw t h e s o f t p a r t s . E x p l o r a t i o n p a t h s o f t e n r u n f r o m t o p t o bottom t o p e r i p h e r y and up t h r o u g h t h e imediast i n u m . Passage f r o m one s i t e t o another i s g e n e r a l l y done by p r o x i m i t y c r i t e r i o n . T h i s group made many i n t e r p r e t a t i o n e r r o r s ( 5 ) .
1-2.2. F o r t h e r a d i o l o g i s t s , d u r a t i o n o f l u n g r a d i o g r a p h e x p l o r a t i o n i s s h o r t e r ( 1 ' 5 " 5 l o " ) and d u r a t i o n o f l o c a t i o n i s l o n g e r (961°0 2 151°0 ) . T h i s group e x p l o r e d a l l t h e areas, g e n e r a l l y o n l y once and s p e n t more t i m e o b s e r v i n g t h e c e n t r a l p a r t o f t h e l u n g which i s used as a v i s u a l p i v o t . V i s u a l p i v o t i s t r a n s f e r e d on c o n f l i c t u a l l o c a t i o n o f t h e p i c t u r e each t i m e t h e r e i s a problem, and as l o n g as t h i s problem i s n o t s o l v e d . T h i s group d i d n o t make i n t e r p r e t a t i o n e r r o r s . 1-3. VAcuhnion
We found t h e same r e s u l t s as t h o s e r e p o r t e d i n t h e b i b l i o g r a p h y : S t r i c t l y speaking, t h e r e i s no common v i s u a l b e h a v i o r between t h e members o f each group and, o f course, between t h e two groups. Nevertheless, t h e r e i s a way t o e x p l o r e a p i c t u r e which i s used by s p e c i a l i s t s (and n o t by non s p e c i a l i s t s ) . T h i s way can be c h a r a c t e r i z e d by : a complete checking o f areas, - a l o n g pause on each l o c a t i o n , a use o f p r e c i s e l o c a t i o n ( g e n e r a l l y t h e upper p a r t o f mediastinum) as a v i s u a l p i v o t , - a g l o b a l a n a l y s i s a t t h e b e g i n n i n g and a t t h e end o f t h e v i s u a l search. The r o l e o f g l o b a l a n a l y s i s has a l r e a d y been evidenced i n o t h e r v i s u a l t a s k s ( h e l i c o p t e r f l y i n g i n 1980, Papin e t a1 ( l o ) . Indeed, a l o n g qaze l o c a t i o n on t h e c e n t e r p a r t o f a p i c t u r e can evidence an unusual mark e v e n i f i t i s i n t h e p e r i p h e r a l v i s u a l f i e l d . Today, t h e r e i s
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no valuable explanation o f information processing i n t h i s case. F i n a l l y , we can argue the f a c t t h a t there i s a common visual behavior, f o r t h e s p e c i a l i s t s and another one f o r the non s p e c i a l i s t s . They seem t o be " r u l e s o f reading", independant o f the nature o f the negative. We s h a l l c a l l such c h a r a c t e r i s t i o "higher features o f v i s u a l behavior". The f i n a l i n t e r e s t would be t o search i n f u t u r e experiments how these general behav i o r s become mentally operational as specialised knowledge i s acquired. I n other words are they consequences o r i n v e r s e l y conditions f o r the acquis i t i o n o f s k i l l e d i n t e r p r e t a t i o n ? Depending on the answer, they could be taught a t a more o r l e s s advanced stage o f studies t o be e f f i c i e n t . I t would a1 so be possible t o have a b e t t e r understanding o f the i n t e l l e c t u a l mechanisms used by the i n t e r p r e t i n g s p e c i a l i s t . I1
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USE OF NAC EYE MARK I N ABDOMINAL ECHOGRAPHY
One o f the NAC eye Mark p r o p e r t i e s i s the great m o b i l i t y o f the apparatus ; another i s t o provide a continuous movie o f gaze d i r e c t i o n . Consequently, we use the display, combined w i t h gestural and manual recording, t o study the echograph work s t a t i o n . The i n t e r e s t o f the method,in a d d i t i o n t o permit q u a l i f y i n g the v i s u a l behavior, i s t o know the consequences o f two new facts : p i c t u r e analysis i n dynamic s i t u a t i o n (dynamic search o f the good picture) , - d i r e c t presence o f the p a t i e n t (problem o f the d o c t o r / p a t i e n t r e l a tionship).
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Three physicians examined two p a t i e n t s ( h o s p i t a l i z e d i n the same h o s p i t a l ) . Physicians had r e s p e c t i v e l y 4,4 and 9 monthsexperience i n l i v e r echograp h i c techniques. Each one had t o examine both p a t i e n t s . A few medical documents were a v a i l a b l e t o them. The f i r s t p a t i e n t had h e p a t i t i s without echographic signs. The second p a t i e n t had l i t h i a s i s w i t h echographic signs. The morphology o f the two p a t i e n t s was s i m i l a r . The echographic examination was conducted i n three steps : 1 - Greeting o f the p a t i e n t , medical examination, complementary quest i o n s , and s h o r t explanation o f echographic techniques. 2 Examination w i t h use o f a mechanic, handheld transducer. This transducer permits r a p i d anatomic e x p l o r a t i o n w i t h d e t e c t i o n o f i n d i c a t o r p o i n t s (as vena cava). Pictures are continuously monit o r e d using a TV monitor. 3 An analysis o f selected p i c t u r e s w i t h the help o f frequency and l o c a t i o n probes, used i n r e a l time ( B Mode) follows the second p a r t . I t i s the r e a l i n t e r p r e t a t i o n p a r t o f the examination. Analysis o f gaze d i r e c t i o n recordings was made w i t h the same c r i t e r i a as i n lung radiography. Simply, we added the duration o f each p a r t o f the examination. Voice recordings and gesturd recordings allowed completimof the understanf o r the doctor/patient r e l a t i o n s h i p . ding o f v i s u a l behavior, essential
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rr-2. RUU Result analysis f i r s t shows t h a t visual behavior g r e a t l y varies between physicians and f o r t h e same physicians, between p a t i e n t s : e.g., time o f the examination varies from simple t o double. Nevertheless, the three echographs f i n d the r e l e v a n t echographic informat i o n about the p a t i e n t ' s i l l n e s s and i t i s possible t o i s o l a t e a few common v i s u a l features :
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The p a t i e n t ' s face i s observed f r o m 3 t o 5 % o f t h e o v e r a l l examin a t i o n time. TV m o n i t o r and t r a n s d u c e r a r e watched f r o m 65 t o 80 %. D u r i n g t h e c o n s t r u c t i o n o f images (phase 2) gaze f o l l o w s t h e d i f f e r e n t changes on t h e TV m o n i t o r . From t i m e t o time, gaze s t o p s on a p o s s i b l e r e l e v a n t i n f o r m a t i o n and does n o t e x p l o r e t h e o t h e r p a r t s o f t h e p i c t u r e ; t h e n e x t image i s i m m e d i a t l y w a t c h e d t o conf i r m o r t o i n v a l i d a t e c u r r e n t r e l e v a n t i n f o r m a t i o n . Such t e c h n i q u e r e c a l l s t h e p i v o t v i s u a l b e h a v i o r observed i n l u n g r a d i o g r a p h explorations. When good images a r e s e l e c t e d , gaze f i x e s t h e c e n t e r p a r t o f t h e TV screen and s t a y s on i t . I n case o f d p a t h o l o g i c a l case, e x a m i n a t i o n i s l o n g e r and p - > echographic images a r e made. The mean checking t i m e o f imar 5 also longer.
11-3.
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For t h e p s y c h o l o g i s t , common f e a t u r e s we f i n d a r e maybe h i g h e r f e a t u r e 5 o f b e h a v i o r as i n l u n g r a d i o g r a p h y . N e t h e r t h e l e s s , t h e i r b a n a l i t y (. . f o l l o w i n g t h e image c o n s t r u c t i o n , f i x i n c l t h e TV image, e t c . . . ) r a i s e g r e a t i n t e r e s t i n i n t e r p r e t a t i o n o f such phenomenon. The f a c t t h a t gaze d i r e c t i o n i s f i x e d on t h e c e n t e r p a r t o f TV d u r i n g a l l t h e i n t e r p r e t a t i o n can reduce t h e i n t e r e s t t i e d t o NAC Eye Mark d i s p l a y . T h i s i s a g r e a t problem i n u s i n g t h e NAC Eye Mark and evidences t h e f a c t t h a t v i s u a l b e h a v i o r i s o n l y p a r t o f t h e general b e h a v i o r which i s a l s o a p a r t o f knowledge. Consequently, i n f o r m a t i o n p r o c e s s i n g can o c c u r w i t h o u t eye movement. F o r t h e c l i n i c i a n , t h e s t u d y o f v o i c e communication and p s t u r a l b e h a v i o r , combined t o v i s u a l b e h a v i o r shows t h a t d o c t o r / p a t i e n t r e l a t i o n s h i p s a r e v e r y poor. P a t i e n t a n x i e t y i n c r e a s e s w i t h t h e poor knowledge o f t h e t e c h n i q u e . A g r e a t e f f o r t must be q u i c k l y made t o improve t h e t e c h n i q u e and t o humanize r e l a t i o n s h i p s . F i n a l l y , reproach can be made t o t h i s d i s p l a y system f r o m an ergonomic s t a n d p o i n t ( b u t t o n s , d i s t a n c e o f t h e TV m o n i t o r ) .
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USE OF NAC EYE MARK I N PEDAGOGY
Because o f t h e n a t u r e o f t h e NAC Eye Mark r e c o r d i n g s ( v i d e o t a p e ) , i t seems t e m p t i n g t o use these as a pedagogical means. Such approach has a l r e a d y been used i n o t h e r branches o f i n s t r u c t i o n : I n s p o r t , i n 1981, Bayless ( 4 ) and R i p p o l l and c o l l ( 1 1 ) . I n f l y i n g , i n 1981 a l s o , Spady and c o l l ( 1 2 ) . I n r a d i o l o g y , as i n s p o r t o r f l y i n g , t r a i n i n g i s a b i g problem. On one hand, much t i m e i s needed t o t r a i n a good s p e c i a l i s t . On t h e o t h e r hand, i t i s o f t e n necessary t o g i v e s u f f i c i e n t t r a i n i n g i n a s h o r t time t o a l l o w d a i l y p r a c t i s e f o r t h e g e n e r a l i s t (case o f l u n g r a d i o g r a p h y ) . The numbers o f i n t e r p r e t a t i o n e r r o r s show t h a t such an approach i s f a r f r o m b e i n g mastered. 111-1. MeAhods
To s i m p l i f i y i n t e r p r e t a t i o n we used a g a i n a r e l a t i v e l y w e l l known model o f radiography : t h e 10 x 10 cm r a d i o p h o t o g r a p h ( a s y s t e m a t i c c o n t r o l s i z e o f l u n g r a d i o graph) * I t i s a complex s o r t i n g t a s k t h a t young p h y s i c i a n s never s t u d y i n t h e i r n o r mal e d u c a t i o n course. Consequently, s p e c i a l t r a i n i n g i s g i v e n i n a one y e a r (Aviation m i l i t a r y a p p l i e d s e s s i o n ( " B r e v e t de Mgdecine Agronautique") M e d i c i n e l i c e n s e ) f o r young m i l i t a r y p h y s i c i a n s . To conduct t h i s e x p e r i m e n t a l approach, we s e l e c t 40 radiophotographs i n two b o b i n s o f 20 exposures, w i t h t h e h e l p o f t h e r a d i o l o g y department o f
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the BEGIN M i l i t a r y Hospital (PARIS) and o f the radiology department o f CPEMPN headed by Doctor PUECH (Centre P r i n c i p a l d'Expertise Mgdicale du Personnel Navigant - PARIS). Each bobi n incl udes : - 5 obvious pathological lungs, 5 pathological lungs more d i f f i c u l t t o diagnose,
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10 normal lungs. The viewing order o f p i c t u r e s i s c o n t r o l l e d by a random table. Special f i l m s and one normal f i l m (100 radiophotographs) are examined by f o u r r a d i o l o g i s t s . D i r e c t i o n o f gaze o f three o f them i s recorded on videotape. Then, these recordings are analyzed w i t h the respective readers ( r a d i o l o g i s t s ) and a psychologist t o assess visual behavior features. The f o u r t h r a d i o l o g i s t i s o n l y interviewed and n o t recorded. He allows us t o v e r i f y the hypothesis b u i l t on the three o t h e r s p e c i a l i s t s ' v i s u a l behav i or. Subsequently, two d i d a c t i v e movies are made. The same process i s used f o r both : 1 - Two r a d i o l o g i s t ' s gaze recordings appear successively f o r one o r many negatives 2 comments are made s h o r t l y t o emphasize each idea 3 drawings give a t the end o f the sequence a summarizing idea o f behavior used by experts 4 - the t h i r d r a d i o l o g i s t ' s gaze recording o f t h i s p o i n t appears a l a s t time t o i l l u s t r a t e the drawing. Durations o f movies are r e s p e c t i v e l y 7'30" and 10'. I n the same time, a t the beginning o f the school year, a f i r s t t e s t i s proposed t o 24 young m i l i t a r y medical students. Notation judges f i r s t the good o r the bad s o r t i n g . I n a d d i t i o n , i t penal i z e s neglects, always serious i n a s o r t i n g task, and minimizes excess c o n t r o l requests. Such n o t a t i o n i s kept f o r the two t e s t s ( a t the beginning and a t the end o f the school year ). A t the end o f the f i r s t t e s t , subjects are divided i n t o two groups w i t h i d e n t i c a l means and standard deviation. The f i r s t group ( c o n t r o l group) has a normal teaching course. The second group (experimental group) has the same teaching course r e i n f o r c e d by presentation o f the movies. A second i n t e r p r e t a t i o n t e s t i s performed a t the end o f the school year t o judge progress, i f any.
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711-2. R Q h d Means o f the two groups stay q u i t e the same f o r the two t e s t s (Student t e s t N.S. a t 05). There i s no b e t t e r performance f o r the experimental group. I n addition, t h e r e i s a great i n s t a b i l i t y i n t h e i n d i v i d u a l scores ; the best subjects lower t h e i r mean and the worst subjects improve t h e i r mean. The end r e s u l t i s t h a t everybody has a comparable mean score a t the end o f the school year Only the standard d e v i a t i o n d i f f e r s between the two groups w i t h a tendency t o reduction for the experimental group (but no s t a t i s t i c a l s i g n i f i c a n c e ) . Duration o f i n t e r p r e t a t i o n i s very long : 20' f o r the c o n t r o l group, 18' f o r the experimental group. These times are double t h a t o f s p e c i a l i s t s ( 9 ' f 30")
222-3. V h c u s b i a n The c o n s t r u c t i o n o f t h i s experiment permits study o f two d i f f e r e n t problems : the v a l i d i t y and the t r a n s m i s s i b i l i t y o f higher features found i n
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t h e f i r s t l u n g r a d i o g r a p h experiment - t h e i n t e r e s t o f i n t r o d u c t i o n o f v i s u a l b e h a v i o r movies i n t e a c h i n g courses. 111-3.1. The v a l i d i t y and t h e t r a n s m i s s i b i l i t y o f h i g h e r f e a t u r e s We found a g a i n t h e h i g h e r f e a t u r e showed i n t h e f i r s t experiment. No more b u t no l e s s . T h i s f a c t a t t e s t s t h e e f f e c t i v e n e s s o f such v i s u a l b e h a v i o r s . The knowledge o f these h i g h e r f e a t u r e s does n o t appear as a s u f f i c i e n t c o n d i t i o n f o r good i n t e r p r e t a t i o n . Probably, we should have g r e a t e r r e t r o s p e c t i v e t o have a p r o p e r view o f t h e m a t t e r . S u r e l y , we were t o o a m b i t i o u s b e l i e v i n g t h a t many y e a r s o f p r a c t i s e would be l e a r n t i n 6 months. 111-3.2.
The i n t e r e s t o f v i d e o l e a r n i n g
I t must be emphasized t h a t s t u d e n t s welcomed t h e method w i t h enthusiasm. T h i s method uses a v e r y a t t r a c t i v e media : t h e movie, and c o n s t i t u t e s a p r i v i l i g e d means o f communication and s e l f t e a c h i n g ( c a s s e t t e s ) . Up t o a p o i n t , w e i g h t o f v e r b a l comments must decrease p r o g r e s s i v e l y t o l e t t h e drawings a l t e r n a t i n g w i t h l a r g e sequences o f NAC. So, accustomed by an Image S o c i e t y , where TV m o n i t o r s appear everywhere, i t would be p o s s i b l e t o make o n e ' s own judgement on t h e q u a l i t y o f v i s u a l s t r a t e g i e s shown. I n t h i s case, t h e NAC would be used f o r i t s t e a c h i n g p r o p e r t i e s ( f i l m o f v i s u a l b e h a v i o r w i t h o u t subsequent d i g i t p r o c e s s i n g ; t h e d i f f i c u l t i e s i n h e r e n t t o t h i s l a s t phase would t h e n be avoided ( p r o c e s s i n g technique, etc.. .) . CONCLUSION F o r t h e l a s t t h r e e years, o u r team which pursues t h e same o b j e c t i v e s , focused i t s i n t e r e s t on t h r e e complementary aspects : - t h e d e s c r i p t i o n o f v i s u a l b e h a v i o r s which d i f f e r e n t i a t e e x p e r t s and b e g i n n e r s (1981-( 1)) : how v i s u a l b e h a v i o r s become o r g a n i z e d as a f u n c t i o n o f experience ? - t h e t e a c h i n g o f these b e h a v i o r s ( 1 9 8 3 - ( 3 ) ) : i s i t p o s s i b l e t o speed t h i s l e a r n i n g and reduce t h e number o f e r r o r s by t e a c h i n g p r e c e d e n t l y i s o l a t e d v i s u a l behaviors ? - f i n a l l y , t h e s t u d y o f v i s u a l b e h a v i o r s i n new r a d i o l o g y t e c h n i q u e s t o assess t h e i n f l u e n c e o f t h e image dynamics e s p e c i a l l y echography ( s u c c e s s i o n o f images on TV screen) and t h e r o l e p l a y e d by t h e p a t i e n t ' s presence ( 1982- ( 2 ) ) These s t u d i e s have v a r i o i l s degrees o f i n t e r e s t f o r s e v e r a l s p e c i a l t i e s : - c l i n i c a n s , r a d i o l o g i s t s , p h y s i c i a n s hope t o draw o u t r u l e s o f " e f f i c i e n t r e a d i n g " and t h u s d i m i n i s h t h e number o f i n t e r p r e t a t i o n e r r o r s ( n e a r l y 30% a c c o r d i n t t o YERUSHALMI (13)), - r e s e a r c h e r s and p s y c h o l o g i s t s hope t o g e n e r a l i z e t h e r e s u l t s o b t a i n e d w i t h complex images and t o have a b e t t e r u n d e r s t a n d i n g o f r e l a t i o n s h i p s which e x i s t between v i s u a l b e h a v i o r and i n t e l l e c t u a l mechanisms i n v o l v e d i n image a n a l y s i s . Consequently, r e s u l t s observed i n these t h r e e experiments must be analysed as a f u n c t i o n o f t h e s p e c i a l t y o f t h e c l i n i c i a n o r p s y c h o l o g i s t : F o r c l i n i c i a n s t h e NAC seems t o o f f e r d r a m a t i c new ways t o evidence v i s u a l b e h a v i o r s . I t p e r m i t s i s o l a t i n g a few s p e c i f i c t r a i t s o f a p o p u l a t i o n h a v i n g t h e same l e v e l o f e x p e r i e n c e and can t h e r e f o r e suggest some a d v i c e o r remarks t h a t c o n t r i b u t e t o t h e e f f o r t t o d i m i n i s h t h e number o f i n t e r p r e t a t i o n e r r o r s . These v i s u a l b e h a v i o r s c o u l d be t a u g h t t o s t u d e n t r a d i o l o g i s t s more capable o f i n c o r p o r a t i n g t h e observed b e h a v i o r i n t o t h e i r knowledge. T h i s s p e c i a l course would complement t h e r e g u l a r t e a c h i n g
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program. Another way r a d i o l o g i s t s can use t h e NAC EYE MARK recorder i s t o v i s u a l i z e t h e i r own v i s u a l behavior i n order t o become aware and analyse t h e i r mistakes, p a r t i c u l a r l y as f a r as t h e d o c t o r / p a t i e n t r e l a t i o n s h i p i s concerned, since t h e number o f times when t h e r a d i o l o g i s t looks a t h i s p a t i e n t dons an a f f e c t i v e and human meaning. F o r psychologists, t h e r a d i o l o g i s t s ' experience i s a consequence o f l e a r n i n g and t r a i n i n g . General behavior ( v i s u a l , gestural, verbal .) i s o n l y a d i r e c t observable consequence o f t h e use o f knowledge. Likewise, v i s u a l behavior i s one expression o f t h e general behavior and no more. Nac Eye Mark today represents one o f t h e b e t t e r t o o l s t o o b j e c t i v e l y study v i s u a l behavior. I n most r a d i o l o g y tasks, numbers o f eye movements and t h e i r amplitudes a r e s u f f i c i e n t t o emphasize t h e way t o p i c k up i n f o r m a t i o n and t o i s o l a t e a l a r g e p a r t o f the needed i n f o r m a t i o n ( d i r e c t e d search). L i m i t s o f t h e Nac appear f o r the understanding o f t h e p i c k up o f i n f o r m a t i o n when gaze stays many times on t h e same p o i n t . Then, i t i s impossible t o know what i s e x a c t l y shown : a d e t a i l , a general ( t i m e t o t h i n k ) s i g h t t o t h e negative o r nothing ! L i m i t s o f t h e Nac a l s o appear i f you want t o q u a l i f y t h e i n f o r m a t i o n process i n g and t h e f i n a l d e c i s i o n made by r a d i o l o g i s t s . I n t h i s case, Nac Recordings can o n l y by used as o b j e c t i v e and common documents which c o n s t i t u t e t h e base o f o t h e r psychological techniques o f c o g n i t i v e e x p l o r a t i o n .
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BARD C., PAILLARD J., GROSGEORGE B. : Caracteristiques de la centration de l'oeil et de la tete sur la cible et son r6le dans l'execution du tir en basket-ball. New paths to sport learning and excellence. ISSP 5th World Sport Psychology Congress, 1982, 32-36.
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SPADY A., JONES D., COATES G., KIRBY R. : The effectiveness of using real time eye scanning information for pilot training. 26th Annual meeting - Proceedings of the human factors society - 1982. : The statistical assessment of the variability in observer perception and description o f roentgenographie pulmonary shadows. Radiologic clinics o f North America, I, 381-90.