THE INSTITUTE OF E D U C A T I O N
UNIVERSITY OF G Ö T E B O R G
AN ECOLOGICAL ANALYSIS OF TEST SCORE CHANGES OVER TIME
K j e l l H ä r n q v i s t a n d Gun S t a h l e
No 64 D e c e m b e r 1 9 7 7
Kjell Härnqvist and Gun Stahle Göteborg University, Sweden
This article, based on a thesis by Stahle, was drafted at the Center for Advanced Study in the Behavioral Sciences, where Härnqvist was a Spencer Fellow during the academic year 1976-1977.
A b s t r a c t
A v e r a g e test s c o r e s in mental a b i l i t y tests i n c r e a s e d b e t w e e n two c o m p a r a b l e n a t i o n a l s a m p l e s of t h i r t e e n - y e a r o l d s in S w e d e n tested with a f i v e - y e a r i n t e r v a l . The i n c r e a s e s w e r e g r e a t e r for g i r l s than for b o y s . The c h a n g e s o c c u r r e d
s i m u l t a n e o u s l y with several c h a n g e s in social and e d u c a t i o n a l c o n d i t i o n s . In o r d e r to a n a l y z e the r e l a t i o n s b e t w e e n test s c o r e c h a n g e s and c h a n g e s in the e n v i r o n m e n t the samples w e r e d i v i d e d in e c o l o g i c a l l y m o r e h o m o g e n e o u s s u b g o u p s and test s c o r e s w e r e c o r r e l a t e d w i t h a n u m b e r of e c o l o g i c a l i n d i c e s . Test s c o r e s w e r e p o s i t i v e l y r e l a t e d to a global e c o l o g i c a l index ( d e n s i t y ) , m o r e so for boys than g i r l s , and m o r e so at the f i r s t than the second o c c a s i o n . The l a t t e r f i n d i n g i n d i c a -ted t h a t an e q u a l i z a t i o n b e t w e e n d i f f e r e n t a r e a s had taken p l a c e d u r i n g the i n t e r v a l . C h a n g e s for boys w e r e p o s i t i v e l y r e l a t e d to e c o l o g i c a l c h a n g e s in the d i r e c t i o n of u r b a n i z a -t i o n , w h i l e c h a n g e s for g i r l s seemed -to have m o r e -to do w i -t h c h a n g e s in the e d u c a t i o n a l system s t r e s s i n g e q u a l i t y of t r e a t -m e n t of boys and g i r l s . This i-mpact was -m o s t s t r i k i n g in the spatial v i s u a l i z a t i o n t e s t .
In recent years a decline in achievement test scores at pre-college level has been observed in the United States. A detailed analysis of different time series by Harnischfeger
and Wiley (1975, 1976) indicated that this decline was real
and not an artifact due to changes in test composition, norms, or tested samples. The decline began in the mid-sixties after a continuous upward trend. It involved grades 5 through 12 and almost all tested achievement areas.
A similar decline from 1960 to 1975 in achievement
scores was found by Flanagan (1976) who compared 9-11 graders in a sample of Project Talent schools on identical tests, i.e. with stronger control on sample and content than regular tes-ting programs can afford. Some ability tests, however, showed opposite trends, e.g. Abstract Reasoning for male and female students,and Mechanical Reasoning and Visualization for fema-les. In general scores on so-called IQ tests have been in-creasing over a long period (Thorndike, 1975; a comprehensive survey of ear 1 ier_jresearcjuXin ding.s. i s grij^en by Stahle, 1 9 7 3 ) .
Harni schf eger and Wiley (OJD. c i t. ) related the decline""" in test scores to concomitant changes in several school and out-of-school variables that might have influenced the de-cline. They made probable that, for instance, tendencies among the high-school students to elect less academic prog-rams were responsible for part of the decline. Available statistical series, however, did not make it possible for them to analyze the relations so closely as they wanted and they indicated a number of additional checks that were needed. Among other things an analysis of factors contributing to
increasing achievement, like that observed until the mid-sixties, should be helpful also for understanding causes of decli ne.
Also from a general development point of view it is of interest to study changes in external conditions as possible change agents for individual traits. Nesselroade and Baltes
(1974) stress the importance of time/cohort effects on adoles-cent personality, but from their review it is also evident that so far very few attempts have been made to systematically analyze the impact of different kinds of historical chanqes.
The p r e s e n t p a p e r p r e s e n t s one such a n a l y s i s m a d e in a S w e d i s h s t u d y of c h a n g e s in a b i l i t y t e s t s c o r e s b e t w e e n 1961 and 1 9 6 6 in n a t i o n a l s a m p l e s from the a g e c o h o r t s born in 1948 and 1953 and t e s t e d at t h i r t e e n y e a r s of a g e . The o v e r -all r e s u l t s s h o w e d a s u b s t a n t i a l i n c r e a s e b e t w e e n the two c o h o r t s . At the same time several c h a n g e s in s o c i e t y took p l a c e . The p r e s e n t a n a l y s i s , w h i c h is based on a t h e s i s by S t a h l e ( 1 9 7 3 ) , t r i e s to e s t a b l i s h l i n k s b e t w e e n test s c o r e c h a n g e s and e x t e r n a l c o n d i t i o n s . E c o l o g i c a l v a r i a b l e s a r e used for the a n a l y s i s of c h a n g e f a c t o r s .
M e t h o d s of a n a l y s i s
A c o m p a r i s o n of a v e r a g e test s c o r e s b e t w e e n two p o i n t s in t i m e g i v e s j u s t one d i f f e r e n c e that can be r e l a t e d to i n i -tial s t a t e s or c o n c o m i t a n t c h a n g e s in o t h e r v a r i a b l e s . The d i f f e r e n c e can be s p e c i f i e d in v a r i o u s w a y s , for i n s t a n c e , for t e s t s w i t h d i f f e r e n t c o n t e n t s , or for m a l e s and f e m a l e s , but still the p o s s i b i l i t i e s for a causal a n a l y s i s r e m a i n v e r y w e a k . I f t h e r e had been m a n y p o i n t s in t i m e , a t i m e s e r i e s for test s c o r e s could have been c o m p a r e d to time s e r i e s for o t h e r v a r i a b l e s . In the p r e s e n t c a s e it is n e c e s s a r y to find o t h e r w a y s for c o m p a r a t i v e a n a l y s i s . One such p o s s i b i l i t y is to break down the n a t i o n a l a v e r a g e into a v e r a g e s for d i f f e r e n t g e o g r a p h i c a l a r e a s and r e l a t e test s c o r e s and test s c o r e c h a n g e s to c h a r a c t e r i s t i c s of the a r e a s .
Even t h o u g h test s c o r e s are a v a i l a b l e for j u s t two p o i n t s in t i m e , area c h a r a c t e r i s t i c s , in p r i n c i p l e , could be c o l l e c -ted on a time s e r i e s b a s i s . This w o u l d m a k e it p o s s i b l e to study the time lag of test s c o r e c h a n g e s in r e l a t i o n to c h a n g e s in e x t e r n a l c o n d i t i o n s , i.e. the time it t a k e s for a c e r t a i n e x t e r n a l c h a n g e to m a k e an i m p a c t on test s c o r e s . A full model c o u l d look like F i g u r e 1.
Insert F i g u r e 1 a b o u t here
It is i m p o r t a n t to note that this model can be a p p l i e d o n l y on an a g g r e g a t e level b e c a u s e that is the o n l y level for w h i c h i d e n t i t y can be e s t a b l i s h e d b e t w e e n o b s e r v a t i o n a l u n i t s
at d i f f e r e n t p o i n t s in t i m e . On the i n d i v i d u a l level the d e -s i g n i -s , of n e c e -s -s i t y , c r o -s -s - -s e c t i o n a l : d i f f e r e n t i n d i v i d u a l -s w e r e t e s t e d at tQ and t, . T h i s is a r a t h e r p a r a d o x i c a l s i t u a
t i o n b e c a u s e w h a t we r e a l l y w o u l d l i k e to s t u d y is an i n d i v i -dual level v a r i a b l e ( a b i l i t y ) in r e l a t i o n to the i n d i v i d u a l c h a r a c t e r i s t i c s of the f a m i l i e s in the a r e a s as c o n t r a s t e d to c h a n g e s in the c o l l e c t i v e c h a r a c t e r i s t i c s of the a r e a s . In o r d e r to m a k e s u c h a d i s t i n c t i o n b e t w e e n c o m p o s i t i o n a l a n d c o n t e x t u a l e f f e c t s ( c f . , e . g . , H a u s e r , S e w e l l & A l w i n , 1 9 7 6 ; A l w i n , 1 9 7 6 ) , or in o t h e r t e r m s d e m o g r a p h i c and g r o u p -c a u s e d e f f e -c t s ( -c f . C r o n b a -c h , 1 9 7 6 ) , a s i m u l t a n e o u s a n a l y s i s h a s to be p e r f o r m e d at i n d i v i d u a l and e c o l o g i c a l l e v e l s , but t h i s p o s s i b i l i t y is e x c l u d e d , at l e a s t in a s t r i c t f o r m , by the n a t u r e of the d a t a .
E v e n the u t i l i z a t i o n at an a g g r e g a t e level of such a p a t h m o d e l , h o w e v e r , m e t w i t h s e v e r a l d i f f i c u l t i e s in the p r e s e n t c a s e . A r e a c h a r a c t e r i s t i c s w e r e a v a i l a b l e o n l y for tQ and t-. , and t h i s is not i n f o r m a t i o n e n o u g h f o r a s t u d y
of t i m e l a g . F u r t h e r m o r e the n u m b e r of o b s e r v a t i o n a l u n i t s b e c a m e r a t h e r l i m i t e d in s p i t e of t e s t i n f o r m a t i o n for l a r g e s a m p l e s . As will be s h o w n 46 u n i t s c o u l d be u s e d , and e v e n t h o u g h t e s t a v e r a g e s f o r t h e s e u n i t s , w i t h b o y s and g i r l s a n a l y z e d s e p a r a t e l y , a r e b a s e d on a b o u t 1 0 0 p u p i l s on a v e r a g e f o r t h e s e u n i t s , s o m e u n i t s got r a t h e r s m a l l . F i n a l l y m o s t e c o l o g i c a l c h a r a c t e r i s t i c s of the u n i t s t u r n e d out to be h i g h l y i n t e r c o r r e l a t e d . T h e small n u m b e r of o b s e r v a -t i o n a l u n i -t s and m u l -t i - c o l l i n e a r i -t y of -the i n d e p e n d e n -t v a r i a b l e s r e s t r i c t the n u m b e r of p r e d i c t o r s t h a t can p r o f i t a b -ly be u s e d in a path a n a l y s i s (cf. H a n u s h e k & J a c k s o n , 1 9 7 7 , p p . 8 6 - 9 3 ) . T h e r e f o r e not e v e n a p a r t of the m o d e l has b e e n u s e d in its s t a n d a r d f o r m , but r a t h e r m o d i f i c a t i o n s b a s e d on s u c c e s s i v e f i n d i n g s in the e m p i r i c a l a n a l y s i s of d a t a . T h e s e w i l l be d e s c r i b e d in d i r e c t c o n n e c t i o n w i t h the r e p o r t i n g of r e s u l t s . S a m p l e s and tests In 1961 all p u p i l s in S w e d i s h s c h o o l s w h o w e r e born on t h e 5 t h , 15th or 2 5 t h in a n y m o n t h of 1 9 4 8 took p a r t in the b a s i c d a t a c o l l e c t i o n f o r a l o n g i t u d i n a l s t u d y , the I n d i v i
-dual S t a t i s t i c s P r o j e c t . The same p r o c e d u r e was r e p e a t e d in 1966 for p u p i l s born in 1 9 5 3 . This m e a n s that the p r o j e c t has a v a i l a b l e data for two n a t i o n w i d e ten p e r c e n t s a m p l e s of
t h i r t e e n y e a r o l d s . D e t a i l s a b o u t the d e s i g n of the p r o j e c t and r e s u l t s from o t h e r s t u d i e s have been r e p o r t e d , i.e. by H ä r n q v i s t ( 1 9 6 6 , 1 9 6 8 ) , S v e n s s o n ( 1 9 7 1 ) , and H ä r n q v i s t and S v e n s s o n ( 1 9 7 3 ) .
The basic data c o l l e c t i o n s i n c l u d e d a d m i n i s t r a t i o n by the c l a s s r o o m t e a c h e r s of a w r i t t e n i n t e l l i g e n c e test w h i c h w a s c o n s t r u c t e d e s p e c i a l l y for the p r o j e c t and not used in any o t h e r c o n n e c t i o n b e t w e e n the two a d m i n i s t r a t i o n s in 1961 and 1 9 6 6 . The test had t h r e e s u b s c a l e s :
V e r b a l : O p p o s i t e s (40 i t e m s , K-R 20 r e l i a b i l i t y in s u b s a m p l e .87) R e a s o n i n g : N u m b e r S e r i e s (40 i t e m s , K-R 20 .92) S p a t i a l : Metal F o l d i n g (40 i t e m s , K-R 20 .88) T a b l e 1 s h o w s the n u m b e r of c a s e s for w h i c h c o m p l e t e t e s t d a t a w e r e a v a i l a b l e in the two s a m p l e s . T h e s e n u m b e r s c o r r e s p o n d to 87 p e r c e n t of the e x p e c t e d s a m p l e size in 1961 and 88 p e r c e n t in 1 9 6 6 : Insert T a b l e 1 a b o u t here C o n s t r u c t i o n of e c o l o g i c a l u n i t s
D i f f e r e n t p r i n c i p l e s can be used for the c o n s t r u c t i o n of e c o l o g i c a l u n i t s . It is p o s s i b l e to use a d m i n i s t r a t i v e s u b d i v i s i o n s of the c o u n t r y , e . g . , . c o u n t i e s , m u n i c i p a l i t i e s , or o t h e r a g g r e g a t i o n s of a d j a c e n t a r e a s . It is also p o s s i b l e to a g g r e g a t e a r e a s in d i f f e r e n t p a r t s of the c o u n t r y that h a v e s i m i l a r c h a r a c t e r i s t i c s a c c o r d i n g to p o p u l a t i o n d e n s i t y or o t h e r r e l e v a n t v a r i a b l e s . Use of a d m i n i s t r a t i v e u n i t s f a -c i l i t a t e s the -c o l l e -c t i o n of s t a t i s t i -c s for o t h e r v a r i a b l e s to be used in the a n a l y s i s ; o f t e n they can be taken d i r e c t l y from p u b l i s h e d o f f i c i a l s t a t i s t i c s . On the o t h e r hand m o s t a d m i n i s t r a t i v e u n i t s have a r a t h e r h e t e r o g e n e o u s c o m p o s i t i o n w h i c h k e e p s much of the i n t e r e s t i n g v a r i a n c e in o t h e r c h a r a c t e r i s t i c s w i t h i n them and l e a v e s r e l a t i v e l y l i t t l e b e t w e e n -v a r i a n c e to be a n a l y z e d . Use of p o p u l a t i o n d e n s i t y m a k e s the
u n i t s f a i r l y h o m o g e n e o u s in d i f f e r e n t r e s p e c t s but may c a u s e d i f f i c u l t i e s in the c o l l e c t i o n of e x p l a n a t o r y v a r i a b l e s .
In the p r e s e n t s t u d y both p r i n c i p l e s w e r e u s e d , S w e d e n w a s d i v i d e d in n i n e a r e a s a c c o r d i n g to l o c a t i o n , each c o n -s i -s t i n g of -s o m e a d j a c e n t p r o v i n c e -s ( " l ä n " ) . T h i -s -s u b d i v i -s i o n will be c a l l e d l o c a t i o n . The city of S t o c k h o l m was one of t h e s e n i n e a r e a s .
The m e a s u r e of p o p u l a t i o n d e n s i t y used w a s the n u m b e r of i n h a b i t a n t s that a c c o r d i n g to the c e n s u s of 1 9 6 0 had t h e i r r e s i d e n c e w i t h i n a c i r c l e with 20 k i l o m e t e r s ' r a d i u s a r o u n d the m i d p o i n t of e a c h p r i m a r y a d m i n i s t r a t i v e unit
("kommun") in the c o u n t r y . (For a g e n e r a l d i s c u s s i o n of this type of i n d e x , see Ö b e r g , 1 9 7 6 , pp. 6 9 - 7 1 . ) T h e r e w e r e 1 0 2 9 such u n i t s and the n u m b e r of i n h a b i t a n t s w i t h i n t h e i r 20 km c i r c l e v a r i e d from 1 to 1126 t h o u s a n d s . The d i s t r i b u t i o n was h e a v i l y s k e w e d w i t h 896 u n i t s b e l o w 100 t h o u s a n d s . N a t u r a l l o g a r i t h m s w e r e used for m a k i n g the s c a l e m o r e s y m m e t r i c a b o u t the m e a n and it was d i v i d e d in f i f t e e n c l a s s e s of
d e n s i ty, w h e r e 15 s t a n d s for the m o s t d e n s e l y p o p u l a t e d a r e a s . Each c l a s s c o m p r i s e d one half unit on the l o g a r i t h m i c s c a l e . The d e n s i t y index had an a v e r a g e of 9.4 and a s t a n d a r d d e v i a -tion of 3 . 1 , a l m o s t e x a c t l y the same for m a l e s and f e m a l e s in the two c o h o r t s .
In o r d e r to get a s u f f i c i e n t n u m b e r of s u f f i c i e n t l y h o m o g e n e o u s u n i t s for the e c o l o g i c a l a n a l y s e s the two c l a s s i -f i c a t i o n s w e r e used in c o m b i n a t i o n . Each o b s e r v a t i o n a l u n i t then b e c a m e f a i r l y h o m o g e n e o u s in r e s p e c t of both p o p u l a t i o n d e n s i t y and l o c a t i o n in the c o u n t r y , w h i c h in turn s h o u l d
have m a x i m i z e d d i f f e r e n c e s b e t w e e n u n i t s . W h e n the two i n d i c e s w e r e t a b u l a t e d a g a i n s t each o t h e r it was f o u n d that o n l y 68 of the p o s s i b l e 135 c e l l s c o n t a i n e d any of the 1029 p r i m a r y a d m i n i s t r a t i v e u n i t s .
When the s a m p l e s of p u p i l s (cf. T a b l e 1) w e r e d i s t r i b u t e d o v e r the 68 c e l l s a c c o r d i n g to l o c a t i o n and d e n s i t y in c o m b i -n a t i o -n , 22 of t h e s e c e l l s had less tha-n 30 c a s e s of e i t h e r sex in e i t h e r y e a r . T h e s e c e l l s , a l t o g e t h e r c o n t a i n i n g 329 p u p i l s in 1961 and 358 in 1 9 6 6 , w e r e e x c l u d e d from the e c o l o -gical part of the s t u d y . This l e a v e s 46 c e l l s with an a v e r a g e cell size of 111 in 1961 and 99 in 1966 w h e n test s c o r e s for boys and g i r l s are a n a l y z e d s e p a r a t e l y .
E c o l o g i c a l v a r i a b l e s
In a d d i t i o n to the l o c a t i o n and d e n s i t y i n d i c e s a l r e a d y d e s c r i b e d e c o l o g i c a l v a r i a b l e s w e r e d r a w n from two s o u r c e s :
1) From the p r o j e c t ' s own data in 1961 and 1 9 6 6Q T h i s
c a t e g o r y i n c l u d e s m e a s u r e s of f a m i l y b a c k g r o u n d ( e . g . , p e r -cent of the p u p i l s in a cell w h o s e f a t h e r s g r a d u a t e d from s e c o n d a r y e d u c a t i o n ) , and school o r g a n i z a t i o n ( p e r c e n t of the p u p i l s in a cell t h a t a t t e n d a c o m p r e h e n s i v e s c h o o l ) . T h e s e i n d i c e s a r e b a s e d on m a l e and f e m a l e p u p i l s t o g e t h e r , i.e., on t w i c e as m a n y c a s e s as the test s c o r e a v e r a g e s . For each v a r i a b l e o n e index w a s c o m p u t e d for 1 9 6 1 , one for 1 9 6 6 , and in a d d i t i o n a d i f f e r e n c e b e t w e e n the two m e a s u r e s « T h i s r e s u l t e d in 23 x 3 v a r i a b l e s based on d a t a from the p r o j e c t . A f t e r the e x c l u s i o n of i n d i c e s w i t h very small v a r i a t i o n b e t w e e n c e l l s or very s k e w e d d i s t r i b u t i o n s 13 initial s t a t e m e a s u r e s and 14 c h a n g e m e a s u r e s r e m a i n e d for f u r t h e r a n a l y s i
The v a r i a b l e s k e p t a r e l i s t e d in A p p e n d i x 1.
2) From o f f i c i a l s t a t i s t i c s a v a i l a b l e at the level o f p r i m a r y a d m i n i s t r a t i v e u n i t s ( " k o m m u n e r " ) . With one e x c e p t i o t h e s e i n d i c e s r e f e r o n l y to 1 9 6 0 or 1 9 6 1 . The v a r i a b l e s c o v e such t h i n g s as t r e n d s in p o p u l a t i o n d e v e l o p m e n t , a v e r a g e t a x a b l e i n c o m e of e c o n o m i c a l l y a c t i v e i n h a b i t a n t s , h o u s i n g s t a n d a r d s , and o c c u p a t i o n a l d i s t r i b u t i o n of e c o n o m i c a l l y a c t i v e m e n and w o m e n . A l t o g e t h e r t h e s e c a t e g o r i e s i n c l u d e 14 v a r i a b l e s . In a d d i t i o n the n u m b e r of t e l e v i s i o n l i c e n s e s per t h o u s a n d i n h a b i t a n t s w a s r e c o r d e d for 1961 and 1966 as well as the d i f f e r e n c e . A f t e r e x c l u s i o n of v a r i a b l e s on the b a s i s of t h e i r d i s t r i b u t i o n s 12 initial s t a t e m e a s u r e s and 1 c h a n g m e a s u r e r e m a i n e d for a n a l y s i s . The v a r i a b l e s kept are l i s t e d
in A p p e n d i x 2 .
The two k i n d s of e c o l o g i c a l v a r i a b l e s d i f f e r in p r i n c i p l e . The f i r s t k i n d , in m o s t i n s t a n c e s , r e f e r s to the c h a r a c -t e r i s -t i c s of -the s a m p l e s s -t u d i e d in -the p r o j e c -t , i.e. -to f a m i l i e s in age g r o u p s that h a v e t h i r t e e n y e a r old c h i l d r e n . T h e o t h e r kind r e f e r s to c h a r a c t e r i s t i c s of the w h o l e p o p u
-l a t i o n in the a d m i n i s t r a t i v e unit and the e n v i r o n m e n t they live in. U n f o r t u n a t e l y a l m o s t all c h a n g e m e a s u r e s are of the f i r s t kind w h i c h c o m p l i c a t e s t h e i r i n t e r p r e t a t i o n . Does a c h a n g e m e a n a c h a n g e in the c o m m u n i t y c h a r a c t e r i s t i c s , or a d i f f e r e n c e b e t w e e n f a m i l i e s from d i f f e r e n t age c o h o r t s , or a
d i f f e r e n c e d u e to s a m p l i n g f l u c t u a t i o n s ? T h e s e a l t e r n a t i v e s have to be c o n s i d e r e d in the i n t e r p r e t a t i o n of r e s u l t s .
One i n d i c a t i o n that m e a s u r e s d e r i v e d from the p r o j e c t data are c h a r a c t e r i s t i c a l s o for the w h o l e c o m m u n i t i e s is found in the c o r r e l a t i o n s b e t w e e n initial s t a t e m e a s u r e s . The a v e r a g e c o r r e l a t i o n s w i t h i n and b e t w e e n d i f f e r e n t c a t e -g o r i e s a r e s h o w n in T a b l e 2 . Insert T a b l e 2 a b o u t here P r o j e c t - b a s e d i n d i c e s (P) c o r r e l a t e n e a r l y as m u c h w i t h t h o s e based on o f f i c i a l s t a t i s t i c s (S) as b e t w e e n t h e m s e l v e s , and n e a r l y as m u c h w i t h d e n s i t y as the o f f i c i a l s t a t i s t i c a l m e a s u r e s d o .
For the w h o l e set of 25 initial s t a t e m e a s u r e s a f i r s t p r i n c i p a l c o m p o n e n t a c c o u n t e d for 63 p e r c e n t of the v a r i a n c e , and o n l y t h r e e m o r e c o m p o n e n t s had e i g e n v a l u e s e x c e e d i n g o n e . All f o u r t o g e t h e r c o v e r e d 82 p e r c e n t of the v a r i a n c e .
The f i r s t v a r i m a x r o t a t e d f a c t o r had its h i g h e s t l o a d -ings in the i n d i c e s based on p e r c e n t of f a t h e r s and m o t h e r s with s e c o n d a r y school g r a d u a t i o n ( P ) , and p e r c e n t of men in w h i t e - c o l l a r o c c u p a t i o n s ( S ) . The 14 v a r i a b l e s that loaded
.70 or m o r e on the f i r s t f a c t o r had an a v e r a g e c o r r e l a t i o n of .84 w i t h d e n s i t y .
The n e x t t h r e e f a c t o r s a r e best c h a r a c t e r i z e d by the f o l l o w i n g i n d i c e s : N o . 2 - P e r c e n t of men in n o n - a g r i c u l t u r a l w o r k i n g - c l a s s o c c u p a t i o n s ( S ) . No. 3 - H o u s i n g u n i t s b u i l t in 1 9 5 1 - 1 9 6 0 in p e r c e n t of all h o u s i n g u n i t s in 1 9 6 0 ( S ) . N o . 4 - P e r c e n t of f a t h e r s in c o m m e r c i a l o c c u p a t i o n s ( P ) . The c h a n g e m e a s u r e s d e r i v e d from p r o j e c t data w e r e less h i g h l y i n t e r c o r r e l a t e d than the initial m e a s u r e s . In this c a s e the first p r i n c i p a l c o m p o n e n t a c c o u n t e d for only 24
p e r c e n t of the v a r i a n c e . Five m o r e c o m p o n e n t s had e i g e n v a l u e s a b o v e o n e , and the six t o g e t h e r c o v e r e d 83 p e r c e n t of the v a r i a n c e in the 14 m e a s u r e s . Only f o u r of the v a r i a b l e s
correlated significantly with density. Together they indica-ted that there was a comparatively larger transfer from agricultural to non-agricultural working-class occupations, and a larger increase in the occupational activity of the m o t h e r s , in the less densely populated areas, i.e., in those where there were substantial groups in the initial state :o draw from«,
Results I: Overall changes between 1961 and 1966
Table 3 reports means and standard deviations based on the individual scores of pupils tested in the two cohorts.
Insert Table 3 about here
All average scores increased between the two years and most markedly so for the girls for whom the increase amounted to a fifth of the initial standard deviations of total scores. The group differences found in the table were checked in a two-way analysis of variance (unweighted means) and the re-sults were expressed in terms of contributions to overall variation in Table 4.
Insert Table 4 about here
Cohort differences contributed most to the variation in the v e r b a l , reasoning and total test scores, while sex differen-ces had a stronger impact in the spatial test. In that test, a significant interaction was found as an expression of a considerable reduction of the sex difference between the
cohorts. The same held for the total score. ...._. The changes in test scores over the five-year period were simultaneous to overall changes in some of the ecological in-dices. Table 5 shows the size of the changes that were signi-ficant when analyzed on the Density x Location level.
Insert Table 5 about here
During the five-year interval a major part of the implemen-tation of two innovations took place at the national level. Compulsory education was extended from eight to nine years, a selective lower-secondary school that existed parallell to grades 7-8 was integrated in a comprehensive compulsory school, and the curriculum was revised for all grades. In 1961 32 percent of the sample attended an experimental version of the comprehensive school, in 1966 81 percent were in the new system which was fully implemented in grade 6 in 1970, through grade 9 in 1973.
The other innovation was the spread of television over the country. During the interval satisfactory receiving con-ditions were achieved in remote areas, and the frequency of licenses required for using a TV set nearly doubled. The
increase was negatively correlated with density (-.70). The other changes recorded in Table 5 are of the order around 30 percent and, with one exception, in the positive direction. The two highest socioeconomic groups increased their share of the families; so did graduation from secondary education among fathers and mothers. Increased participation by mothers in the labor market was shown in two indices. The only decrease over the interval was for the agricultural socioeconomic group. As already was mentioned increased occupational activity among mothers and transfer from agri-culture occurred more often in the sparsely populated areas. This location of the change suggests that the ecological changes shown in Table 4 are likely to be more general than just referring to the characteristies of two groups of parents with a five-year interval.
Results II; Test scores related to density
The density index was highly correlated with most of the initial ecological variables and to a moderate extent also with some of the changes. Therefore we will begin with showing the relation between density, taken as a global ecological index, and test scores in both cohorts. These relations then
will be s p e c i f i e d w i t h the help of o t h e r v a r i a b l e s in the two f o l l o w i n g s e c t i o n s .
R e g r e s s i o n s l o p e s for test s c o r e s in r e l a t i o n to d e n s i -ty are r e p o r t e d in T a b l e 6.
Insert T a b l e 6 a b o u t here
One step u p w a r d s on the d e n s i t y s c a l e m e a n s r o u g h l y 50 p e r -c e n t i n -c r e a s e of the p o p u l a t i o n found w i t h i n 20 km r a d i u s . In
1961 such a step led to an a v e r a g e i n c r e a s e in the total test s c o r e of .79 u n i t for boys and .51 for girls. In 1966 t h e s e
i n c r e a s e s w e r e s i g n f i c a n t l y s m a l l e r (.45 and . 2 0 ) . S i m i l a r d e c r e a s e s in r e g r e s s i o n c o e f f i c i e n t s w e r e found in all s u b -t e s -t s even -t h o u g h -they w e r e no-t s i g n i f i c a n -t in N u m b e r S e r i e s and Metal F o l d i n g for g i r l s . The s c o r e s of the boys w e r e s i g n i f i c a n t l y m o r e r e l a t e d to d e n s i t y than t h o s e of the g i r l s , e x c e p t in O p p o s i t e s both y e a r s and Metal F o l d i n g in 1 9 6 6 .
When d i f f e r e n c e s in m e a n s and in r e g r e s s i o n s l o p e s w e r e c o m b i n e d an i n t e r e s t i n g o v e r a l l p a t t e r n of the c h a n g e s a p p e a -red, and it is shown in F i g u r e s 2 - 4 .
Insert F i g u r e s 2-4 a b o u t here
In the verbal test both boys and g i r l s c h a n g e d u p w a r d s all a l o n g the d e n s i t y s c a l e but m o r e so in the s p a r s e l y p o p u l a t e d a r e a s than at the top of the d e n s i t y s c a l ^ .
In the r e a s o n i n g test and the s p a t i a l test the g i r l s c h a n g e d u p w a r d s all a l o n g the d e n s i t y s c a l e , but test s c o r e s for boys i n c r e a s e d o n l y in the lower p a r t s of the d e n s i t y s c a l e . Boys e x c e l l e d g i r l s in the d e n s e l y p o p u l a t e d a r e a s ; m u c h less s o , or not at a l l , in the s p a r s e l y p o p u l a t e d a r e a s .
With this we have e s t a b l i s h e d (1) that there are r e l a -t i o n s b e -t w e e n a global e c o l o g i c a l v a r i a b l e and -tes-t s c o r e s and and test score c h a n g e s , and (2) that t h e i r r e l a t i o n s d i f f e r both b e t w e e n boys and g i r l s and b e t w e e n d i f f e r e n t a b i l i t i e s .
Next we will see if the o t h e r v a r i a b l e s can c o n t r i b u t e to an u n d e r s t a n d i n g of these r e l a t i o n s h i p s .
R e s u l t s I I I : Initial test scores r e l a t e d to e c o l o g i c a l v a r i a b l e s
MuIti coll i near i ty, in c o m b i n a t i o n w i t h the limited num-ber of o b s e r v a t i o n s for each v a r i a b l e ( N = 4 6 ) , would m a k e s t r a i g h t f o r w a r d m u l t i p l e p r e d i c t i o n of test score a v e r a g e s from the w h o l e m a t r i x of e c o l o g i c a l v a r i a b l e s r a t h e r m i s -l e a d i n g . T h e r e f o r e three a -l t e r n a t i v e a p p r o a c h e s have been
used -- all of them in o r d e r to d e t e c t m o r e s p e c i f i c r e l a t i o n s b e t w e e n area characteristies and test s c o r e s than the d e n s i t y index can i n d i c a t e .
1) Test score a v e r a g e s were c o r r e l a t e d with the d e n s i t y index and with each one of the 25 v a r i a b l e s d e r i v e d from p r o j e c t data (P) and official s t a t i s t i c s ( S ) . Then d e n s i t y w a s p a r t i a l l e d out of the other e c o l o g i c a l v a r i a b l e s and the r e m a i n d e r was c o r r e l a t e d with test s c o r e s (part, not p a r t i a l , c o r r e l a t i o n ) .
2 ) One c h a r a c t e r i s t i c v a r i a b l e from each of the f i r s t four f a c t o r s d e r i v e d from the e c o l o g i c a l i n d i c e s was used for p r e d i c t i n g test score a v e r a g e s , for one s u b t e s t at a t i m e , by m e a n s of m u l t i p l e r e g r e s s i o n .
3 ) The same p r e d i c t o r v a r i a b l e s w e r e used also in a c a n o n i c a l c o r r e l a t i o n with the t h r e e s u b t e s t s s i m u l t a n e o u s l y on the c r i t e r i o n s i d e .
T a b l e 7 shows the r e s u l t s of the first a p p r o a c h . Only part c o r r e l a t i o n s s i g n i f i c a n t at 5 p e r c e n t level are r e c o r d e d . E c o l o g i c a l v a r i a b l e s are listed in o r d e r of their l o a d i n g s on the f i r s t f a c t o r .
Insert Table 7 a b o u t here
The c o r r e l a t i o n s with the d e n s i t y index is a n o t h e r way to d e -m o n s t r a t e what a l r e a d y has been shown by the r e g r e s s i o n
c o e f f i c i e n t s in Table 6. The r e l a t i o n s are s t r o n g e r for boys than for g i r l s , and for the verbal than for the r e a s o n i n g and spatial t e s t s .
Significant part correlations appear mainly for variables that have high loadings on the first factor. This strengthens the impression gained from the results for density that test scores on an ecological level vary positively with characte-ristics that distinguish urban from rural areas -- more people with education above the compulsory level, more white-collar j o b s , higher taxable incomes, and better housing.
Table 8 shows the results of the multiple and canonical correlation a p p r o a c h e s , together with the zero order correla-tions for the predictor variables.
Insert Table 8 about here
The addition of three more dimensions increases the variances explained with 3-6 percentage units for boys and 4-9 for
girls. The larger increment for girls is due to higher corre-lations for new-built housing and negative correcorre-lations for commercial occupations.
The canonical weighting of the tests results in a slight increase over the multiple correlation for unweighted totals for boys, and in a large increase for girls. The difference is due to the larger variation in correlations between tests for girl So
In the optimal case the ecological indices explain 55 percent of the variance in test score means for boys and 47 percent for girls. More could hardly be expected since the test score averages have a considerable sampling variation also. With the group sizes involved the expected sampling variances amount to between 50 and 60 percent, on a v e r a g e , of the observed variances for test score means.
Results IV; Test score increases related to ecological variables
The correlations between test score changes and density are much smaller than those reported in the previous section and thus it does not seem necessary to partial out density from other ecological correlations with changes. Neither are the correlations between ecological changes high enough to
r e q u i r e a s e l e c t i o n a m o n g the e x p l a n a t o r y v a r i a b l e s . T h e r e -f o r e zero o r d e r c o r r e l a t i o n s will be used in this s e c t i o n .
T a b l e 9 r e p o r t s the c o r r e l a t i o n b e t w e e n test s c o r e in-c r e a s e s , d e n s i t y and e in-c o l o g i in-c a l i n d i in-c e s in the initial s t a t e . E x c e p t in r e l a t i o n to d e n s i t y , o n l y c o r r e l a t i o n s s i g n i f i c a n t at the 5 p e r c e n t level will be l i s t e d .
Insert T a b l e 9 a b o u t here
D e n s i t y has small n e g a t i v e c o r r e l a t i o n s w i t h all t e s t s c o r e i n c r e a s e s e x c e p t Metal F o l d i n g for g i r l s . Only the o n e w i t h O p p o s i t e s is s i g n i f i c a n t , h o w e v e r . The g e n e r a l p i c t u r e
is one of d e c r e a s i n g v a r i a t i o n b e t w e e n l e v e l s of d e n s i t y o v e r the p e r i o d -- a trend that w a s m o r e e a s i l y o b s e r v e d in the r e g r e s s i o n s of i n d i v i d u a l s c o r e s in T a b l e 6 and F i g u r e s 2 - 4 .
The c o r r e l a t i o n s b e t w e e n initial s t a t e m e a s u r e s and test s c o r e i n c r e m e n t s s u p p o r t this n o t i o n of e q u a l i z a t i o n b e t w e e n a r e a s . V a r i a b l e s t h a t are r e l a t e d to m i d d l e - c l a s s and u r b a n l i v i n g c o n d i t i o n s are n e g a t i v e l y c o r r e l a t e d w i t h i n c r e m e n t s ; t h o s e r e l a t e d to w o r k i n g - c l a s s and a g r i c u l t u r a l o c c u p a t i o n s p o s i t i v e l y c o r r e l a t e d . The n e g a t i v e c o r r e l a t i o n for " W o r k e r s a m o n g m o t h e r s " d o e s not r e a l l y m e a n an e x c e p t i o n to this g e n e r a l i z a t i o n s i n c e this v a r i a b l e has to be seen in c o n t r a s t to the i n c i d e n c e of o c c u p a t i o n a l l y n o n - a c t i v e w o m e n r a t h e r than to that of w h i t e - c o l l a r o c c u p a t i o n s . T h u s it seems that a r e a s w h i c h i n i t i a l l y l a g g e d b e h i n d in i n t e l l e c t u a l p e r f o r m a n c e b e c a m e s o m e w h a t b e t t e r off d u r i n g the f i v e - y e a r p e r i o d . A c o m p a r i s o n b e t w e e n the v a r i a b l e s in T a b l e 9 and t h o s e that had s i g n i f i c a n t part c o r r e l a t i o n s w i t h initial t e s t s c o -res ( T a b l e 7 ) s h o w s that s e v e r a l of the v a r i a b l e s are the same in both t a b l e s . This is e s p e c i a l l y true for the g i r l s for whom all f i v e v a r i a b l e s in T a b l e 7 a p p e a r a l s o in T a b l e 9. In all t h e s e c a s e s p o s i t i v e part c o r r e l a t i o n s in T a b l e 6 c o r r e s p o n d to n e g a t i v e c o r r e l a t i o n s of r o u g h l y the s a m e size
in T a b l e 8 . A r e a s w h i c h i n i t i a l l y s c o r e d h i g h e r than e x p e c t e d from t h e i r d e n s i t y lost this s u r p l u s o v e r the p e r i o d . This
looks like an interesting substantive result but there is reason to suspect that it, to some extent, depends on samp-ling variation. If the sample from a certain district that took the test in 1961 scored above the mean for all pupils in the age cohort in the district, then the sample mean for the same district in 1966 is likely to have regressed to-wards its population mean resulting in a negative difference over the period. Such mechanisms could give rise to the pat-tern shown by Tables 7 and 9 in combination. If so, the cor-relation between initial measures and test score changes should not be interpreted too specifically. Still the indi-cations of an equalization between more and less densely po-pulated areas remain from the analysis of individual scores.
Finally, in Table 1 0 , significant correlations between test score increases and concomitant changes in ecological variables are reported.
Insert Table 10 about here
The significant correlations are few but positive which means that improvements covary in a consistent manner. Most of the correlations have to do with increase in the proportion of secondary education and white-collar occupations -- three of the correlations interestingly enough with increases among the m o t h e r s . For these correlations three different interpre-tations have to be considered. One is that the increase in the ecological index meant an increase for the areas as such, which was accompanied by test score increases. The other two have to do with the nature of the indices as derived from project data. One alternative is that the increases are real but refer only to cohort differences between families having thirteen-year-old children in 1961 and 1966. Another alter-native is that the increases are spurious and reflect simul-taneous sampling fluctuations in test scores and background characteristics (correlated e r r o r s ) .
For two of the variables, however, the last two explana-tions cannot reasonably hold. A positive correlation between increase in socioeconomic group E (non-agricultural
working-c l a s s o working-c working-c u p a t i o n s ) and test sworking-core i n working-c r e a s e s is not l i k e l y to r e s u l t from c o h o r t i n c r e m e n t s of t h i s g r o u p a m o n g the p a r e n t s , n e i t h e r from o v e r - s a m p l i n g of w o r k i n g - c l a s s p u p i l s , b e c a u s e p u p i l s w i t h this b a c k g r o u n d tend to s c o r e b e l o w a v e r a g e not a b o v e . The i n c r e a s e in c o m p r e h e n s i v e school c o v e r a g e r e -fers to all p u p i l s in the d i s t r i c t and not o n l y to the t e n t h of the age c o h o r t that was s a m p l e d .
In the f i r s t i n s t a n c e the e c o l o g i c a l c h a n g e is l i k e l y to i n d i c a t e an i n c r e a s e in u r b a n i z a t i o n and i n d u s t r i a l i z a t i o n of the d i s t r i c t , s i m i l a r to that r e g i s t e r e d a l o n g the d e n s i t y s c a l e and its c o r r e l a t i o n w i t h c h a n g e m e a s u r e s . The o t h e r e d u c a t i o n a l and o c c u p a t i o n a l i n d i c e s in T a b l e 10 fit into the same p a t t e r n .
The i n c r e a s e d c o v e r a g e of the c o m p r e h e n s i v e school c o u l d , in p r i n c i p l e , be an i n d i c a t i o n of some s i m i l a r trend but
s i n c e it is r a t h e r u n r e l a t e d to o t h e r e c o l o g i c a l v a r i a b l e s it m i g h t be r e g a r d e d as a s p e c i f i c c h a n g e a g e n t . P r i m a r l y it is
r e l a t e d to the i n c r e a s e in spatial test s c o r e s a m o n g the g i r l s -- the m o s t s t r i k i n g c h a n g e in r e l a t i o n to t r a d i t i o n a l sex d i f f e r e n c e s . F i g u r e 5 s h o w s the r e l a t i o n b e t w e e n i n c r e a s e s in the two v a r i a b l e s at each level of the d e n s i t y s c a l e .
Insert F i g u r e 5 a b o u t here
The two s e t s of a v e r a g e s are wery l i t t l e r e l a t e d to the d e n s i t y s c a l e but f o l l o w e a c h o t h e r c l o s e l y . In the d i s c u s s i o n we will try to i n t e r p r e t this in the c o n t e x t of the o t h e r f i n -d i n g s .
D i s c u s s i o n and c o n c l u s i o n s
We b e g a n the p r e s e n t a t i o n of r e s u l t s by s h o w i n g that an o v e r a l l i n c r e a s e in test s c o r e s o c c u r r e d b e t w e e n n a t i o n a l s a m p l e s in 1961 and 1 9 6 6 . The i n c r e a s e was l a r g e r for g i r l s than for b o y s . D u r i n g the s a m e interval several c h a n g e s in the e n v i r o n m e n t took p l a c e . School c u r r i c u l u m was r e v i s e d . T e l e v i s i o n r e a c h e d a b r o a d e r a u d i e n c e . F a m i l i e s w i t h t e e n -a g e r s m o v e d u p w -a r d s -along the e d u c -a t i o n -a l -and o c c u p -a t i o n -a l l a d d e r s . O c c u p a t i o n a l a c t i v i t y i n c r e a s e d among m o t h e r s . A g r i
-c u l t u r a l o -c -c u p a t i o n s b e -c a m e less f r e q u e n t .
In t r y i n g to e s t a b l i s h causal r e l a t i o n s b e t w e e n e n v i r o n m e n t a l and test s c o r e c h a n g e s we d i v i d e d the c o u n t r y in s m a l
-ler a r e a s c h a r a c t e r i z e d by a global e c o l o g i c a l v a r i a b l e --d e n s i t y -- a l o c a t i o n i n --d e x , a n --d a n u m b e r of m o r e s p e c i f i c e c o l o g i c a l i n d i c e s for each D e n s i t y x L o c a t i o n g r o u p based on p r o j e c t data and o f f i c i a l s t a t i s t i c s .
Initial test s c o r e s w e r e r a t h e r s t r o n g l y r e l a t e d to d e n s i t y for boys g e n e r a l l y and for g i r l s at least in v e r -bal a b i l i t y . The e c o l o g i c a l v a r i a b l e s that w e r e c h o s e n to r e f l e c t m o r e s p e c i f i c c h a r a c t e r i s t i c s of the a r e a s , or the f a m i l i e s in the a r e a s , w e r e in g e n e r a l h i g h l y c o r r e l a t e d b e t w e e n t h e m s e l v e s and with d e n s i t y , and being so they w e r e not a b l e to very m u c h s t r e n g t h e n or s p e c i f y the r e l a t i o n s h i p b e t w e e n p e r f o r m a n c e and e n v i r o n m e n t .
O v e r the f i v e - y e a r period the r e l a t i o n b e t w e e n test
s c o r e s and d e n s i t y was r e d u c e d and test s c o r e s i n c r e a s e d m o r e in s p a r s e l y than in d e n s e l y p o p u l a t e d a r e a s . Q u i t e c o n c e i v a b -ly this c o u l d h a v e to do with c h a n g e s in the d e n s i t y of the a d m i n i s t r a t i v e u n i t s b e t w e e n the c e n s u s of 1 9 6 0 on w h i c h the
index was b a s e d , and 1966 for w h i c h the same index was u s e d . Not m a n y u n i t s , h o w e v e r , can have c h a n g e d p l a c e s a l o n g the s c a l e d u r i n g a f i v e - y e a r p e r i o d . A c h a n g e of one step on the d e n s i t y s c a l e t a k e s , on a v e r a g e , 50 p e r c e n t p o p u l a t i o n inc r e a s e or 33 p e r inc e n t p o p u l a t i o n d e inc r e a s e . The a v e r a g e p o p u -l a t i o n g r o w t h in one y e a r ( 1 9 6 0 - 1 9 6 1 ) w a s 6.3 per mi-l-l w i t h a s t a n d a r d d e v i a t i o n of 18.4 per mill a m o n g the u n i t s . W i t h f i v e such c o n s e c u t i v e i n c r e m e n t s , all of them two s t a n d a r d d e v i a t i o n s a b o v e the m e a n , the e x p e c t e d i n c r e a s e w o u l d be 23 p e r c e n t . With five such c o n s e c u t i v e d e c r e m e n t s , all of t h e m two s t a n d a r d d e v i a t i o n s b e l o w the m e a n , the e x p e c t e d d e -c r e a s e w o u l d be 6 p e r -c e n t . Both -c a s e s a r e h i g h l y u n l i k e l y and w o u l d not r e s u l t in a c h a n g e in d e n s i t y e x c e p t for u n i t s n e a r the b o r d e r l i n e s of the d e n s i t y c l a s s e s . A c c o r d i n g to t h i s , lack of c o n s t a n c y in the d e n s i t y c l a s s i f i c a t i o n is not l i k e l y to be r e s p o n s i b l e for the r e d u c e d r e l a t i o n b e t w e e n d e n s i t y and test s c o r e s . It r a t h e r s e e m s that the c h a r a c t e r of the D e n s i t y x L o c a t i o n u n i t s c h a n g e d and m o r e so in the s p a r s e l y p o p u l a t e d a r e a s . It w o u l d m e a n that a real e q u a l i -z a t i o n took p l a c e b e t w e e n m o r e and less d e n s e l y p o p u l a t e d
a r e a s of the c o u n t r y .
One p o t e n t i a l e q u a l i z i n g i n f l u e n c e was the spread of TV o v e r the c o u n t r y w h i c h a f f e c t e d s p a r s e l y p o p u l a t e d a r e a s
m o r e than a v e r a g e ( - . 7 0 ) . TV i n c r e a s e , h o w e v e r , was not found a m o n g the v a r i a b l e s that had s i g n i f i c a n t c o r r e l a t i o n s w i t h t e s t s c o r e i n c r e m e n t s . Still t h e r e w a s a s l i g h t i n d i c a t i o n of i n f l u e n c e on g a i n s in verbal as c o n t r a s t e d to spatial t e s t s c o r e s a m o n g g i r l s (Table 1 1 ) .
Insert T a b l e 11 a b o u t here
A n o t h e r p o t e n t i a l e q u a l i z e r on the n a t i o n a l level was the i m p l e m e n t a t i o n of the c o m p r e h e n s i v e s c h o o l . It had p o s i t i v e c o r r e l a t i o n s with all test s c o r e s , s o m e of them even r e l a t i -v e l y l a r g e (Table 1 1 ) .
Even t h o u g h c o m p r e h e n s i v e school g r o w t h was u n r e l a t e d to d e n s i t y (.03) it m i g h t have had d i f f e r e n t impact in r u ral than in u r b a n a r e a s . In rural a r e a s it c r e a t e d a p o s s i b i -lity of c o n t i n u i n g w i t h an a c a d e m i c t y p e of l o w e r - s e c o n d a r y e d u c a t i o n in the home c o m m u n i t y w h i c h had not been a v a i l a b l e in the s e g r e g a t e d s y s t e m . This c e r t a i n l y i n c r e a s e d the a s p i -r a t i o n s fo-r a c a d e m i c c h o i c e s (cf. Hä'-rnqvist, 1 9 6 6 ) and m a y b e i n d i r e c t l y a l s o test s c o r e s . F u r t h e r m o r e the new c u r r i c u l u m s t r e s s e d e q u a l i t y b e t w e e n boys and g i r l s in v a r i o u s w a y s , p e r h a p s m o s t c o n c r e t e l y so in h a n d i c r a f t i n s t r u c t i o n . T r a d i -t i o n a l l y o n l y -the g i r l s had d o n e n e e d l e w o r k and o n l y -the boys w o o d w o r k . The new c u r r i c u l u m r e q u i r e d a m i n i m u m of 20 h o u r s of w o o d w o r k for g i r l s and 20 h o u r s of n e e d l e w o r k for b o y s . A l t h o u g h this is a m i n o r part of the h a n d i c r a f t i n s t r u c t i o n , let a l o n e the total p r o g r a m , it s h o u l d have i n t r o d u c e d g i r l s to i n t e r p r e t i n g b l u e p r i n t s of t h r e e - d i m e n s i o n a l o b j e c t s --s/ery s i m i l a r to the task in the spatial t e s t . Even m o r e im-p o r t a n t , h o w e v e r , this and o t h e r c u r r i c u l u m c h a n g e s m i g h t h a v e i n f l u e n c e d the e x p e c t a t i o n s as to w h a t g i r l s s h o u l d be a b l e to a c c o m p l i s h . This is o u r i n t e r p r e t a t i o n of the " s u r -p l u s " c o r r e l a t i o n for the s-patial t e s t .
T h i s r e s u l t has s o m e w h a t of a p a r a l l e l l in F l a n a g a n ' s s t u d y ( 1 9 7 6 ) and he d e s c r i b e s his f i n d i n g s in the f o l l o w i n g
t e r m s .
Both of the r e m a i n i n g two t e s t s h a v e been found p r e d i c -tive of s u c c e s s in m e c h a n i c a l w o r k . I n t e r e s t i n g l y , both show m o d e s t g a i n s for the f e m a l e s and yery s l i g h t l o s s e s for the m a l e s . -- This a p p e a r s to r e f l e c t a
c h a n g e away from the sex s t e r e o t y p i n g that c h a r a c t e r i z e d the 1 9 6 0 g r o u p . A n o t h e r p a r a l l e l ! is found in a s t u d y by F e n n e m a and S h e r m a n ( 1 9 7 7 ) w h e r e sex d i f f e r e n c e s in spatial v i s u a l i z a t i o n d i s a p p e a r e d w h e n the n u m b e r of " s p a c e r e l a t e d " c o u r s e s w a s c o n t r o l l e d by m e a n s of a n a l y s i s of c o v a r i a n c e . A l s o f i n d i n g s in F i g u r e 4 can be i n t e r p r e t e d in t e r m s of sex r o l e s and v a r y i n g s i m i l a r i t y in the e x p e r i e n c e s of boys and g i r l s . In rural a r e a s boys and g i r l s are l i k e l y to h a v e had m o r e s i m i l a r e v e r y d a y e x p e r i e n c e s of p r a c t i c a l t h i n g s and a c t i v i t i e s , and this c o u l d e x p l a i n why sex d i f f e -r e n c e s in the n o n - v e -r b a l tests a-re so m u c h s m a l l e -r in -ru-ral than in u r b a n a r e a s . It is t e m p t i n g to g u e s s that they m i g h t h a v e been even s m a l l e r if the i n c r e a s e d e x p o s u r e to TV had not had a d i f f e r e n t i a l i n f l u e n c e on a b i l i t i e s in the o p p o s i t e d i r e c t i o n but a d m i t t e d l y t h e s e c o r r e l a t i o n s fail to r e a c h s i g n i f i c a n c e .
Seven m o r e i n d i c e s based on p r o j e c t data c h a n g e d s i g n i -f i c a n t l y b e t w e e n the two y e a r s (c-f. T a b l e 5 ) . In the initial s t a t e all of them w e r e h i g h l y c o r r e l a t e d with d e n s i t y (mean . 8 2 , r a n g e .73 - .88) and all had high l o a d i n g s on the f i r s t e c o l o g i c a l f a c t o r (mean . 8 0 , r a n g e .67 - . 9 0 ) . The o v e r a l l d e v e l o p m e n t in the D e n s i t y x L o c a t i o n u n i t s went in the d i r e c -tion of u r b a n i z a t i o n and i n d u s t r i a l i z a t i o n . This trend w a s s t r o n g e r in the less d e n s e l y p o p u l a t e d u n i t s as shown by the c o r r e l a t i o n s b e t w e e n d e n s i t y and c h a n g e in e c o l o g i c a l i n d i c e s (more n o n - a g r i c u l t u r a l w o r k e r s , h i g h e r o c c u p a t i o n a l a c t i v i t y a m o n g m o t h e r s ) .
Four of the seven i n d i c e s w e r e r e p r e s e n t e d by s i g n i f i c a n t test c h a n g e c o r r e l a t i o n s in T a b l e 10 and t h e s e s u p p o r t e d the i n t e r p r e t a t i o n that g a i n s w e r e l a r g e r in a r e a s d e v e l o p i n g in the d i r e c t i o n of u r b a n i z a t i o n - i n d u s t r i a l i z a t i o n . Taking all test c h a n g e c o r r e l a t i o n s for the seven e c o l o g i c a l c h a n g e m e a s u r e s into a c c o u n t m a k e s the p a t t e r n m o r e c o n f u s i n g , h o w -e v -e r , as th-e d i s t r i b u t i o n s of c o r r -e l a t i o n s for boys and g i r l s
s h o w ( T a b l e 1 2 ) . I n s e r t T a b l e 12 a b o u t h e r e T h e c o r r e l a t i o n s for b o y s s u p p o r t the i n t e r p r e t a t i o n t h a t t h e c h a n g e s r e g i s t e r e d in the e c o l o g i c a l v a r i a b l e s to s o m e e x t e n t h a v e b e e n i n s t r u m e n t a l in i m p r o v i n g t h e c o n d i t i o n s for i n t e l l e c t u a l g r o w t h . W h e t h e r it is on the f a m i l y level or t h e a r e a level r e m a i n s i n c o n c l u s i v e and so d o e s the q u e s t i o n
w h e t h e r t h e y a r e " t r u l y e n v i r o n m e n t a l " or n o t . The c o r r e l a t i o n s f o r g i r l s , on the c o n t r a r y , do n o t s u p p o r t t h i s h y p o -t h e s i s , bu-t i n s -t e a d -t h e y a r e c o m p a -t i b l e w i -t h -the e a r l i e r
f i n d i n g s t h a t both i n i t i a l and final t e s t s c o r e s , in g e n e r a l , a r e less r e l a t e d to d e n s i t y for g i r l s t h a n for b o y s - a
f i n d i n g t h a t m a y i n d i c a t e t h a t u r b a n and rural e n v i r o n m e n t s f u n c t i o n m o r e e q u a l l y in r e l a t i o n to g i r l s t h a n to b o y s . Still the g i r l s ' test s c o r e s h a v e i n c r e a s e d and in s o m e r e s p e c t s e v e n m o r e so t h a n t h o s e of the b o y s . L o o k i n g b a c k u p o n the r e s u l t s for the two " n a t i o n a l i n n o v a t i o n s " -- TV and c o m p r e h e n s i v e s c h o o l - we find the o p p o s i t e p a t t e r n . On the w h o l e t h e s e w e r e m o r e r e l a t e d to the g i r l s ' t h a n to the b o y s ' t e s t s c o r e s .
T h u s it s e e m s t h a t both i n i t i a l level and g a i n s for b o y s w e r e m o r e i n f l u e n c e d by c o n d i t i o n s in t h e i r i m m e d i a t e e n v i r o n m e n t r e p r e s e n t e d by the e d u c a t i o n a l and o c c u p a t i o n a l level of the f a m i l y or in the a r e a . M a c r o l e v e l c o n d i t i o n s had m o r e i m p a c t on the g i r l s . I n t e r e s t i n g l y , the l a r g e s t g a i n in the v e r b a l t e s t w a s for g i r l s in w o r k i n g - c l a s s f a m i l i e s in c o m m u n i t i e s w h e r e u p p e r - s e c o n d a r y e d u c a t i o n w a s not a v a i l a b l e ( S v e n s s o n , 1 9 7 1 , A p p e n d i x 2 ) , and t h i s is not a g r o u p w h e r e o n e e x p e c t s the m o s t e f f e c t i v e s t i m u l a t i o n f r o m the i m m e d i a t e e n v i r o n m e n t . R a t h e r a c o m p e n s a t o r y i n f l u e n c e is n e e d e d and t h i s w o u l d h a v e to c o m e t h r o u g h m o r e u n i v e r s a l c h a n n e l s --m a s s --m e d i a , s c h o o l , and c o n t a c t s w i t h o t h e r s o c i a l g r o u p s . It d o e s not e v e n h a v e to be e x c l u s i v e l y an i n t e l l e c t u a l s t i m u l a -t i o n . A c h a n g e in e x p e c -t a -t i o n s and s e l f - c o n c e p -t s -- l i k e -the o n e a i m e d at in the c o m p r e h e n s i v e s c h o o l and p r o p a g a t e d in
c o n t e m p o r a r y s o c i e t y -- m i g h t also h a v e an impact on g i r l s ' p e r f o r m a n c e s . As M a c c o b y and J a c k l i n ( 1 9 7 4 , p. 1 3 3 ) c o n c l u -d e :
the s t u d i e s on p e r s o n a l i t y c o r r e l a t e s of i n t e l l e c -tual p e r f o r m a n c e have c o n t i n u e d to s u g g e s t that in-t e l l e c in-t u a l d e v e l o p m e n in-t in g i r l s is f o s in-t e r e d by in-t h e i r being a s s e r t i v e and a c t i v e , and h a v i n g a s e n s e that they can c o n t r o l , by their own a c t i o n s , the e v e n t s that a f f e c t t h e i r l i v e s . T h e s e f a c t o r s a p p e a r to be less i m p o r t a n t in the i n t e l l e c t u a l d e v e l o p m e n t of boys -- p e r h a p s b e c a u s e they are a l r e a d y s u f f i c i e n t l y a s s e r t i v e and have a s u f f i c i e n t s e n s e of personal control o v e r e v e n t s , so that o t h e r i s s u e s (e.g. how well they can control a g g r e s s i v e i m p u l s e s ) b e c o m e m o r e
i m p o r t a n t in how s u c c e s s f u l l y they can e x p l o i t t h e i r i n t e l l e c t u a l p o t e n t i a l .
Some f u r t h e r s u p p o r t for the g e n e r a l i z a t i o n a b o u t g i r l s is p r o v i d e d by W e r n e r s s o n ( 1 9 7 7 , Ch. 7) who found that s e x -typing of a c t i v i t i e s and b e h a v i o r was less f r e q u e n t a m o n g g i r l s w i t h a m o r e c o n c e p t u a l i z i n g c o g n i t i v e s t y l e than among boys g e n e r a l l y and among m o r e " c o n c r e t e " g i r l s . The r e l a t i o n b e t w e e n i n t e l l e c t u a l p e r f o r m a n c e and p e r s o n a l i t y c o r r e l a t e s is even l i k e l y to be c i r c u l a r : a m o r e a s s e r t i v e o u t l o o k f o s t e r i n g i n t e l l e c t u a l d e v e l o p m e n t , and a m o r e c o n -ceptual a p p r o a c h r e d u c i n g sex d i f f e r e n t i a t i o n in a t t i t u d e s and b e h a v i o r , and so o n .
The "other i s s u e s " r e l e v a n t for boys a c c o r d i n g to M a c c o b y and J a c k l i n m i g h t p o s s i b l y be c o n s t r u e d to i n c l u d e a l s o the f o l l o w i n g o b s e r v a t i o n s . In g e n e r a l , boys are less well a d j u s t e d than g i r l s to the i n s t i t u t i o n a l d e m a n d s set up by school ( S v e n s s o n , 1 9 7 1 , p p . 1 2 2 - 1 2 4 ) . They also are m o r e d e p e n d e n t than g i r l s on o c c u p a t i o n a l g o a l s v s . a c a d e m i c
i n t e r e s t s in t h e i r c h o i c e of an e d u c a t i o n a b o v e the c o m p u l s o -ry (Hä'rnqvist, in p r e s s ) . In the " s t a t u s a t t a i n m e n t p r o c e s s " (Sewell & H ä u s e r , e.g. 1 9 7 6 ) , w h e r e t h e s e c h o i c e s play an i m p o r t a n t r o l e , s o c i o e c o n o m i c b a c k g r o u n d , parental e n c o u r a g e -m e n t and the e d u c a t i o n a l a s p i r a t i o n s of f r i e n d s are h i g h l y
i n f l u e n t i a l . T h e s e f i n d i n g s t o g e t h e r s u g g e s t t h a t , in o r d e r to c h a n n e l b o y s ' a c t i v i t i e s in a c o g n i t i v e and a c a d e m i c
up and r e i n f o r c e d by the i m m e d i a t e e n v i r o n m e n t . T h i s w o u l d e x p l a i n the b o y s ' side of the p a t t e r n of c o r r e l a t i o n s .
Still t h e r e is not i n f o r m a t i o n e n o u g h to w e i g h i n f l u e n -ces from the b o y s ' own f a m i l i e s a g a i n s t p o s s i b l e c o n t e x t u a l
i n f l u e n c e s from the o p p o r t u n i t i e s , v a l u e s and b e l i e f s c h a r a c -t e r i z i n g -the c o m m u n i -t i e s w h e r e -they g r e w u p . E c o l o g i c a l
c h a n g e m e a s u r e s based on s t a t i s t i c s f r o m the w h o l e c o m m u n i -t i e s m i g h -t have h e l p e d s o m e w h a -t , bu-t c o n s i d e r i n g -the high c o r r e l a t i o n s b e t w e e n a l m o s t all k i n d s of e c o l o g i c a l i n d i c e s in the initial s t a t e , and the r e l a t i v e l y small n u m b e r of o b -s e r v a t i o n a l u n i t -s , -such a d d i t i o n a l m e a -s u r e -s w o u l d not h a v e been l i k e l y to bring this a n a l y s i s m u c h f o r w a r d . As a l r e a d y has been s t a t e d a c o m p l e t e m u l t i l e v e l a n a l y s i s is o u t s i d e the p o s s i b i l i t i e s of the p r e s e n t a p p r o a c h .
A n o t h e r d e f i c i e n c y from an a n a l y t i c a l p o i n t of v i e w is the lack of time s e r i e s i n f o r m a t i o n on e c o l o g i c a l c h a r a c t e r i s -tics w h i c h m a k e s the s t u d y of time lag i m p o s s i b l e . T h i s lack of i n f o r m a t i o n is not i n h e r e n t in the d e s i g n but it w o u l d have t a k e n an i m m e n s e a m o u n t of w o r k to s u p p l y such a d d i t i o -nal d a t a .
Still it is p o s s i b l e to s p e c u l a t e a b o u t time l a g s . The e c o l o g i c a l c h a n g e s that seem to have i n f l u e n c e d g a i n s a m o n g boys m i g h t very well be j u s t the l a t e s t o b s e r v a b l e part of a d e v e l o p m e n t that has been going on for a long time in the d i r e c t i o n of i n c r e a s e d e d u c a t i o n a l level and t r a n s f e r to n o n -a g r i c u l t u r -a l o c c u p -a t i o n s in the less d e n s e l y p o p u l -a t e d -a r e -a s . The full m o d e l of F i g u r e 1 w o u l d have m a d e it p o s s i b l e to e s t i m a t e an o p t i m a l i n t e r v a l b e t w e e n c h a n g e s in i n d e p e n d e n t and d e p e n d e n t v a r i a b l e s . It s e e m s to us q u i t e l i k e l y that t h i s is l o n g e r than the interval o b s e r v e d in the s t u d y .
The i m p a c t on g i r l s of c o m p r e h e n s i v e school and TV looks less g r a d u a l b e c a u s e both i n n o v a t i o n s w e r e q u i t e new a n d , on the i n d i v i d u a l l e v e l , one e i t h e r had them or not at the two p o i n t s in t i m e . The " m e s s a g e " , on the o t h e r h a n d , that e s p e c i a l l y the c o m p r e h e n s i v e school was t h o u g h t to c o n -vey the c h a n g i n g n o t i o n of f e m a l e r o l e s in s o c i e t y --was not t h a t n e w , but its d i s s e m i n a t i o n c e r t a i n l y g a i n e d m o m e n t u m d u r i n g the ' 6 0 s . If t h e r e had been e x p l a n a t o r y
v a r i a b l e s that r e c o r d e d the spread of the m e s s a g e i n s t e a d of the m e d i a , it m i g h t have been p o s s i b l e to e s t i m a t e time lags
also in this c o n n e c t i o n . But this is far out from w h a t could be f o r e s e e n w h e n this study was p l a n n e d .
In c o n l u s i o n we t h i n k that we h a v e been a b l e to e s t a b lish several i m p o r t a n t r e l a t i o n s b e t w e e n e c o l o g i c a l c h a r a c t e r i s t i c s and test s c o r e c h a n g e s . The m o s t i n t e r e s t i n g r e -s u l t -s have to do w i t h d e c r e a -s i n g d i f f e r e n c e -s b e t w e e n boy-s and g i r l s and t h e i r d i f f e r e n t i a l r e s p o n s e to e c o l o g i c a l c o n d i t i o n s . T h e s e r e s u l t s c a n n o t be v e r i f i e d t h r o u g h r e p l i -c a t i o n of the s t u d y b e -c a u s e it is of n e -c e s s i t y bound to a r a t h e r s p e c i a l c o n t e x t of s o c i e t a l c h a n g e s and i n n o v a t i o n s . *• Still it m a y g i v e c i r c u m s t a n t i a l e v i d e n c e to h y p o t h e s e s that a l s o can be s t u d i e d in o t h e r c o n t e x t s . F u r t h e r m o r e it p o i n t s to m e t h o d o l o g i c a l a p p r o a c h e s and i m p r o v e m e n t s that can be a p p l i e d in o t h e r s t u d i e s of c h a n g e s in p s y c h o l o g i c a l v a r i a b -les as r e l a t e d to s o c i e t a l t r e n d s .
F i n a l l y we have a s k e d o u r s e l v e s w h e t h e r this s t u d y of i n c r e a s i n g test s c o r e s has any i m p l i c a t i o n s for the s t u d y of d e c r e a s i n g s c o r e s a l s o . In s p i t e of the fact that the o b s e r -v a t i o n s r e l a t e to d i f f e r e n t d o m a i n s ( a b i l i t y -v s . a c h i e -v e m e n t ) and d i f f e r e n t a g e g r o u p s ( e l e m e n t a r y v s . s e c o n d a r y ) some
s u g g e s t i o n s seem to be p o s s i b l e .
The p r e s e n t study i n d i c a t e s that it m a y be f r u i t f u l to a n a l y z e the c a u s a t i o n s e p a r a t e l y for m a l e and f e m a l e s t u d e n t s even w h e r e o v e r a l l t r e n d s are s i m i l a r f o r both s e x e s . The g e n e r a l l y p o s i t i v e d e v e l o p m e n t o v e r t i m e of the s o c i o e c o n o m i c i n d i c e s that w e r e r e l a t e d to g r o w t h a m o n g boys m a y seem in-c o m p a t i b l e with d e in-c r e a s i n g s in-c o r e s . H o w e v e r , t h e s e i n d i in-c e s can be looked upon as p r o x i e s for p a r e n t a l and e n v i r o n m e n t a l e n c o u r a g e m e n t , and the level of e n c o u r a g e m e n t m i g h t very well have d e c r e a s e d o v e r time in r e l a t i o n to the e d u c a t i o n a l and o c c u p a t i o n a l level of the f a m i l y and its s u r r o u n d i n g s . A m o r e d i r e c t m e a s u r e of e n c o u r a g e m e n t then w o u l d be n e e d e d in o r d e r to e s t a b l i s h s i m i l a r r e l a t i o n s in a p h a s e of d e c l i n i n g s c o r e s . As to the g i r l s ' test s c o r e s H a r n i s c h f e g e r and W i l e y ( 1 9 7 5 , p. 1 1 7 ) a l r e a d y have the h y p o t h e s i s that s c o r e l o s s e s a m o n g g i r l s h a v e been m o r e a f f e c t e d by c h a n g e s in c u r r i c u l u m , work h a b i t s and t e l e v i s i o n v i e w i n g than t h o s e a m o n g the b o y s . This is a s o m e w h a t d i f f e r e n t i n t e r p r e t a t i o n than o u r s of the im-pact of t h e s e f a c t o r s , but still c o m p a t i b l e w i t h the n o t i o n that boys and g i r l s r e a c t d i f f e r e n t l y to e n v i r o n m e n t a l c o n -d i t i o n s .
