Development of cognitive structures and information processing strategies of elementary school students learning about biological reproduction

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Development of cognitive structures and

information processing strategies of elementary

school students learning about biological

reproduction

Chin-Chung Tsai

a

& Chao-Ming Huang

a a

Center for Teacher Education and Institute of Education , National Chiao Tung

University , Hsinchu, Taiwan

Published online: 13 Dec 2010.

To cite this article: Chin-Chung Tsai & Chao-Ming Huang (2001) Development of cognitive structures and information

processing strategies of elementary school students learning about biological reproduction, Journal of Biological

Education, 36:1, 21-26, DOI:

10.1080/00219266.2001.9655791

To link to this article: http://dx.doi.org/10.1080/00219266.2001.9655791

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Educational Research

Development of cognitive

structures and information

processing strategies of

elementary school students

learning about biological

reproduction

Chin-Chung Tsai and Chao-Ming Huang

Center for Teacher Education and Institute of Education, National Chiao Tung

University, Hsinchu, Taiwan

The purpose of this study was to explore 28 Taiwanese fifth graders' development of knowledge on biological

reproduction. The students received three weeks of instruction about biological reproduction and were inter­

viewed to determine their cognitive structures. The interviews were conducted three times, at weekly intervals

throughout the instruction, and an additional interview was conducted two months after the instruction. The

interview data were analysed through a flow map method to show cognitive structure, and the students' infor­

mation processing strategies, derived from an analysis of the flow map data, were also explored. The results

suggest that there are three stages of cognitive structure development. In the first stage, categorised as

'knowledge development', both the extent of knowledge and the richness of networking of ideas increase. In

the second stage, categorised as 'knowledge extension', only the amount of knowledge continues to increase.

In the final stage, called 'knowledge refinement', the amount of knowledge recalled decreases, while the rich­

ness in networking of ideas remains stable. At the same time, the use of higher-order information processing

modes (e.g., narrative containing statements inferring and explaining) increases dramatically. This implies that

the rich connections between concepts and the use of higher-order information processing strategies may facil­

itate maturation of connected knowledge in memory.

Key words: Cognitive structure, Biological reproduction, Flow map, Taiwan.

Introduction

Understanding how students acquire knowledge is always an

important issue for science education researchers. Educators

and cognitive scientists have tried to represent acquired knowl­

edge in terms of 'cognitive structures'. A cognitive structure is a

hypothetical construction showing the relationships between

concepts in a learner's long-term memory (Shavelson, 1974).

Over the past two or three decades, many science educators

have explored aspects of student cognitive structures using a

variety of methods (e.g., Preece, 1976; West and Pines, 1985;

Bahar et ai, 1999). However, many early studies on cognitive

structures have certain limitations. First, they focused largely on

more mature students (high school or college students).

Secondly, many of them did not document the development of

student cognitive structures over time. Hence, most of these for­

mer studies did not provide information about how students'

knowledge interacted with instruction as it unfolded, nor how

students developed conceptual knowledge during instruction.

To contribute more broadly to our understanding of how stu­

dents develop knowledge networks, the present study explored

a group of elementary school pupils' conceptual development

during short-term instruction on biological reproduction. Their

knowledge recall using interview methods was examined to

determine how the instruction may have influenced their

ideational development of biological reproduction, and knowl­

edge networking in particular. This study also investigated stu­

dent information processing strategies based on content analyses

of their recall narratives. This may provide a deeper under­

standing about the nature of student knowledge construction

during meaningful learning, as typically occurs in the classroom.

Clearly, research of this kind on cognitive structures is con­

sistent with current constructivist theory as applied to science

instruction (Bodner, 1986; Anderson, 1992). Constructivist the­

ory asserts that knowledge is actively constructed by the learner

and is not simply recorded in memory. Therefore, every learner

within the same learning environment is likely to develop

f J Cognitive structure development Tsai and Huang

ferent cognitive s t r u c t u r e s a n d varied ways of organising scientific information, even t h o u g h t h e information p r e s e n t e d and t h e conditions of learning m a y super­ ficially s e e m i d e n t i c a l . F u r t h e r m o r e , research on cognitive structures is consis­ t e n t with s c h e m a t a t h e o r y (e.g., H o w a r d ,

1988). T h e research r e p o r t e d h e r e could b e viewed as an investigation i n t o h o w n e w e x p e r i e n c e s influence t h e r e c o n ­ struction of existing schemata.

To summarise, this study e x p l o r e d h o w a g r o u p of e l e m e n t a r y s c h o o l p u p i l s d e v e l o p e d organised representations of k n o w l e d g e a b o u t biological r e p r o d u c t i o n and h o w their information processing strategies changed during t h e course of biological instruction.

l.Somc plants use seeds and stems for reproduction

2.The methods of reproduction for animals include vi\ iparity. oviparity. ovoviviparity

3.Beans use their seeds for reproduction

4.Roses use their stems for reproduction

Birds' reproduction is by laying eggs, so they arc oviparous

6.Some snakes' reproduction is by oviparity. but some snakes' reproduction is by ovoviviparity

7.The goal of reproduction is to generate offspring

Method

Subjects

A fifth grade class of 3 2 pupils (11 years

old) in Taiwan participated in this study. However, four s t u d e n t s did n o t finish all of t h e data collection, therefore their data w e r e e x c l u d e d from final analyses. T h e final s a m p l e included 14 boys and 14 girls. T h e i r t e a c h e r is an e x p e r i e n c e d m a l e t e a c h e r w i t h m o r e t h a n 10 years of t e a c h i n g experience.

Description of lessons taught

According t o t h e National Standards of E l e m e n t a r y Science Education in Taiwan, t h e instructional unit on biological r e p r o ­ duction for fifth graders should take a b o u t nine 4 0 m i n u t e class periods. Consequently, t h e s t u d e n t s in this study received nine periods of relevant instruction, w h i c h w e r e arranged into t h r e e successive weeks ( t h r e e periods per w e e k ) . T h e regular t e a c h e r was t h e instructor for t h e s e classes. T h e first t w o weeks covered different m e t h o d s of flowering p l a n t r e p r o d u c t i o n . T h e first week largely focused on t h e use of seeds for vegetative r e p r o ­ duction. T h e second w e e k mainly covered t h e use of o t h e r parts of plants for r e p r o d u c t i o n (for e x a m p l e , stems, roots). In t h e final week, different m e t h o d s of fauna r e p r o d u c t i o n , including viviparity, oviparity, and ovoviviparity w e r e i n t r o d u c e d . In these t h r e e weeks, t h e s t u d e n t s also h a d an o p p o r t u n i t y t o p l a n t s o m e seeds and record their g r o w t h .

Flow map method

Interviews w e r e used t o obtain a record of s t u d e n t narratives t o b e analysed using flow m a p m e t h o d s as evidence of t h e stu­ d e n t ' s cognitive structures. Since this p a r t of t h e interview n e e d e d t o b e c o n d u c t e d in a non-directive way t o h e l p t h e stu­ d e n t express w h a t h e or she k n o w s w i t h m i n i m u m bias by t h e interviewer, t h e interview questions w e r e k e p t as simple as pos­ sible, e.g.:

• Please tell m e w h a t are t h e m a i n ideas or ways of biological r e p r o d u c t i o n .

• C o u l d you tell m e m o r e a b o u t t h e ideas you have m e n t i o n e d ? • C o u l d you tell m e t h e relationships b e t w e e n t h e ideas you

have already told m e about?

8.One more way of reproduction is called cell culture

Figure 1 John's (pseudonym) flow map about biological reproduction (obtained from the third inter­ view).

T h e responses t o these questions w e r e tape-recorded, and t h e n transcribed into t h e format of a flow m a p (Anderson and D e m e t r i u s , 1993). Figure 1 shows a s t u d e n t ' s flow m a p about biological r e p r o d u c t i o n . T h e flow m a p is constructed by enter­ ing t h e s t a t e m e n t s (equivalent t o a clause or sentence) in t h e s e q u e n c e t h e y w e r e u t t e r e d by t h e student. T h e sequence of discourse is e x a m i n e d and r e c u r r e n t ideas (representing a con­ necting n o d e t o prior t h o u g h t ) are linked by connecting arrows. T h e linear or serial arrows s h o w t h e direct flow of s t u d e n t nar­ rative, while r e c u r r e n t linkages s h o w revisited ideas among t h e s t a t e m e n t s displayed in t h e flow map. (It should b e noted that n o t all of t h e revisited ideas w e r e elicited by t h e third interview question p r e s e n t e d previously. S t u d e n t s ' narratives contained m a n y revisited ideas p r o b e d by o t h e r interview questions.) For e x a m p l e , t h e s t u d e n t ' s narrative m a p p e d in Figure 1 shows a sequential p a t t e r n beginning w i t h plant r e p r o d u c t i o n and pro­ gressing to m e t h o d s of fauna r e p r o d u c t i o n . Furthermore, t h e s t u d e n t stated s o m e concrete e x a m p l e s of biological r e p r o d u c ­ tion, such as beans, roses, birds, and snakes. Moreover, recurrent arrows are inserted t h a t link revisited ideas to t h e earliest step w h e r e t h e related idea first occurred. S t a t e m e n t 3, for example, 'beans use their seeds for r e p r o d u c t i o n ' includes one major revisited idea 'seeds for r e p r o d u c t i o n ' . Therefore, s t a t e m e n t 3 has o n e r e c u r r e n t arrow d r a w n back t o s t a t e m e n t 1 ( t h e earliest step containing a s t a t e m e n t a b o u t seeds for reproduction; for further details a b o u t t h e flow m a p m e t h o d , see A n d e r s o n and D e m e t r i u s , 1993; Anderson et al, 2 0 0 1 ; Tsai, 1998a, 2 0 0 0 , 2 0 0 1 ) . A flow m a p representation exhibits b o t h t h e sequential p a t t e r n of recall and also evidence of an underlying intercon­ n e c t e d t e x t u r e of ideas in cognitive structures. T h e flow maps provide researchers with information about t h e complexities and idiosyncrasies of an individual's cognitive structures, and organisational schemata as r e p r e s e n t e d by t h e evidence of con­ n e c t e d knowledge c o n t a i n e d in t h e flow m a p data (e.g., Bischoff and A n d e r s o n , 2 0 0 1 ) .

T h e following t w o variables representing knowledge con­ struction are obtained from t h e flow m a p data:

Q

Cognitive structure development Tsai and Huang

Linear linkages: t h e n u m b e r of ideas and

their sequential organisation as s h o w n in t h e flow map, an indicator of t h e e x t e n t of recalled knowledge (8 in Figure 1).

Recurrent linkages: t h e n u m b e r of revisited

and linked ideas indicated by r e c u r r e n t linkages shown in t h e flow m a p , an indi­ cator of t h e richness of knowledge n e t ­ w o r k s w i t h i n a s t u d e n t ' s cognitive structure (5 in Figure 1).

1 Different seed has ils own shape and color 2.Plants can be reproduce

stems and roots

* b v

\

means of some parts of their body, for example.

3.We planted some seeds at schoolyard and have to record their growth everyday

i

4.Teacher said that roses could be reproduced by means of their stems

5.We observed bean seeds, celen seeds and so on T h e r e w e r e a total of four flow-map inter­

views in this study. T h e first t h r e e interviews were c o n d u c t e d at t h e end of each w e e k of instruction. T h e final interview was con­ ducted t w o m o n t h s after t h e instruction t o obtain evidence of longer t e r m retention of knowledge. Figure 1 is a student's flow m a p obtained from t h e third interview. T h e same student's flow m a p s obtained from t h e first, second, and final interview are shown in Figure 2, Figure 3, and Figure 4, respec­ tively. T h e reliability of flow m a p diagram­ ming was d e t e r m i n e d by asking a second i n d e p e n d e n t researcher to diagram a subset of t h e s t u d e n t interview narratives. T h e inter-coder agreement for sequential state­ m e n t s (i.e., linear linkages) was 0.89 and for recurrent linkages was 0 . 8 3 . (For t h e calcu­ lation of t h e reliability coefficient, please refer to Anderson and D e m e t r i u s (1993).) Based on this evidence, this m e t h o d was d e e m e d to b e sufficiently reliable for t h e purposes of this research study. In general, reliabilities greater t h a n 0.80 are considered sufficient for narrative analyses.

This study also used c o n t e n t analysis m e t h o d s to e x a m i n e s t u d e n t s ' cognitive o p e r a t i o n s and i n f o r m a t i o n p r o c e s s i n g strategies based on t h e flow maps. Each of t h e students' ideas, s h o w n in t h e flow maps, was categorised into one of t h e following five levels of information processing m o d e s : • Defining: Providing a definition of a con­

cept or a scientific t e r m , e.g., Oviparity indicates animals t h a t lay eggs and h a t c h outside t h e m o t h e r ' s body.

• Describing: Depicting a p h e n o m e n o n or a

fact, e.g., S o m e snakes' r e p r o d u c t i o n is by oviparity, b u t s o m e snakes' r e p r o d u c t i o n is by ovoviviparity.

• Comparing: Describing t h e relationships b e t w e e n (or a m o n g ) subjects, things, or m e t h o d s , e.g., C o m p a r e d t o o t h e r m e t h o d s of reproduction, t h e oviparity could generate m o r e offspring at one time.

• Conditional Inferring: A description a b o u t w h a t will h a p p e n u n d e r certain conditions, e.g., If t h e pollen deposits o n t o a pis­ til, it may generate seeds.

• Explaining: Presenting an account t o justify t h e causality of t w o facts or events, e.g., Since t h e oviparity lacks parental care, it needs a large a m o u n t of eggs t o increase t h e survival rate.

Figure 2 John's flow map obtained from the first interview.

l.Wc inserted a section of rose stem into schoolyard and see its growth

2. Teacher said that orchid could be reproduced by means of cell culture

atbi

3. We can use sweet potato or potato roots for reproduction and then generate its

offspring I , 4. Plants can use different methods for reproduction, for example, bean

seeds, rose stems and potato roots

5.The goal of reproduction is to generate offspring

I

6.Moss can use spore for reproduction

Figure 3 John's flow map obtained from the second interview.

£ 1 .Plants can use different ways for reproduction, for example, bean seeds, rose ►•stems and potato roots and so on

2.Some plants are not easy to reproduce with seeds, therefore the fanner will use other parts of plants for reproduction, for example, rose stems, potato roots and so on 1

3.Animals have three ways to generate their offspring including viviparily. oviparity and ovoviviparity

4.The nutrient of viviparity comes from maternal body but oviparity and ovoviviparity depend on egg's own

5.The main goal of reproduction is to generate offspring

Figure 4 John's flow map obtained from the final interview.

This categorisation s c h e m e was t h e same as t h a t used in Tsai (1999a, 2 0 0 1 ) . T h e p u r p o s e of t h e information processing analyses was t o acquire a d e e p e r u n d e r s t a n d i n g a b o u t a stu­ d e n t ' s reasoning w h e n (re) constructing science knowledge. A total c o u n t of t h e c o d e d s t a t e m e n t s occurring in each of t h e cat­ egories was o b t a i n e d by examining t h e s t a t e m e n t s in t h e flow m a p narrative. S t u d e n t s w h o frequently use higher-order m o d e s of information processing (e.g., 'explaining') w e r e viewed as having b e t t e r strategies for organising information during recall. A n inter-coder reliability of 0.88 was o b t a i n e d for t h e c o n t e n t analysis. (This m e a n s t h a t t h e t w o coders h a d t h e s a m e way of categorization on 8 8 % of s t u d e n t s ' ideas). After t h e reliability

Q

Cognitive structure development Tsai and Huang analysis was c o m p l e t e d , t h o s e s t a t e m e n t s

t h a t lacked inter-coder a g r e e m e n t w e r e dis­ cussed b e t w e e n t h e t w o coders and consen­ sus reached.

Results

Table 1 presents data on s t u d e n t cognitive s t r u c t u r e o u t c o m e s and categories of infor­ m a t i o n processing m o d e s gathered from t h e four c o n s e c u t i v e i n t e r v i e w s . T h i s s t u d y s h o w e d t h a t t h e e x t e n t of s t u d e n t s ' cognitive structures (i.e., linear linkages) increased as a r e s u l t of t h e i n s t r u c t i o n ; h o w e v e r , t w o m o n t h s after instruction, t h e linear linkages s h o w n in t h e flow m a p s regressed t o almost t h e original a m o u n t as elicited in t h e first interview ( 5 . 1 8 at t h e final interview versus 5.14 in t h e first interview). T h e finding is s o m e w h a t consistent w i t h a conclusion c o m ­ monly revealed in science e d u c a t i o n research t h a t s t u d e n t s r e t u r n to almost their original

c o n c e p t u a l f r a m e w o r k s s o m e t i m e after t h e i n s t r u c t i o n (Wandersee et ai, 1994; Tsai, 1998b, 1 9 9 9 b ) . It is also consis­ t e n t w i t h classical studies on m e m o r y t h a t s h o w a decline in available recall k n o w l e d g e w i t h time. However, t h e r e c u r r e n t linkages s h o w e d s o m e encouraging findings. S t u d e n t s ' r e c u r r e n t linkages increased from t h e first interview t o t h e second inter­ view, b u t r e m a i n e d stable after t h e second interview. This implies t h a t t h e r e c u r r e n t linkages, t h a t is, t h e richness of stu­ d e n t cognitive s t r u c t u r e s r e p r e s e n t e d by i n t e r c o n n e c t e d ideas, may n o t decay rapidly even s o m e t i m e after t h e instruction. In o t h e r words, t h e e x t e n t of t h e k n o w l e d g e store in m e m o r y may decrease relatively soon after t h e instruction, b u t t h e richness of k n o w l e d g e n e t w o r k s m a y r e m a i n in long-term m e m o r y and exhibit m o r e consistency.

S t u d e n t information processing strategies also s h o w e d s o m e interesting t r e n d s across t h e interviews. For e x a m p l e , t h e 'defin­ ing' m o d e of information processing was d e t e c t e d frequently during instruction ( m e a n = 0.64, 0.50, and 0.57 for t h e first t h r e e interviews respectively), b u t rarely used t w o m o n t h s after t h e instruction ( m e a n = 0 . 1 8 ) . A similar result was found for t h e use of t h e 'describing' m o d e w h i c h was t h e least used in t h e final interview. This suggests t h a t t h e lower-level information processing m o d e s such as 'defining' and 'describing' m a y b e m o r e frequently e x h i b i t e d during k n o w l e d g e construction b u t less prevalent in later recall. T h e s e categories m a y n o t b e e x h i b ­ ited in later recall narrative, b e c a u s e students, at this p o i n t of knowledge m a t u r a t i o n w i t h i n this particular d o m a i n of infor­ m a t i o n , use higher-level m o d e s in

organising knowledge, t h u s e n h a n c i n g t h e integrity of k n o w l e d g e n e t w o r k s and facilitating efficiency in informa­ tion retrieval and application. T h e increased o c c u r r e n c e of t h e 'inferring' a n d ' e x p l a i n i n g ' c a t e g o r i e s t h a t r e a c h e d a m a x i m u m t w o m o n t h s after t h e instruction appears t o s u p p o r t this conclusion. In particular, t h e use of 'explaining' increased as t h e instruc­ tion progressed, and its frequency in

Table 1 Student cognitive structure outcome and information processing modes across interviews (n = 28). First interview Mean (SD) [Range] Second interview Mean (SD) [Range] Third interview Mean (SD) [Range] Final interview Mean (SD) [Range] Linear linkages Recurrent linkages Defining Describing Comparing Inferring Explaining 5.14 (6.95) [ 1 - 3 4 ] 3.29 (5.59) [ 0 - 2 1 ] 0.64 (0.68) [ 0 - 2 ] 3.57 (4.84) [0 - 24] 0.18 (0.61) [ 0 - 3 ] 0.61 (1.34) [ 0 - 6 ] 0.14 (0.59) [ 0 - 3 ] 5.50 (6.71) [ 1 - 3 1 ] 4.64 (7.08) [0 - 26] 0.50 (0.88) [ 0 - 4 ] 3.71 (4.22) [ 0 - 1 8 ] 0.43 (1.00) [ 0 - 4 ] 0.68(1.39) [ 0 - 6 ] 0.21 (0.50) [ 0 - 2 ] 5.61 (4.86) [ 1 - 2 1 ] 4.54 (5.44) [ 0 - 2 3 ] 0.57 (0.79) [ 0 - 3 ] 3.54 (2.52) [ 1 - 1 1 ] 0.96 (1.99) [ 0 - 1 0 ] 0.32 (0.86) [ 0 - 4 ] 0.21 (0.69) [ 0 - 3 ] 5.18 (5.24) [0 - 22] 4.54 (7.20) [ 0 - 3 3 ] 0.18(0.39) [ 0 - 1 ] 3.04 (2.63) [ 0 - 1 2 ] 0.71 (1.33) [ 0 - 5 ] 0.79(1.73) [ 0 - 8 ] 0.50 (1.37) [ 0 - 5 ]

t h e final interview was m o r e t h a n d o u b l e t h e previous one (0.50 in t h e final interview versus 0.21 in t h e third interview). This indicated t h a t s t u d e n t s s e e m e d gradually to (re)construct their k n o w l e d g e frameworks t h r o u g h higher-order m o d e s of informa­ tion processing after instruction and, perhaps, these higher order m o d e s of representation h e l p e d t o increase t h e generalis-ability and inclusiveness of t h e information.

Table 2 presents t h e correlation coefficients among s t u d e n t cognitive s t r u c t u r e o u t c o m e s and information processing strate­ gies. T h e s e correlational analyses w e r e based on t h e research data gathered from t h e third interview. T h e third interview was c o n d u c t e d i m m e d i a t e l y after t h e instruction; hence, students w e r e likely t o have t h e richest store of available knowledge and t h u s sufficiently varied information in their recall narratives to s u p p o r t a r o b u s t correlation analysis. Table 2 shows t h a t t h e e x t e n t of s t u d e n t cognitive structures (linear linkages) was sig­ nificantly correlated w i t h all m o d e s of information processing. This suggests t h a t t h e e x t e n t of available knowledge during recall is an i m p o r t a n t c o n c o m i t a n t variable in supporting a vari­ ety of information processing strategies. T h e n u m b e r of recur­ r e n t linkages, a major indicator of networking in recalled knowledge, was significantly correlated with t h e use of 'describ­ ing', 'comparing', 'inferring', and 'explaining', b u t n o t 'defin­ ing'. Moreover, a m o n g these correlations, t h e coefficient was relatively low b e t w e e n r e c u r r e n t linkages and 'describing'. This m a y imply t h a t t h e richness of information n e t w o r k linkages in cognitive structures (recurrent linkages) is m o r e likely t o be

Table 2 The relationships between cognitive structure outcomes and information processing modes based on the data gathered from the third interview (n = 28).

Linear linkages

Recurrent linkages

Defining Describing Comparing Inferring

Recurrent linkages Defining Describing Comparing Inferring Explaining 0.93** 0.43* 0.77** 0.65** 0.83** 0.85** 0.33 0 . 5 5 " 0 . 8 3 " 0.75** 0.81** 0.31 0.13 0.21 0.10 0.09 0 . 5 3 " 0.53** 0.50* 0.60* 0.94** *p < 0.05, " p < 0.01

Q

Cognitive structure development Tsai and Huang Interview I to 2 Stage Stage feature Knowledge development Both the extent and the richness of cognitive structures increase. related to higher-level m o d e s of

information processing. T h a t is, t h e n u m b e r of r e c u r r e n t linkages could be a good predictor in explaining s t u d e n t use of higher-level i n f o r m a t i o n p r o c e s s i n g strategies, such as 'inferring' a n d 'explaining'. Table 2 also shows t h a t t h e use of 'defining' was n o t significantly related to t h e use of

other information processing modes. However, s t u d e n t s w h o m o r e frequently phrased their ideas in t h e m o d e of 'explaining' tended t o use 'describing', ' c o m p a r i n g ' , and 'inferring' m o r e fre­ quently. This suggests t h a t t h e u s e of 'explaining' m a y m u t u a l l y enhance t h e use of o t h e r information processing strategies.

Discussion and educational implications

Based on the flow m a p analyses of the fifth grade students' narra­ tives, this study showed that students' knowledge storage decreased two months after instruction; however, the richness, or degree of interconnection of knowledge during recall, did not show a similar decline. Teachers should encourage students to make connections between concepts to stabilise as m u c h information as possible while supporting the higher order information processing modes as described later. T h e decrease in linear linkages found in later inter­ view data, coupled with almost no change in t h e n u m b e r of recur­ rent linkages, also suggested that students seemed to build u p m o r e integrated conceptual frameworks after d i e instruction.

C o n t e n t analyses of student information processing strategies showed that students' lower-level modes of information process­ ing decreased and higher-level modes increased as instruction pro­ gressed and also in t h e interval after instruction. In particular, t h e highest mode, 'explaining', was used most in t h e final interview (i.e., t w o m o n t h s after t h e instruction), while t h e lowest mode, 'defining', was rarely found in t h e final interview. This m a y imply that students tended gradually to refine their knowledge struc­ tures by a series of reformulations involving use of explanations, principles, and generalisations, b u t with less emphasis on defini­ tions or descriptions. This refinement m a y help students to organ­ ise t h e concepts m o r e effectively, and reduce cognitive load w h e n retrieving or applying these concepts. This interpretation is also consistent with t h e previously stated finding t h a t students t e n d e d to construct m o r e integrated knowledge frameworks in t h e weeks following instruction. T h e use of higher-level information p r o ­ cessing strategies and t h e increase

in networking connections a m o n g existing concepts may mutually reinforce one another and, at t h e same time, help t o refine or con­ dense t h e body of knowledge, therefore, in turn, yielding a m o r e integrated body of knowledge in memory. Hence, biology teachers are encouraged to p r o m o t e stu­ d e n t s ' higher-order cognitive operations. Tsai (2001) has sug­ gested that t h e use of Prediction-Observation-Explanation ( P O E ) instructional activities, Socratic dialogues, and interactive

ques-Table 3 A model of the processes of student cognitive structure development.

Interview 2 to 3 Interview 3 to 4

Knowledge extension The extent of cognitive structures keeps increasing; however, the richness and the use of high-order information processing modes do not necessarily increase.

Knowledge refinement The extent of cognitive structures decreases, while their richness remains stable. The use of higher-order information processing modes increases dramatically.

tioning may b e useful for enhancing students' information p r o ­ cessing levels.

T h e data gathered from this study suggest a three-stage m o d e l for t h e acquisition of science knowledge, at least as e x h i b i t e d w i t h this particular learning situation. T h e s e stages are ' k n o w l e d g e d e v e l o p m e n t ' , ' k n o w l e d g e e x t e n s i o n ' , a n d 'knowledge r e f i n e m e n t ' as s h o w n in Table 3, a n d further illus­ trated in Figure 5. In t h e first stage, b o t h t h e e x t e n t and t h e richness of cognitive s t r u c t u r e s increase; t h a t is, t h e k n o w l e d g e storage a n d connections a m o n g c o n c e p t s are developed. In t h e second stage, only t h e e x t e n t of knowledge in cognitive struc­ t u r e s keeps increasing; however, t h e richness of i n t e r c o n n e c ­ tions and t h e use of higher-order information processing m o d e s do n o t necessarily increase. Therefore, in this stage, t h e m a i n focus of k n o w l e d g e construction is a p p a r e n t l y an extension of t h e existing b o d y of knowledge. In t h e final stage, w h i c h m a y occur s o m e t i m e after t h e instruction, t h e e x t e n t of information recalled decreases, w h i l e t h e richness of i n t e r c o n n e c t i o n s in t h e n e t w o r k e d k n o w l e d g e remains stable. A t t h e s a m e time, t h e use of higher-order information processing m o d e s increases d r a m a t ­ ically. Students, in this stage, m a y refine their knowledge struc­ t u r e s i n t o m o r e i n t e g r a t e d f r a m e w o r k s t h r o u g h m o r e sophisticated cognitive operations. In o t h e r words, t h e rich con­ nections b e t w e e n c o n c e p t s and t h e use of higher-order informa­ tion processing strategies facilitate t h e m a t u r a t i o n of k n o w l e d g e reconstruction and refinement. ( O r vice versa, t h a t is, t h e m a t ­ u r a t i o n of k n o w l e d g e r e c o n s t r u c t i o n a n d r e f i n e m e n t m a y e n h a n c e t h e connections a m o n g existing c o n c e p t s a n d t h e use of higher-order information processing.) This m o d e l is based on t h e research data collected b y this study and, clearly, m o r e research is necessary to e x a m i n e t h e generalisability of this m o d e l . Nevertheless, this m o d e l gives e d u c a t o r s s o m e clues a b o u t t h e processes a n d m e c h a n i s m of s t u d e n t knowledge d e v e l o p m e n t in science, especially at an early age w h e n i m p o r

-6 5 4 3 2 1 0

Interview 1

h « —

Interview 2

—■*+«

Interview 3

— ► H —

Interview 4

► | Stage of Knowledge

I

Development

II

Extension

III

Refinement

Figure 5 The stages of knowledge acquisition suggested by the study.

• Explaining

♦ Linear linkages ■ Recurrent linkages

I j Cognitive structure development

t a n t k n o w l e d g e structures and orientations t o w a r d science are being c o n s t r u c t e d by t h e learner.

T h e correlation analysis b e t w e e n cognitive s t r u c t u r e o u t ­ comes and information processing strategies also revealed t h a t an a d e q u a t e b o d y of i n t e r c o n n e c t e d k n o w l e d g e and a variety of information processing strategies m a y m u t u a l l y reinforce o n e another. S t u d e n t s ' use of 'explaining' was also strongly related t o t h e n u m b e r of linear linkages and r e c u r r e n t linkages, and their use of 'inferring'. This implies t h a t t h e use of 'explaining' m a y b e d e v e l o p m e n t a l l y linked t o t h e richness of intercon­ n e c t e d ideas in cognitive s t r u c t u r e during s h o r t t e r m learning experiences and may b e dynamically linked to o t h e r higher-level information processing strategies as t h e learners reconstruct and solidify information in m e m o r y .

This study also suggests s o m e research issues for further exploration. For example, it may b e interesting to explore t o w h a t e x t e n t did t h e s t u d e n t s recall t h e information in a s e q u e n c e t h a t was c o m p a r a b l e t o t h e s e q u e n c e of instruction by t h e t e a c h e r across t h e t h r e e weeks. In addition, m o r e research w o r k can be c o n d u c t e d to see w h e t h e r s t u d e n t s w h o e x h i b i t greater evidence of i n t e r c o n n e c t e d t h o u g h t and use of higher-order cognitive operations s e q u e n c e d their t h o u g h t s in a differ­ e n t way from o t h e r students.

In conclusion, this study s h o w e d s o m e evidence t h a t e l e m e n ­ tary school students, w h o learned a b o u t biological r e p r o d u c ­ tion, gradually d e v e l o p e d m o r e integrated knowledge structures as r e p r e s e n t e d by recall narrative, w h i c h w e r e also a c c o m p a n i e d by evidence of higher-level m o d e s of information processing. This study also d e m o n s t r a t e s t h a t t h r o u g h t h e use of t h e flow m a p m e t h o d , biology teachers can assess s t u d e n t cognitive structures and information processing orientations, and use such information t o identify t h e cognitive d e v e l o p m e n t , m i s c o n c e p ­ tions, strengths, and weaknesses of each s t u d e n t ' s k n o w l e d g e g r o w t h within a specific scientific topic. T h e findings derived from this study also suggest t h a t biology teachers n e e d t o encourage s t u d e n t s to use higher-level information processing and, concurrently, t o develop richer and m o r e integrated knowl­ edge frameworks during biology instruction.

Acknowledgment

This research work was supported, in part, by funds from National Science Council, Taiwan, under grants NSC 89-251 l-S-009-027 and NSC 90-251 l-S-009-001. The authors also express their gratitude to two anonymous referees for their helpful comments in the further development of this paper.

References

Anderson O R (1992) Some interrelationships between constructivist models of learning and current neurobiological theory, with

implica-Tsai and Huang tions for science education. Journal of Research in Science Teaching, 29, 1 0 3 7 - 1058.

Anderson O R and Demetrius O J (1993) A flow-map method of rep­ resenting cognitive structure based on respondents' narrative using science content. Journal of Research in Science Teaching, 30, 953 - 969. Anderson O R, Randle D, and Covotsos T (2001) The role of ideational

networks in laboratory inquiry learning and knowledge of evolution among seventh grade students. Science Education, 85, 410 - 425. Bahar M, Johnstone A H, and Suttcliffe R G (1999) Investigation of stu­

dents' cognitive structure in elementary genetics through word asso­ ciation tests. Journal of Biological Education, 33, 134 - 141. Bischoff P J and Anderson O R (2001) Development of knowledge

frameworks and higher order cognitive operations among secondary school students who studied a unit on ecology. Journal of Biological

Education, 35, 81 - 88.

Bodner G M (1986) Constructivism: a theory of knowledge. Journal of

Chemical Education, 63, 873 - 878.

Howard R (1988) Schemata: Implications for teaching science.

Australian Science Teachers Journal, 34, 29 - 34.

Preece P F W (1976) Mapping cognitive structure: A comparison of methods. Journal of Educational Psychology, 68, 1 - 8.

Shavelson R J (1974) Methods for examining representations of a sub­ ject-matter structure in a student's memory. Journal of Research in

Science Teaching, 11, 231 — 249.

Tsai C-C (1998a) An analysis of Taiwanese eighth graders' science achievement, scientific epistemological beliefs and cognitive struc­ ture outcomes after learning basic atomic theory. International Journal

of Science Education, 20, 413 - 425.

Tsai C-C (1998b) Science learning and constructivism. Curriculum and

Teaching, 13, 31 - 52.

Tsai C-C (1999a) Content analysis of Taiwanese 14 year olds' informa­ tion processing operations shown in cognitive structures following physics instruction, with relations to science attainment and scientific epistemological beliefs. Research in Science and Technological

Education, 17, 125 - 138.

Tsai C-C (1999b) Overcoming junior high school students' misconcep­ tions about microscopic views of phase change: A study of an analogy activity. Journal of Science Education and Technology, 8, 83 - 91. Tsai C-C (2000) The effects of STS-oriented instruction on female

tenth graders' cognitive structure outcomes and the role of student scientific epistemological beliefs. International Journal of Science

Education, 22, 1099 - 1115.

Tsai C-C (2001). Probing students' cognitive structures in science: The use of a flow map method coupled with a meta-listening technique.

Studies in Educational Evaluation, 27, 257 - 268.

Wandersee J H, Mintzes J J, and Novak J D (1994) Research on alter­ native conceptions in science. In Handbook of Research on Science

Teaching and Learning, Ed. Gabel D L. pp. 177 - 210. New York,

USA: Macmillan..

West L H T and Pines A L (Eds.) (1985) Cognitive structures and con­

ceptual change. Orlando, FL, USA: Academic Press.

Chin-Chung Tsai and Chao-Ming Huang work in the Centre for Teacher Education, National Chiao Tung University, 1001 Ta Hsueh Rd, Hsinchu 300, Taiwan. Tel. + 886 3 5731671; Fax. + 886 3 5738083; Email: cctsai@cc.nctu.edu.tw