Educational Research Journal (~1f~1E~~llJ, Vol. 14, No.2, Winter 1999

©Hong Kong Educational Research Association 1999

Cooperative CBI: The Effects of Heterogeneous versus Homogeneous Grouping, Student Ability and Learning Accountability on Achievement

Hong Kian-sam Universiti Malaysia Sarawak

This study investigated the effects of cooperative group composition, stu­

dent ability, and learning accountability on achievement during computer­

based instruction. A total of 94 students aged between 14 to 15 years were

randomly assigned to heterogeneous and homogeneous dyads. Groups were

also assigned as having group or individual accountability for mastery of

lesson content. Cooperative dyads completed lessons on simple transfor­

ma~ional geometry using a computer microworld. Students completed a post­

test five days later. There was an interaction effect between group composi­

tion and students' ability. Low ability students peiformed better in hetero­

geneous than in homogeneous groups. High ability students performed

slightly better in homogeneous than in heterogeneous groups. No signifi­

cant difference was found between individual and group accountability

groups.

Key words: cooperative learning; computer-based instruction;

mathematics achievement

Correspondence concerning this article should be addressed to Hong Kian-sam,

School of Education, University of Otago, P. 0. Box 56, Duredin, New Zealand.

302 Hong Kian-sam

Introduction

One frequently cited benefit of computer-based instruction (CBI) is the po­

tential to individualise instruction according to the needs of the learning

task, processing requirements and the current performance of the learner.

However, the costs of providing uniquely adaptive lessons delivered via

individual computers for each student are often prohibitive. Furthermore

the learning environment of such a learning scenario is inherently limited to

those strategies, explanations, and resources directly under computer control.

Students are not able to receive the varied explanations of their peers nor

gain the cognitive benefits associated with teaching among peers (Bargh &

Schul, 1980). Students who work individually for extended periods also

tend to become lonely, bored, or frustrated, resulting in lower achievement

motivation and a sterile and impersonal learning environment.

Educators interested in implementing CBI in education are concerned

with identifying models that maximise learning. One model that has gained

much attention involves the use of cooperative learning (Carrier & Sales,

1987; Johnson & Johnson, 1986; Johnson, Johnson & Stanne, 1985;

Meevarech, Stem & Levita, 1987; Webb, Ender & Lewis, 1986). To many,

cooperative learning has both strong intuitive appeal and compelling practi­

cal significance. The limited availability of computers in the classroom of­

ten mandates the use of a group model (Hannafin, Dalton & Hooper, 1987).

In most cases, individual learning at the computer may be both unnec­

essary and unwise (Hooper & Hannafin, 1988). That cooperative learning

methods can overcome many of the potential pitfalls of isolation while im­

proving students' achievement has been validated for CBI (Dalton, Hannafin,

& Hooper, 1989; Johnson, Johnson, & Stanne, 1985, 1986). Johnson and

Johnson (1989), in reviewing 180 studies comparing the achievement re­

sulting from cooperative versus individual learning, found an effect size of

0.66 in favour of cooperative methods.

Cooperative learning involves the selection of a number of students

(between two and five) to work in groups. The question of interest to educa-

Cooperative CBI 303

tors then is how should these cooperative groups be formed? How should

learners of varying abilities be grouped to maximise the benefits of coop­

erative grouping? A description of the learning phases, proposed by

Rummelhart and Norman (1978), may help to predict an effective model of

cooperative learning. They characterised learning as a process during which

the learner passes through three stages of understanding. In the first stage,

"accretion", the learner is able to discriminate between examples and non­

examples, but is unable to apply knowledge to new situations or provide in­

depth explanations. During the second stage, "restructuring", the learner

can transfer some learning but is still unable to provide deep understanding.

At the final stage, the learner enters the highest level of learning, "tuning",

and is able to solve novel problems, to work effectively under stress and to

provide deep explanation.

Based on this model, cooperative learning advocates typically recom­

mend that students are grouped heterogeneously, that is, group composition

is manipulated to include students with diverse experiences. Heterogeneous

grouping is encouraged for both affective and cognitive considerations. Stu­

dents encounter wider diversity in heterogeneous than in homogeneous

groups. Thus, heterogeneous grouping is more likely to improve inter-per­

sonal attraction among group members and help dismantle social barriers

(Johnson & Johnson, 1989). Heterogeneous ability grouping benefits both

high and low ability students. Less able or disadvantaged students receive

more instructional support and regulation from their partners than from the

classroom teacher, are more actively involved, and may observe their part­

ners' learning strategies (Swing & Peterson, 1982). Furthermore, low abil­

ity students in homogeneous groupings are likely to flounder in an environ­

ment that requires group members to explain cognitive information.

Concurrently, more able students may also benefit cognitively from explain­

ing lesson concepts to their partners and from the opportunity to practise

important skills in both heterogeneous or homogeneous groups (Bargh &

Schul, 1980; Mayer, 1984).

304 Hong Kian-sam

Despite the potential social benefits, the cognitive effects of heteroge­

neous ability grouping have not been established. Some research indicates

that heterogeneous grouping of high and low ability students supports the

needs of one group at the expense of another. Beane and Lemke (1971)

found that heterogeneous ability grouping improved the achievement of the

most able group members at the expense of the least able. In contrast, Hooper

and Hannafin (1988) indicated that heterogeneous grouping increased the

achievement of low ability students by approximately 50% compared to

their homogeneously grouped peers. However, homogeneous grouping in­

creased the achievement of high ability students by approximately 12%

compared to their heterogeneously grouped counterparts. This suggests sig­

nificant payoffs for low ability students from heterogeneous groupings but

potential decrements in the performance of their high ability cooperative

learning partners.

The effectiveness of cooperative learning is often attributed to interac­

tion among group members (Webb, 1989), but little is known about the

relationship between intra-group interaction and achievement. Webb, Ender

and Lewis (1986) indicated that the nature of intra-group cooperation is

potentially of greater importance than group composition per se. It is im­

portant to determine how group composition influences intra-group inter­

action and to develop methods that promote successful interaction.

One method to promote interaction involves increasing individual

accountability, wherein each group member must demonstrate mastery of

content embedded in the instruction. Compared with deriving a "team

response", where less able students might simply defer to those who are

more able, or more able students may attempt to dominate, individual ac­

countability may promote superior interaction, qualitatively and

quantitatively. This method may be used to isolate and overcome potential

learning problems within a group and to provide an additional incentive to

cooperate (Hooper, Ward, Hannafin, & Clark, 1989). This method may re-

Cooperative CBI 305

duce the damaging "free rider" and "sucker" effects (Kerr, 1983; Kerr &

Bruun, 1983) by motivating more able group members to provide help, and

less able members to invest sufficient mental effort to master instruction.

Malaysian schools have an estimated enrolment of 5.8 million students

(Ministry of Education, 1997). Aiming for individualized CBI will be unat­

tainable and unrealistic, and as Hooper and Hannafin (1988) state, unneces­

sary and unwise. Cooperative CBI is an approach worth exploring to enable

Malaysian students to benefit from the use of computers in schools. In the

Malaysian educational setting, two papers that support the use of coopera­

tive learning and cooperative CBI were authored by Gan (1992, 1994). Gan

argued that the use of cooperative learning is suitable in the context of the

integrated curriculum practised in the Malaysian educational system and

the multiracial nature of Malaysian classrooms. Gan also successfully de­

veloped and used environmental education courseware for cooperative learn­

ing activities in Malaysian classrooms.

Purposes of Study

The purposes of this study were to examine (a) the effects of heterogeneous

and homogeneous group ability composition on achievement; and (b) the

effects of strategies requiring different levels of performance accountability.

The achievement and interaction of high and low ability students were com­

pared in heterogeneous and homogeneous groups featuring either individual

or group performance accountability. It was predicted that low ability stu­

dents would demonstrate higher achievement in heterogeneous than in ho­

mogeneous groups. High ability students in heterogeneous groups were pre­

dicted to demonstrate equal or better achievement as compared to those in

homogeneous group. It was also predicted that achievement would be higher

for students in individual accountability groups than for those in group ac­

countability groups.

306 Hong Kian-sam

Method

A sample of 94 Form Two students (aged 14 to 15 years) from an urban

school in Malaysia participated in the study. Only students with uniformly

high or low performances on both the Form One final examination

(mathematics test) and study pre-test were included. High ability students'

were defined as students having scores at above the 70th percentile for the

mathematics test in the Form One final examination and above the mean on

a pre-test specifically designed for the study; low ability students scored at

or below the 40th percentile and below the mean on the pre-test.

Materials

Measurement Instruments

The pre-test and post-test are the same measurement instrument but with

different sequencing of the test items. The measurement instrument com­

prised 30 multiple choice items on simple translation, reflection and rota­

tion in transformational geometry. The use of multiple choice items for trans­

formational geometry for students aged 14 to 15 years was supported by

Perham's (1978) research. The measurement instrument was modelled by

constructing a test specification table based on the Malaysian Lower Sec­

ondary Mathematics Syllabus. Face validity for the measurement instru­

ment was done by a mathematics education lecturer from SEAMEO

RECSAM (Regional Centre for Science, Mathematics and Technology

Education) and two practising mathematics teachers in the participating

school. The Cronbach Alpha reliability for the measurement instrument was

0.93.

Cooperation Training

Training was designed to facilitate effective intra-group interaction and

cooperation. The first training session emphasised peer awareness. Students

were introduced to the game "Broken Circles" (Cohen, 1986). Broken Circles

is a puzzle that cannot be completely solved unless students sacrifice indi-

Cooperative CBI 307

vidual success for the good of the group. During this training session, groups

of four to six members were formed. Each member was given an envelope

that contained pieces of a circle. None were given pieces that were initially

adequate to construct a complete circle, and the objective of this activity

was for every group member to create a circle. Interaction was limited. Stu­

dents were allowed to offer pieces, but talking was not permitted and taking

game pieces from other group members was forbidden.

The aim of the second training session was to promote oral

summarisation between group members. Students in dyads completed three

tasks involving identifying and summarising rules to a partner. The first

task required students to work together to learn a large number which repre­

sented the square of a series of natural numbers (e.g. 149,162,536 repre­

sents "1 ", "4", "9", "16", "25", "36" - the squares of the number 1 through

6). The second task required that students identify the number of rectangles

or squares embedded within a complex figure. Students were told to iden­

tify the rules that governed each task and then take turns summarising the

rules to each other. When a task was completed, students were asked to

explain the rules. Between each task, feedback concerning the appropriate­

ness and effectiveness of student behaviour was provided.

CBI Lesson Content

A computer microworld TRANSFORM which simulates the transforma­

tion geometry lesson was developed by the researcher. A microworld is a

computer-based learning environment that embodies mathematical concepts

in a context which is engaging to the learner and which allows a certain

degree of self-directed exploration or discovery of the implicit ideas and

processes (Edwards, 1985). TRANSFORM enables students to draw ob­

jects and perform simple transformations (i.e., translation, reflection and

rotation). Students view the results of their actions on the computer screen.

TRANSFORM was designed to fit the requirements of the Malaysian school

syllabus on transformational geometry for 14-to 15-year-old students in terms

of appearance, terminology and symbols. Working in dyads, students ex-

308 Hong Kian-sam

plored this microworld guided by simple cooperative-based worksheets

(Hong, 1996).

Design and Data Analysis

The study employed a 2 x 2 x 2 factorial design. The between subjects

factors included Ability (high, low); Cooperative Group Composition

(heterogeneous, homogeneous); and Accountability (group, individual). The

dependent measure, post-test scores were analysed through ANOVA pro­

cedures using a significant level of 0.05.

Procedures

The pre-test was administered to all potential students in the target school

to identify those with high or low mathematics ability. Students thus identi­

fied then completed three 30-minute training sessions during a two-day

period. Students were informed they would work in dyads. Using stratified

random sampling, heterogeneous and homogeneous ability groups were

established. Heterogeneous groups contained one high ability student and

one low ability student. Homogeneous ability groups contained two high

ability students or two low ability students. Each group was assigned to a

computer and completed either the group or individual accountability ver­

sion of the CBI lesson. Students from the individual accountability dyads

were each given quiz booklets to be completed without help from their

prutners; students in group accountability condition were given a single quiz

booklet to complete cooperatively. Students were allocated eight 40-minute

sessions to follow the instructions and practice segments of the lesson. Sub­

jects received the post-test five days after the completion of the CBI lessons.

Results

Post-test means and standard deviations for each treatment are shown in

Table 1. The results of the corresponding AN 0 VA are found in Table 2. The

overall post-test means of the high ability (24.604) and low ability (12.163)

Cooperative CBI 309

groups were significantly different, E(1,86) =811.942, 11 < 0.0005. The overall

post-test means of the heterogeneous (19.542) and homogeneous (17.225)

groups were significantly different, E(1,86) = 28.151,11 < 0.0005. No sig­

nificant differences were found for responsibility, .E(l,86) = 0.499, 11 = 0.

482.

Table 1 Post-test means and standard deviations

Ability Accountability Homogeneous Heterogeneous Total

High IRM 25.250 24.000 24.625

SD 2.4921 2.000 2.246

(n) 12 12 24

GR M 24.750 24.417 24.583

SD 1.658 1.677 1.668

(n) 12 12 24

Total M 25.000 24.208 24.604

SD 2.075 1.839 1.957

(n) 24 24 48

Low IRM 9.000 14.667 11.833

SD 1.954 1.875 1.915

(n) 12 12 24

GRM 9.900 15.083 12.492

SD 3.348 1.621 2.485

(n) 10 12 22

Total M 9.450 14.875 12.163

SD 2.651 1.748 2.199

(n) 22 24 46

Overall Total M 17.225 19.542 18.383

SD 2.363 1.793 2.078

46 48 94

IR: Individual Responsibility GR: Group Responsibility

A significant interaction effect was detected between student ability

and type of grouping E(1,86) = 50.678, 11<0.00005. Follow-up contrast re-

vealed that the mean post-test scores of low ability students in heteroge-

neous groupings (mean= 14.875) was significantly higher than those in

homogeneous groupings (mean= 9.450); nonetheless the mean post-test

310 Hong Kian-sam

scores for high ability students in heterogeneous groupings (mean= 24.

208) was not significantly different from those in homogeneous groupings

(mean= 25.000).

No other significant differences were found for other levels of interaction,

i.e., ability x responsibility, E(l ,86) = 0.643, n. = 0.425; group x

responsibility, E(l,86) = 0.062, n. = 0.805; and ability x group x

responsibility, E(1,86) = 0.643, IL= 0.425.

Discussion

The predicted interaction between ability and group composition was

significant. Ability grouping appears to influence achievement. Learning

was most efficient for homogeneously grouped high ability students and

least efficient for homogeneously grouped low ability students; apparently

low ability students benefited from, but slightly slowed, the progress of

high ability students. These findings tend to support previous cooperative

learning studies that cooperative learning poses little risk to more able tu­

tors (Hopper & Hannafin, 1988).

In this study, students who collaborated on the quizzes did not score

higher on the post-test than those who completed the quizzes individually.

This finding suggests that the "free rider" effects, which often occur in group

learning, were absent in this study.

Recommendations for Future Research

Four recommendations for future research should be noted. First, group

learning was not compared to individualised instruction in this study. Fu­

ture research should include control groups to compare the effects of ability

grouping across groups and individual treatments. Second, findings from

this group may not be generalised to larger groups. Free-riding is more apt

to occur when groups include more than two persons; thus the issue of so­

cial dilemmas may be more important in larger groups. Researchers should

also examine whether free-riding will be more prevalent during longer treat-

Cooperative CBI 311

ments as free-rider effects may be less prevalent during a short experimen­

tal study due to novelty effects. Thirdly, in this study heterogeneous groups

consist of high and low ability students. Controversy and argumentation

increase as intra-group heterogeneity increases (Johnson & Johnson, 1989).

The results may not be generalisable to other kinds of heterogeneous groups,

i.e., groups containing students of high and average abilities, average and

low abilities, or high and low abilities. Further research is needed to exam­

ine the effects of these group compositions. Finally, what are the precise

cooperative processes during the cooperative CBI: What do students really

do in groups? Do their behaviours differ depending on their partner's ability?

These questions can only be answered if further research involving video

data is carried out.

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