effects of cooperative incentives and heterogeneous arrangement on achievement and interaction of...

JOURNAL OF RESEARCH IN SCIENCE TEACHING VOL. 32, NO. 3, PP. 291-299 (1995)

Effects of Cooperative Incentives and Heterogeneous Arrangement on Achievement and Interaction of Cooperative Learning Groups

in a College Life Science Course

Scott B. Watson

Department of Science Education, East Carolina University, Greenville, North Carolina 2 7858-4353

James E. Marshall

Department of Curriculum, Teaching, and Educational Technology, California State UniversiQ, Fresno, Fresno, California 93740-0002

Abstract

The purpose of this study was to examine the importance of cooperative incentives and heterogeneous grouping as elements of cooperative learning in a college life science course. Cooperative learning may be defined as a classroom learning environment in which students work together in heterogeneous groups toward completion of some task. Cooperative incentive structures provide some type of group reward based on group products or individual learning. In heterogeneous grouping, students are arranged in order to maximize variety within groups. A 2 X 2 design was utilized in this study. The independent variables considered included (a) use of cooperative incentives in learning groups, and (b) use of heterogeneous grouping in cooperative learning groups. Dependent variables for all treatment groups were scores from a multiple-choice instrument developed for an earlier, related study, along with direct observational data on frequency of cooperative interactions. Analysis of covariance (ANCOVA) was used as the data analysis procedure for the achievement portion of the study, and analysis of variance (ANOVA) was used for analysis of the cooperative interaction portion of the study. No significant differences were found between the treatment groups.

Cooperative learning may be defined as a classroom learning environment in which students work together in heterogeneous groups toward completion of a common goal. Cooperative learning may be especially important in the teaching of science, in part because of the preva- lence of grouping for lab instruction in science, and in part because science in actual practice involves working with others collaboratively (R. Johnson, D. Johnson, Scott, & Ramolae, 1985). A great deal of research evidence has been collected over the years in the area of cooperative learning, and much of the evidence points to the effectiveness of these techniques for improving academic achievement (D. Johnson & R. Johnson, 1989; Slavin, 1984; Watson, 1991). Humphreys, R. Johnson, and D. Johnson (1982) had a group of teachers utilize the cooperative, competitive, and individualistic approaches in science classrooms. Their study involved 44 ninth-grade students: The cooperative students were instructed to work together as a

0 1995 by the National Association for Research in Science Teaching Published by John Wiley & Sons, Inc. CCC 0022-4308/95/030291-09

292 WATSON AND MARSHALL

group; the competitive students were told to try to outperform each other; and the individualistic students were instructed to work alone. The researchers found significantly greater performance among the cooperative group as compared to the others in both immediate achievement and retention, and the students’ attitudes toward the approaches favored the cooperative approach. Okebukola (1985) made comparisons in science classrooms of a pure cooperative approach, a cooperative-competitive approach, and pure individual competition. Okebukola’s study involved 630 eighth-grade students. Students in the cooperative-competitive groups registered significantly larger gains than the others, followed by the cooperative groups, and the competitive students. Tingle and Good (1990) examined the effect of cooperative groups heterogeneously based on proportional reasoning ability on problem solving in high school chemistry classes. No significant differences were found between students who problem solved in cooperative groups or individually. However, results of that study, which included 178 students, did indicate that the students and teachers enjoyed the cooperative learning strategy.

Several specific elements of cooperative learning, including cooperative task structures, cooperative incentive structures, individual accountability, and heterogeneous grouping, may be necessary for maximizing achievement in cooperative learning situations. Cooperative task structures are situations in which 2 or more students are encouraged or required to work together toward completion of some task. To complete the task, group members must coordinate their efforts. Cooperative learning as used in the classroom always includes a cooperative task structure (Slavin, 1986). Two differing task structures are commonly used: task specialization and group study. In task specialization, each group member is given responsibility for a unique part of the activity. In group study, all members of a group work together and do not have separate responsibilities.

Cooperative incentive structures provide some type of group reward based on group products or individual learning (Slavin, 1983b). The use of a cooperative incentive structure has generally been shown to have positive effects on achievement (Sherman, 1989), and research findings indicate that group work that does not include a cooperative incentive does not have significant positive effects on achievement (Slavin, 1984, 1991). Results from a cooperative learning study by Hulten and DeVries ( 1976) involving 299 seventh-grade mathematics students indicated the importance of cooperative incentives for increasing achievement. In a study that included 125 sixth- and seventh-grade mathematics students, Hooper and Hannafin (1991) found that students in a group accountability condition cooperated more frequently than students in an individual accountability condition ( F = 18.29, p < .OOl). However, they did not find a statistically significant difference in terms of achievement between group accountability and individual accountability conditions ( F = 3.33, p < .071). Webb (1982) indicated that results of studies which compared the group reward for group work condition to the individual learning condition show more peer tutoring and on-task behavior in the group reward condition. Webb and Lewis (1988) indicated that the frequency and type of cooperative interaction within a group may significantly influence the effectiveness of cooperative learning.

Individual accountability is a method of evaluation by which the learning of each individual student is monitored. According to D. Johnson and R. Johnson (1987), one of the purposes of cooperative learning or any other instructional method is individual mastery of the learning material. Individual accountability appears to be necessary to maximize learning in a cooperative learning situation (Slavin, 1987). There seems to be general agreement among researchers that individual accountability is essential if cooperative learning is to increase achievement.

Heterogeneous grouping of students in cooperative learning is so commonly accepted that it is often included as part of the definition of cooperative learning. Evidence has shown that although cooperative groups are normally heterogeneously arranged, traditional learning groups

COOPERATIVE INCENTIVES AND HETEROGENEOUS GROUPINGS 293

are typically homogeneous (Hooper & Hannafin, 1991; D. Johnson & R. Johnson, 1987). Virtually all of the cooperative learning methods developed in the 1970s utilized heterogeneous grouping (Slavin, 198 1). In heterogeneous grouping, students are assigned in order to maximize variety within groups using factors such as ability or achievement, sex, racial o r ethnic back- ground, age, attitude toward subject matter, and leadership ability. Although heterogeneous grouping is almost universally utilized with cooperative learning, there is little research evidence on its effectiveness. Okebukola and Ogunniyi (1984) conducted a study involving 1,025 science students in which one of the hypotheses dealt with achievement of students in heterogeneous learning groups as compared to homogeneous high, medium, and low ability groups. Results of the study indicated that the high ability groups had the highest achievement, followed by the heterogeneous groups and by the medium ability and low ability groups. However, differences in achievement of the groups were analyzed using an analysis of variance (ANOVA) of the posttest scores, so it should be expected that the high ability students would score highest. In a study involving high and low ability eighth-grade mathematics students, Hooper and Hannafin (1988) found that the use of heterogeneous grouping increased achievement of low ability students by approximately 50% compared to low ability homogeneously grouped students. They also found that high ability heterogeneously grouped students scored approximately 12% lower than homogeneously grouped high ability students. In a later study (Hooper & Hannafin, 1991), it was found that low ability students in homogeneous groups interacted less than in any of the other possible grouping arrangements. This supports the contention by Webb and Lewis (1988) that the effectiveness of cooperative learning may be attributed to interaction among group members. One of the dangers of heterogeneous grouping is that the contributions of low achievers will be somewhat limited, leading to resentment among the high achievers (Slavin, 1981). There is some evidence of this resentment. A study by Engelhard and Monsaas (1989) was designed to determine the attitude of varied ability levels of third, fifth, and seventh graders toward cooperative learning. Findings indicated that the high ability students had a poor attitude toward group work. Some researchers recommend that a slightly different structure for groups is needed in which only two levels of ability are included. This is due to a tendency for high ability students to help the lowest ability students in their groups, but not necessarily those in the middle (Webb, 1985).

Purpose of the Study

There has been a great deal of research completed in the area of cooperative learning over the last 100 years, and there is considerable evidence for effectiveness of these techniques in improving academic achievement. There has been little research, however, on the importance of the individual components or elements of cooperative learning. The purpose of this study was to try to clarify the importance of the various elements of cooperative learning. The specific elements that were experimentally manipulated include heterogeneous grouping and cooperative incentives. A cooperative task structure (task specialization) and individual accountability were also built into this study, but were not manipulated in the different experimental groups. Both of these elements have been shown through previous research to be important elements of cooperative learning (D. Johnson & R. Johnson, 1987; Slavin, 1986, 1987, 1991), and excluding either of them in any of the treatment groups would have probably limited achievement.

Specific research hypotheses for this study are as follows:

I . Achievement of students in groups that receive cooperative incentives based on achievement will be significantly higher than achievement of students in groups that do not receive cooperative incentives.


2. Achievement of students who are placed in heterogeneous learning groups will be significantly higher than achievement of students who are pIaced in homogeneous learning groups.

3. Achievement of students who are placed in heterogeneous learning groups and receive cooperative incentives will be significantly higher than achievement of students in the following treatment groups: (a) students in homogeneously arranged learning groups that use cooperative incentives; (b) students in heterogeneously arranged groups that do not utilize cooperative incentives; and (c) students in homogeneous learning groups that do not utilize cooperative incentives.

A further objective of this study was to determine if any major differences existed in the frequency of cooperative interactions within groups in each treatment condition. Cooperative interactions are defined for this study as any verbal or written communication directly related to the topic being covered. Based on the limited research evidence, research Hypotheses 4, 5, and 6 addressing the frequency of cooperative interactions would reflect the same variations as postulated in the hypotheses for achievement (Hypotheses 1, 2, and 3).

Sample

A total of 116 students from three classes of an introductory life science course for elementary education majors at East Carolina University in Greenville, North Carolina were included in this study. Although this study could have been completed using elementary- or secondary-aged students as subjects, the fact that little cooperative learning research has involved college students made this sample particularly interesting. Approximately 90% of the students in the sample were female, and approximately 80% were White. The ages of students taking part in the study ranged from 19 to 32 years. Due to a possible test-ceiling effect, scores of 7 students who scored over two standard deviations above the pretest mean were eliminated from the data set, leaving 109 subjects in the sample.

The experimental portion of this study took place during March and April, 1990. The pretest was given 2 days before the treatment began, and the posttest was given 2 days after the treatment ended.

Instrumentation

Dependent variables for all treatment groups were scores on a 50-item multiple-choice achievement test developed for an earlier, related study (Watson, 1991). Content for this instrument was based on general ecology topics covered in most general biology courses. The instrument was determined by three experts in the field of biology education to exhibit content validity using a technique developed by Hambleton and associates (cited in Martuza, 1977). Validators further classified items as being recall items, application items, or problem-solving items, and also classified all items as covering process skills or content information. Internal consistency of the instrument was determined to be .90 using Kuder-Richardson’s Formula 20. The same instrument, with questions in a different order, was used for both the pretest and posttest.

Design and Procedure

A 2 x 2 analysis of covariance (ANCOVA) design was utilized for this study. Independent variables included (a) use of cooperative incentives in cooperative learning groups, and (b) use

COOPERATIVE INCENTIVES AND HETEROGENEOUS GROUPINOS 295

Grouping Heterogenous Homogeneous

Cooperative/lndividual

Individual Only Incentives

Figure I. Factorial Design Showing Treatment Groups.

of heterogeneous grouping in cooperative learning groups. As part of the ANCOVA procedure, the effect of each variable was considered alone and in interaction with the other independent variable. Specific treatments are shown in the in Figure 1. All four treatments included eight groups of students. Group size was either 3 or 4 students, with an approximately equal distribu- tion of three and four member groups in each treatment condition. All groups used the same learning materials during the treatment period, which lasted 4 weeks. Materials utilized were cooperative learning packets on ecological topics from the Group Educational Modules (GEM) program, based at the University of Florida and directed by Parker Small, Jr. Group Educational Modules are self-instructional packets of materials designed for use with groups of biology students. Individual packets include a data pack, a group report, and a scenario in which each group member plays a different role. The GEM program is similar to other cooperative learning approaches, and is based loosely on Aronson’s (1978) “Jigsaw Classroom”. GEM materials were chosen for use in this study in order to insure that all treatment groups would be exposed to the same content information. Specific topics covered included adaptations to the environment, relationships between humans and nature, and problem solving as related to biology. All students practiced the cooperative learning approach used in the packets by completing a similar packet before the treatment began.

Students were pretested before the treatment began. Each student was then randomly assigned to either the heterogeneous or homogeneous group structure using the following procedure: Students in each class were arranged, in order, from highest to lowest pretest score. The 1st student on the list was assigned, at random, to either the heterogeneous or homogeneous condition. The 2nd student on the list was assigned to the opposite condition. This process continued until all students were assigned to a treatment condition. Each group included 3 or 4 students. Heterogeneous groups were arranged using a procedure developed by Slavin (1983a) in which each group included a high achiever, a low achiever, and one or two in between. Homogeneous groups were made up of students who had similar pretest scores, which resulted in high achievement, low achievement, and medium achievement groups. After the groups were arranged, they were assigned, at random, to utilize either group incentives along with individual incentives, or individual incentives alone. Students in the group incentive treatment groups were assigned grades for both their individual test scores and for their group mean. (The actual score recorded was the mean of the individual and group scores.) Students in the individual incentive condition received only individual test scores.

The first treatment condition consisted of students who were placed in heterogeneous learning groups and received cooperative incentives (along with individual incentives). In the second treatment condition, students were placed in heterogeneous learning groups but received only individual incentives. The third treatment condition consisted of students who were placed in homogeneous learning groups and received both cooperative and individual incentives. The fourth treatment condition was made up of students who were placed in homogeneous learning groups and received only individual incentives.


Table 1 Meuns and Standard Deviutions j iw Treatment Groups (Achievement)

~~

Treatment Pretest Posttest

M SD M SD

I . Heterogeneousicooperative incentive 35.55 I .88 40.14 I .67 2. Heterogcneousiindividual incentive 36.03 1.62 40.30 1.61 3. Hornogeneous/cooperativc incentive 35.74 4.25 40.13 3.74 4. Homogeneousiindividual incentive 35.79 4.89 40.86 2.78

Results

The unit of analysis for this study was each of the 32 cooperative groups of students. Means for the pretest and posttest for each of these groups were calculated and served as the basis for statistical analysis. Means and standard deviations for each treatment group are shown in Table 1.

Results of the ANCOVA are shown in Table 2. Sources of variance include incentives (group or individual), grouping (heterogeneous or homogeneous), Grouping x Incentives (interaction effect), and the covariate (pretest).

Overall, the first three research hypotheses were rejected due to lack of statistical signifi- cance. However, meaningful trends in learning did occur. With an overall pretest mean of 35.8 and an overall posttest mean of 40.4, groups gained 4.6 points following treatment. A t test revealed this to be a statistically significant gain, t (107) = 8.64, p < .OS. Table 3 shows posttest means and gain scores for visual comparison.

In order to determine if there were any major differences in the interaction patterns of students in the different treatment conditions, groups were observed to determine the number of cooperative interactions. Cooperative interactions were defined as any verbal or written communication directly related to the topic being covered. Two observers were trained for this purpose, and in 10 instances they observed the same groups at the same time. In these 10 cases, the observers were in complete agreement as to the number of cooperative interactions occurring.

Each group of students was observed three times for a period of 5 min. A mean number of interactions per 5-min period was then determined for each group. Results are shown in Table 4. An analysis of variance (ANOVA) was utilized to determine if any statistically significant differences existed between treatment groups in terms of cooperative interactions. Results are shown in Table 5 .

Although no significant differences were found between the treatment groups in terms of Hypotheses 4, 5 and 6, i t should be noted that there were meaningful differences between the

Table 2 ANCOVA Summary (Achievemenr)

Source df M' F ~~

Incentives I 2.05 0.43 Grouping 1 I .77 0.38 Incentive X Grouping I 1.16 0.24 Covariate 1 89.10 18.84 Error 27 4.73


Table 3 Posttest Means and Gain Scores

Treatment Posttest Mean Gain Score Mean

Heterogeneous Arrangement 40.22 Homogeneous Arrangement 40.50 Cooperative Incentives 40.14 Individual Incentives 40.58

4.44 4.72 4.36 4.80

Table 4 Means and Standard Deviations {Cooperative Interactions)

Cooperative Interactions

Treatment M SD

1 . Heterogeneous/cooperative incentive 24.92 8.13 2. Heterogeneous/individual incentive 26.79 8.08 3. Homogenous/cooperative incentive 20.48 4.71 4. Hornogeneous/individuaI incentive 23.03 3.97

Table 5 ANOVA Summary (Cooperative Interactions)

Sources (rf M 2 F

Incentives 1 38.28 0.79 Grouping 1 133.03 2.74

Error 28 48. I5 incentive X Grouping 1 0.78 0.02

heterogeneous and homogeneous groups, with the heterogeneous groups exhibiting more interactions. It should also be noted that the standard deviations for the heterogeneous groups were nearly twice as large as for the homogeneous groups, indicating larger variation between groups in the same treatment condition.

Conclusions and Implications

Results of this study do not support the use of cooperative incentives as an element of cooperative learning, although cooperative incentives are normally recommended as a compo- nent of most cooperative learning models (Slavin, 1984). Findings of this study seem to contradict the findings of other cooperative learning researchers who have investigated the importance of cooperative incentives (Hulten & DeVries, 1976; Slavin 1984, 1991). Results of this study support the findings of Hooper and Hannafin (1991), which indicated no differences in the achievement of students in the group accountability and individual accountability conditions.


The results of this study do not support the use of heterogeneous arrangement of cooperative learning groups as a means for improving achievement. Although heterogeneous grouping is an element of nearly all cooperative learning methods (Slavin, 1981), there is little research to support the use of heterogeneous grouping. The findings of this study are similar to those of Tingle and Good (1990), in which no significant differences were found in problem-solving ability of students who solved problems in heterogeneous groups as opposed to individually. It should be noted, however, that students in the Tingle and Good study were grouped based on proportional reasoning ability and not achievement. Hooper and Hannafin (1988), were able to demonstrate an increase in achievement of low ability students in heterogeneous groups as compared to low ability students in homogeneous groups. However, their results also indicated that high ability students in heterogeneous groups scored lower than high ability students in homogeneous groups.

One of the factors that makes this study somewhat different than most other cooperative learning studies is that it involved college students as subjects. Most of the research in cooperative learning has been at the secondary level and below. It is possible that different results would have been obtained if a lower grade level had been involved. A possible limitation of this study is that the specific population involved tends to be rather homogenous in terms of sex, race, and age, and that it was difficult to produce truly heterogeneous groups in terms other than ability or achievement. Another factor that may have influenced the results is the attitude of students involved toward cooperative learning. Many of these students have been exposed to cooperative learning techniques in several of their preservice education courses. Whether the effect of this repeated exposure is positive or negative is an appropriate topic for further study.

The results of this study seem to add more questions than answers. Studies should be conducted at a variety of grade levels before any generalizations about the effectiveness of the elements of cooperative learning can be made. Even if specific elements such as heterogeneous grouping are not found to be effective in terms of achievement, there may be other effects that make them worth utilizing. Included are improved relationships between different racial and ethnic groups and between handicapped and nonhandicapped students (D. Johnson & R. John- son, 1989; Slavin, 1983a). Further studies should be conducted to clarify these effects.

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Manuscript accepted June 11, 1993.

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