We present the results of an empirical study, which investigated the effects of the amount of information and the type of information refuted in refutation texts. The study compared the effects of three refutation texts on elementary school children's understanding of the scientific concept of the Earth. One text refuted only the belief that the Earth is flat, the second refuted in addition the belief that people cannot live at the 'bottom' of the spherical Earth because they would fall down, and the third added the categorical information that the Earth is an astronomical object. The term 'categorical information' is used to refer to information about the category to which a concept belongs. We hypothesized that the text refuting more information as well as the one that included the categorical information that the Earth is an astronomical object would be more effective in improving students' scientific knowledge about the Earth. The refutation of categorical information is important because it is generic and carries a great deal of implicit information that can guide new learning. The findings showed that the text that included more information as well as the categorical information facilitated scientific understanding most. The results support the hypothesis that both the amount of information and the kind of information being refuted need to be taken into consideration when deciding what to refute in a refutation text.
Science texts are difficult to understand, especially for young,
elementary school children
Wu, 1997; Kendeou & van den Broek, 2005, 2007). However, refutation text studies have not adequately addressed the question of how much information as well as what kind of information should be refuted.
In the present study we investigated the effects of refuting
more information as well as of adding categorical information.
More specifically, the texts used refuted prior knowledge
representing the belief that the Earth is flat, and the belief that
people cannot live at the bottom of the Earth because they will
fall down. In addition, we investigated the effect of adding in
the text information about the scientific category to which the
Earth belongs. Conceptual change research has shown that
learning science often requires re-assignment of the category
to which a concept belongs
Categorization is one of the most powerful learning
mechanisms
Categorization is a dynamic rather than a static process..
During development many concepts may change category, i.e.
plants are considered to belong to the category of non-living
things at first but later change category and are considered to
belong to the category of living things
Many of the misconceptions children form are the result of
assimilating scientific information into their background
knowledge without changing their initial categorizations
Previous research has shown that children have considerable
difficulty understanding that the Earth is a sphere that rotates
around its axis and revolves around the Sun
A substantial body of cross-cultural research supports the
conclusion that during the preschool years children construct
an initial concept of the earth based on interpretations of
everyday experience in the context of lay culture. According
to this initial concept, the Earth is a flat, stable, stationary, and
supported physical object. Objects located on the earth obey
the laws of up/down gravity, and space is organised in terms
of the dimensions of up and down. The sky and solar objects
are located above the top of this flat earth, which is thought to
occupy a geocentric universe
The scientific concept of the Earth, to which children are exposed at least as soon as they enter elementary school, violates practically all of the characteristics that apply to children’s initial Earth concept. According to the scientific concept, the Earth is a planet, i.e., an unsupported, spherical, astronomical object, which rotates around its axis and revolves around the sun, in a heliocentric solar system. People live all around the spherical Earth and gravity operates towards the centre of the earth. Understanding the scientific concept of the Earth requires that children re-categorize the earth to a new ontological category, that of an astronomical object.
Previous studies have shown that when children’s initial
beliefs about the Earth are addressed, their understanding of
the spherical shape of the Earth is improved. A study
comparing a control group that received traditional instruction
with an experimental group that received additional
information about the spherical shape of the Earth and gravity
based on simulations, showed much improved understanding
of the scientific concept of the Earth for the experimental
group
Three refutation texts were compared. The first dealt with the belief that the Earth is flat (Text 1), the second also refuted the belief that people cannot live at the bottom of the Earth because they will fall down (Text 2), and the third added to the above the information that the Earth is an astronomical object rather than a physical object (Text 3), i.e., a spherical planet in a heliocentric solar system. More specifically, Text 1 explicitly stated “the Earth is not flat but spherical, like a very big ball” and explained that “the Earth looks flat to us who live on a very small piece of it, like Greece”. Text 2 added to this the information that “gravity is the force that holds us on the Earth so that we do not fall down. It pulls everything that is found on the Earth’s surface towards the center of the Earth. Because of gravity people can live on all the parts of the spherical Earth without falling”. Finally, Text 3 also stated “the Earth is one of the planets of our solar system. Today we know that our solar system is heliocentric. All planets revolve around the sun. The sun is located in the middle of the solar system. The Earth is also a planet with all the characteristics of planets. All planets are spherical, round like very large balls”.
We hypothesized that Texts 2 and 3 that refuted more information would be better in improving children’s understanding compared to Text 1. However, it was also hypothesized that Text 3, which contained the categorical information that the Earth is an astronomical object, would be more effective than the other two.This is the case because categorical information is generic and allows inferences about the characteristics of astronomical objects while it prevents inferences of the sort that the Earth is stable and in need of support, and of ‘up/down’ gravity.
Eighty-one 3rd grade students (mean age 8 years and 4 months) from a middle-class school in Athens, Greece, participated in the study. 3rd graders were selected because previous studies have shown that although they are exposed to scientific information about the Earth they do not yet fully understand the Earth concept. Furthermore, this is the youngest age at which we expected the children to be able to read and understand a simple science text.
The materials used were: (a) three different refutation texts which referred to the Earth, and (b) a questionnaire consisting of 14 open-ended questions. As mentioned earlier, Text 1 refuted the belief that the Earth is flat and explained that it is spherical (310 words). Text 2 included all the information found in Text 1 and also refuted the belief that people can fall off the Earth and explained that there is force called gravity that holds people on to the surface of the spherical Earth (410 words). Text 3 included all the information found in Texts 1 and 2 and also added the information that the Earth is an astronomical object (510 words). All texts were of comparable readability level (Flesch index: 57.84 for text 1, 61,32 for text 2 and 73,24 for text 3).
The questionnaire was used both as a pre-test and as a post-test. The questions were divided in two groups: (1) explicit questions, some of which arose directly from all the texts (common explicit), and some only from Text 3; and (2) inferential questions, the answers to which were not explicitly stated in the texts but could be inferred from it. Again, some inferential questions could be inferred from all texts (common inferential), while others could be inferred only from Text 3.
Children were randomly assigned to one of the experimental conditions. More specifically, each classroom was randomly given one of the three texts to read. The pre-test was administered first. When all children finished answering the pretest, the answer sheets were collected and a written copy of one of the refutation texts was distributed. They had 15 minutes to read it on their own. At the end of the reading period, the experimenter read the text aloud in order to make sure that the children could decode all the words. Then the written texts were withdrawn and the posttest was administered..
Scoring. Two judges agreed on a scoring key, which they used to score independently children’s responses in all the questions. The judges’ agreement was calculated at 95% [Kendall’s tau τ=0.939; Ν=81; p<.001]. All disagreements were discussed until a common score had been achieved on all the items. Children’s responses to each of the 14 questions received a score of 3 if they were scientific, of 1 if they were “initial” (if they were consistent with the flat Earth model), and of 2 if they revealed exposure to scientific information, which was however not fully understood. No responses were scored as 0. Thus, for each student the total score could range from 0 to 42.
A group type (text1*text2*text3) ANOVA was used to test whether there were any significant pretest differences between the two experimental groups assigned to the different text conditions.. The results showed no statistically significant differences between the three experimental groups in the pretest [F(1,78)=.710, n.s.; η2=.004].
Children’s total scores in all the common (explicit and inferential) questions in the pretest and posttest were subjected to a mixed two-way ANOVA with text type as a between subjects variable and pre-post test performance as a within subjects variable. The results showed that all refutation texts improved significantly children’s responses in the posttest [F(1,78)=49.742, p<.001] (see Table 1) and the size effect for this analysis [η2=.387] exceeded the convention for a large effect (η2=.025).
The analysis also showed a statistically significant interaction between text type and students difference in performance from pretest to posttest [F(2,78)=7.438, p<.001]. The effect size for this analysis [η2=.160] was found to exceed the convention for a large effect (η2=.025). The students who read Text 3 showed greater improvement in their responses in the posttest compared to the pretest, as opposed to the students who read Text 1 and Text 2 (Figure 1).
Post hoc comparisons using the LSD test indicated that the mean score difference from pretest to posttest for Text 3 was statistically significant only when Text 3 was compared to Text 1. The mean score difference between Text 2 and Text 3 was in the expected direction but not statistically different (see Table 2). Similarly, the mean score difference between Text 1 and Text 2 was not statistically different. Taken together, these results suggest that Text 3, improved children’s responses in the posttest more than the other two texts, but the difference was statistically significant only between Text 1 and Text 3..
A similar mixed ANOVA was conducted separately for the common explicit and the common inferential questions only. In the case of the common explicit questions the analysis showed statistically significant improvement in children’s responses from pretest to posttest in all three texts [F(1,78)=20.058; p<.001; η2=0.205]. No statistical significant interactions were obtained [F(2,78)=.637; n.s.; η2=0.006], despite the fact that Text 3 had a greater effect in children’s responses in the posttest compared to the other two texts ( see Table 3).
In the case of the common inferential questions a statistically significant improvement in children’s responses from pretest to posttest in all three texts was obtained [F(1,78)=20.058; p<.001; η2=0.205] (see Table 4). Significant interactions were obtained only in the case of the inferential questions [F(2,78)=6.410; p<.005]. The η2 effect size value for this analysis [η2=.141] was high. Figure 2 is a pictorial representation of these results.
It appears that Texts 1 and 2 slightly improved children’s responses in the posttest, while Text 3 had a greater impact on children’s posttetst explanations compared to the other two texts. Additional post-hoc analyses using the LSD test showed that this difference was in favor of Text 3 compared to the other two texts (Table 5).
It seems that, once again Text 3, which included the categorical information, improved children’s responses in the inferential questions more than the other two texts.
Science texts are difficult to understand, especially for young
elementary school children
In addition, the results of the present study indicate that the
refutation text that included the categorical information was
more effective than the other texts in improving children's
understanding of the scientific information about the Earth.
The children who read Text 3, which included the information
about the categorization of the Earth, improved their responses
in the inferential questions in the posttest more compared to
their peers who read the other two texts. This finding is
consistent with our hypothesis that categorical information is
more important than other types of information, because it is
generic and carries with it a great deal of implicit information
that can be used by the learner to guide new learning
Overall, the present results support the conclusion that
when using refutation text, it is important to consider what
kind of information is being refuted as well as how much
information is refuted. It appears that texts are more effective
when more information is refuted as well as when the
refutation includes categorical information
Learning science very often requires changes in the
ontological category to which an object belongs. These
changes are considered to be the most difficult conceptual
changes to achieve