This section is organized into three subsections: “Participants”, “Materials”, and “Design and procedure”. In “Participants” subsection, participants are described in detail and some demographics are presented, which includes both the CG and the non-CG students. Also, the sampling strategy is clarified. In “Materials” subsection, the PSVT is described as the research tool utilized to measure VSA. Finally, in “Design and procedure”subsection, three research goals are defined, as well as the strategy and statistical analysis to address each goal. A brief justification about the selection of the PSVT is also discussed.
Participants
Participants in this study were students enrolled on the CG course at the UACJ offered during Fall-2017, Spring-2018, and Fall-2018. They belonged to either a morning class (11:00–13:00 group) or an evening class (20:00–22:00 group). Due to the relatively small quantity of students enrolled in CG each semester (typically 15–20 per group), it was decided to include all students who voluntarily wanted to participate and who fulfilled one basic condition: being a “first-time” CG student (i.e., not a repeating student in this course). Therefore, the sampling strategy in this study does not imply a selection method more than the aforementioned condition. The term sample in this study only denotes that participant students are a small fraction of all students that have taken CG at the UACJ at some point. This approach facilitated a broad representation of students’ conditions (e.g., single, married, male, female, working, young, mature, brilliant, average), despite having so few participants per semester. A total of 100 students were sampled, 55 from morning groups and 45 from evening groups. Demographics of participants (regarding age, gender, and VSA self-perception) are summarized in the following charts and tables.
The age of students was in a range from 19 to 38, with a median of 22, and with 20 as the most frequent age. These figures were consistent across the morning and the evening groups, with just a small difference in the average age, it was 22.33 in the morning and 24.76 in the evening. These age statistics are shown in Figs. 7, 8 and 9.
Regarding gender, the global population of students enrolled in the program of computer systems is, in general, heavily biased to male. This situation was consistent with the gender statistics of the sampled CG students in this study. In the morning groups, the ratio of females/males was 14/41, while it was 5/40 in the evening groups. These figures give a ratio of 19/81 in the total sampled students, as shown in Figs. 10, 11 and 12.
Two questions were included in the demographics section of the test to reveal a general background for each student’s level of visual/spatial intelligence. The first question was about previous experiences using any commercial package of 3D design or whether they had considerable practice playing videogames. The second question was about their self-perception of how easy or difficult they found the task of mental manipulation of 3D objects or their ability to remain oriented in 3D (real or virtual) environments. Answers for the second question were given in a scale from 1 to 5, being 1=“Too difficult,” 2=“Difficult,” 3=“Regular,” 4=“Easy,” and 5=“Too easy.”
Statistics for these two questions showed that 92% of the sampled students said that they already experienced activities well known for promoting visual/spatial intelligence. Also, 59% of students perceived their own confidence in their visual/spatial abilities as “regular” and 24% as “easy,” while a minority of students chose the rest of the options (“too difficult,” “difficult,” or “too easy”). These statistics are presented in Figs. 13 and 14.
A complementary test was performed on 25 students from the same computer systems engineering program, but not related to the CG course. These students were invited and gathered from other classes (14 from computer theory and 11 from intelligent systems), with the only constraint being that they had not yet taken CG. Their average age was 23.4 years, the median, and the most frequent age was 23 years. The gender ratio was 20% females to 80% males; 92% reported previous experiences in activities demanding visual/spatial intelligence. Finally, 60% perceived their own visual/spatial abilities as “regular,” 32% as “easy,” and 8% as “difficult.”
Materials
The PSVT was the tool utilized to measure the students’ VSA. It was acquired through the Educational Testing Service (ETS) organization, and it included four test booklets. The first contained a mixture of twelve problems in each category (“developments,” “rotations,” and “views”), totaling thirty-six problems. The second, third, and fourth booklets included thirty problems each in just one category. A multimedia presentation was prepared from the digital format acquired, assigning one slide per question. A recommended time to answer each booklet was 20 min, which corresponds to 40 s per problem. Therefore, each slide was set to a fixed time of 40 s in a self-paced animation. Participants were tested only with “rotations” and “views” (third and fourth booklet) because these areas were the most closely related to the contents of the CG course. Complementing the PSVT multimedia presentation, was a paper-based answer sheet (bubble-style) that included a small “demographics” section.
Design and procedure
This study was developed at the UACJ during three consecutive semesters (Fall 2017, Spring 2018, and Fall 2018). At the beginning of the semester, all students enrolled on the CG course were informed about the purpose of the study and invited to participate as volunteers. Participants were not provided with any special treatment or educational strategies. They took the entire semester of CG in standard conditions, the same as every other student enrolled in this course.
This study was designed to test three different cases, described as follows:
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Case 1: Testing whether VSA increased after taking a full semester of CG. The statistical test chosen for this case was a paired t-test. It was applied to the scores obtained by students in the PSVT in the pre/post phases. The same testing was applied to three data sets. First, to the total number of sampled CG students. Then, just to test consistency, only to the morning groups, and only to the evening groups.
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Case 2: Testing whether a preexisting level of VSA at the beginning of the semester had some association with performance on the CG course. In this case, a bivariate correlation was applied in two different data sets. First, to measure the correlation of the scores of students in the PSVT pre-test phase and their final grades in CG; and second, to correlate the same PSVT scores but now with the students’ results in the midterm exam, which is a comprehensive evaluation of the topic of 2D/3D geometric transformations.
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Case 3: Testing whether the PSVT scores increased after presenting this test twice. This testing was similar to Case 1 but directed to non-CG students and with the pre/post phases much closer in time. The scores obtained by non-CG students in the PSVT during the pre/post phases were analyzed with a paired t-test. The purpose of this case was to estimate the effect of repetition (when a student takes the test twice) on improving the PSVT score. In this case, the pre-test was conducted in the third week of the semester, and the post-test five weeks later.
In Case 1, the pre-test was conducted in the second week and the post-test close to the end of the semester, in the fifteenth week. The same set of students were tested in both phases. If a student, for any reason, was not able take the second phase, their data was removed from the study. Case 2 utilized the same data gathered in the Case 1 pre-test phase but it was correlated with the scores of the mid-term exam and with the final CG grades (two different analyses for Case 2).
Case 3 was a complementary, but relevant, test for considering the possibility that an increase in the PSVT scores by CG students could be influenced more by the repetition of the test than by the full semester studying CG. If the repetition of the test for the non-CG students did not increase their score, it would provide more support to the theory that the CG course itself is the relevant factor for any VSA improvement in CG students.
The PSVT was chosen as the research tool for this study due to its general advantages, described earlier in “The Purdue spatial visualization test” section. Certainly, other standardized tools such as the MCT or MRT could also be applied. These tests have similar characteristics and reliability, according to Gorska & Sorby, (2008), even though there is still some debate about the specific cognitive ability each test is really measuring (e.g. spatial visualization, spatial orientation) (Branoff, 2000). However, all these options are still mainly oriented towards educational research, which is the case of this study. In contrast, other tests are more oriented towards use by professionals in psychology as part of a study or construction of psychological profiles. Additionally, the choice of the PSVT was favored by the type of problems included in its “rotations” and “views” sections, which are similar in nature to the contents of the CG course in this study. Other tests, on the other hand, prioritize less relevant problems, like those related to solve “folding” tasks on 3D models.
The application of the PSVT in this study was administered in the following conditions. Students answered 60 questions in total; the first 30 were related to rotations, the other 30 related to views. A self-paced multimedia presentation was run, where each slide was available for 40 s, totaling 20 min for each set of questions (rotations and views). Under these conditions, participants took the test in a synchronized manner (i.e., the whole group was answering the same question at the same time). These conditions were similar to those in the traditional paper-based PSVT. The difference in this case was that participants were only provided with the answer sheet rather than the printed booklet. These conditions limited the possibility of leaving a question and returning to it later or giving the test a final review according to the remaining time. Despite these minor constraints, the authors of this study believe that these testing conditions correctly reflected the essence of measuring participants’ VSA.
Concerning ethical considerations, all participants provided their informed consent after receiving detailed information regarding the study conditions, such as purpose, methods, any harmful effects (there were none), confidentiality of data, anonymity, voluntary participation, and their right to withdraw at any time. This study did not set an educational intervention of any kind. At no stage of the study were participant students treated with any learning strategy or placed in conditions different to non-participant students. Participation consisted of taking the PSVT twice and completing a short demographics section. The results obtained in the PSVT (scores in the pre/post phases) were provided to all participants (individually).