Teaching and learning methods compared: A pedagogical evaluation of problem-based learning (PBL) and lecture methods in developing learners’ cognitive abilities

Abstract Using a mixed method, quasi-experimental pre-test-post-test non-equivalent group design, this study inquired into the possibilities of enhancing learners’ cognitive abilities, with problem-based learning (PBL; -experimental) and lecture method (control) as predictor variables. Aided by the random scorecards, a group of 51 students was assigned to the experimental (26) and control (25) streams, where their cognitive performance was compared on both the lower and higher-order learning attributes for 15 weeks. Whereas there was a slight difference in the mean scores of the two groups on the three lower-order learning parameters measured at the pre-test, the difference (Xc = 55.32 < Xe = 55.8; t-statistic 0.176 < critical t- 2.01) was not statistically significant. However, at the immediate-post-test, the mean scores of the two groups on the three higher-order learning parameters statistically differed (Xc = 66.81 > Xe = 59.21) in favor of the control group (t = 2.967 > 2.01; p = .005 < 0.05). Although a reduction in weekly learning hours from 3 to 2 was accompanied by a significant improvement in students’ cognitive development on the three higher-order learning attributes at the delayed post-test for the experimental group, that of the control group, improved marginally (Xc = 76.36 < Xe = 86.31). Even though the generalization of these findings may be limited due to the examination of a single learning discipline, the qualitative and quantitative analyses suggest that PBL is a true stimulant of students’ cognitive development over time.


PUBLIC INTEREST STATEMENT
Although teaching and learning effectiveness is a well-trodden territory for researchers, it is still one of the areas that are not well addressed in sufficient terms. That being the case, this study is set out to work as a bridge that connects research to practice and practice to research.

Introduction
Although there is a relentless debate about the constituents of teaching and learning effectiveness (TLE), there is little disagreement that cognitive development is a core determinant (Mohsen et al., 2018;Applin et al., 2011;Murphy et al., 2011;Sangestani & Khatiban, 2013a). The existing body of literature shows that the question of what TLE is, never has had a clear answer, although a practical position seems to have been reached in practice that TLE is the ability to identify and utilize learning resources to stimulate and direct learners towards achieving the intended learning goals (King & Watson, 2010;Rockoff & Speroni, 2010;Stronge et al., 2011;Goldhaber et al., 2013). Whereas this definition meets the minimum expected standards of an idealist, it falls short of the following; it does not help one to understand what teaching strategies most stimulate learning, with what student, under what learning conditions, with what learning resources, and in what subject area. If these are to be considered, then ensuring TLE just got much more difficult.
Decades of research have produced a sizable body of empirical evidence to guide practice. Freire, 1996) the father of the critical pedagogy movement claimed that TLE is the ability to link knowledge to action. Although Freire's work has had considerable influence on progressive educators, his education philosophy does not appeal to the critical questions raised above; rather, it concentrates on the narrow view that knowing leads to action, which in the actual sense is not obvious. This facile analysis of TLE gave birth to new inroads in the analysis of TLE. John Dewey  contends that knowledge and ideas emerge only from situations in which learners have to draw them out of experiences that have meaning and importance to them (Devries, 2000). Under this analysis, it is tempting to believe that, meaningful learning takes place when learners are empowered to construct knowledge by themselves from what they personally experience as they try to comprehend their world. This pragmatic approach to learning not only requires but demands a radical departure from the teacher-centric mode of learning to learner centered with increased involvement and engagement.
Motivated by the pragmatic view, universities across the world joined the movement to adopt pedagogies of engagement which grant graduates the capacity to effectively apply the acquired knowledge and skills in response to the uncertainties of the ever-changing world of work (Astin, 1999;Murphy, 2006;Hallinger et al., 2011). PBL which exposes learners to the realities of the world to see possibilities beyond the existing ones, gained prominence among educationists at this point (Barrows & Tamblyn, 1980;Boud & Feletti, 1991;Bridges & Hallinger, 1993). Available evidence from medical education provides more empirical support for the effectiveness of PBL (Patel et al., 1993;Norman & Schmidt, 2000;Yuan et al., 2011;Baker et al., 2007;Bastable, 2007;Quintero, 2014). It is claimed that PBL has been a cornerstone in almost every credible scientific breakthrough in the medical schools (Patel et al., 1993). While this may convince one to regard PBL as the "magic wand" that can rise to the occasion whenever applied, it should not be forgotten that most learning contexts do not support it. Nonetheless, Hallinger et al. (2011) further emphasize that, it is the engine upon which a university's contribution to society depends. Consequently, & F. Dochy et al., 2003); and Gijbels et al. (2005) contend that, while PBL application is associated with challenges, its predictive effect on TLE is indisputable.
Although the empirical evidence provided justifies the need to apply PBL, proponents of the lecture method argue otherwise. They claim that the lecture method is economical and flexible, and supports the critical thinking of which PBL is short (Govender, 2015). It is one method that has proved to be more suitable for large classes and the delivery of content-loaded curricula (Samantha Govender, 2015). Killen (2011) revealed that the lecture method is a reliable mode of instruction in teaching factual-based content that is highly structured within a restricted timeframe. Although the lecture method is popular in resource-stricken learning environments, its credence has been questioned in various scholarly discourses. It indisputably gives teachers control over the teaching and learning processes by determining when, how, and what to learn (McCarthy & Anderson, 2000) but it does not empower learners to imagine beyond the immediate world.
In an attempt to improve teaching and learning processes at Kampala International University (KIU), the College of Education, Open, Distance, and e-Learning (CEODL) was tasked by the Quality Assurance Unit (QAU) to guide the University towards identifying and implementing suitable instructional strategies. This decision was informed by the Quality Audit Report (QAR) of the 2015/16 academic year, in which a yawning gap in the teaching and learning processes was highlighted, and a robust intervention was demanded. As research on PBL at the time of the release of the QAR was replete with successful stories, the CEODL administrative team wondered whether the adoption of a student-centered instructional strategy such as PBL would not improve students' cognitive abilities in courses such as Geography which the QAR had singled out as poorly performing. Against this background the Head of Department (HOD) instructed me to evaluate the effectiveness of PBL in one of my Geography courses through a systematic experiment. Therefore, this experimental study, was in part, conceived to examine how teaching and learning effectiveness at KIU could be enhanced.

Hypothesis (H 0 )
The researcher pondered whether students' cognitive abilities would still not improve if taught using PBL.

Literature review
Recently, TLE has become a staple in many conferences and workshops across the HE spectrum. Although it is a well-trodden territory for researchers and practitioners, it is still one of the areas that are not adequately addressed. Therefore, TLE might be judged an area that is widely researched, but little understood at the same time. Its susceptibility is dependent upon the complex nature of the instructional methods, failure to match teaching strategies and students' learning behaviors, quality of the learning resources, and learners' academic backgrounds to name but a few (Hunt et al., 2009;Paul & Chinooneka, 2015). Despite this reality, employers have continued to exert pressure on universities in demand for employable and solution-oriented graduates (Paul & Chinooneka, 2015). This pressure has demanded a radical shift in instructional methods and a departure from teacher-centered philosophies. It is against this background that studies on TLE have increased in number with the view of guiding practice. In a trilogy study where pure PBL, hybrid PBL, and lecturing methods were joined in an experiment, Mohsen et al., (2018) established that pure PBL and hybrid PBL were effective in enhancing students' overall performance in Pediatric Nursing. Nevertheless, the findings fail to afford readers the opportunity to appreciate how students' learning proficiency differed while using the lower-order and higherorder learning activities.
Regardless of this gap, researchers such as Brandon and All (2010) and Freeman et al. (2014) have independently concluded that higher mental functions take place through a constructive learning environment where learners are engaged in active processes of discovering knowledge. This submission is consistent with Jean Piaget's (1896-1980) philosophy of learning, which posits that learners tend to remember whatever is learned from the experience of what they have put together (Handelsman et al., 2007;Freeman et al., 2014). Constructivists hold that, learners develop cognitively when they ask questions on a given problem and then begin to interact with their environment in the search for practical solutions (Owolabi & Kyolaba, 2007;Ssemugenyi, 2022a). While this may be regarded as effective learning, proponents of the teacher-centric philosophy have challenged this mode of learning on the grounds that; it does not offer guidance on how information is processed, transferred, and understood by learners. Its conformity to structured learning content in a restricted timeframe is questionable (P. A. Kirschner et al., 2006). Conversely, researchers such as Moreno (2004); and Brown and Campione (1994) submit that it is unwise to assume that learning can take place with the minimal involvement of teachers and more by learners.
The claim that teachers' presence is critical for the effectiveness of any learning mode are premised on the classical epistemic justification that knowledge exists in one's mind (Locke, 2015). The cultural rigidities which consider teachers the only source of truth and fountain of knowledge have for decades denied student-centered approaches to learning a favorable ground to flourish. It is believed that teachers dispense truth and no one has the mandate to challenge that truth (Ssemugenyi, 2022a). These claims have long provided firm grounds for the continued application of the lecture method and a denial to try out student-centered learning models. One thing that can be said with confidence is that, despite constant attack, the method has endured to the present day; it has distinguished itself as a reliable tool for stimulating learners, giving perspective on the subject, guiding discussion, and logically presenting ideas in a way that no other method can do (Brown & Campione, 1994). Although one can consider this submission obsolete on temporal basis, it should be emphasized that recent studies such as; (Casado, 2000;Struyven et al., 2008;Marmah, 2014) have all corroborated this claim.
Although there are compelling reasons to support the lecture method, there is however concerted effort across universities to stifle it on the basis that, it deprives learners of the responsibility to determine when and how to learn (Govender, 2015). Thus, students assume a receptive and passive role in their quest for knowledge (Armstrong, 2012). Since education today is geared towards meeting the needs of the emerging Fourth Industrial Revolution, the need to revisit instructional methods has become a pressing issue in HE discourse, hence, this study.

Methodology
The study employed a mixed method, quasi-experimental pre-test-post-test non-equivalent group design (Creswell, 2007;Yin, 2008). The collection of qualitative and quantitative data unfolded concurrently over 15 weeks of intensive engagement. The PBL group was subjected to the experimental treatment while the control group was exposed to the lecture method. Both groups took the pre-test to determine their prior learning experiences, problem-solving skills, knowledge base, and critical learning abilities. This baseline served as a yardstick to track students' progress in cognitive development and at the same time to aid the facilitator in determining whether the intervention had an impact through the comparison of the pre-test and post-test scores. Two posttest evaluation were conducted: the immediate post-test (in the 7 th week) and the delayed posttest (in the 15 th week). The immediate post-test evaluation was an intentional control mechanism to check whether the learners were responding to the treatment so as to give the teacher the chance to manipulate the parameters of X well before the final post-test evaluation.

Conceptualizing students' cognitive development in consideration of PBL and the lecture method
Although proponents of cognitive development theory appear to attack each other for oversimplification, their position on the role of instruction in learners' cognitive development is not in dispute. They claim that cognitive development originates from situations where the course of thinking is an integral part of the adopted instructional strategies in the teaching and learning processes (Piaget, 1980;and Franco et al., 2017). Accordingly, this study conceptualized cognitive development as a process through which an instructional strategy stimulates learners to actively construct knowledge as they try to comprehend learning tasks. The basis of this view lies in the constructivist school of thought that views effective learning as a process in which knowledge is constructed out of learners' experiences (Ssemugenyi, 2022a). Given that PBL is believed to be an appropriate cognitive stimulant, in this study its effectiveness in learners' cognitive development was evaluated while using the lecture method as a control mechanism. The learning activities under the PBL stream were limited to; active group participation in projects, roleplaying, individual presentations, peer-critiquing, debating, and writing individual and group reports. In addition, the researcher recognizes the fact that there are many forms of lecture method (e.g., formal, informal, and semiformal; Lowman, 1995); however, in this study, the scope of lecture method was limited to the formal lecture method that supports the logical verbal presentation of subject matter by the instructor to a group of students, augmented by visual aids in a designated classroom (SPENCE, 1928).

Participants
The target population in this inquiry was 2 nd year, Semester 2 students of the CEODL offering Geography of World Development (GEO 2202) as one of their specialized subjects in the academic year 2016/2017. Given that this cohort of learners had previously been exposed to a problem-oriented learning style in their Year 2 Semester 1 by the same facilitator, it was found reasonable to subject the same cohort to this intervention. The total target population was 54, but as 3 students failed to participate in a fact-finding survey before the pre-test, only 51 participants were considered in this study. Since the population was relatively small, the researcher did not apply any sampling strategy for fear of affecting its representativeness (Amin, 2005). In quasiexperiments, the necessary conditions for random assignment are hard to meet (Mackey, 2017), but given that this treatment was done on the same group of students, taught by the same facilitator, same subject matter, same learning hours, and relatively similar learning conditions, the 51 subjects were distributed randomly to PBL (26) and control (25) groups using random score cards. Both groups took the pre-test, immediate post-test, and delayed post-test to measure the learners' cognitive development dynamics at different stages of learning engagements. For qualitative data, nine participants (e.g., GEO1 c , GEO2 c , GEO3 c , & GEO4 c , and GEO1 e , GEO2 e , GEO3 e, GEO4 e, & GEO5 e ) were identified to take part in the interview sessions in the immediate and delayed post-test evaluations.

Numerical data
Using a revised Bloom's Taxonomy, a Cognitive Performance Test (CPT) consisting of 25 multiplechoice items and 10 open-ended questions was devised to measure the lower-order cognitive abilities of students before actual treatment. The intention was to establish the students' level of lower-order cognition before subjecting them to higher-order treatment, and to use these data as a baseline to track students' cognitive development rate at the immediate and delayed post-test evaluations. The reliability of this instrument was assessed by a Cronbach's Alpha value of 0.80. The multiple-choice questions focused on remembering, and information processing, while the open-ended questions focused on students' ability to use reasoning during knowledge application. Two points were assigned to each correct answer to the multiple-choice items and five points to each of the elaborately expressed responses to the open-ended questions. Therefore, the overall students' cognitive performance on the two sections of the lower-order test ranged between 0 and 100.
After the baseline survey, the experimental group was further reorganized into five groups with six members in one group and five members in the rest of the four groups. Using the pre-test scores, the above-average, average, and below-average students, were identified and distributed carefully into five groups to avoid biasing the evaluations. Thus, each experimental sub-group contained at least one or two above-average, average, and below-average students. Before the actual treatment, the PBL group agreed with the facilitator on the intended learning outcomes, and they were given probing questions to keep them on track, tools for data collection and analysis, appropriate instructions on how to construct their own knowledge during and after the intervention, and guidance on how to prepare and present project reports. Four projects were identified for the whole course; the first two projects informed both the numerical and nonnumerical datasets for the immediate post-test evaluation, while the last two informed the delayed post-test. The control group also received a briefing on how the lectures would progress with the lecturer in the control from week 1 to week 15. A balanced CPT anchored on Bloom's higher-order learning skills was devised to evaluate the rate of students' cognitive development at the immediate and delayed post-test. The instrument for the immediate post-test was informed by the content covered between weeks 1 and 7, while for the delayed post-test, the content covered from week 8 to week 15 informed the tool. These instruments were evaluated for internal consistency using Cronbach's alpha test, yielding α = 0.76 for the immediate post-test instrument, and 0.73 for the delayed post-test.

Interviews
In addition to numerical data, structured interviews were conducted to explore students' learning experiences throughout the engagement period. This was done to minimize the bias that is usually associated with the mono-method approach (Tashakkori & Teddle, 2003;Fred et al., 2021;& Ssemugenyi, 2022a), and provide broader perspectives regarding the problem under investigation (Molina Azorín & Cameron, 2010). Given that the target population for the numerical data was relatively small, the researcher further found it necessary to conduct interviews to increase the validity, generalizability, and confirmability of the study findings. Triangulation is used when the strength of one method offsets the weaknesses of the other, so that together, they provide a more comprehensive set of data (Fred et al., 2021). In this study, the interview sessions were transcribed to identify patterns and themes (Braun & Clarke, 2006); the identified themes included; Applying and Analyzing Facts (A&AF), and Evaluating and Creating (E&C) for higher-order cognitive learning skills. The interview guide contained 10 items all of which were systematically applied to the nine participants (e.g., GEO1 c , GEO2 c , GEO3 c , & GEO4 c , and GEO1 e , GEO2 e , GEO3 e , GEO4 e, & GEO5 e ) to obtain their unique lived experiences during the engagement period.

Internal and external validity
For internal validity, the researcher was interested in establishing whether the observable changes in the experimental group at the immediate and delayed post-tests were not a result of confounding factors but, rather, a result of the experimental treatment. This was ensured through the effective manipulation of variables, non-biased selection of subjects, and control of over-reactivity. For external validity, the researcher was concerned about the generalizability of the study findings beyond the experimental setting (Olive et al., 2003). Accordingly, a pre-test was conducted to ascertain whether the subjects were at the same level of cognition so as to appreciate the impact of the treatment on the experimental group. Again, both groups were assigned equal learning hours per week (three hours), exposed to the same curriculum, the same facilitator, and on different learning days to minimize interaction between the two groups.

Data analysis
The students' assessment scores at the three evaluations, constituted the numerical data set, while for the narrative inquiry, nine respondents with the pseudonyms GEO1 c , GEO2 c , GEO3 c , & GEO4 c , and GEO1 e , GEO2 e , GEO3 e , GEO4 e , & GEO5 e were considered for the interviews. The narrative inquiry elicited students' stories regarding the teaching implementation strategies while seeking students' in-depth appreciation of the two methods of learning (Connelly & Clandinin, 1990). The null hypothesis that there would be no significant difference between the mean post-test gains of the control and experimental groups on the two post-tests was verified at a 95% level of significance using the independent-samples t-test. Given that the primary target was to compare the mean scores of two groups whose population size in each of the two streams was less than 30, an independent-samples t-test was applied (Amin, 2005). This inferential statistical test was based on this formula; t ¼ X t À X e ffi ffi ffi ffi ffi ffi ffi ffi ffi ffi ffi ffi ffi where, t; is the test statistic, X; is the mean score, S 2 ; is the variance of the scores, n; is the sample size, while c and e; refer to the control and experimental groups respectively.
For narrative inquiry, interview sessions were transcribed to identify patterns and themes (Braun & Clarke, 2006). The identified themes included Applying and Analyzing Facts (A&AF) and Evaluating and Creating (E&C) for higher-order cognitive learning skills. Triangulation of data was applied in this study as a quality control mechanism to determine whether different methods of analyzing a similar phenomenon could produce similar results for increased generalizability.

Study findings
Before the treatment, the researcher had wondered if students' cognitive abilities in GEO 2202 would still not improve if taught using PBL. To prove whether PBL would make a difference, this null hypothesis was tested by subjecting the control and experimental groups to the pre-test, immediate post-test, and delayed post-test evaluations. The pre-test intended to establish the students' prior knowledge in the subject area, critical thinking skills, and problem-solving abilities before the treatment, so as to appreciate the impact of the intervention on students' cognitive development. The immediate posttest intended to establish whether the treatment could impact students' cognitive development in the short-term (7 weeks) so as to give the teacher the chance to manipulate the parameters of X well before the final post-test evaluation. The delayed-post-test evaluation was conducted to test the assumption that the effects of the intervention may be stronger in the long run than in the short run.
At the pre-test evaluation, students' prior knowledge base and learning experiences were examined with respect to lower-order learning attributes (e.g., remembering, information processing, and reasoning) as shown in Table 1. Although there was a slight difference in the mean scores of the two groups in the three learning parameters measured, this difference (X c = 55.32 < X e = 55.81) was not statistically significant because the computed t statistic (0.176) was lower than the critical t (2.01). Based on these results, the null hypothesis was accepted, and it was concluded that; the average performance in GEO 2202 of the two groups was not statistically different. The results imply that the two groups are virtually at the same level of cognition, in terms of remembering, information processing, and reasoning. Therefore, the observable slight differences in the scores are mostly random and could have been caused by sampling error rather than group differences.
Using the pre-test scores for both the control and experimental groups as a baseline, it was clear that all students were at the same level in terms of remembering, information processing, and reasoning regardless of the group, hence a justification to proceed with the treatment. The first phase of the treatment took seven weeks and the aim was to establish whether the intervention could have had a short-term impact on students' cognitive development. Parameters of measurement included; analyzing, evaluating, and creating as provided in Table 2.
After seven weeks of active learning engagements, the teacher, in this case the researcher, wanted to establish whether students were responding to the treatment. Using scores from projects 1 and 2 for the experimental group, (e.g., Globalization and development, and Dependency and socio-economic progress), numerical data and non-numerical responses were obtained and analyzed. Similarly, the classroom-based formative assessments and students' lived experiences during the lecture sessions, were the data sources for the control group. Consistent with the experimental group, the formative assessments for the control group focused on the content that had been covered up to the 7 th week (e.g., globalization and development, measures of development, and economic dependency and poverty). The processed numerical data in Table 2 and the students' interview responses in the corresponding narrative section demonstrate the short-term impact of the intervention on students' cognitive development. Table 2 shows that the difference in performance between the control and experimental groups is statistically significant. The t-statistics are statistically significant at the 95% level and the p- values do not exceed the standard calculated probability (t = 2.967 > 2.01; p = .005 < 0.05). The mean scores significantly differed (X c = 66.81 > X e = 59.21) in favor of the control group, and the computed t-statistic for overall performance (2.967) was greater than the critical t-statistic (2.01) at 49 degrees of freedom. This implies that keeping the other factors at zero, there will be an observable significant difference in the mean scores of the experimental and control groups in 95 out of 100 replications of the experiment.

Concerning A&AF and E&C, participants GEO1 c and GEO3 c observed that; "the lecturer delivers the would-be hard concepts in a very simplified manner that enables every learner to sufficiently achieve the intended learning objectives." They further noted that, although teacher dominance may make the learning process boring, on the other hand, his guidance logically breaks down content into meaningful and easily absorbable learning themes for all." Participant GEO1 c further remarked, "how would I have managed the calculations on the Gross Domestic Products (GDP), Gross National Product (GNP), Human Development Index (HDI), Infant Mortality Rate (IMR)
, among others without the guidance of our teacher?" Before covering this course, these terms were just mere economic terminologies that had less meaning to me, "I can now apply them, help one understand and appreciate them, which wasn't the case before."

Participant GEO2 c remarked that "the lecture method is just great for me. I enjoyed the economic dependence and poverty sessions; prior to this, I didn't know how bad it is to depend on others for economic development. It is high time, we relied on the locally made and provided goods and services for economic stability."
In a similar tone, participant GEO4 c , observed, "it was great having a conversation about the global issues in this subject. The lecturer made it easier for me to appreciate economic independence and development, economic dependence and poverty, and the role of culture in the country's development agenda, I became aware that poverty is by choice; we can collectively liberate ourselves from poverty, it is just a matter of mindset change." On the other hand, respondent GEO1 e regarding the themes (A&AF and E&C) observed that; "it is quite difficult to make sense of PBL given the heavy learning load, and long learning hours per week. It is exhausting and I think our teacher has to do something about it. That notwithstanding, my group demonstrated strong abilities in data processing, report writing and presentation, and investigative inquiries. My group had the best project and the presentation was superb. I must say that it was a great experience for me to work with others on projects and look forward to more." Participant GEO2 e noted that "although exhausting, it was quite exciting to relate with the community during the investigations . . . so funny that those who are regarded as rich in the community are still poor by global standards. I learned that being poor at the household level goes beyond having no access to shelter and food, to the poverty of being uncared for, unwanted, and unloved. This was evident during the investigations where children in some households were left to fend for themselves with no or little support from their parents. It was such a sad situation!" Participant GEO3 e noted that "Investigating a problem with people whose minds sometimes are not focused on the learning task is really a challenge. It was hard working with some group members. Nonetheless, being a team leader made me improve my confidence levels in areas such as; investigative inquiry, report writing, and presentation. But generally, it was a struggle for most of us." Participant GEO4 e mentioned that "being a first-timer to investigate a community-based problem and work in groups, I found it hard to believe that learning could really take place with students in control. Little did I know that the best learning is by doing . .

. I enjoyed this kind of learning, and for the first time, I have generated my own notes, interpreted scenarios in the way I understood them, and discussed them with my peers. Although these two projects were intensive and exhausting, I am confident that, with this little experience, I can significantly improve my performance in the subsequent projects."
Participant GEO5 e said, "although my scores for mid-semester are not so good, I have significantly improved in investigative inquiry and presentation skills. Working in groups, interacting with the real world, and producing new or original work is such a wonderful learning encounter I have ever had." As per the results, it is clear that in the short-run PBL did not give an advantage to students over the lecture method on the three cognitive measures. The control group performed significantly better, which prompted the facilitator/teacher to further manipulate the predictor variables for improved performance in the PBL stream. With the aid of the interview responses, the teacher noticed that poor performance in the PBL stream could have been caused by anxiety, cognitive overload, and low confidence levels among learners.
With this evidence, the teacher immediately obtained approval from the HOD to reduce the weekly learning hours from 3 to 2 for both the control and experimental groups in order, to reduce stress and cognitive overload for improved cognitive performance across the board. The results in Table 3 demonstrate the impact of the intervention on learners' cognitive trajectory over a longer period (15 weeks) with a reduced weekly learning load for the 2 nd part of the semester. Projects 3 and 4 (e.g., Environment, natural resources and development, and Urbanization and world economy) and classroom-based learning engagements were used as sources of data for the experimental group and control stream respectively. Table 3, the delayed post-test revealed surprising cognitive development dynamics among learners. A remarkable finding was that; a consistent reduction in weekly learning hours was accompanied by a consistent improvement in the cognitive abilities of learners on the three measures across the board, although with a significant inclination towards PBL. All the computed t-statistics significantly surpassed the corresponding critical t-values at the 95% confidence level and all the p. values were below the 5% cut off, leading to rejection of the null hypotheses (t = 4.200 > 2.01; p = .000 < 0.05). Although the overall mean score for the control group was reasonable, that of PBL significantly differed (X c = 76.36 < X e = 86.31). Keeping other factors constant, it is not unreasonable to conclude that in the long-run PBL can prove to be an effective mode of instruction and a "magic wand" for improved academic performance. For all the troubles and inconveniences the teacher experienced throughout the 15 weeks in identifying a more suitable mode of instruction, the interesting results at the delayed post-test can be regarded as a remarkable breakthrough in his teaching career and a benchmark for other teachers in similar teaching and learning contexts.
On themes A&AF and E&C, respondents GEO1 c ,GEO2 c , and GEO3 c independently, though similar in response mentioned that; "Our final performance slightly improved in the three areas of measurement (e.g., analyzing, evaluating, and creating) and this may be attributed to a reduction in the weekly contact hours, and the continued support from the teacher." However, I cannot deny that his monotony could have slowed our rate in terms of performance. But generally, we enjoyed the lectures! Respondents GEO2 c , and GEO4 c , stated in a similar tone that, "if it weren't for a reduction in the weekly contact hours, we are certain our performance was bound to deteriorate. But we Participants GEO1 c ,GEO2 c , and GEO3 c while sharing their experiences regarding Project 4, independently though relatedly in response noted that, "the agglomeration of people and firms in urban areas reduces production costs which in turn trigger development. It is not surprising that most investors target urban areas." Participant GEO1 c , further noted that "I can now imagine why Kampala city is heavily loaded with secondary and tertiary activities yet remote areas have almost none." Participant GEO3 c mentioned that "I have come to appreciate the role of urban centers and towns in shaping a country's economy." Participant GEO1 e observed that, "I have indeed benefited from the learning tasks of Project 4 to the extent that I was able to practically establish and confirm that the relationship between urbanization and economic growth is non-linear." Respondent GEO2 e observed that, "it was great discovering that a higher urbanization level means a higher economic development." Participant GEO3 e observed that, "prior to this project, I did not know that cultural forces have a positive bearing on urbanization, it is only now that I have come to appreciate this relationship." In a similar tone, respondent GEO4 e , mentioned that, "many interpretations of urbanization and the economy are very abstract when taught in the classroom more than in the real world.

I was able to relate with the real world, gather views, perspectives, real-life examples, and scenarios all of which have finetuned my worldview on urbanization and economy."
Participant GEO5 e submitted, "working actively and collaboratively on projects has to a great deal transformed all of us in so many areas; for instance, unlike before, we were able to make our own notes from the engagements with the real world, solicited peoples' views on various aspects, obtained real-life examples and first-hand information, used our colleagues as learning aids, developed new learning perspectives, improved our report writing skills and presentation, and above all owned the teaching and learning process. Kudos to our teacher for this new learning approach."

Discussion
Hypothetically the researcher wondered whether students taught using PBL would perform significantly better than those taught using the lecture method. The results revealed that in the shortterm (immediate post-test) the lecture method proved to be a more reliable teaching technique than PBL on the three higher-order learning constructs. This could have been attributed to anxiety, low confidence levels in PBL, attitude, and prior learning experiences, as Kong et al. (2014); and Chan (2013) indicate that the implementation of PBL is usually challenged by attitude, prior learning experiences, and rigidity. Although this was the case, the delayed post-test revealed that learners under the PBL strategy had a superior overall performance on the three higherorder learning parameters. This agrees with Loyens et al. (2015); Sangestani & Khatiban, 2013b); & F. Dochy et al., 2003); Zhou et al. (2016), and Mohsen  who independently observed that the PBL strategy is a true predictor of students' academic performance over time.
Conversely, Chou and Chin (2009) while analyzing students' academic performance, concluded that the PBL strategy was a more reliable predictor of students' learning precision over time than the lecture method. Although Chou and Chin's conclusion may excite an average mind to assume that the longer the time the more the learning proficiency, it may not be a wise conclusion to a realist. The argument should shift from this simplistic viewpoint to consider; what forms of teaching and learning interactions extend over time in the causal chain to make PBL a successful story. Although researchers such as Mohsen ; Levine, 2005); and Murphy (2006) sufficiently meet these requirements in their analyses, my point of departure is on the inherent natural stimulus of a teacher to drive learning to a recognizable level regardless of the inconvenience encountered. This resilience was found critical in predicting PBL success in this inquiry.
Another remarkable finding related to learning effectiveness was that, in the short run, PBL students gained slightly less knowledge, but with longer interventions, they made significant progress in skill-based engagements such as report writing, presentation, and investigative inquiry. This supports the ideas raised by Ssemugenyi Ssemugenyi, 2022a); and  that the strength of PBL in imparting skills is not in dispute. That notwithstanding, proponents of the lecture method hold that it is the most flexible, economical, and reliable mode of instruction, but its usefulness has been undermined for many years (Killen, 2011). In view of this claim, it is clear that the delayed post-test lecture method recorded better scores than the immediate post-test, suggesting that although PBL was found to be a superior strategy at the delayed posttest, its value did not greatly exceed that of the lecture method. The message in this is that both instructional methods are effective if applied in conditions that permit their effective implementation.
At the immediate post-test, although the average scores for the control group were better than those for the experimental group, they were too low and unconvincing. Guided by the narratives of students and observation of the lecturer, it was found logical to manipulate the predictor variables for improved academic achievements. Given that students' complaints largely concerned the heavy learning load and many contact hours per week, the lecturer reduced them. The weekly contact hours were reduced from 3 to 2 and the focus was put on reducing the extraneous load and more of the germane load just to give learners space to solve the problems in need of high mental effort with less effort. This strategy corroborates the results of Hmelo-Silver (2004), F Kirschner et al. (2009), andSsemugenyi (2022a) who independently observed that a reduction in cognitive load usually has a positive effect on learning effectiveness.
Emerging prominently from the study findings is that, immediate feedback is critical to making PBL a successful endeavor. The researcher contends that, if it were not for the immediate post-test evaluation, it would have been very hard for him to identify students' learning challenges and develop feasible remedies to the said learning difficulties. This instructional component has proven effective in enhancing students learning precision across the three higher-order learning measures. Although Pearce et al. (2010) consider immediate feedback overwhelming and a burden to teachers, Stecker, Fuchs, & Fuchs (2005); and Hattie (2012) contend that immediate feedback has proved to be very helpful in enhancing learners' performance. True, in some rare cases, immediate feedback may be daunting to both learners and teachers especially if it is not purposeful, but if it is provided to refine the learning processes as the case was in this inquiry, then its usefulness cannot be underestimated.
Whereas PBL is regarded as a useful strategy for epistemological reforms in HE (Maudsley, 1999), its usefulness is challenged by the rigid nature of the ontological space. The belief that knowledge is absolute and exists in one's mind (Locke, 2015), has not only suffocated efforts of knowledge creation, but has also made teachers and learners assume that there is always only one way to know reality and that it is the responsibility of the teacher to dispense truth. It was noted with concern that, during the PBL tutorial presentations, most of the students lacked confidence in their own constructed knowledge and that of their peers. The belief that teachers are the only custodians of truth, undermined students' efforts towards knowledge creation and almost negated the implementation process of PBL mostly at the immediate post-test level. This was probably the case because of their prior learning experiences which were strongly inclined to regarding the teacher as the only source of wisdom. For no fault of their own, the fact that lecture presentations are usually logical, structured, and focused, (Scott et al., 2007) makes learners believe that is the best mode of learning.

Study implications
Whereas the impact of PBL may not be over-emphasized, it is not unreasonable to remember that it creates a major departure from the lecture method, and its implementation not only requires but demands a substantial commitment of resources without a guarantee of success (Boud & Feletti, 1991;Hallinger, 2010;Hallinger & Bridges, 2007;Margetson, 1991). The fact that CEODL at the time of this intervention was resource stricken, challenged the implementation of this pilot, for the researcher partially relied on his instructional resources to make the pilot a successful undertaking. The PBL method is a resource-intensive instructional strategy whose implementational success heavily hinges on available and accessible resources.
The desire to join the global movement towards the use of more active teaching and learning methods like PBL comes at a time when the Curriculum and Instructional Unit at the CEODL is not entirely prepared for such a radical shift. For instance, the curricula at the college are structured in a manner that conforms to the tenets of the lecture method, and substituting it for PBL may seem like turning a ship in the middle of the Suez Canal. Adopting a refined lecture method (participative/interactive lecture method) which presents challenges that are solvable through active and creative learning may be the most feasible undertaking at the moment in preparing for the years ahead. Meaningful learning occurs when students are presented with challenging situations which stimulate critical thinking and reasoning (Julie, 2004) all of which are attainable through the interactive lecture method.
Notably, emerging from the study findings is that students' cognitive development may not be sufficiently explained by instructional methods, but rather, by other variables of the prevailing institutional learning culture and the art of teaching. During the first phase of the treatment (immediate post-test), PBL almost failed and this was perhaps due to the sharp contrast the method caused in the learning culture and the absence of an institutionalized structure to support student-centric learning at the College and in the University at large. This may be a warning bell to other institutions with similar learning contexts, a mere change in the instructional method may not be an ultimate solution to teaching and learning challenges, but rather, would constitute a baby step in getting ready for more challenging learning encounters within the realm of student centric learning.
Although the performance of the control group compared well with the experimental group on the delayed post-test, it is important to note that the students' cognitive progress rate from the immediate post-test to the delayed post-test was very low and statistically negligible in the control group, yet sound and statistically significant in the experimental group. This may mean that, the predictive power of the lecture method in cognitive development holds within a very limited timeframe, beyond which, students get bored of the teacher's monotony and a decline in progress sets in. On the contrary, the PBL experience showed that the longer the timeframe of learning engagement, the greater the chances of improving students' learning proficiency and cognitive development. This agrees with Hallinger et al. (2011) who opined that over time, PBL produces positive effects on learning principles that underlie the creation and application of knowledge. In the same vein, Mohsen et al., (2018) consider the instructional proficiency of PBL to be high for longer durations of learning engagement.
The slow progress of the control group between the immediate post-test and delayed post-test confirms that the lecture method encourages cramming facts that are forgotten after a short while (Finucane et al., 1998). The overwhelming content load coupled with the vast amount of knowledge that needs to be covered in a restricted timeframe undermines the role of learning in shaping students' cognitive abilities. Although a negligible improvement was observed at the delayed-post-test in the control group, it was not clear if this improvement could be consistently demonstrated by the same group, in a different subject area, with a different teacher. On the contrary, a sharp improvement in cognitive abilities in the experimental group at the delayed-posttest, and the appropriate application of knowledge to different learning contexts is a testimony that PBL encourages knowledge creation and/or retention and supports meaningful use of knowledge in real-life situations.
The results further indicate that although PBL emerged superior at the delayed-post-test level, it did not deny lecture method the opportunity to shine. The academic gains of the control group were reasonably sound, a proof to support the proponents of lecture method that; it is a suitable teaching method in a learning context where student-centric methodologies are hard to support. At the College, the lecture method is the predominant instructional method, and students find it easy to learn through this method. However, it is noteworthy that, between the immediate posttest and the delayed post-test, this method was found to be very weak at stimulating earners, while PBL spurred cognitive development beyond the expected levels. This suggests that, while the College has no structures in place to support the full-scale implementation of PBL, it is an opportune time for the College to integrate PBL into the teaching and learning culture, for it has proved worthwhile. A blended learning mode (hybrid-lecture method) that integrates the components of PBL and the lecture method should be considered in preparation for pure PBL in the years ahead.

Conclusions and recommendations
While the differential effects of PBL on both lower-order and higher-order learning appeared to be non-significant at the immediate post-test, there is growing evidence at the delayed post-test that PBL produces positive effects on learning principles that underlie the creation and application of knowledge. Learners demonstrated strong abilities in creating their own knowledge through selfdirected learning and applying it to numerous learning contexts on a short-term (immediate posttest) and longer-term (delayed-post-test) basis. These findings support the view that PBL when well-implemented inculcates productive learning attitudes which empower learners to thrive in the practical world after university. To make PBL work, the College must institutionalize it (i.e., by refining curricula to suit PBL learning structures, refining teaching and learning policies, retooling teachers, and providing adequate resources to support its implementation).
Despite a heavier workload, students' instructional satisfaction significantly increased over time in the PBL group. At first, the performance of the group was poor, for learners struggled to adjust to the new learning style, while others resisted it claiming it was a ploy for the teacher to dodge his primary responsibilities. This partly explains why PBL scores were very poor at the immediate posttest. However, with persistence, both learners and the teacher came to value the benefits of the increased use of PBL in attaining the desired learning outcomes. This suggests that, for PBL to be successful both learners and teachers must be prepared to withstand pressure, and any form of inconvenience associated with its implementation. A significant improvement in cognitive development against a consistent corresponding reduction in the learning load was observed across the board although the statistical significance was greater in the experimental group at the delayed-post-test. This corroborates the view that effective learning takes place when there is little pressure on the mind and more on doing/action. This calls for a refinement in the existing curricula mostly on the aspect of the weekly contact hours and learning load. Reducing weekly contact hours from 3 to 2 without necessarily compromising the content scope, and refining the content to suit the PBL learning structure by reducing the extraneous load and more of the germane load may be regarded as a sound step in shaping the journey from lecture-based learning to a student-centric mode of learning. Although these recommendations are contextually credible, replicating them in other learning contexts, should be done with caution because this study only evaluated one subject (GEO 2202) of a program for a single semester, which may somewhat limit generalization.