Editing Problem-based learning (section)

===Cognitive load===
Sweller and others published a series of studies over the past twenty years that is relevant to problem-based learning, concerning [[cognitive load]] and what they describe as the guidance-fading effect.<ref name="Sweller_2006">{{cite journal|last1=Sweller|first1=John|year=2006|title=The worked example effect and human cognition|journal=Learning and Instruction|volume=16|issue=2|pages=165–169|doi=10.1016/j.learninstruc.2006.02.005}}</ref> Sweller et al. conducted several classroom-based studies with students studying algebra problems.<ref name="Sweller_1988">{{cite journal|last1=Sweller|first1=J|year=1988|title=Cognitive load during problem solving: Effects on learning|journal=Cognitive Science|volume=12|issue=2|pages=257–285|doi=10.1016/0364-0213(88)90023-7|doi-access=free}}</ref> These studies have shown that active problem solving early in the learning process is a less effective instructional strategy than studying [[Worked-example effect|worked examples]] (Sweller and Cooper, 1985; Cooper and Sweller, 1987). Certainly active problem solving is useful as learners become more competent, and better able to deal with their working memory limitations. But early in the learning process, learners may find it difficult to process a large amount of information in a short time. Thus the rigors of active problem solving may become an issue for novices. Once learners gain expertise the [[Instructional scaffolding|scaffolding]] inherent in problem-based learning helps learners avoid these issues. These studies were conducted largely based on individual problem solving of well-defined problems.

Sweller (1988) proposed [[cognitive load]] theory to explain how novices react to problem solving during the early stages of learning.<ref name=Sweller_1988 /> Sweller, et al. suggests a worked example early, and then a gradual introduction of problems to be solved. They propose other forms of learning early in the learning process (worked example, goal free problems, etc.); to later be replaced by completions problems, with the eventual goal of solving problems on their own.<ref>{{cite journal|last1=Sweller|first1=John|last2=Van Merrienboer|first2=Jeroen J. G.|last3=Paas|first3=Fred G. W. C.|year=1998|title=Cognitive Architecture and Instructional Design|journal=[[Educational Psychology Review]]|volume=10|issue=3|pages=251–296|doi=10.1023/A:1022193728205|s2cid=127506}}</ref> This problem-based learning becomes very useful later in the learning process.

Many forms of scaffolding have been implemented in problem-based learning to reduce the cognitive load of learners. These are most useful to enable decreasing ("fading") the amount of guidance during problem solving. A gradual fading of guidance helps learners to slowly transit from studying examples to solving problems. In this case backwards fading{{clarify|date=November 2017|reason=The Hmelo-Silver reference is hidden behind a paywall, so checking the reference to decipher "backwards fading" is forbidden to most Wikipedia readers.}} was found to be quite effective and assisting in decreasing the cognitive load on learners.<ref name="Hmelo2004">{{cite journal|last1=Hmelo-Silver|first1=Cindy E.|year=2004|title=Problem-Based Learning: What and How Do Students Learn?|journal=Educational Psychology Review|volume=16|issue=3|pages=235–266|doi=10.1023/B:EDPR.0000034022.16470.f3|s2cid=15702585}}</ref>

Evaluation of the effects of PBL learning in comparison to traditional instructional learning have proved to be a challenge. Various factors can influence the implementation of PBL: extent of PBL incorporation into curriculum, group dynamics, nature of problems used, facilitator influence on group, and the motivation of the learners. There are also various outcomes of PBL that can be measured including knowledge acquisition and clinical competence.<ref name="Neville_PBLmedicaledu40yrs">{{cite journal|last1=Neville|first1=Alan J.|year=2009|title=Problem-Based Learning and Medical Education Forty Years on|journal=Medical Principles and Practice|volume=18|issue=1|pages=1–9|doi=10.1159/000163038|pmid=19060483|doi-access=free}}</ref><ref>{{cite book|url=https://books.google.com/books?id=Hac-uARBrdgC&q=Factors+affecting+small-group+tutorial+learning:+a+review+of+research.+&pg=PA19|title=Problem-based learning : a research perspective on learning interactions|last=Schmidt|first=H. G. and Moust, JHC|publisher=L. Erlbaum|year=2000|isbn=978-0805826456|location=Hillsdale, N.J.|pages=19–51}}</ref> Additional studies are needed to investigate all the variables<ref name=Neville_PBLmedicaledu40yrs /> and technological scaffolds,<ref>{{cite journal|last1=Henry|first1=Holly R.|last2=Tawfik|first2=Andrew A.|last3=Jonassen|first3=David H.|last4=Winholtz|first4=Robert A.|last5=Khanna|first5=Sanjeev|year=2012|title="I Know This is Supposed to be More Like the Real World, but . . .": Student Perceptions of a PBL Implementation in an Undergraduate Materials Science Course|journal=Interdisciplinary Journal of Problem-Based Learning|volume=6|doi=10.7771/1541-5015.1312|doi-access=free}}</ref> that may impact the efficacy of PBL.