Jörg Wittwer

Why Instructional Explanations Often Do Not Work: A Framework for Understanding the Effectiveness of Instructional Explanations

Although explanations are a common means of instruction, research shows that they often do not contribute to learning. To unravel the factors giving rise to the ineffectiveness of instructional explanations, we propose a framework that brings together empirical work on instructional explanations from a variety of research fields, including classroom instruction, tutoring, cooperative learning, cognitive skill acquisition, learning from texts, computer-supported learning, and multimedia learning. In our framework, we identify the distinctive characteristics of instructional explanations, present general guidelines for designing instructional explanations, and describe factors influencing both the generation and use of instructional explanations. It is argued that future research should uncover in more detail the interrelations between the different aspects of providing and using instructional explanations and their specific effects on learning.

The worked-example effect: Not an artefact of lousy control conditions

Recently it has been argued that the worked-example effect, as postulated by Cognitive Load Theory, might only occur when compared to unsupported problem-solving, but not when compared to well-supported or tutored problem-solving as instantiated, for example, in Cognitive Tutors. In two experiments, we compared a standard Cognitive Tutor with a version that was enriched with faded worked examples. In Experiment 1, students in the example condition needed less learning time to acquire a comparable amount of procedural skills and conceptual understanding. In Experiment 2, the efficiency advantage was replicated. In addition, students in the example condition acquired a deeper conceptual understanding. The present findings demonstrate that the worked-example effect is indeed robust and can be found even when compared to well-supported learning by problem-solving.

Information about a layperson's knowledge supports experts in giving effective and efficient online advice to laypersons.

To give effective and efficient advice to laypersons, experts should adapt their explanations to the laypersons knowledge. However, experts often fail to consider the limited domain knowledge of laypersons. To support adaptation in asynchronous helpdesk communication, researchers provided computer experts with information about a laypersons knowledge. A dialogue experiment (N = 80 dyads of experts and laypersons) was conducted that varied the displayed information. Rather than sensitizing the experts to generally improve the intelligibility of their explanations, the individuating information about the layperson enabled them to make specific partner adjustments that increased the effectiveness and efficiency of the communication. The results are suggestive of ways in which the provision of instructional explanations could be enhanced in Internet-based communication.

How do Experts Adapt their Explanations to a Layperson's Knowledge in Asynchronous Communication? An Experimental Study

Despite a plethora of recommendations for personalization techniques, such approaches often lack empirical justification and their benefits to users remain obscure. The study described in this paper takes a step towards filling this gap by introducing an evidence-based approach for deriving adaptive interaction techniques. In a dialogue experiment with 36 dyads of computer experts and laypersons, we observed how experts tailored their written explanations to laypersons’ communicational needs. To support adaptation, the experts in the experimental condition were provided with information about the layperson’s knowledge level. In the control condition, the experts had no available information. During the composition of their answers, the experts in both conditions articulated their planning activities. Compared with the control condition, the experts in the experimental condition made a greater attempt to form a mental model about the layperson’s knowledge. As a result, they varied the type and proportion of the information they provided depending on the layperson’s individual knowledge level. Accordingly, such adaptive explanations helped laypersons reduce comprehension breakdowns and acquire new knowledge. These results provide evidence for theoretical assumptions regarding cognitive processes in text production and conversation. They empirically ground and advance techniques for adaptation of content in adaptive hypermedia systems. They are suggestive of ways in which explanations in recommender and decision support systems could be effectively adapted to the user’s knowledge background and goals.

Kann man dem Internet trauen, wenn es um die Gesundheit geht?

Zusammenfassung. In der vorliegenden Studie geht es um die Beurteilung der Glaubwurdigkeit und Verstandlichkeit medizinischer Informationen. In einem Vergleich zwischen den Medien Internet und Zeitschrift wurde an unabhangigen Stichproben experimentell uberpruft, welche Wirkung das Medium auf die von Laien beurteilte Glaubwurdigkeit und Verstandlichkeit der Informationen hat und ob die Bewertung zusatzlich durch die Aufbereitung der Informationen beeinflusst wird. Es zeigte sich, dass die in der Zeitschrift prasentierten Informationen unabhangig von der Gestaltung als signifikant glaubwurdiger beurteilt wurden als dieselben Informationen im Internet. Wahrend den Informationen mit Abbildungen ebenfalls mehr Glaubwurdigkeit zugeschrieben wurde, hatte die zusatzliche Aufbereitung des im Internet dargebotenen Texts mit Hyperlinks keinen Einfluss. Bezuglich der perzipierten Verstandlichkeit der Informationen ergaben sich keine Unterschiede zwischen den untersuchten Medien.

Does it Make a Difference? Investigating the Assessment Accuracy of Teacher Tutors and Student Tutors.

Tutors often have difficulty with accurately assessing a tutees understanding. However, little is known about whether the professional expertise of tutors influences their assessment accuracy. In this study, the authors examined the accuracy with which 21 teacher tutors and 25 student tutors assessed a tutees understanding of the human circulatory system in the course of tutoring. The authors found that the teacher tutors were more accurate than were the student tutors in assessing whether a tutee had a low or high level of knowledge about concepts relevant to the human circulatory system. In addition, in comparison with the student teachers, the teacher tutors more accurately assessed the number of concepts that a tutee would know. However, the teacher tutors and the student tutors did poorly in assessing a tutees mental model of the human circulatory system even though the teacher tutors were more aware of their assessment difficulties than were the student tutors.

Antezedenzien und Konsequenzen informellen Lernens am Beispiel der Mediennutzung von Jugendlichen

Wahrend die Bedeutung informeller Lernprozesse fur den Kompetenzerwerb unbestritten ist, liegen bislang wenige empirische Untersuchungen hierzu vor. Deshalb werden in diesem Artikel die Bedingungen und Konsequenzen informeller Lernprozesse am Beispiel der freizeitbezogenen Medienaktivitaten von Jugendlichen in den Blick genommen. Auf der Grundlage der PISA 2006-Stichprobe aus Deutschland wurde untersucht, in welcher Weise die Art der Mediennutzung durch die soziale Herkunft beeinflusst ist und sich differentiell auf die schulische Kompetenz auswirkt. Die Ergebnisse zeigten, dass sich Jugendliche in der Art ihrer Mediennutzung voneinander unterschieden, was zu einem erheblichen Anteil durch familiare Struktur- und Prozessmerkmale zu erklaren war. Zudem schienen Jugendliche, die vor allem anspruchsvollen Medienaktivitaten nachgingen, infolge informeller Lernprozesse hohere Kompetenzen in den Bereichen Naturwissenschaften und Lesen aufzuweisen. Die Befunde verdeutlichen die Wichtigkeit informeller Lernprozesse fur die schulische Kompetenz und lassen vermuten, dass soziale Ungleichheiten bei der Kompetenzentwicklung aufgrund einer unterschiedlichen Nutzung von Medien und damit einhergehenden informellen Lerngelegenheiten reproduziert oder gar vergrosert werden.

Scripting Laypersons’ Problem Descriptions in Internet-Based Communication with Experts

In the information age, laypersons have to rely on experts in many domains and situations. Expert advice can be invaluable, for example, when new and complex software has to be learned, or an unexpected technical problem with the computer suddenly occurs. In order to communicate effectively with experts, laypersons should be able to provide the expert with a concise and comprehensive description of their problem. However, previous research on computer helpdesks has shown that laypersons’ problem descriptions often suffer from a number of serious drawbacks. Their deficient and fragmentary knowledge makes it hard for them to formulate their queries in a way that would make it possible for the expert to understand their problem. Based on an analysis of these deficiencies, a problem formulation script was developed that supports laypersons in describing their problems with the computer. An experimental study showed that computer experts reconstructed the actual problem from the layperson’s description best if the laypersons were prompted to describe successively (1) the aim of their interaction with the computer, (2) the steps they had so far undertaken, and (3) a hypothesis why they had failed to reach the aim. The script helped the laypersons to provide the expert with the relevant context information necessary to develop an adequate mental model of the layperson’s problem.

What Influences the Agreement Among Student Ratings of Science Instruction

In multilevel research on classroom instruction, individual student ratings are often aggregated to the class level in order to obtain a representative indicator of the classroom construct under study. Whether students within a class provide ratings consistent enough to justify aggregation, however, has not been the object of much research. Drawing on data from N = 9524 students from 391 classes who participated in the national extension to the PISA 2006 study in Germany, the interrater reliability and interrater agreement of student ratings of science instruction were examined. Results showed that students within a class tended to accurately and reliably rate various aspects of their science lessons. However, agreement among ratings was influenced by class size, learning time, school track, and science performance. In multiple regression analyses, science performance turned out to be of particular importance in accounting for differences in the homogeneity of ratings. The findings suggest that agreement among students’ perceptions of instruction should be a central consideration for researchers using aggregated measures to examine classroom teaching.

Toward an Integration of the Learning and Communication Perspectives in Computer-Supported Instructional Communication

Research on computer-supported instructional communication (CSIC) involves the study of interactions between instructors, learners, and system components in computer-based learning environments. At least two strands of research can be identified that are crucial for the understanding of CSIC: From the learning perspective, rooted in cognitive and educational psychology, CSIC is analyzed with regard to its potential for promoting specific cognitive processes, and thus ultimately for improving learning. From the communication perspective, rooted in social psychology and communication science, CSIC is analyzed with regard to conditions that affect its effectiveness and efficiency. CSIC researchers face the challenge of integrating the two traditionally separate research strands and their distinct methodological frameworks. In turn, new methods and findings emerging from an integrative application of research methods are leading to new conceptual challenges regarding the causal mechanisms mediating between the interindividual and the intraindividual levels in CSIC. We provide examples of CSIC research that demonstrate successful methodological integration, and introduce open conceptual challenges.