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Frequently Asked Questions


What is the LearnLab?

Learnlab is a facilty designed to dramatically increase the ease and speed with which learning researchers can create the rigorous, theory-based experiments that pave the way to an understanding of robust learning.

Run jointly by Carnegie Mellon University and the University of Pittsburgh, LearnLab makes use of advanced technologies to facilitate the design of experiments that combine the realism of classroom field studies and the rigor of controlled theory-based laboratory studies.

PSLC's LearnLab is a national resource for learning research that includes:

  • Authoring tools for online courses, experiments, and integrated computational learner models
  • Support for running in vivo learning experiments
  • Longitudinal microgenetic data from entire courses
  • Data analysis tools, including software for learning curve analysis and semi-automated coding of verbal data.

learn more..

What is in vivo experimentation?

Rigorous experimentation with laboratory-quality methods in real classroom settings.

Features of an in vivo learning experiment include: extending realism to an existing laboratory result, extending rigor to an existing classroom result, extending generalization to a result from a different domain, using rigorous experimental design features like random assignment, using technology to provide tight control on the micro-structure of instruction, making use of fine-grained longitudinal data by analyzing second-by-second interactions happening over weeks, and coding and analyze such data in terms of general cognitive theory and a specific theory of domain knowledge.  It is precisely these features that PSLC allows researchers to more easily address as never before. 


What is robust learning?

Learning is robust if the acquired knowledge or skill meets at least one of the following three criteria:

 Retention: It is retained for long periods of time, at least for days and even for years.

 Transfer: It transfers, that is, it can be used in situations that differ significantly from the situations present during instruction.

Future Learning: It accelerates future learning. That is, when related instruction is presented in the future, this knowledge allows them to learn more quickly and effectively learn from it.


How is in vivo research conducted?



The PSLC component relationships are displayed above.  Using in vivo experimentation, principles of robust learning are tested in studies that occur in actual classrooms (LearnLab Courses) during an actual course.  This leads to a better understanding of learning theory which, in turn, leads to more in vivo experimentation.  PSLC Enabling Technology supports these activities by providing course development, logging, and analysis tools.

Research is conducted in seven core LearnLab courses: Algebra, Geometry, Physics, Chemistry, French, Chinese and English as a second language.  These courses as well as some affiliate courses host PSLC’s in vivo experimentation. 


How is running a in vivo study different from running a lab study?

To test a hypothesis requires a tightly controlled design where the only difference between experimental and control conditions is the principle being tested.  For the test to be useful and trustworthy, it should meet as many of the features of an in vivo learning experiment as possible: extend realism to an existing laboratory result, extend rigor to an existing classroom result, extend generalization to a result from a different domain, use rigorous experimental design features like random assignment, use technology to provide tight control on the micro-structure of instruction, make use of fine-grained longitudinal data by analyzing second-by-second interactions happening over weeks, and code and analyze such data in terms of general cognitive theory and a specific theory of domain knowledge.  It is precisely these features that PSLC allows researchers to more easily address as never before. 


What do I do if I have problems with a LearnLab course chair or with a LearnLab teacher?

If you are having difficulties with a course chair and you feel that your issues cannot be resolved amicably, please see the PSLC Managing Director, Michael Bett.  Michael will negotiate with the course chair and the researcher in order to find a workable and amicable solution.

If you are having difficulties with a course instructor that you feel cannot be resolved, please contact both the Course Leader and the PSLC Site Manager (or the PSLC Managing Director).  All of these folks will work together to resolve the issues.



Using the PSLC Website

Who is the PSLC webmaster? 

Michael Bett currently manages the PSLC website.  Contact Michael with any issues regarding the PSLC website.


What mailing lists are there and how so I subscribe?

Mailing lists exist for each thrust, LearnLab course, graduate students, and executive committee as well a general announcement list. To subscribe to one or more of these mailing lists, contact Jo Bodnar via email (jobodnar @


How do I get events added to the PSLC calendar?

To have an event added to the calendar, contact Jo Bodnar (jobodnar @ If you will need to have regular access to the calendar to add or modify events, contact Michael Bett.




Publications & Conferences:

How do I acknowledge funding and support provided by PSLC?

In the acknowledgements section of your paper please state:

Funding for this research was provided by the Pittsburgh Science of Learning Center which is funded by the National Science Foundation award No. SBE-0836012.


Where can I find a list of educational technology conferences?




Where can I find a list PSLC publications?

PSLC publications are listed under research on the PLSC webpage. See


Is there a PSLC reprint/publication print series?

No, but most of the PSLC related papers can be found on our publications page.  See




The DataShop team maintains an FAQ on their site.




What is CTAT?

CTAT stands for the Cognitive Tutor Authoring Tools.  These tools can be used to create computer-based tutors for use in LearnLab experiments and LearnLab courses in all 7 LearnLab subject matter areas.

 CTAT supports two types of tutors. Example-Tracing Tutors can be built without programming. Cognitive Tutors require Artificial Intelligence programming to develop a cognitive model. Both types of tutors provide step-by-step assistance to students as they solve problems.

 CTAT builds on the success of the Cognitive Tutors for high-school math, which were developed at CMU and have been proven to improve student learning, compared to regular classroom instruction.  More information can be found about CTAT by going to

What is the role of CTAT in LearnLab?

CTAT is a key enabling technology within the PSLC. Tutors built with CTAT are suitable vehicles for a particular type of in vivo experiment, in which tutors are used to deliver experimental treatments. The advantages of using computer tutors for that purpose are that one can administer experimental treatments in a consistent manner (e.g., no unwanted “random” variability) and ensure detailed logging of student activities in DataShop format. CTAT can also be used by LearnLab course developers to add tutoring capability to their courses.

How do I budget for help from the CTAT team in my project plan?

 The CTAT project team offers consulting and technical services to the PSLC community, as part of their mission within the PSLC. It also tries hard to be driven by requests from real users when implementing new features. To find out more about how you can use CTAT consulting resources, or to suggest a new CTAT feature, contact either Vincent Aleven (aleven @ <mailto:aleven @>) or Bruce McLaren (bmclaren @ <mailto:bmclaren @>).


How do I record logs of student activities with CTAT-built tutors?

All CTAT tutors have easy to switch on / switch off logging support. These tutors log a detailed record of all student-tutor interactions to the PSLC DataShop, a service offered by the PSLC for recording and analyzing data from LearnLab experiments. These facilities make it possible to do detailed analyses of students’ learning trajectories and also to do longitudinal analyses.

A comprehensive FAQ on logging to the PSLC DataShop exists on the DataShop web site:

 In order to make it possible to provide logging from (Java or Flash) applications that are not built with CTAT, Java and Flash logging libraries are made available separately (see

Can I use Flash with CTAT-built tutors?

CTAT supports tutors whose user interface is built in either Flash or Java.  This goes for Example-Tracing Tutors and Cognitive Tutors.

Tutors with a Flash interface provide somewhat better web delivery of Example-Tracing Tutors than tutors with a Java-based interface. However, Cognitive Tutors built with a Flash interface do not yet run over the web. They do run locally. This restriction is likely to be lifted in the future, so please check back with us.


Can I use CTAT to build tutors that work on the web?

Yes. Flash-based Example-Tracing Tutors run on the web. Java-based Example-Tracing Tutors and Cognitive Tutors run on the web, using Java Webstart technology. In the future, we are likely to extend CTAT so that all Flash-based tutors run on the web (i.e., Example-Tracing Tutors and Cognitive Tutors).


How do I extend CTAT so that it is better suited for the way I plan to use tutors in one of the LearnLab courses?

 The short answer is: if you need some capabilities that CTAT does not provide and have the technical means to implement them yourself, the CTAT team will likely (a) make the necessary source code available to you and (b) offer to consult with you on how to design your new feature and code modifications in such a way that they will likely be of benefit to other PSLC researchers.

One way to extend CTAT’s capabilities that may be attractive to development teams within the PSLC is to add to CTAT’s set of interface widgets. CTAT comes with a variety of “tutorable” Java and Flash widgets that allow you to build tutors without programming. Those who need new widgets can create them either in Flash or in Java. These new widgets must be made to observe the API for CTAT tutor widgets. Once a new widget is built, it can be used to develop tutors in the usual way. For example, Example-Tracing Tutors that include the new widget can be developed without programming.

The Flash-based tutor widgets can be customized relatively easily, by writing ActionScript without having to author complex event listeners and handlers; you only need to define the code that runs when student input in a widget is marked as correct or incorrect.

Contact either Vincent Aleven (aleven @ or Bruce McLaren (bmclaren @, to find out how to get help in extending/customizing CTAT.