Figures missing from PDF version:

• Figure 2. Coaching on an ambiguous support relation involving an And link.
• Figure 3. Expert Belvedere diagram for the TWA 800 crash problem.
• Figure 4. Coaching that recommends a non-obvious diagramming action.
• Figure A1. Example screen layout for the experimental sessions.
• Figure A2. Screen after clicking on "Evidence for this hypothesis".
• Figure A3. Screen after clicking on "Plane's proximity to dry land", clicking on Data icon, and copying statement.
• Figure A4. Screen after placing new Data box in diagram.
• Figure A5. Screen after drawing For link from new Data box to an existing Hypothesis box.
• Figure A6. Screen after clicking on "Consider Possible Causes".

Figure 2. Coaching on an ambiguous support relation involving an And link.

Figure 3. Expert Belvedere diagram for the TWA 800 crash problem.

Figure 4. Coaching that recommends a non-obvious diagramming action.

Figure A1. Example screen layout for the experimental sessions.

Figure A2. Screen after clicking on "Evidence for this hypothesis".

Figure A3. Screen after clicking on "Plane's proximity to dry land", clicking on Data icon, and copying statement.

Figure A4. Screen after clicking on "Plane's proximity to dry land".

Figure A5. Screen after drawing For link from new Data box to an existing Hypothesis box.

Figure A6. Screen after clicking on "Consider Possible Causes".