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As scientists who are interested in studying people's mental models, we must develop appropriate experimental methods and discard our hopes of finding neat, elegant mental models, but instead learn to understand the messy, sloppy, incomplete, and indistinct structures that people actually have. A complex dynamic system can be thought of as a collection of(More)
2 ABSTRAC T Measuring change in the mental models of the participants in systems thinking and system dynamics interventions is unavoidable if the relative effectiveness of different interventions in promoting learning is to be assessed. However, existing methods for organizing, representing, eliciting, and mapping mental models are designed primarily to(More)
A prominent television station developed a special series of newscasts and public service announcements about radon. This was combined with their advertising of the availability of reduced-price radon test kits in a local supermarket chain. The large number of test kits sold was a success from a marketing perspective, but not from a public health(More)
Educational programs leading to degrees in system dynamics are rare and thus of critical importance to the future of the field of system dynamics. However, to a large extent such programs have not yet been made transparent to the system dynamics community as a whole. The present article describes the design and rationale for undergraduate and graduate(More)
We demonstrate the tradeoffs between interpreting code in compact forms (such as the bytecoded method formats used in Smalltalk and Java), and direct execution of code (as in dynamic-translation Smalltalk and just-in-time Java compilers). Experiments with the interpreted Smalltalk language show that the widely held belief that direct execution is always(More)
There is a long-standing debate in the field of social psychology as to which is the primary determinant of behavior, the situation or system in which people act or the personalities of the role players. Psychologists have long studied this problem with controlled experiments on human subjects, and have now come to a general resolution of the debate.(More)
This is an Open Access journal. This means that it uses a funding model that does not charge readers or their institutions for access. Readers may freely read, download, copy, distribute, print, search, or link to the full texts of articles. This journal is covered under the CC BY-NC-ND license. Abstract It has long been recognized that engineers need a(More)