Case: Thermostats — Folk Theory vs Good Model
The folk-theory problem: Most people hold a wrong "valve" model of a thermostat — believing setting it to maximum heats/cools the room faster. In fact most home thermostats are on/off switches and most heating/cooling is all-or-nothing: setting the extreme doesn't speed anything and causes overshoot + wasted energy. The ordinary thermostat gives almost no evidence of how it works → people invent a false story (see "People as Storytellers").
The good counterexample — Nest (Nest Labs): A thermostat designed to project a correct model:
- Colorful display, normally off, turns on when it senses you nearby.
- Shows current temperature, target temperature, and whether heating (orange) or cooling (blue) or neither (black).
- Gives predictive feedback: "Now 75°, will be 72° in 20 minutes."
- Learns daily patterns; switches to "away" mode automatically; companion app gives detailed energy analysis.
Lesson: As sensor/display costs dropped, designers can now provide rich feedback that helps users build accurate conceptual models — of both the device and the home's energy use. "Is Nest perfect? No, but it marks improvement in the collaborative interaction of people and everyday things."
(Same chapter: praise for Microsoft's calendar accepting any date/time/phone format — accommodating people instead of forcing rigid input.)
Confidence
1.0 — explicit contrasting cases.
Sources: ["DOET ch.2 'Providing a Conceptual Model for a Home Thermostat' p.68-69; 'People as Storytellers' p.57-59"]