Phase I: On, Off, or Asleep?: User Perceptions of Power Controls on Common Office Equipment
This survey investigated existing consumer attitudes and perceptions concerning power control symbols and indicator lights on standard office equipment. In addition to determining existing attitudes towards indicator light colors and states, sleep symbols, and power states, we also test users reaction to two different standards power state symbols: the existing international standard and one proposed by the Lawrence Berkeley National Laboratory (LBL).Results indicate that users found the proposed LBL standard more intuitive. Users interpreted the proposed LBL standard in a more consistent manner than they did the current international standard.

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Phase II: Power Controls -- Form and Function: Mapping the User's Mental Model
The experiment described in this study investigates existing consumer expectations of power control button functionality - - given the symbolic form of the button.  This is Phase II of the Power Controls project for the Lawrence Berkeley National Laboratory (LBL).  In Phase I of this project we determined that the power control symbols proposed by the LBL are more intuitive to users - as compared to the current international standard.  Results of Phase II indicate that users of electronic devices have a definite mental model of power control button behavior that is partly based on the symbolic form of the button.  Results indicate that while users expect the LBL sleep symbol button to move the device into the sleep state from the on state, their general attitude is that device go into sleep mode automatically or through the use of software controls - - not through the use of a button.  About fifty percent of users expect pressing the LBL sleep symbol button to wake the device up when it is already in the sleep state.  Thus, based on user expectations of functionality, the LBL sleep symbol button need not be a toggle switch.  Users are more likely to press the LBL power button than the LBL sleep symbol button to wake a device from the sleep state.  Based on current expectations, redundancy should be built into the LBL power symbol button such that when a device is asleep, pressing the LBL power symbol would wake it up.  In other words, the function of the LBL power button should differ based on the current device state.

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