• Placebo button

    Placebo button

    • A placebo button is a push-button with apparent functionality that actually has no effect when pressed. Such buttons can be psychologically rewarding to pressers by giving an illusion of control. They are commonly placed in situations where it would have once been useful to have such a button but the system now proceeds automatically.

      In some cases the button may have been functional, but may have failed or been disabled during installation or maintenance or was, in a relatively small number of cases, installed to keep people contented, much in the same way as placebos.

      In many cases a button may appear to do nothing but in fact cause behavior that is not immediately apparent; this can give the appearance of it being a placebo button.

      Many walk buttons at pedestrian crossings were once functional in New York City, but now serve as placebo buttons.

      In the United Kingdom and Hong Kong, pedestrian push-buttons on crossings using the Split Cycle Offset Optimisation Technique may or may not have any real effect on crossing timings, depending on their location and the time of day, and some junctions may be completely automated, with push-buttons which do not have any effect at all. In other areas the buttons only have an effect during the night.

      London Underground , and include door control buttons. The doors are normally driver operated, but a switch in the driving cab can hand control to passengers once the driver activates the buttons, much like mainline railway stock. In addition, used on the District line were built with door open buttons which worked much like those of the 1992, 1995 and 1996 stock. These buttons were subsequently removed when the stock was refurbished.

      It has been reported that the temperature set point adjustment on thermostats in many office buildings in the United States is non-functional, installed to give tenants' employees a similar illusion of control. In some cases they act as input devices to a central control computer but in others they serve no purpose other than to keep employees contented.

      A common implementation in buildings with an HVAC central control computer is to allow the thermostats to provide a graded level of control. Temperatures in such a system are governed by the central controller's settings, which are typically set by the building maintenance staff or HVAC engineers. The individual thermostats in various offices provide the controller with a temperature reading of the zone (provided the thermocouples are not installed as inline duct sensors), but also serve as modifiers for the central controller's set point. While the thermostat may include settings from, for example, 60 to 90 °F (16 to 32 °C), the actual effect of the thermostat is to apply "pressure" to the central controller's set point. Thus, if the controller's setting is 72 °F (22 °C), setting the thermostat to its maximum warm or cool settings will deflect the output temperature, generally by only a few degrees Fahrenheit (about two degrees Celsius) at most. So, although the thermostat can be set to its lowest marking of 60 °F (16 °C), in reality, it may only change the HVAC system's output temperature to 70 °F (21 °C). In this case, the thermostat has a "swing" of 4 °F (2 °C) — it can alter the produced temperature from the main controller's set point by a maximum of 2 °F (1 °C) in either direction. Consequently, while not purely a placebo, the thermostat in this setup does not provide the level of control that is expected, but the combination of the lower setting number and the feeling of a slight change in temperature can induce the office occupants to believe that the temperature was significantly decreased.

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    • Placebo button