What?? No. A thermostat is like a light switch only controlled by heat. In the case of the wafer thermostat, it is wired in between the heat source and the electricity source. The wafer itself is filled with ether. When heated, it expands and presses a microswitch, turning the light and heat off. When it cools off about .5 of a degree, it has shrunken enough to release the switch and complete the circuit, letting the light turn on again. It's a pretty sensitive mechanism. I have about a 15-30 cycle in my incubator if I remember correctly.
A thermometer simply measures the temperature, and the hygrometer measures humidity levels. It will not influence them.