Surely, upon an increase in temperature, the atoms within the thermistor would vibrate with more energy and therefore more vigorously, hence making the electrons flowing through the electric circuit more likely to collide with one of the atoms, so increasing resistance.
However, the effect of temperature on a thermistor is contrary to this. I can't understand how it can be.
It's analogous to running across a playground: if everyone is still you're less likely to collide with someone, however if everyone is constantly moving from left to right then a collision is more likely.
So why does an increase in temperature decrease the resistance of a thermistor?