There are any number of stimuli that could trigger thoughts about cheese. The smell of food, being hungry, a colour, another thought about a time in which you

There are any number of stimuli that could trigger thoughts about cheese. The smell of food, being hungry, a colour, another thought about a time in which you were hungry, something round, something wedge shaped.... The fact that humans are so bad at picking random numbers and so often pick 7 does not seem so unusual if we are based on patterns. Actually, that is the sort of emergent phenomenon that seems rather obvious to me.