I classmate in my abnormal psychology class asked our professor basically the same question. He prefaced it with there’s no blanket answer that covers this for everyone with a foot fetish, but there is/was apparently one commonly referenced example. He said it has to do with wiring of the brain & certain visual & behavioral connections made in formative years as a child when you are taught shame, & guilt in connection with nudity. To elaborate he said young kids are already taught not to be naked, & so they already think of seeing others naked is taboo. Now take a common occurrence like parents changing their own clothes or getting out of the shower & up until a certain age there’s no issue of your baby or toddler seeming you temporarily undressed. The problem comes in when they are just a bit older like 5 or more, & they accidentally see a parent nude. The learned shame & modesty now causes them to look down especially if the unaware parent is speaking to them. So the child faces with the discomfort of seeing their parent undressed & while not attracted to them it’s still triggering a natural response connected to sexuality. The child looking down though is generally seeing the parents feet hence the confusion & crossed wiring happening in their brain becoming hardwired to associate feet with sexuality.
