What is a "purpose"? Something people wish something would only be used for, right? How does it relate to, what influence does it have on what something will end up being used for?
(STS seems to be https://en.wikipedia.org/wiki/Superior_temporal_sulcus in the temporal lobe, so I guess it's the "I sense a presence" region.)
Explain the potential to exploit strong stimulation of specific visual regions for evil. "Oh, I very much detect a face/place/body/motion/pattern/human", says the subject. What are you going to do with that, startle them?
IMO it's terrifying to imagine that adtech companies could plug this stuff into their optimizers and just run an experiment on broad swaths of the population to figure out if there's any effects.
What exactly is your new fear here?