|"We are but dreams amid wanton sleep..." Bloody Mary affiche by binarymind|
The fallacy that humans don't utilise the entirety of their brain mass has been dispelled over and over and while what I'm about to delve into is related to that, it's not the whole story...
Sci-fi often depicts advanced races as comprising of super intelligent beings that are able to perform mental gymnastics way beyond our paltry ability. Ignoring, for the moment, those sci-fi universes where embedded circuitry and other shenanigans improve the knowledge and processing power of intelligent beings to god-like levels, it is often assumed that with increasing technological prowess, increasing mental ability is attained.
It's interesting because there is not really any evidence to support this. Humans (specifically Homo sapiens sapiens), are not more intelligent despite our huge and exponentially increasing technological gains over the last two centuries. You can't even argue that we are smarter (with smartness being application of knowledge) because our knowledge base is expanding all the time so application of knowledge will always increase with an increase with available knowledge to draw upon.