This paper does not mention IQ or giftedness (going by media coverage and the abstract), but I'd guess that higher-IQ people are less disturbed by the lack of external stimuli, although the sex difference found in the paper indicates that it's not just a matter of IQ. I wonder if the ability to just think without stimuli can be fostered.

http://www.sciencemag.org/content/345/6192/75
Just think: The challenges of the disengaged mind
by Timothy D. Wilson et al.
Science 4 July 2014:
Vol. 345 no. 6192 pp. 75-77
Abstract:
In 11 studies, we found that participants typically did not enjoy spending 6 to 15 minutes in a room by themselves with nothing to do but think, that they enjoyed doing mundane external activities much more, and that many preferred to administer electric shocks to themselves instead of being left alone with their thoughts. Most people seem to prefer to be doing something rather than nothing, even if that something is negative.

Discussed in the Washington Post at http://www.washingtonpost.com/news/...selves-than-be-alone-with-their-thoughts .