First, we will define each.
Improvise is the impromptu do of things. Ostentation is the exaggerated
display of knowledge to attract affirmation from others. Speculate is to make
guesses without prior evidence. Visionary is trying to foresee the future and
making plans about it.
Out of the 4, speculate does not utilize the logical/rational/left side
of the brain. It uses the gut feeling, to decide and give opinion on things and
events. This is different from improvise as it needs quick thinking and the
ability to think with inititative.
