AUCTeX: turning off large fonts for section headings (in Emacs display)?

[Adam Funk]

I really like AUCTeX except for one thing: the oversized, variable-space
fonts used to highlight the arguments of sectioning commands.

Is it possible to turn this off?  I'd prefer for these fields to be
highlighted in bold or a dark colour (or both) but in the same
monospace font as the rest of the emacs display.

Thanks,
Adam