according to a report in the daily telegraph if you won't to be seen to be an expert you need to point.
the finger alerts people to your authority.
the report says that children learn from an early age that the finger pointing rquates to something important.
so if you have to tell someone something you want them to take notice of you need to use the finger.
just in case you need some tips on which fingers to use.
this one is effective in some situations but is more antagonistic than being an expert.
this classy use of the finger (well fingers) is especially poignant for the french. also known as the reverse churchill.
probably best to avoid this one as well when you are trying to expand on your point.
in order to show that you really know your stuff and that you are the knowledgable one then i suggest that you use this one.
and use it liberally and everyone will bow to your wisdom.
trust me i read it in the daily telegraph