[Psientist]

There are many times during midgame when I asked myself - which would be faster, researching to the next level of Evocation (or whatever), or taking Thaumaturgy (or whatever) from level 0 to 4?

Here is the standard research point requirement per level (not cumulative). It seems to be independent of era.

Research to level # / # of points needed
1=40
2=60
3=100
4=160
5=260
6=420
7=680
8=1100
9=1780

Note that this works out as each new level costs as much as the previous two levels added together (e.g., level 4 points = level 3 points + level 2 points).

Also note this was collected using "standard research" settings.