[uriegas]

I agree. Most of the time people think STEM is harder but it is not. Yes, it is harder to understand some concepts, but in social sciences we don't even know what the correct concepts are. There hasn't been so much progress in social sciences in the last centuries as there was for STEM.

[diamondage]

I'm not sure if you're correct. In fact there has been a revolution in some areas of social science in the last two decades due to the availability of online behavioural data.

[uriegas]

Yeah, there is also the work of primatologists which challenges some of our beliefs of what we think is human sciences (like politics). See Frans De Waal.

Yet, I believe there hasn't been much progress as compared with STEM. But it is just a belief at the end of the day. There might be some study about this out there.