Don't get me wrong, we do a lot of data science in the public sector these years, but we also measure it's efficiency and capability and compare it to the past 100 years of us doing the same thing without AI, and things haven't improved. At least not yet.
Mean while, the social sciences have given us tool that help us inflict actual lasting change on groups of people simply by using language in a specific way or working toward a shared consensus.
So maybe the question shouldn't be what social sciences have to offer AI research, but rather, what data science has to offer social fields.
I'm well aware that data science has it's value in other fields. We use it to troll through massive amounts case files and save thousands of man-hours in the process, but why would you want to use social science for that?