"Affective" means causing emotional feelings. "Effective" means sensibly producing the desired result, assuming you know what that result is. Took me almost 60 years to grasp the distinction long enough to retain it for more than three and half minutes. Affective in the title "Reducing Affective Partisan Polarization" means reducing the level of emotion, or hostility, in partisan polarization. The subtitle of the study is the question "Warm Group Relations or Policy Compromise?" One argument as to why everyone seems to hate each other has to do with policy differences, and it's these policy differences that cause the sets of emotions that lead to hostility and an angry partisan divide that doesn't respond well to, let's call it discourse.
The other argument suggests that policy differences are fairly eternal and goes on to suggest that emotions that lead to hostility over policy differences are much ameliorated when leaders are seen to get along with each other, express comradeship in a warm and friendly kind of way without too much hugging and kissing, but certainly not shouting at each other, getting red in the face and saying things like 'what goes around comes around.' In other words, at heart, we're still more like Chimpanzees. The whole study makes huge sense to a gardener affectively struggling with his winter ground covers, weed seeds in his compost, rock hard ground, drought and the physical capacities of what effectively might just as well be a 900 year old Octopus lubbering around on land.