psych research applied to persuasion on the topic of abortion

Within the practical (vs. ethical) arguments on abortion, here's Professor of Psychology Nicholas DiFonzo in First Things on perceptions of outcomes and its impact on one's position.

This will be increasingly important as pro-choicers move from subjective metaphysical claims on abortion-- toward science, civil rights, and logic.

Cognitive research shows how our attitudes about an issue can be strongly predicted by how likely we think certain possible results of an action (like changing the legal status of abortion) will be and also by how bad or good we think those results will be.

For example, those who think that making abortion illegal will cause women to seek “back alley” abortions and who view this outcome as a great evil will likely be pro-choice. Those who think that making abortion illegal will save the lives of innocent babies and consider this result a great good will likely be pro-life. The pro-life movement can persuade others most effectively not by arguing philosophically for the humanity of the unborn (though those arguments must be made), but by battling misinformation about the nature and likelihood of specific results of abortion...

He cites research that:
 
Pro-choice students changed stances more often than pro-life students did, largely because pro-life students had already considered challenges to their own position, whereas pro-choice students tended not to have done so. The attitudes of pro-choice students were more susceptible to challenge because they had not critically evaluated them. These results suggest that persuasive pro-life strategies ought to include multiple simple challenges to the pro-choice position that are unlikely to have been considered.

But he also notes that "one’s position on abortion is rarely only a matter of knowledge. It also involves personal, and typically emotional, interests."

Citing other research...

...pro-choice people who were asked to assume the role of a Democratic legislator conceded more to a pro-life negotiator when they had just written about a personal characteristic that was important to them...The insight to be gained here is that in attempts at persuasion it is important to take into account underlying defensive motivations. One cannot ignore defensive sentiments and rely solely on cognitive challenges or logic.

And then...

One final thought: Getting people to think about an issue more deeply by “staying the course” is key to changing minds. Civil-rights advocates, for example, persisted in calling for equal rights despite enduring contempt, hatred, and even violence. They grounded their movement in biblical injunctions of equal dignity for all human beings, values that the people they were trying to persuade held, though they did not apply them to civil rights. Many people who held them formed their opinions privately at first but later reached a “tipping point”...