Shadur's answer has the gist but I will add more details.
Basically it allows you to pick the dialogue choices that are most likely to convince the person you are speaking to. In short it comes with the pheromones and you can match those to the right person whatever the first high rating is the subject will be. For example, a guy who scores two alphas then two beta will be an alpha, but if they score three omega then they are omega.
Alphas are best spoken to either by Redirecting or appeasing they are actually the easiest to beat in social battles because the appease option will most always work though be careful not to use the other as you will end up losing out quickly.
Betas are harder because they often mix with either Alpha or omega and only listen to rational arguments Luckily there's a grand total of 5 betas in the game. Betas respond to the charm tactic and facts.
Omegas are easy to negotiate with like alphas but be careful as two omegas in the game can mess up later levels badly and others will cause a drop in potential rewards, they respond to the pressure tactic (aka hard speech tough love etc).
Two characters have all three classes: Malik And Zelazny. They cannot be negotiated with at all but you can get extra dialogue from them.
There are tips on one side about the social boss battles that make them easier (Sarif is very easy thanks to this) besides that there are small line next to the dialogue options that help there too they look somewhat like this:
///// ones with longer dashes are better options.
One pro tip: don't guess the type by appearance or character in the game, some are not clear cut and others are strongly one way when you would think they are the other just look at the boxes others can be a royal pain in the ass even with the mod (Taggart and Tong in particular) generally as a hard and fast rule though:
- Appease/ redirect an Alpha
- Charm/ Compliment a Beta
- Pressure/ persist an omega.
Always choose the Dialogue with the most
///////////// on it and you will do fine.