Complex sentence: The students were more likely to pair attractive people with desirable positions on the given issue, and more likely to be persuaded by an attractive speaker to take an undesirable position on a topic than by an unattractive speaker.
Split into simpler sentences: The students were more likely to pair attractive people with desirable positions on any given issue. They were also more likely to be persuaded by attractive speakers to take an undesirable position on a topic than by an unattractive speaker.