Positive and Negative Reinforcement & Differentiation for Engagement

At the end of a lecture with the sophomores, Bill asked me a couple of questions. I copied them down (and elaborated on them) below:

• How was positive and negative reinforcement used?
• The class seemed kind of slow to answer questions; it felt like they were guessing at the answers rather than answering from what they knew. When they answered incorrectly, Bill would sometimes ignore their guess and others he would explain why their answer was wrong. But at times when the class should have known the answer, the class was "scolded" as a group.
• One of the student's answers, even though it was wrong, was praised because it was "on the right track". (He said it was Haiti that gained independence in 1776). 
• Directly after class, students that stood out in the lecture were also praised. 

• To what extent was there differentiation to create engagement in the lesson?
• It didn't really feel like there was much differentiation for engagement. It felt like everyone was "on the same boat"; some students knew some things and others knew other things, but in general the whole class was having trouble and benefited from placing events in context.