April, a music major, and her boyfriend Hassan, who is a mechanic, have been dating for more than a year. They frequently do things April likes to do, such as going to concerts, dancing, and eating out with friends. One Tuesday night, they were discussing what they could do together during the upcoming weekend. April was excited about some free tickets to a jazz concert her friend had given her, and Hassan agreed to go.
The day before the concert, April asked Hassan if he was looking forward to it. He shrugged his shoulders, looked at the floor, and mumbled, "Yeah, sure." April was confused. "You said you wanted to go. I don't understand," she said. April and Hassan talked for a while. They decided that April would attend the jazz concert with friends, and then April and Hassan would go out together the following night. April and Hassan went to the new Fast & Furious movie and then to a local bar for a few games of pool.
Which of the following nonverbal communication characteristics most likely explains why April and Hassan changed their plans?