Why and when might someone’s (individual) performance be better or worse in the presence of others versus alone?

Why and when might someone’s (individual) performance be better or worse in the presence of others versus alone? Give an example of each circumstance (e.g., alone, in front of others vs. complex task, simple task). Make sure to relate these examples to the theories of audience arousal. Similarly, why and when might individual performance be better or worse in group performances? Give an example of each and relate it to the theories of social loafing.