Final answer:
The Hawthorne study showed that the Hawthorne effect was primarily influenced by social factors, such as clear communication and unity of command.
Step-by-step explanation:
The Hawthorne study conducted by Elton Mayo and his colleagues at Western Electric's Hawthorne Works demonstrated the presence of the Hawthorne effect. The researchers found that the increase in productivity was not solely due to economic incentives (A) or changed physical conditions (C), but rather, it was primarily influenced by social factors, such as clear communication (D) and unity of command (E). They discovered that individuals performed better when they were observed by researchers or supervisors, indicating that the attention and interaction from those in authority had a positive impact on productivity.