Final answer:
Men have traditionally taken part in psychological studies more often than women due to gender bias and historical gender roles.
Step-by-step explanation:
The reason why men have traditionally taken part in psychological studies more often than women is due to gender bias and the Historical gender roles and expectations placed on men and women. Throughout history, there have been societal beliefs about the different abilities and characteristics of men and women. For example, it was widely believed that men were better at math and spatial relationships, while women were better at language skills. These beliefs led to a focus on studying men more often in certain areas of research, including psychology.