Psychologists are interested in studying biological rhythms because these rhythms play a crucial role in human behavior and cognition. Biological rhythms, such as the sleep-wake cycle or circadian rhythms, influence our sleep patterns, mood, and cognitive performance. Understanding how these rhythms impact human functioning can help psychologists develop interventions and treatments for sleep disorders, mood disorders, and other conditions related to disruptions in biological rhythms. Additionally, studying biological rhythms can provide insights into the impact of lifestyle factors, like shift work or jet lag, on human functioning.