One of the many pitfalls in science is that researchers are prone to psychological biases, one of which is the streetlight effect. The streetlight effect is a type of observational bias that occurs because people are more likely to search for something where it is easier to look. We are prone to studying things that are easy to observe, such as by using convenient data or using surrogate markers. In essence, the streetlight effect is embraced due to its low-risk nature. In the long run, however, the streetlight effect can slow the rate of medical progress by leading us in unfruitful directions. In the second part of the chapter, we extend the discussion by interpreting the streetlight in a more literal sense, focusing on how physical capital influences the rate and direction of research. In general, physical capital, such as laboratories and equipment, is a crucial enabler in allowing science to be conducted. It functions as a rate-limiting factor, meaning that without certain equipment or physical resources, some research undertakings are necessarily impossible to complete.