Humans act according to theories. Noteworthy, theories are not only a matter of science. Instead, they structure and permeate virtually every aspect of human life. The Heidelberg Structure-Formation Technique is a qualitative method to visualize so-called subjective theories. It is not limited to a particular area. This technique was, for instance, adapted to gain insights into the needs of palliative care patients or engagement with alternative health measures. The inner logic is that subjective theories guide everyday action and comprise structured and relational beliefs and states of knowledge. Semi-structured interviews are followed by a cooperative theory visualization to clarify these theories. Based on the interview, expert rates try to identify the structure of a subjective theory which is then mirrored to the participant. The participant is now asked to comment and correct this proposal, leading to a harmonized version of the theory proposal. To aid this process, the specific parts of the theories are written down and arranged on paper cards. The result is the theory, expressed with a set of spatially ordered cards that reveal key concepts and underlying relationships. This talk reports findings on subjective theories about extraterrestrial intelligence. Theories of three laypeople reveal patterns of thinking, best described as a mixture of inadmissible and admissible anthropocentrism. Theories were somewhat complex and seriously contemplated the possibility of intelligent life beyond Earth. These findings provide a novel and in-depth perspective into how humans think about extraterrestrials. As the function of these theories is the guidance of action, they can be used to predict human reactions to first contact. Furthermore, they can be used to increase better attune science communication and address potential misconceptions.