The Hitchhiker's guide to hallucination research

Hallucination research is a fast‑growing, inherently interdisciplinary field bridging psychology, neuroscience, psychiatry, and philosophy. This article maps out key conceptual and methodological issues underlying the study of hallucinations. We begin by unpacking core theoretical issues - how hallucinations differ from other perceptual alterations, whether they form a single construct or several, and how these distinctions influence study design and interpretation. Next, we review the most commonly used experimental paradigms. A clear distinction is drawn between tasks that measure enduring hallucinatory tendencies and those that capture hallucinations in real time. We also review the most widely used rating instruments - including confidence scales - and discuss the phenomenological approach, which foregrounds participants' first‑person experience. The final section offers a concise, though not exhaustive, checklist of variables researchers must account for - ranging from sensory modality and context to cognitive style, affective state, and cultural background. Taken together, the article serves as an entry‑level guide, posing critical questions that every researcher should answer before designing a study on hallucinations.