The technique described is a Mind map. A Mind Map is a non-linear, visual tool used for structuring information and generating ideas around a central concept. It is characterized by having a central image or topic from which topic-related branches and sub-branches radiate. The structure helps the business analyst (or a group in a workshop) to organize complex, unstructured thoughts, visualize associations, and explore an area holistically. This technique is often used in the initial stages of investigation, such as problem analysis or requirements elicitation, to help gain a broad understanding of the scope and related issues. This is distinct from a Process map (which shows the flow of activities), an Entity relationship diagram (which models data structures), or the Business analysis process model (which models the BA's work steps).

(Reference: BCS Foundation Certificate in Business Analysis / BCS Business Analysis Practice – Investigative Techniques, Mind Maps)