Final answer:
In Treisman's theory, features are combined into a coherent whole during the preattentive stage.
Step-by-step explanation:
In Treisman's theory, features are combined into a coherent whole during the preattentive stage. This stage involves the automatic processing of sensory stimuli without conscious attention. This initial processing allows for the identification of basic features, such as color and shape, before focused attention and processing occur.