In communication, channel richness is highest in the case of

Channel richness is highest in face-to-face conversation, which carries the fullest range of cues.

It offers instant feedback, tone, facial expression and body language all at once.

Television delivers sound and image but gives no real-time two-way feedback, so its richness is lower.

Newspapers carry only printed words and static pictures, making them a lean channel.

Formal reports are purely written and impersonal, offering the least richness of these.

The more cues and the faster the feedback a channel allows, the richer it is.