Coherence is a term drawn from linguistics, notably social semiotics and the work of Michael Halliday and Ruqaiya Hasan  (1976). Coherence names the effect of arrangements such that everything in the arrangement gives the appearance of ‘naturally’ belonging together. It characterizes what appears as an unproblematic state of affairs whether in a social arrangement, or a multimodal sign, text or object.  One aspect of coherence is the idea of textual completeness.

Cohesive ties refers to the entities through which coherence is explicitly produced – that is the ways in which texts are made to hang together. In absence of cohesive ties coherence needs to be established through inference

Theo van Leeuwen (2004) has developed notions of coherence to examine how multimodal cohesion is realized through composition, dialogue, information linking, and rhythm across a range of modes. He uses cohesion to describe how different kinds of semiotic resources are integrated into multimodal texts.

Van Leeuwen identifies four processes that he considers as pertinent for understanding cohesion across a range of modes. Composition he argues provides coherence and meaningful structure to a range of modes including spatial arrangements, images, and multimodal layout encompassing notions of foreground, background, the information value of elements in relation to each other and to audience. Dialogue explores how multimodal cohesion is realized through the structures of dialogic exchange in multimodal texts and communicative events – this can include dialogue/turn taking across modes. Information linking relates to how temporal or causal links are established between elements in multimodal texts. Rhythm he argues ‘provides coherence and meaningful structure to events unfolding over time and is crucial for everyday interaction and time-based media – with attention to measures and pulses, tempo’. Elisabetta Adami (2009) has developed these ideas of cohesion in relation to digital texts. She has shown, for example, how video threads on YouTube are created through cohesive ties of repetition and variation of elements of any kind, from objects, words, gestures and music, including the multimodal deployment of a video.

See also: Composition, Layout, Information values, Timescales

Editor: Carey Jewitt
Other contributor: Elisabetta Adami

Key References
Adami, E. (2010)
‘”We/YouTube”: exploring sign-making in video-interaction’
Visual Communication,  8, 4, 379-399

van Leeuwen, T. (2004)
Introducing Social Semiotics: An Introductory Textbook
London: Routledge.