Sequentially (or linearity) institutes an unchanging order which determines access to content. Most of our media, from conversation to literature, comics to animation, slideshows to cinema, is sequential. Linearity is the most common form of information organisation and, arguably, is implicit in any communicative transaction. We live and experience life sequentially, following time's arrow from birth to death and, whilst it may be possible to experience several things simultaneously, we tend to remember and relate events consecutively. Indeed, sequentiality is pivotal to the production of meaning -- Russian morphologist Vladmir Propp, for example, persuasively demonstrated that the content of narratival morphemes (chunks of narratival action), was unimportant, rather it was their arrangement in correct sequence that determined the sense of a story. Early Russian cinematic experiments into montage also demonstrated that sequential congruence determines the meaning that an audience gives to a series of images. More >>

Strict sequentiality may, of course, be undercut by alternative experiential possibilities implicit in the display medium -- for example, a novel is intended to be read in a sequential fashion from first to last page, but many readers flip ahead to see how a story ends or dip in and out of books they know well. Similarly, cinematic works are intended to be seen sequentially, however the potential to fast-forward, rewind and freeze allowed by VCRs and DVDs means that viewers can have far more control over their viewing experience than intended by the director.

Digital media, paradoxically, can create a far more rigorously enforced sequential structure than older analogue media. Powerpoint and other public presentations are typified by strict linearity -- what could be called a 'tunnel' effect -- 'next' and 'back' buttons allowing users to only move one page forward or back at any time. Despite much vaunted claims of non-sequentiality, many hypertexts (and hyper-essays) are similarly directive, users forced to click through sequences in unvarying order with no skipping ahead or 'lucky dipping' as though each screen 'chunk' were a slide on a projection carousel.

Strict linearity holds many advantages: it allows authors to control the order in which users can access bits of information thus allowing the development of discursive argument, works of art, teaching and/or testing of skills of knowledge, etc. Linearity is a natural when content centers around process or flow -- it makes intuitive sense to follow the components of a process in consecutive order rather than encouraging users to dip in and out at random. Rhetoric (originally the art of aural persuasion, but now more generally applied to mean the techniques used to present persuasive content in any medium), is incremental and systemic; rhetorical methodology is most suited to sequential mediums because it is about shaping and controlling the user's experience. Of course it is entirely possible that equally persuasive nonlinear rhetorical techniques will be (and are being) developed, but it seems likely that such developments will shape emotional rather than intellectual experiences.

Linear displays generally involve other display/arrangement options. For example: time lines -- exercises in sequentiality -- may include zoom features (see MIT), parallel info presentation: (see 'Multimedia: From Wagner to Virtual Reality' TIMELINE of Pioneers)

timelines