Hypertext has transformed our reading habits. An article or an essay on the internet is not just plain text like what one experiences while reading printed books. Hypertext consists of embedded links that can help us to jump to the relevant section of an essay (think Wikipedia articles), explore evidence for an assertion on another webpage (like this) and even guide us towards pre-requisites for understanding a concept, without leaving the article of interest.

Benefits of Hypertext are obvious so I won’t go into it here. What I didn’t know about were it’s effects on our understanding and reading abilities that seem to have been transformed in last couple of decades.

Reading is a cognitively demanding task. There is some cognitive load associated with it. Research on our comprehension abilities while using electronic media has hypothesized that Hypertext tends to increase the cognitive load. This is especially true if the link contains semantically distant content compared to the content in current link.

Following correlations between hypertexts and reading ability have been found:

• Navigation performance i.e. ability to find answers from some text tends to decrease when the user is thrown more hypertext (increase in links).
• Navigation is slower when the text consists of semantic links (links to distantly related content on other pages: cause & effect, concept examples, definitions) compared to text that only contains hierarchical links (usually same page with semantically closer distance than semantic links).
• In kids, restricted navigation with branching hypertext tends to increase learning compared to hypertext that allows more freedom (“high degree of self direction”) and lacks structure.

But things are usually not as simple. The ability to learn from hypertext or linear text also seem to be related to the default cognitive ability of the student. A 1998 study found that “students who had grade averages in the A range learned equally well from hypertext and linear text, whereas students who had grade averages in the B and C ranges were disadvantaged in the hypertext conditions, as measured by errors on a comprehension test”. Another 1995 study found that “hypertext instruction was only beneficial to participants who were able to quickly learn lessons in computer programming.”

Children and older adults tend to have lower working memory and hence the cognitive load while reading tends to be higher in them. A study from 2003 compared hierarchial and semantic hypertext among older adults and found former to be more useful and efficient while reading. The hypothesis is that comprehension with hypertext should be lower overall among children and older adults. Although I couldn’t find a good study proving this hypothesis.

On the brighter side, hypertexts can be structured in a way to increase comprehension. As the authors of the this comprehensive review from 2007 mention:

Hypertexts that were structured to capitalize on the inherent organization of the domain (usually hierarchical structures for informational content) often resulted in better comprehension, memory, and navigation. These benefits were most evident for less knowledgeable readers, who seemed particularly influenced by the way that hypertext can illustrate the conceptual structure of a text. Some ofthe simplerorganizational aids (e.g., hierarchical graphical overviews) also enhanced readers performance, although as these increased in complexity they were either not used or detracted from navigation and understanding. In general, learners with low prior knowledge were more affected (both positively and negatively) than more knowledgeable readers by structural manipulations such as link structures (e.g., hierarchical versus networked), the presence of graphical overviews, or the restriction of navigation within the hypertext.

So structure your hypertext so that it stays on point and provides an overview of the domain of study. As long as they are not throwing the users into a rabbit hole of seemingly related content but with much higher cognitive load, hypertext links will largely enhance the comprehension.