Resumen de Towards a hypertext comprehension model: the role of reading strategies and cognitive load
Rafael Ignacio Madrid López
Hypertext, thanks to the extensiveness of Internet use, is replacing traditional linear printed text as the main information media. Their impact in important areas such as education, journalism, communication and commerce over the last decade is obvious and their use is present in the daily life of most people in modern countries. Thus, there is a need for a new online digital literacy that can provide readers with the skills needed in this new digital age. This online digital literacy has been conceptualized not as an issue of technology and information, but as a reading issue (Coiro, 2009).
Together with the speed and ubiquitous access to information, there is a claim that hypertext improves the learning and comprehension processes compared with linear text. However, the advance of hypertext has not been accompanied by research results supporting this claim (Chen & Rada, 1996; Dillon & Gabbard, 1998; Shapiro & Niederhauser, 2004). Therefore, it is important to analyze how readers comprehend the information presented in hypertext to obtain an understanding of the real benefits of using hypertext for comprehension and learning.
From a user-centered perspective (Unz & Hesse, 1999), the most important research objective in hypertext comprehension is to understand the interaction process, that is, how the user interacts with the hypertext system in order to gain knowledge. Our literature review has shown evidence that both user and system variables affect hypertext reading. User variables such as prior knowledge, cognitive abilities and experience with computers, and system variables as the number of links shown by the system, the provision of navigation support and the system structure determine comprehension and, what is more important for the aim of this thesis, the way in which readers process the hypertext.
We propose a hypertext comprehension model (see Figure 1) in which the interaction between the hypertext user and the hypertext system can be defined through user processing characteristics. These user processing characteristics have two components:
1) A behavioral component: hypertext reading strategies The behaviour of users during hypertext use is an important research topic, since hypertext systems allow readers to control the presentation of information that they contain (Scheiter & Gerjets, 2007). Users exert this control through reading strategies, which have been examined from two different (although complementary) perspectives. Firstly, a set of studies have focused on the reader's navigation behaviour, identifying different navigation patterns in order to describe and analyze their effect on comprehension. From this perspective, variables such as the reading order of pages, the amount of information accessed or the use of navigation tools can be used to objectively define the reading strategies followed by hypertext readers. Secondly, another set of studies consider reading strategies as implicit decision rules that readers follow to select which parts of a set of hypertext documents to read and in which order (Salmerón, Cañas, Kintsch & Fajardo, 2005; Salmerón, Kintsch & Cañas, 2006a). There are different decision rules that hypertext readers can use, which have different effects on comprehension based on their prior knowledge. For example the coherence strategy (reading the hypertext node most related with the previously read one in order to maintain text coherence) and the interest strategy (reading first the most interesting nodes for the user, delaying the less interesting ones) have been identified.
2) A cognitive component: cognitive load Cognitive load in hypertext reading can be seen as the amount of cognitive resources required by the hypertext reading task. Traditionally, there are two different approaches for considering the role of cognitive load in hypertext reading. From the first approach, hypertext features increase overall cognitive load if compared with linear text which could lead to disorientation and hinder comprehension (Conklin, 1987; DeStefano & LeFevre, 2007). From the second approach, that of the Cognitive Load Theory (Sweller, 1988; Sweller, van Merriënboer & Paas, 1998; Zumbach, 2006), hypertext features can increase overall cognitive load if compared with linear text but their effect on comprehension and learning depends on the tradeoff between different types of cognitive load: intrinsic (depending on the interactivity of materials and prior knowledge), extraneous (detrimental for learning) and germane cognitive load (the extra resources devoted to active processing and deep learning).
We propose that both behavioral and cognitive components influence mutually and determine hypertext comprehension and learning. Our research has shown that different reading strategies lead to different levels of cognitive load and, on the other hand, we assume that the availability of cognitive resources affects the selection and development of reading strategies.
Both reading strategies and cognitive load can be predicted by an interaction between user and system characteristics. The main objectives of this dissertation are:
1. To analyze the mediating role of user processing characteristics on hypertext comprehension. Do the reading strategies performed and cognitive load experienced by hypertext readers affect comprehension outcomes? If so, which are the specific mechanisms by which these effects occur? 2. To determine which specific user and system variables affect which user processing characteristics. Do individual differences in variables such as cognitive abilities and prior knowledge play a role in readers' cognitive load and reading strategies? Can system features as the number of links or the provision of navigation support be used to promote a pattern of user processing characteristics that subsequently enhance comprehension? 3. To investigate the relation between reading strategies and cognitive load and their effect on comprehension. Do the reading strategies that users follow determine their experienced cognitive load? Next, the main results of the three studies conducted in this thesis are summarized.
Study 1: Cognitive factors and reading strategies involved in comprehension with hypertext systems (Madrid, Salmerón & Cañas, Under review) Interactive graphical overviews are frequently used by hypertext designers and authors to give orientation and provide access to the main set of hypertext documents. However, the way in which readers use and benefit from this navigation tool seems to depend on their abilities and experience. In this study, we tested the relation between a set of cognitive abilities and the reading strategies that low prior knowledge hypertext readers follow when using an interactive graphical overview, and how reading strategies can predict comprehension. Results showed that readers' spatial abilities predicted a set of variables characterizing reading strategies: readers with higher spatial abilities accessed more different hypertext nodes, spent less time using the graphical overview and followed a reading order more related with the structure suggested by the graphical overview, which in turns leads to higher reading text coherence and better comprehension at both textbase and situation model level.
Study 2: Effect of number of links and navigation support on cognitive load and learning (Madrid, Van Oostendorp & Puerta Melguizo, 2009) Does the number of links included in a hypertext system determine readers' cognitive load and comprehension? Is it possible to help readers to reduce cognitive load and to enhance learning by providing navigation support? These two questions were examined in an investigation in which low prior knowledge readers used an hypertext either with 3 or 8 links per page in which navigation support was provided or not. Navigation support was provided by signalling the two links that were more related with the text just read, which helped readers to develop a coherence strategy. Results showed that there was a benefit of using link suggestions for comprehension at situation model level, but no effect of the number of links per page was found. Moreover, the reading order that participants selected mediated the effects on cognitive load and comprehension: those readers that performed a more coherent reading order learned more and experienced less cognitive load than those who followed a less coherent one.
Study 3: The effect of prior knowledge and reading strategies on cognitive load and learning (Madrid & Cañas, 2009) Following the results of Study 2, this study compared the effect of two different reading strategies (coherence vs. interest) on cognitive load and reading comprehension, both for low and high prior knowledge readers. Main results showed that the interest reading strategy causes higher levels of cognitive load during text reading than the coherence strategy both for low and high prior knowledge readers. Regarding comprehension and learning, the coherence strategy showed to be better for low prior knowledge readers, while both strategies lead to similar results for high prior knowledge readers. These results are interpreted as a greater investment of germane cognitive load for high prior knowledge readers in the interest condition.
The empirical evidence provided by the studies described above supports the hypertext comprehension model proposed. It stresses the importance of user processing characteristics. Furthermore, both the development of reading strategies and cognitive load seems to be influenced by user and system variables.
In conclusion, these user variables (such as spatial abilities) and system variables (such as the number of links or the navigation support) can determine the reading strategies that users follow (and thereby the selected reading order and other reading strategy variables) and/or the cognitive load level that they experience during hypertext reading, and subsequently the comprehension and learning outcomes. The coherence of the reading order is robustly shown to determine the comprehension level, at least for low prior knowledge readers. Results also support the approach adopted by the Cognitive Load Theory suggesting that, under some circumstances and for certain readers, increases in overall cognitive load could be beneficial if it is caused by a greater investment of germane cognitive load. From our point of view, the relation between cognitive load and hypertext comprehension is a matter of cognitive resources distribution between the different tasks that are involved in hypertext reading. To enhance comprehension in hypertext extraneous cognitive load has to be reduced while germane cognitive load has to be promoted (Zumbach, 2006).
However, increasing germane cognitive load by activating prior knowledge can be only possible for high or moderate prior knowledge readers that are able to engage in active processing activities.
This work concludes with describing the theoretical implications (regarding the hypertext comprehension model proposed), methodological implications (about the measurement of both reading strategies and cognitive load) and practical implications (both for usability engeenering and instruction).
