Interpreting different types of reading through eye tracking data

purpose for reading (goal setter) guides the type of reading (careful / expeditious, local / global) that will be used. This model recognises that there are several different types of reading that can be utilised by the reader to achieve their reading goals and that these goals may also dictate how much of the text will need to be processed. As stated towards the end of section 2.3.3, this study proposes to use the types of reading suggested by Khalifa and Weir (2009) to assist with the classification of reading. The following paragraphs explain how the physical properties of eye-movements in reading could be interpreted, in light of the Khalifa

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and Weir model, to suggest the types of reading that participants engage in as they process through a reading into writing task. Eye-movements are classified, and types of reading inferred by use of an algorithm which considers the properties of each fixation and larger patterns formed by successive fixations.

As discussed earlier in section 2.4.2, detecting reading from eye tracking data the researcher concluded that the Campbell and Maglio (2001) could be best adapted to suit the purposes of this researcher project. To explain, algorithms to detect reading from eye tracking data rely either on examining the pattern of fixations over a set number (window) of fixations or, as in the Campbell and Maglio approach, defining events that indicate when reading starts and using an accumulating set of fixations to base calculations on. The disadvantage of the moving window technique is that you are unable to detect reading until sufficient fixations have taken place (if your window size is 20 fixations, then 20 fixations must elapse before you can make your first calculation). With the ‘episodic’ approach you need only three fixations before a decision on reading behaviour can be made. This makes detection of reading faster and more flexible for tasks such as reading into writing where reading is likely to be conducted in a piece-meal fashion for large parts of the task (for instance when reading occurs during bouts of writing).

The research sought primarily to distinguish careful reading as described by Khalifa and Weir, from other types of selective reading. The researcher also wished to try and distinguish between Khalifa and Weir’s local and global categories if possible. (See section 2.3.5.3 in this chapter for a more detailed explanation for Khalifa and Weir’s four types of reading). However, the technical limitations of the algorithm prevented the researcher from categorising eye-movement behaviour to align precisely with the types of reading identified

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by Khalifa and Weir’s model. Therefore, this section explains where the researcher’s classifications and Khalifa and Weir’s classifications align exactly and where they differed.

First the case of careful reading, both local and global, will be discussed. At the beginning of every episode the reading classification was reset to ‘selective’ reading. To begin classifying fixations as part of careful reading, a minimum of three short forward moving fixations needed to occur. On the third short forward moving fixation the classification changes from selective to careful reading. However, an additional constraint was imposed. short forward moving fixations must also be occurring at a ratio of 3:1 in relation to regressions. Only when both these criteria were met would fixations be classified as belonging to careful reading. Long jumps forward through the text were not permitted as part of careful reading and therefore the advent of a long jump forward would cause that episode of careful reading to end, resetting the classification to ‘selective’.

To determine if the reading was local or global the algorithm also monitored whether reading in an episode remained within a single sentence. Khalifa and Weir suggest that the reader’s goal in careful local reading is to arrive at sentence level understanding. This would therefore seem to limit the reading processes used in word recognition, lexical access, syntactic parsing and establishing propositional meaning. Khalifa and Weir suggest that some inferencing may be required but that careful local reading does not involve integrating individual propositions into a large meaning representation. Therefore, as long as the fixations classified as careful remained within a single sentence, the label Careful Local reading was applied. If the succession of careful fixations continued into a second adjacent sentence the categorisation would update to Careful Global reading. Khalifa and Weir suggest that careful global reading occurs when readers link individual propositions to build up a text level understanding of the text. Therefore, careful global reading also neatly aligns. As the

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methodical sequential parsing of one sentence is followed by the next sentence, the reader must necessarily integrate the new information, drawing inferences and making connections with the reader’s knowledge of the world to in order to establish a broader text level understanding. The researcher suggests therefore, that the eye-movement patterns identified as careful global reading reflect this cognitive process.

The link between Khalifa and Weir’s Expeditious global reading and Expeditious local reading and the researcher’s selective global and selective local (as the difference in names suggests) is less clear cut and do not align exactly. In Khalifa and Weir’s model expeditious reading incorporates skimming to establish gist, search reading to find information on a predetermined topic or scanning to find an exact word or figure. The global and local classifications are applied slightly differently in the case of expeditious reading than in the case of careful reading. Let us reflect on the Global and selective local classifications generated by the researcher’s algorithm and consider how they align or differ from Khalifa and Weir’s Expeditious global and Expeditious local classifications.

According to Khalifa and Weir, skimming is selective sampling of the text in order to establish the overarching theme of the text and whether it aligns with the reader’s goals for reading. Skimming will necessarily include long jumps forward through the text with quick sampling of sections of the text. The reader will not attempt to ‘carefully’ parse individual sentence as Khalifa and Weir suggest that readers will use as few details as possible to arrive at their understanding. Skimming must necessarily operate across more than one sentence. The researcher’s algorithm would classify this as selective global reading and Khalifa and Weir classify it as Expeditious global reading.

In search reading, Khalifa and Weir suggest the reader is searching for information on a pre-determined topic. It differs from scanning as when scanning the reader is looking for

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an exact lexical match. When searching the reader is considering any word which might provide a semantic link to the information they are searching for. Search reading will necessarily involve long jumps through the text and will be distinguished by an absence of sustained short forward moving fixations. Khalifa and Weir suggest that when the search is confined to a single sentence it is Expeditious local and when the search incorporates a wide area of text it is Expeditious global. These categories align with the researcher’s definitions as seen in Table 2.

The difficulty arises when considering scanning. Khalifa and Weir suggest that because scanning involves hunting for a specific fact or piece of information that is likely to be contained within a single sentence, it should be considered as Expeditious local reading, even though the search may inevitably involve searching across larger portions of text (paragraphs or pages). The researcher’s algorithm will necessarily classify this as selective global reading, because it extends beyond a single sentence.

Table 2 Types of reading as identified by this study and Khalifa and Weir

Form of reading More than 3 short forward to 1 regression? Long jumps permitted? Incorporates more than one sentence? Algorithm classification Khalifa and Weir classification

Careful _{Yes No} No Careful Local Careful Local

Yes Careful Global Careful Global Skimming No Yes Yes Selective _Global Expeditious _Global

Searching No Yes

Yes Selective _Global Expeditious _Global No Selective _Local Expeditious _Local

Scanning No Yes Yes

Selective

Global Expeditious Local No Selective _Global Expeditious _Local

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