Alexander Henka
email: henka@hdm-stuttgart.de

Gottfried Zimmermann
email: gzimmermann@acm.org

Status Quo and Lessons learned from a Persona-Based Presentation Metaphor of WCAG

Keywords: Personas, HCI, Accessibility, WCAG, Presentation Metaphor, Meaning Making, Creating Tension, PersonaBrowser

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

It was reported that accessibility resources can overwhelm web authors (i.e. all persons involved in the making process of a web application) with information [START_REF] Swallow | Speaking the Language of Web Developers: Evaluation of a Web Accessibility Information Resource (WebAIR)[END_REF][START_REF] Petrie | i2web Deliverable 3.2: Requirements for web developers and web commissioners in ubiquitous Web 2.0 design and development[END_REF]. Also, the classification how severe reported accessibility issues are for some users, is not always evident for a web author [START_REF] Brajnik | Beyond Conformance: The Role of Accessibility Evaluation Methods[END_REF][START_REF] Dias | HEUA: A Heuristic Evaluation with Usability and Accessibility Requirements to Assess Web Systems[END_REF] and the interpretation differs even more between beginners and experts [START_REF] Brajnik | Testability and validity of WCAG 2.0: the expertise effect[END_REF]. While experienced evaluators have the knowledge on how a certain WCAG success criterion should be applied and how different users can benefit from its compliance, it can be tough for beginners to make the connection between a WCAG success criterion and the benefits for users that comes with its compliance [START_REF] Brajnik | Testability and validity of WCAG 2.0: the expertise effect[END_REF]. Since accessibility is considered strongly a user centered issue [START_REF] Brajnik | Beyond Conformance: The Role of Accessibility Evaluation Methods[END_REF][START_REF] Cooper | A challenge to web accessibility metrics and guidelines: putting people and processes first[END_REF], and is characterized as follows: "[Accessibility is, when] specific users with specific disabilities can use it [the software] to achieve specific goals with the same effectiveness, safety and security as non-disabled people" [START_REF] Brajnik | Beyond Conformance: The Role of Accessibility Evaluation Methods[END_REF], it should be an obligation to feature the connection to the user, and to provide a motivation for the relevance of each success criteria. This is especially important for beginners in the application of WCAG. Therefore, the usage of automatic testing tools, checking a web applications' accommodation to WCAG, is not fully sufficient to state the accessibility of a web application [START_REF] Kelly | Accessibility 2.0: People, Policies and Processes[END_REF][START_REF] Brajnik | Web Accessibility Testing When the Method Is the Culprit[END_REF]. While WCAG (version 2.0) forms the technical foundation, and provides rules and instructions to solve -or avoid -defects on web applications, there is also the other side of the coin (respectively: the barrier).

Following the user centered view on barriers, as stated above, a defect on a web application only turns into a barrier if the defect hinders a specific user with specific traits from achieving their specific goals. It is this tension, i.e. seeing a barrier from the user perspective, that can actually create meaning for barriers, and for the success criteria of WCAG, and therefore help to meet the requirements of people with impairments.

From a sociology point of view, Bowker and Star [START_REF] Bowker | Sorting Things Out: Classification and its Consequences[END_REF] stated: "We [humans] know what something is by contrast with what is not"; e.g., light versus darkness, or in the way that silence makes musical notes perceivable. As they further explained: "We often cannot see we take for granted -unless we encounter someone who does not take it for granted". Bowker and Star conclude that "tension" between contexts is necessary to create meaning and that information, generally spoken, only gains weight if it can be interpreted in multiple ways.

This provides a sociological explanation why web authors who are new to the topic of accessibility have issues to classify the severity of reported accessibly issues. It can therefore be hard for novices to see barriers and distinguish between severe and trivial accessibly issues [START_REF] Dias | HEUA: A Heuristic Evaluation with Usability and Accessibility Requirements to Assess Web Systems[END_REF], since they themselves can perform all use-cases in a web application. Hence, they take the interaction paradigm of a web application for grantedunless, they encounter someone who is actually facing barriers during the interaction, for example while observing a user test. On the other hand, the values of constructional accessibility, like ramps to bypass stairs, are easier recognized, since we encounter them almost every day. We can regularly observe people and situations in which the physical circumstances of our world impose a barrier. In contrast, interaction with software is usually a more private affair; there is no (legal) way of overseeing a product's users.

Another difference between software-and constructional accessibility is that constructional accessibility can imply meaning for everybody. If someone is facing stairs in the contextual situation of traveling with a baby buggy or carrying heavy luggage, the importance of a ramp or an elevator is highly valuated. In other situations, however, the barrier that stairs can imply may be overlooked or not be recognized. Therefore, a specific object or situation may be experienced differently in different contexts, which then creates meaning, following the argumentation of Bowker and Star. This tension between contexts is stripped away when focusing solely on (automatic) tools, which evaluate the conformance of web application to WCAG. This could be problematic for beginners as literature suggests [START_REF] Brajnik | Beyond Conformance: The Role of Accessibility Evaluation Methods[END_REF][START_REF] Brajnik | Testability and validity of WCAG 2.0: the expertise effect[END_REF]. At some point, a web author has internalized WCAG to an extent in which WCAG and its success criteria are taken "for granted". Hence, the web author can state the severity of potential accessibly issues and has in-depth knowledge on how people with disabilities interact with web applications; thus, the web author has become a web accessibility expert. This process is called: naturalization [START_REF] Bowker | Sorting Things Out: Classification and its Consequences[END_REF]. At this point, the web author has an intrinsic knowledge of the meaning of web barriers. Forgotten are the struggles of being new to the accessibility topic when everything was strange and odd.

Rooted in the disciplines of human centered design, personas [START_REF] Cooper | The Inmates are Running the Asylum[END_REF] are a widelyused concept to transport user needs and requirements and to keep track of them during the product development process. Using walkthrough techniques to question product features and evaluating interaction paradigms, personas can be a tool to create contextual tension, thus seeing the product through the eyes of the persona.

In this paper, we present and discuss an approach for creating tension in the presentation of WCAG by using personas as a classification schema. The underlying principle is that each success criterion of a guideline should be represented as a set of personas affected by the success criterion; similar concepts have been discussed in [START_REF] Henka | Persona Based Accessibility Testing[END_REF] and [START_REF] Zimmermann | Accessible design and testing in the application development process: considerations for an integrated approach[END_REF]. This paper provides an insight on the status quo of augmenting WCAG with personas. Hence, this work outlines some major issues when adding personas to WCAG and seeks to identify steps on how personas should be constructed and used in this context to overcome these issues. The remainder of this paper is structured as follows. Section 2 provides an overview on our persona in context concept and how it differs from the persona concept advocated by Alan Cooper [START_REF] Cooper | The Inmates are Running the Asylum[END_REF]. Section 3 introduces our work in this area, the PersonaBrowser, and a user experience study we conducted with students. In Section 4, we present the lessons that we have learned from our study and our conclusions.

Personas

Personas can be useful to solve some main obstacles and traps in the product development process: the elastic user; the self-referential design; and design edge cases [START_REF] Cooper | The Inmates are Running the Asylum[END_REF][START_REF] Adlin | The Persona Lifecycle[END_REF][START_REF] Massanari | Designing for imaginary friends: information architecture, personas and the politics of user-centered design[END_REF], and they limit the action space [START_REF] Adlin | The Persona Lifecycle[END_REF][START_REF] Stiegler | Gamification and Accessibility[END_REF].

The elastic user refers to the issue that without having a common framing, the "user" is -metaphorically spoken -stretched to justify any decision and feature of a product. The self-referential design points to the common mistake of developers putting themselves "into the seat" as the later users of a product; hence, ignoring the needs and goals of the real users. Personas can also provide guidance in political disputes and discussions on design edge cases, helping to decide the issue of whether a certain feature should be included or excluded in a product, or on issues of the general design approach. With personas, the blurry "user" becomes tangible -with specific needs and requirements. One can refer directly to "Anna" and state: "Yes, someone might want that feature, but we are not designing for someone -we are designing for Anna" [START_REF] Cooper | The Inmates are Running the Asylum[END_REF]. If the usage of personas is engrained into the working habits of the project team from the beginning [START_REF] Massanari | Designing for imaginary friends: information architecture, personas and the politics of user-centered design[END_REF][START_REF] Blomquist | Personas in action: ethnography in an interaction design team[END_REF], personas can indeed become a boundary object [START_REF] Bowker | Sorting Things Out: Classification and its Consequences[END_REF] among team members and stakeholders.

Personas support the "limitation of action space" pattern [START_REF] Adlin | The Persona Lifecycle[END_REF][START_REF] Stiegler | Gamification and Accessibility[END_REF] since they cluster the needs and requirements of a product's end users by reducing the complexity from satisfying "the user", a vague and unknown entity, to a manageable number of personas (cf. [START_REF] Henka | Using Video Game Patterns to Raise the Intrinsic Motivation to Conduct Accessibility Evaluations[END_REF]).

Personas: Vehicle and Information

Personas are, in their essence, just a different form of conveying user needs and requirements in a product development cycle, mainly advocated by the scholar of user centered design. To understand this tool, one has to distinguish between the vehicle, which is the shape or appearance, respectively, and the information, transported in said vehicle.

According to Cooper et al [START_REF] Cooper | The Inmates are Running the Asylum[END_REF], the important information that is conveyed in personas are the goals and motivations of end user towards the usage of certain product [START_REF] Cooper | About Face: "The Essentials of Interaction Design[END_REF]. These are usually gathered through interviews and observations. It is the narrative framing that forms the vehicle and brings a persona to life [START_REF] Adlin | The Persona Lifecycle[END_REF]. This framing puts a mental model into the reader's head; it thus makes the behavior of that pictured personas vivid. To bolster the vividness, personas are usually accompanied by a photo, a name and other details that makes a persona an authentic character. Despite the fact that they are often called hypothetical users, personas are never an image or a representation of the average user-group, they are, as said, vehicles to communicate the important information -of real users -during product development in the most appropriate way for the development team.

The distinction between the information and the vehicle raises an interesting question: Can any form of information be more vivid and memorable if told by dint of personashere, in the sense of wrapping something "bulky" up in the most delightful way for the audience? Much like one would hide a dog's medicine, a "bulky" but important piece, in a sausage slice so that a dog would eagerly swallow it. This work explores to reveal principles of how this vehicle needs to be designed to create tension and support meaning making to make WCAG more comprehensible for beginners. Following the dog's medicine analogy, WCAG is the "bulky" information and personas are the sausage.

Using Personas to Communicate the Relevance of WCAG Success Criteria

The benefits of personas as a vehicle to transport the needs and requirements of people with disabilities have been highlighted in various works, notably in tools and learning environments [START_REF] Bailey | Development and trial of an educational tool to support the accessibility evaluation process[END_REF][START_REF] Loitsch | Teaching Accessibility with Personas[END_REF][START_REF] Schulz | Creating personas with disabilities[END_REF][START_REF] Wöckl | Basic Senior Personas: A Representative Design Tool Covering the Spectrum of European Older Adults[END_REF][START_REF] Isacker | A UCD Approach towards the Design, Develop-ment and Assessment of Accessible Applications in a Large Scale European Integrated Project[END_REF]. Besides [START_REF] Schulz | Creating personas with disabilities[END_REF], where personas with disabilities are used in the original fashion, these are all examples where the information that needs to be transported is the needs and preferences of the user group itself. This differs from the approach explored in our work. Here, the important information is not the needs and preferences of the user group but a set of rules. And these rules are not directly bound to the goals and motivations of a future user.

Ontologies have been developed [START_REF] Lopes | Towards the universal semantic assessment of accessibility[END_REF][START_REF] Ponsard | Augmenting Accessibility Guidelines with User Ability Rationales[END_REF] to provide links between success criteria and impairments for which those criteria are considered essential. While these ontologies also make use of user entities similar to personas, they are dedicated to classifying the success criteria according to their relevance for certain impairments.

We envision to adapt the narrative persona concept to convey information outside its designated usage fashion, as introduced by A. Cooper [START_REF] Cooper | The Inmates are Running the Asylum[END_REF]. The stories told by personas are tightly coupled with the information contained, or in other words, the stories are the information told in a narrative way. The information is constructed by clustering the goals and motivations of the end user towards a certain product. When using personas to communicate the relevance of WCAG success criteria, there are no goals or motivations directly involved to tell the story. People, artificial or real, are driven by motivations to reach a certain goal. When an application, for example a web shop, is compromised by defects that lead to barriers and hinders people from achieving their goals, then this application should adhere to WCAG. But, WCAG success criteria do not represent "goals" for users in any sense. This raises the question of what "items" the narrative nature of personas should be constructed of to convey the meaning for the success criteria (for details see section 4).

The PersonaBrowser

In a web application called PersonaBrowser, we implemented a visualization of the connection between WCAG success criteria and personas for which the conformance of certain success criteria is essential. As a structural foundation, we used the ontology described in [START_REF] Lopes | Towards the universal semantic assessment of accessibility[END_REF]. The PersonaBrowser illustrates nine personas, grouped into four categories of general impairment types: visual, auditory, physical, and cognitive. The personas are based on the "day-in-the-life" stories developed by the MOOCA project [START_REF]MOOCs for Accessibility Partnership[END_REF]. The term "persona" was actually avoided in MOOCAP to emphasize the fact, that they were created by experts and not by newly researched data. Nevertheless, the validity and the benefits of the MOOCAP's stories for conveying the needs and requirements of people with disabilities have been presented in [START_REF] Loitsch | Teaching Accessibility with Personas[END_REF]. For their usage in the PersonaBrowser, we added additional web links featuring further information about the impairment and used assistive technologies. A user of the PersonaBrowser can read about a persona, their life, needs, and essential WCAG success criteria. We also provided a mechanism to filter the WCAG success criteria for each persona according to conformance levels and (on a second view) all success criteria according to impairments and conformance levels.

User Experience Study with the PersonaBrowser

Since novices could benefit from featuring WCAG in a human-centered fashion (cf. section 1), we used the PersonaBrowser as a teaching tool in an introductory HCI course (jointly hosted by the bachelor course programs media informatics and mobile media at the Stuttgart Media University) to field-test the PersonaBrowser over a period of three months. The study consisted of two parts with different goals. In the first part, we wanted to get insights on principles of how personas should to be constructed to serve as proper vehicles for WCAG success criteria, by identifying current issues in linking success criteria and personas based on impairments; thus, tackling the question raised in section 2.2. This part consisted of observations in the class when using the PersonaBrowser for teaching accessibly, and informal feedback from the students (section 3.2). In the second part, we wanted to quantify the effect on a user's experience with WCAG as generated by the means of personas. Therefore, we compared the user experience of the PersonaBrowser with that of the WCAG Quick Reference [START_REF]W3C. Web Content Accessibility Guidelines (WCAG) 2.0[END_REF], which we used in a prior instance of the same course (with different students) as a teaching tool. The quantitative measurement of the user experience was based on the User Experience Questionnaire (UEQ) [START_REF] Laugwitz | Construction and evaluation of a user experience questionnaire[END_REF].

Results of the User Experience Study

For the quantitative comparison of the user experience between the PersonaBrowser and the WCAG Quick Reference, we included the WCAG Quick Reference in the PersonaBrowser, literally, with original colors and font styles as in the specification [START_REF]W3C. Web Content Accessibility Guidelines (WCAG) 2.0[END_REF]. We surveyed 65 undergraduate students from two semesters, all novices in accessible design. One group of students (n=38) worked solely with the PersonaBrowser, while the other group (n=27) worked solely with the WCAG Quick Reference. We assessed the user experiences of both groups, using the User Experience Questionnaire (UEQ) [START_REF] Laugwitz | Construction and evaluation of a user experience questionnaire[END_REF] (see Fig. 1). In general, the UEQ yields the following aspects of user experience, including pragmatic and hedonic aspects: Attractiveness: Do users like or dislike the product? Perspicuity: Is it easy to learn how to use the product? (pragmatic). Efficiency: Can users solve their tasks without unnecessary effort? (pragmatic). Dependability: Does the user feel in control of the interaction? (hedonic). Stimulation: Is it exciting and motivating to use the product? (hedonic). Novelty Is the product innovative and creative? (hedonic). For each aspect, the scale ranges from -3 to +3. [START_REF] Schrepp | User Experience Questionnaire Handbook[END_REF]. The UEQ considers scores starting at 0,8 as positive and starting at -0.8 as negative. The overall user experience is therefore, at best, in the scale of average, for both systems. It should be noted that the study took place within the context of a mandatory lecture and that the results could have been influenced by a rather low motivation of some participants towards the topic of HCI and accessibility. Nevertheless, our result shows the issues of the WCAG Quick Reference when it comes to its usability for beginners. We did not expect any significant differences in the pragmatic values (perspicuity, efficiency), since the only thing we added in the PersonaBrowser is the connection between success criteria and personas based on their impairments, but the higher efficiency score can be seen as a hint for the benefits of a user-centered presentation metaphor due to its complexity reduction (cf. section 4). While the average scores of perspicuity, efficiency and stimulation are higher for the PersonaBrowser, the pertaining T-Tests showed no significant differences (α=0,05). Only for novelty, the study reveals a significant difference between the PersonaBrowser and the WCAG Quick Reference. The UEQ score for novelty is still low, but this seems to be a hint that a user-centered presentation metaphor can be effective to catch the interest of web authors. While the PersonaBrowser has a higher efficiency score, the lower score for dependability was rather unexpected. This discrepancy can be explained under the spotlight of an issue that occurs if impairments are used as the only mean to link success criteria to the personas -the elastic system, see section 4.

Discussion

We have learned some lessons from actively using the PersonaBrowser as a preparation tool for the accessibility course.

Elastic System. Using only impairments as anchors to success criteria leads to an elastic system, where personas can be stretched to justify almost any success criteria. Personas are never an embodiment of the average user. Just because one persona can benefit of a success criterion does not mean that a second persona, sharing the same or similar impairment, can benefit from that criterion as well; especially if the two personas do not use the same assistive technologies. The link between a persona and a success criterion should always be reliable in the sense that it is clearly described why this criterion is considered as relevant and another not. Personas are specific and so are their impairments and needs. In the PersonaBrowser, we have two personas with macular degeneration (Maria and Monika). While Maria uses text-to-speech software to help her speed up things with office applications, Monika does not use any text-tospeech software. Maria therefore clearly benefits from the compliance of WCAG 2.0 success criterion 1.1.1 ("None-text content"). If we stated that Monika can also benefit from text-to-speech and therefore of success criterion 1.1.1, we would stretch Monika to fit our assumption that every person with macular degeneration can benefit from text-to-speech and so should Monika -even though the persona does not hold for this assumption. This would blur the personas towards average users and would therefore make them less precise. But, being precise and specific is what personas make vivid and suitable for the construction of a mental model [START_REF] Cooper | The Inmates are Running the Asylum[END_REF][START_REF] Adlin | The Persona Lifecycle[END_REF]. Therefore, the meaning should be constructed based on the entire persona (including its context) and not only on their impairments. Issues with this elasticity can also be seen in the average score for "dependability" in the user experience test (see Fig. 1).

Action Space Shift. One exercise in the accessibility course was to examine a web application for barriers. This exercise was split up into three sessions each focusing on one WCAG principle. (Exception: Principles 3 and 4 were combined since principle 4 has only two success criteria.) The students using the WCAG Quick Reference had to state the conformance for all success criteria of a single principle during a session. Doing so, the complexity for the tutors was moderate, as they had to explain the success criteria of each principle once during a session. In contrast, the PersonaBrowser offers a more user-centered approach. A student had to pick a set of three personas for which they had to state the conformance of one principle per session. Since not every success criterion is relevant for every persona, the complexity for the students was reduced. At the same time, the complexity for the tutors increased, since they had to discuss every success criterion nine times during one session, one time for every persona. Combined with ambiguity due to the elasticity of the personas, the complexity was actually not reduced but shifted from the students to the tutors. While this might be unique for teaching scenarios, it advocates the meaning for precise personas.

WCAG as the culprit. From our observations, the descriptions of the WCAG success criteria, including what barriers they address and what needs to be tested for their assessment, were hardly read by the students using the PersonaBrowser. While the personas reduced the action space, the students often tried to conclude the implications of a success criterion by the needs of the personas and the heading of a criterion. This is probably triggered by the task given to the students, namely to state the accessibility for the chosen persona set. As one students puts it: "The vita of the fictitious people are cumbersome, if one is just interested in the impairments [hence, which criteria applies]." We have learned from this thatwhen used in the context of personasthe description of WCAG needs to be adapted in order to be told from the perspective of personas and in a more application-oriented manner (cf. [START_REF] Swallow | Speaking the Language of Web Developers: Evaluation of a Web Accessibility Information Resource (WebAIR)[END_REF]). This would better accommodate the needs of web authors, namely being able to assess the accessibility of their applications. The low result for "stimulation" in the UEQ (see Fig. 1) can be interpreted in light of this effect.

Barriers as a tie to wrap the stories around. As described above, a mapping between a success criteria and impairments is not sufficient to establish a confident vehicle to convey the relevance and meaning of the success criterion. As in the example with ramps and stairs (section 1), meaning for solutions is only created if the problem becomes obvious. Most success criteria are actually a set of solutions for which the problems are not evident. In the run-up of this study, we conducted a survey among accessibility novices. After working in accessibility and with WCAG for several months, we asked for their opinion on what would make accessibility resources more comprehensible. From 44 participants, a vast majority (86%) agreed that it would be helpful for comprehension to highlight the impact if a criterion is not met; hence, this empathizes the relevance of featuring barriers. This leads back to our question on how the narrative shape of a persona should be constructed to convey WCAG in a vivid way. We therefore argue that the barriers should be the center around which the stories are told.

This study provided insights into the status quo of a persona-centered presentation metaphor for WCAG, discussed the potential of such a system and outlined the issues that arise with it. We stated that using impairments as a link between personas and WCAG success criteria is not sufficient and creates an overly elastic system. Based on our experience and observations, we discussed some initial suggestions to overcome the issues. Yet, more research is needed e.g., to test if novices, using a system, built on the principles discussed here, will have a better comprehension of WCAG or the impact of said system on experts, since our initial study focused solely on novices and, as discussed in section 4, there might be implications that are unique for teaching scenarios.

Fig. 1 .

 1 Fig. 1. Results of the UEQ. Comparison of scale means and the corresponding 5% confidence intervals.


Theja Kuruppu Arachchi
email: theja.kuruppuarachchi@hdr.qut.edu.au

Laurianne Sitbon
email: laurianne.sitbon@qut.edu.au

Jinglan Zhang
email: jinglan.zhang@qut.edu.au

Enhancing Access to eLearning for People with Intellectual Disability: Integrating Usability with Learning

Keywords: Accessibility and usability, Inclusive design, People with intellectual disability, eLearning, Human computer interaction (HCI)

eLearning can provide people with Intellectual Disability (ID) extended learning opportunities in using information technology, thus potentially increasing digital inclusion. In order to make this a motivating experience, designs of eLearning are required to be compatible with their cognitive abilities. It is as yet unclear how to design an engaging eLearning environment that integrates usability with learning. This paper aims to explore the applicability of learning theories along with usability guidelines in designing an eLearning environment for people with ID. We discuss psychological theories on teaching and learning, and literature on challenges and opportunities of eLearning for people with ID. Based on that understanding, we present guidelines that integrate different learning theories with eLearning, for learner centered interaction design of eLearning modules for people with ID. We present a case study of applying these inclusive design considerations to an eLearning module about health information access.

Introduction and Background

Working with the Internet has been identified as a motivating involvement in digital participation among people with Intellectual Disability (ID). The Internet supports its user to be independent. Hence, as noted by Harrysson et al., the opportunity to use the Internet creates a 'smart and awesome" episode for people with ID [START_REF] Harrysson | How people with developmental disabilities navigate the Internet[END_REF]. However many still experience difficulties when interacting with the Internet and accessing information. Rocha et al. reported that people with ID are able to increase their ability to navigate the Internet, provided that they receive continuous training [START_REF] Rocha | Accessibility and usability in the internet for people with intellectual disabilities[END_REF]. Hence, the introduction of training programs on Internet access, for people with ID, is set to support them to improve and maintain their ability to engage with the Internet [START_REF] Wong | Competence of people with intellectual disabilities on using human-computer interface[END_REF]. According to Sitbon et al., "satisfying an information need may act as a motivator to encourage users to develop skills they may not otherwise be interested in developing" [START_REF] Sitbon | Towards universal search design[END_REF]. We aim to develop an accessible eLearning module that teaches people with ID to access online health information. This provides the opportunity to learn skills to use the Internet in an eLearning platform, while interacting with a computer and the Internet, in a motivating, learning environment [START_REF] Standen | Using virtual environments with pupils with learning difficulties[END_REF]. eLearning also has the potential to support a learner to practice skills to use the Internet in context. eLearning, as the term itself denotes, is learning facilitated with technology [START_REF] Mayes | Learning and e-learning[END_REF]. eLearning delivers instruction using a web-based medium, for the learner to access remotely. In an eLearning platform, the learner uses the Internet to navigate through learning materials. eLearning allows the learner to practise at their own pace with adequate support [START_REF] Standen | The effective use of virtual environments in the education and rehabilitation of students with intellectual disabilities[END_REF]. The opportunity to learn skills to use the Internet, in an eLearning platform provides the learner with an appropriate environment for practising such skills. According to Kolb's experiential learning theory, which emphasises learning from experience, learning is a process "whereby knowledge is created through transformation of experience" [START_REF] Kolb | Experiential learning: Experience as the source of learning and development[END_REF]. Knowledge results from the combination of grasping and transforming experience. Hence, we posit that eLearning platforms best fit with such learning situations as improving skills to use the Internet.

Designing an eLearning module for people with ID needs to consider the learner's specific abilities and context. Version No. 031 of The Victorian Intellectually Disabled Persons Services Act 1986 defines intellectual disability thus: "intellectual disability in relation to a person over the age of five years, means the concurrent existence of -(a) significant sub-average general intellectual functioning; and -(b) significant deficits in adaptive behaviour -each of which became manifest before the age of 18 years" [START_REF] Victoria | Intellectually Disabled Persons Services Act[END_REF]. Intellectual disability is different from "Learning Disability". According to official definition adopted by the Learning Disabilities Association of Canada January 30, 2002, learning disability is generally referred to as "a group of disorders, presumed due to central nervous system" [START_REF]National Definition of Learning Disabilities Adopted by the Learning Disabilities Association of Canada[END_REF]. In this paper, we investigate how to address the conceptual needs of people with ID, beyond the needs of people with learning disability. The main focus of the process of designing eLearning modules for people with ID should be guided by minimising the cognitive capacity required by the learner to interact with the system and the content in order to maximise the cognitive resources available for the learning process [START_REF] Melis | Lessons for (pedagogic) usability of eLearning systems[END_REF]. The eLearning designs should be usable and accessible to them.

eLearning designs should address the cognitive capacity, different abilities and needs of people with ID. Web accessibility has been outlined to ensure that "people with disabilities can perceive, understand, navigate, and interact with the web" [START_REF] Henry | Introduction to Web Accessibility: Web accessibility initiative (WAI) W3C[END_REF]. Learning theories have suggestions on designing learning materials, considering the learner situation. The literature suggests that it is important to consider existing usability guidelines and learning theories together, in order to increase the accessibility, usability, and pedagogical values of eLearning designs [START_REF] Squires | Usability and educational software design: special issue of interacting with computers[END_REF], and offer the learner a motivating learning environment [START_REF] Maldonado | E-learning motivation, Students' Acceptance/Use of Educational Portal in Developing Countries: A Case Study of Peru[END_REF]. Learners with ID have not been included in most of the designs and the online collaborations present in the typical eLearning designs presently available. eLearning designs should allow people with ID to learn at their own pace. Most of the currently available eLearning approaches are knowledge driven. They aim to teach subject knowledge such as mathematics [START_REF] Seo | The identification, implementation, and evaluation of critical user interface design features of computer-assisted instruction programs in mathematics for students with learning disabilities[END_REF], languages and communication. Practice driven eLearning aims to support the learner to improve abilities through continued practical activities, such as practising skills to use computers and the Internet. Having on-site support persons, such as tutors, presents additional opportunities to develop the learner's education potential in eLearning [START_REF] Standen | The effective use of virtual environments in the education and rehabilitation of students with intellectual disabilities[END_REF]. The availability of such support people is often critical, and should be embedded in the design. The paucity of research on designing these types of eLearning for the people with ID, led us to investigate designing a motivating, rich eLearning experience for learners with ID. Addressing the gap in the literature, around eLearning design guidelines that integrate existing usability principles with strategies from learning and pedagogical psychology, this paper contributes a set of new guidelines that can be applied to a learner-centered interaction design of eLearning modules for people with ID.

In the forthcoming section, section 2 of this article, we review studies on challenges and opportunities of eLearning for people with ID. In section 3, we discuss psychological theories on teaching and learning, which will be used to understand design considerations for an eLearning module for people with ID. Then, we present a theoretical view of the interactions in an eLearning environment for people with ID in section 4. In section 5, these are incorporated in a functional model for eLearning design that integrates learning theories. Then we further integrate the identified learning theories into a theoretical framework of design guidelines for learner centered interaction design of eLearning environments for people with ID. Section 5 ends with a presentation of new design guidelines, which reflect the usability requirements as well as the pedagogical requirements of an eLearning environment for people with ID. In section 6, we present an application of these guidelines in a case study that develops a prototype of an eLearning module for people with ID.

eLearning for People with Intellectual Disability

Information and communication technology (ICT) empowers people with ID. Although people with ID experience difficulties in meeting demands of day-to-day life compared to others [START_REF] Harris | Intellectual disability: Understanding its development, causes, classification, evaluation, and treatment[END_REF], they can be supported to increase their capacity to be included in society by adjusting the environment, allowing them to experience, acquire and improve their abilities.

Renblad explored the views of people with ID on their experience with ICT and empowerment [START_REF] Renblad | How do people with intellectual disabilities think about empowerment and information and communication technology (ICT)[END_REF]. The study employed qualitative methods of data collection; study of original sources of groups' reports from a conference, participant observation and interviews. The study reports that information and communication technology increases the opportunities for people with ID to be involved in social relationships and make decisions. Opportunity to use technology in eLearning adds motivational value to the learning environment that leads to a better learning experience [START_REF] Maldonado | E-learning motivation, Students' Acceptance/Use of Educational Portal in Developing Countries: A Case Study of Peru[END_REF]. Hence, the eLearning module we design aims to empower people with ID to be included with the Internet and use online health information, which will be a support for them to look at their health issues with confidence.

Wong et al. explored ICT training needs among people with ID, with reference to their competency of using human computer interfaces [START_REF] Wong | Competence of people with intellectual disabilities on using human-computer interface[END_REF]. A total of 57 people with mild or moderate intellectual disability, aged between 14 and 17 years participated in the study. Researchers identified that Microsoft's Internet Explorer (IE) was the most popular web browser among the participants, and that the most popular activities were exploring websites, searching with Yahoo, and working with bookmarks, as well as using the print and save functions. They defined three task categories: general, hardware related, and software related. Software-related tasks were to "start web browser, close web browser, explore websites, respond to dialog box, use customised bookmarks, add book marks, take printouts, save website, open saved website and use search engine". According to the performance of participants in the assigned tasks, the researchers concluded that the training programs for people with ID should be twofold: basic training associated with improving basic computer skills among low-performance groups, and advanced training on essential functions, including "orientation and attention" on the Internet. As Wong et al. noted, learning programs on computer skills designed for people with ID should be ability-specific.

Ogunbase designed a Web-Based Learning Environment (WBLE) model, and studied the effect of the learner's culture on their engagement with the learning environment [START_REF] Ogunbase | Pedagogical Design and Pedagogical Usability of Web-based Learning Environments: Comparative Cultural Implications between Africa and Europe[END_REF]. According to the study, Ogunbase reported that the use of WBLE among African and European learners had been affected by different learning cultures shaped by their cultural background. Ogunbase highlights the need to consider cultural issues, in order to design WBLEs effectively. Hence, eLearning environments for people with ID should incorporate their cultural values.

For strengthening the interactions of people with ID with the learning environment, eLearning modules should be designed in conference with learning theories. Seo and Woo developed 'Math Explorer', a multimedia computer assisted instruction program for teaching mathematics for elementary level students with learning disabilities [START_REF] Seo | The identification, implementation, and evaluation of critical user interface design features of computer-assisted instruction programs in mathematics for students with learning disabilities[END_REF]. In the test for acceptance of the interface features, they identified three types of critical user interface design features: "instruction driven, manifest structure and adaptive interaction interfaces". One of the instruction driven features they identified was to introduce the subject content in small amounts. The other instruction-driven feature was to use visual representations, animations and graphics to provide an attractive and motivating experience. Manifest structure interface features were to "maintain simplicity and consistency", use "appropriate fonts and colours", and to highlight and colour-code the current tasks. Researchers utilised adaptive interaction interface features to provide feedback adaptive to student performance, and to support them with adaptive multimedia. According to the user study, Seo and Woo concluded that specific interface design guidelines should be incorporated in designs of computer assisted teaching programs, considering the capacity of the short-term memory of the students with learning difficulties.

Following a "community based ICT training program" for people with ID, Li-Tsang et al. conducted a study to identify additional support needed [START_REF] Li-Tsang | A 6-month follow-up of the effects of an information and communication technology (ICT) training programme on people with intellectual disabilities[END_REF]. The interview with the participants of the training program and their caregivers showed that while the training program had increased the participants' interest in using computers, there remained the need for continued training on Internet use, with close support. Bunning et al. investigated the teachers' interaction with students with ID during eLearning [START_REF] Bunning | Interaction between teachers and students with intellectual disability during computer-based activities: The role of human mediation[END_REF]. They studied five single cases with severe intellectual disability, aged 11-18 years, using video ethnography. The study showed that teacher interaction supported the learner to increase their motivation to learn. Heath et al. reported that it was encouraging for the learner to have closer interaction with the teacher, who encouraged them with signposts "you do it, you have a go", with nonverbal behaviours, looking at the child and pointing at the screen, and then with movements prompting initiation of action. The study concluded that, on-site teacher interaction, as a mediator of eLearning, was a support for students with ID to execute learning activities better.

Together these studies indicated that eLearning environments for people with ID could create a motivating learning experience, when designed according to the learning theories attending to their specific needs.

Pedagogical Approaches for Learner Centered Design

Designing eLearning environments for people with ID is a complex process. eLearning design should devote attention to well-defined learning tasks as well as the usability of learning interfaces [START_REF] Mayes | Learning technology and usability: a framework for understanding courseware[END_REF] that address leaners' needs and learning patterns [START_REF] Ogunbase | Pedagogical Design and Pedagogical Usability of Web-based Learning Environments: Comparative Cultural Implications between Africa and Europe[END_REF]. Learning theories guide the design of motivating learning environments. eLearning modules need to be developed referring to the learning theories, so the contents and the presentation are psychologically appropriate to the learner' status quo. The learning and teaching principles reported from decades of research and practice belong to three commonly accepted learning theories: behavioural theory, social cognitive theory and constructivist learning theory [START_REF] Snowman | Psychology Applied to Teaching[END_REF]. Different theorists describe different points relevant to teaching and learning situations. One single theory cannot address everything to be considered in a particular educational setting. Schunk states that it is necessary to "be eclectic" and use a blend of theories to address a learning situation [START_REF] Schunk | Learning theories[END_REF]. Similarly, the American Psychological Association's Board of Educational Affairs used psychological principles belonging to these three theories, to define fourteen learner-centered psychological principles that provide a learner-centered approach for educational designs at schools [START_REF] Apa | Learner-Centered Psychological Principles: A Framework for School Reform & Redesign[END_REF]. Our contribution in this article is selecting the principles that are relevant and integrating them with eLearning design guidelines.

Behavioral Learning Theory

Behavioural theory explains the effect of external stimulators and inhibitors on the individual's behaviour. Skinner's theory, operant conditioning, clarifies learning as a behaviour to obtain or avoid the consequences that follow [START_REF] Skinner | Operant behavior[END_REF]. Accordingly, positive reinforcements can be incorporated in eLearning designs to encourage the learner to be engaged. Skinner's approach to achieve this is to define clear goals of instruction, sequence the subject content logically, allow learner's pace of learning, and provide im-mediate feedback for the learner's performance. Each phase is designed to be appropriately small enough and to include subject content that prepares the learner for the next phase, and supports the learner to complete the tasks at optimal speed [START_REF] Skinner | The shame of American education[END_REF].

Social Cognitive Theory

Social cognitive theory focuses on interactions of behavioural and personal factors with social settings. It explains that learning behaviours could be inspired through observing and imitating a model [START_REF] Snowman | Psychology Applied to Teaching[END_REF]. Hence, cognitive theory describes learning as an internal process in which the learner uses his memory, thinking reflection, abstraction and metacognition skills. Bandura described learning behaviour as a result of interactions among these three factors; personal characteristics, behavioural patterns and social environment [START_REF] Bandura | Social foundations of thought and action: A social cognitive theory[END_REF]. According to Bandura, personal characteristics relate to beliefs about the ability to carry out learning tasks. Hence, clear goals and reduced anxiety support a better learning experience. Considering the learners' working memory capacity, subject content should be presented in appropriate amounts, and in sequence. Learning tasks should not overload the learners' working memory [START_REF] Anderson | The theory and practice of online learning[END_REF]. The learner must be supported to make memory links between new experiences and some related information from long-term memory. Hence, designs for eLearning should accommodate functions with familiar examples that increase the learners' ability to complete given tasks.

According to social cognitive theory, personal and behavioural factors dominate the environmental factors, in determining the learning behaviour. Bandura describes this concept as personal agency, which relates to the habit of self-controlled and self-regulated learning. The learner's preference for self-regulation suggests the need of endowing eLearning modules with choices for the learner according to their learning needs.

Online learning designs should include information in small amounts, and provide opportunity to link new knowledge with existing knowledge, and apply it in real life. Allowing for learner choice creates positive thinking to engage with learning activities.

Constructivist Learning Theory

Constructivism describes the nature of learning; how people develop as meaningful learners. It involves the learner' process of understanding how to perform a task according to a previous experience. Bruner described this type of learning as discovery learning [START_REF] Bruner | The act of discovery[END_REF]. According to Schunk, constructivist learning environments are designed for "meaningful learning" [START_REF] Schunk | Learning theories[END_REF]. Teacher's involvement supports the learner to experience the topics in multiple perspectives. Brooks and Brooks described five principles with reference to constructivist learning environments [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF]. The first principle is to incorporate teaching lessons that "seek and value learners' points of view". It suggests the importance of considering the learners' perspectives when designing learning environments. Constructivist learning environments not only identify the learner, but also address them. Hence, a constructivist learning environment acknowledges relativity, talks to and with the learner, gives op-portunity to express the learners' point of view, follows up with the learner's elaboration, and accounts for "interesting ideas" instead of grouping into "right" and "wrong" [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF].

The second principle puts forward that constructivist learning environments are developed around primary concepts and "big ideas". Instead of presenting the curriculum in separate subtopics, the use of a holistic approach supports the learner to understand how the concepts relate as a whole [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF]. Subject concepts for the eLearning module needs to be integrated with the holistic aim of supporting the learner. Structuring eLearning about online information seeking around "big ideas" and broad concepts supports the learner to understand multiple access points to the subject content.

According to the third principle, constructivist learning environments are designed to address the learners' suppositions. Learning activities are designed so that they support the learner to develop their skills, either consistent with, or counter to, the learners' beliefs. Cognitive, social and emotional demands of the learning materials are matched with the learner's abilities [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF]. Brooks and Brooks' functional principles; "posing problems emerging relevance, structuring learning around primary concepts, and seeking and valuing students' points of view", assist curriculum designs that value student suppositions.

The fourth principle mentions that constructivist learning environments pose problems in emerging relevance. Relevant subject content is identified by probing pre-existing learning needs. An alternative strategy is to stimulate the learner's interest by allowing them to recognise the value for life [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF].

The fifth principle deals with assessments, and declares that constructivist learning environments "assess student learning in the context of daily teaching". Instead of the true -false and multiple choice questions, constructivist learning environments conduct assessments by providing the learner the opportunity to demonstrate acquired skills, or to describe or discuss the learned topics in terms of value for their life [START_REF] Schunk | Learning theories[END_REF]. This is used as a nonjudgmental feedback process between learners themselves and the instructor [START_REF] Brooks | In search of understanding: The case for constructivist classrooms[END_REF]. This type of assessment focusses on the next step after student feedback, that encourages teacher to consider redesigns for learning activities. [START_REF] Schunk | Learning theories[END_REF].

These learning theories, that are defined in three contexts: the learner behaviour (Behavioural learning theory), the learner's cognitive process (Social cognitive theory), and learning as an experience and learner development (Constructivist learning theory), can collectively be considered when designing eLearning environments.

Interaction Design and eLearning

Anderson describes six forms of educational interactions in online learning: studentstudent interactions, student-content interactions, student-teacher interactions, teachercontent interactions, teacher-teacher interactions, and content-content interactions [START_REF] Anderson | The theory and practice of online learning[END_REF].

Garrison states that the interactions among learners, subject content and the teacher, in online learning provide a connective and collaborative learning environment [START_REF] Garrison | Implications of Online Learning for the Conceptual Development and Practice of Distance Education[END_REF]. The theory of online learning interaction presented by Anderson suggests the possibility of substituting various forms of student interactions for each other, depending on the situations that matter ("costs, content, learning objectives, convenience, technology used and time availability"), without affecting the quality of learning. According to Anderson, maintaining an extensive mastery of one of the three forms of interactions is sufficient for successful learning [START_REF] Anderson | Getting the mix right again: An updated and theoretical rationale for interaction[END_REF]. However, in learner-centered design of eLearning, the value of learner-interface interaction cannot be discounted [START_REF] Melis | Lessons for (pedagogic) usability of eLearning systems[END_REF][START_REF] Seo | The identification, implementation, and evaluation of critical user interface design features of computer-assisted instruction programs in mathematics for students with learning disabilities[END_REF][START_REF] Metros | INTER) FACE: The Role of the Graphical User Interface in Engaging eLearners[END_REF][START_REF] Fryia | Human-computer interface design in an e-Learning system for individuals with cognitive and learning disabilities[END_REF][START_REF] Hillman | Learner-interface interaction in distance education: An extension of contemporary models and strategies for practitioners[END_REF].

Interactions in eLearning

In an eLearning environment, the learner interacts directly with the interface to maintain the other interactions: with the teacher, with the content and with other students. Hence, we propose that interaction design of eLearning should consider four additional interactions: content-interface, learner-interface, teacher-interface, and interface-interface (Fig. 1).

Fig. 1. A generic model of Interactions in eLearning

Learner-Interface Interaction. The learner interacts with the interface to access learning material, to submit completed activities, discuss with peers and the teacher. The learners can read each others' discussion threads and post replies. Interface supports the learner to save and print the subject content as well as discussion pages.

Content-Interface Interaction. Content-interface interaction creates an opportunity to present the subject content in appropriate formats and in accessible amounts. It acts as the medium for instruction display. The content can be presented with readable font size, acceptable colours, relevant visual images, and concept maps. The presentation of content can be facilitated with audio and video descriptions.

Interface-Interface Interaction. Interface-interface interaction focuses on organisation of the eLearning module. It allows the learner to navigate between the subject content list, discussion threads, assessments and personal account from any page. The presentation of repetitive functions consistently in appropriate places of each page, supports the learner to navigate between pages and perform functions using a reduced amount of working memory.

Teacher-Interface Interaction. Teacher-interface interaction provides space for the teacher to introduce the module, present subject content, give announcements, introduce links to further reading, and clarify technical issues and assessment procedures.

A major factor that needs to be considered when designing an eLearning module that encourages these types of interactions is how to increase the learner's motivation. As pointed out by Li-Tsang et al., [START_REF] Li-Tsang | A 6-month follow-up of the effects of an information and communication technology (ICT) training programme on people with intellectual disabilities[END_REF], people with ID need close support when learning digital skills. We propose that such context can include a tutor, who supports the leaner on-site. The tutor interacts with the learner and the eLearning interface, thus adding the following interactions to the model.

Tutor-interface Interaction. The eLearning module for people with ID should include an additional tutor interface, with which the tutor directly interacts to support the learner by personalising the interface according to the learner preferences: font size, colours, level of challenge etc. Furthermore, the tutor may clarify welcome messages as well as help pages.

Tutor-Learner Interaction. The tutor interacts with the learner to support them to perform learning tasks, provide additional concrete examples from their day-to-day life, and clarify wording of the module where appropriate.

Integrating Usability with Learning

An eLearning module that maintains the above mentioned interactions performs four main functions: delivering subject content, sharing feedback and support, performing assessments, and providing the platform/interface. Instructional strategies should be carefully chosen to design these functions to motivate the learner and to make them relevant to the learner. We developed a functional model for better understanding of the applicability of learning theories in eLearning designs (Fig. 2). According to this functional model, the subject content of the eLearning module needs to be designed considering learning theories, in order to make the subject content relevant to the learner context as well as to make it accessible.

According to the learning theories, the subject content should be designed considering pre-existing learning needs (need to learn internet functions as identified by Wong et al. [START_REF] Wong | Competence of people with intellectual disabilities on using human-computer interface[END_REF]), student suppositions (need more clarifications to content with on-site support and/ or videos) and organised with well-defined goals. Social cognitive theory describes that subject content in online learning should be described in small amounts with examples linked to existing memory, to support the learner with limited capacity of working memory [START_REF] Anderson | The theory and practice of online learning[END_REF]. Redesigns for the subject content should be considered according to emerging educational needs with introduction of new technologies, levels of challenge, and how to stimulate the learner's interests.

eLearning designs should follow assessment strategies described in learning theories referring to the learner's context. Constructivist learning theory mentions that assessments should be non-judgemental parallel to teaching and learning, and allow the learner to demonstrate skills learnt and discuss applications in life. Social cognitive theory that emphasises the need of preventing working memory overload during learning, suggests that assessments should occur the learner practises or applies the skills in real life. In a typical eLearning environment, the learner can be assessed considering the contribution in the form of their posts on activities given, and discussions with peers. Assessment strategies need to be selected according to the learner's background.

In an eLearning environment for people with ID, assessment should be defined as a role of the on-site tutor. Parallel to learning, the on-site tutor observes the learner demonstrating skills, discusses applications of skills, encourages the learner with nonjudgmental feedback on the learner's performance, and identifies redesign needs as a continuous user evaluation of the module. The tutor needs to keep notes on redesign needs according to the learner's performance.

Learning theories that have recommendations on interface design should be followed to make the designs relevant to the learner abilities and to create motivating learning environments. Personalised welcome, as suggested in social cognitive theory and constructivist theory, can be incorporated in eLearning interface design, by providing an introduction to the learning module, referring to the needs of the expected learner, for encouraging them to be engaged with learning. eLearning environments should be designed to be supportive to perform learning activities at the learner's pace, considering the learner's cognitive level.

According to Schunk, some developmental limitations can cause slower responses in self-regulated learning [START_REF] Zimmerman | Self-regulated learning and academic achievement: Theoretical perspectives[END_REF]. Hence, social cognitive theory suggests that designs for eLearning modules for people with ID need to include well described content. Multimedia presentations that display skills can be incorporated for the learner to observe, imitate, and improve the self-regulatory skills for a given task. The interface should be designed with the use of known symbols to represent known actions. Such eLearning environments support the learner with limited cognitive skills. Interface designs should provide immediate feedback on the learner's performance, by acknowledging errors that have occurred and facilitating corrections to offer an engaging learning environment. Furthermore, these interface designs need to be iteratively redesigned referring to revisions introduced to the content, and suggestions from student and instructor assessments and feedback.

The proposed functional model integrates the learning theories with relevant functions of an eLearning module. It can be used as a guide by designers, as well as by teacherts, to identify applicable strategies, including the modifications described to develop eLearning environments appropriate to the learner context.

Guidelines for eLearning Designs for People with Intellectual Disability

People with ID, having limited cognitive and functional abilities experience difficulties in accessing eLearning environments designed for the general population. Our aim is to describe the applicability of pedagogical theories in designing eLearning environments for increasing accessibility to people with ID. For motivating people with ID to be engaged with eLearning, designs should follow guidelines that strengthen the interactions in an eLearning environment, referring to the learner context. While learning in an eLearning environment, the learner interacts with subject content, instructor, peers and the interface. The learner should initially learn how to use the interface. Usability deals with presenting the interface in a format that is "easy to learn and remember, effective, and pleasant to use" [START_REF] Molich | Improving a human-computer dialogue[END_REF]. Nielsen presents nine heuristics for evaluating user interfaces [START_REF] Nielsen | Enhancing the explanatory power of usability heuristics[END_REF] [39]. Nielsen's heuristics emphasise real conversation, user friendliness, consistent format, instant feedback, effective navigation, expertise benefit, efficient feedback, minimising errors, documented guidance.

Referring to existing literature on usability and instructional approaches, Mehlenbacher et al. presented a heuristic tool for evaluating eLearning environments [START_REF] Mehlenbacher | Usable e-learning: A conceptual model for evaluation and design[END_REF]. Their usability heuristics focussed on the challenges of designing and evaluating eLearning environments. They discuss five dimensions in eLearning design: "the learner's background, knowledge and social dynamics, instructional context, instruction display, instructor activities, and environment and tools". Costabile et al. presents usability criteria and guidelines for eLearning platforms, considering the effectiveness and efficiency of the platform for learning. These guidelines are applicable in eLearning designs. Still, there is a need for eLearning design guidelines that address the context of the learner with ID who needs additional attention on cognitive accessibility and approaches to increase motivation and engagement. As literature suggests, eLearning design guidelines should integrate learning theories with usability criteria for guiding accessible eLearning designs.

Accessibility refers to inclusive design that strengthens interactions between the user and web-based design. Our aim is to present design guidelines that integrate usability principles with theories from learning and pedagogical psychology, and which can be used in inclusive designs of eLearning modules accessible to people with ID. For achieving that aim, we outline a theoretical framework of guidelines for learner centered design of eLearning environments for the learners with ID (Fig. 3). The framework models a set of guidelines for interaction design from a learner-centered perspective which accounts for the learner's individuality as well as their interactions.

Fig. 3. A theoretical framework of guidelines for learner centered interaction design of eLearning environments for people with intellectual disability

At this point, we describe design guidelines about the subject content and the interface.

Implications for Designing Subject Content. Learner-centered design of subject content should reflect the learner context: their learning needs and interests, their suppositions about learning the proposed content, and ability to read, understand and memorise the content presented in one page. Design guidelines that integrate both usability criteria and learning theories guide this type of design to develop motivating and engaging learning experiences.

The study of the problem situation, needing new eLearning design, creates an understanding of the learner context to be incorporated with the design. This problem analysis should aim to understand the accessibility requirements to make the content learner friendly, easy to understand and relevant. To achieve the identified accessibility requirements in content design, design guidelines should take on board relevant psychological principles about teaching and learning. This suggests that to make eLearning accessible to the learner with intellectual disability, design guidelines should include the following principles: make the topics and content appropriately challenging; organise the content around big ideas with a holistic approach; introduce topics with emerging relevance; use content, examples and images linked to existing knowledge and experiences. Emerging relevance can be connected with topics already discussed in the content, learner interests and abilities, new developments in technology and/ or in the discussed subject, and current topics in discussion.

Implications for Designing the Interface. Learner-centered design for the eLearning interface should understand and address the learner context: learner's abilities, cognitive capacity and level of attention. For making eLearning accessible to people with ID, the design should consider the accessibility requirements representing the learner's context.

The eLearning interface design should minimise distractions, maintain consistency, and be easy to operate, read, and navigate. The interface should be supportive, providing quick (response time) and feedback, as well as with personalisation features. Design guidelines regarding accessible eLearning designs for people with ID should include prospects from both learning theories and usability criteria. Referring to learning theories, the eLearning interface should appropriately use known symbols, logical arrangement with a course map and less than three levels structure to enhance navigability. Personalisation by allowing learning at learner's pace, providing options to save the content, make bookmarks, customise fonts, font size, colours and graphics is important to motivate the learner with personalised welcome. eLearning interface should be helpful with immediate and understandable feedback. Usability criteria can be incorporated to guide the eLearning interface design to be accessible by means of minimising distractions. They include avoiding too many graphics, blinking, and animations, four different colours or less, giving priority to the learner's preference about font type and colour, avoiding capital letters, using colours to highlight, and minimising hyperlinks (with acknowledgements that the learner will be directed to a website outside the eLearning module). Considering the learner's capacity to use the mouse to move around, icons and menus should be appropriately large, clues as pop-ups or written words close to the icon should be used to help the learner as necessary. In order to increase the readability and visualisation, suitable font size (> 14 point), sentence length (<7 words), and number of sentences per screen (<4) should be decided during an iterative design process. A white background and space between the lines can increase visibility. Each page of the eLearning module should follow a consistent format to help the learner's orientation within the page, minimising the use of cognitive capacity for positioning, and reducing the possibilities for misleads and distractions.

Designing an eLearning module for People with ID needs considerations on their cognitive capacities and abilities. The guidelines we suggest here use learning theories and usability criteria in combination to address the accessibility needs of People with ID, as an approach to guide learner-centered interaction design of eLearning. Table 1 presents the guidelines from a practical standpoint. We apply these guidelines in designing an eLearning module to increase the abilities of people with ID to be included in online information. The eLearning module describes and teaches how to access health information. It offers the user an opportunity to improve skills needed to use the Internet while learning in the practical environment, navigating between pages and the units of the module.

One unit of that module is about describing for the learner, how to find a Medical Centre close by, and then identifying the link for making an appointment. In the meantime, the learner becomes familiar with two other types of information: location and the opening hours of the Medical Centre. The two screens of the prototype we designed are presented in Fig. 4 and Fig. 5 respectively. This eLearning module does not include an assessment. Instead, a tutor, who gives on-site support to the learner, observes the learner's behaviour during learning and gives non-judgemental feedback, to encourage engagement with learning. We adopted the following key guidelines while designing the content of our prototype. We have divided the module into small units. For example, one of them, which we describe here, includes eight screens. Each screen includes a small amount of information, and can be viewed without scrolling. The screen in fig. 4 includes only three sentences, which comprise thirteen words. The content is described in simple language.

Referring to the learners' cognitive capacity, contents have been further clarified with examples and images. Use of several examples for clarifying one term aims at making it familiar to most. Furthermore, the content is arranged in logical order. The first page of our prototype (Fig. 4) includes a topic that describes the goal of the unit, "Meet a doctor". Then it describes the background, and extends to the objective of the unit; learn how to make an appointment online, instead of mentioning it as a single sentence "This unit aims to teach you, how to make an appointment for meeting a doctor when you are sick".

We have used different screens to discuss different sub topics: entering key words to search, using the search results page etc. Each of these subtopics has been described with two examples that search for two different Medical Centre websites and familiarise with links to online appointments, opening hours and the location of each Medical Centre (Fig. 5). Each unit introduces questions that support them to discuss what they learnt from the unit. For example, the unit we describe here gives a question to find a Medical Centre close to them, and find the link to make online appointments, the location of the Medical Centre, and opening hours.

Learning tasks have been selected for the learner to develop navigation and online searching skills as well as the ability to communicate with others using Internet, referring to their existing skills and preferences. This module helps them to experience how a menu and the forward and backward buttons work, as they use the module to learn how to access online health information. They also experience how the link from the search results directs them to a website. The opportunity to make an appointment online explains to them that the Internet can deliver their request to the Medical Centre.

In each page, we presented large icons for better and improved visibility. We included menu buttons, back and forward buttons, and an icon to access audio, which are large enough as well. The menu and the other icons have been included in every page in the same position. We have not included animations and blinking pictures to minimise distractions. We have made the screen designs simple and understandable, consistently using the same format. The menu guides the learner to navigate through the module. Furthermore, we have used a known symbol, with a description word "Listen" to encourage its use. Font size and colours have been selected to personalise the interface to the learner. Each screen of the unit prepares the learner to learn the next screen.

Conclusion

Designing accessible eLearning modules requires careful attention to technological usability as well as the psychological appropriateness of the teaching material presented. This article suggests eLearning design guidelines that consider principles of teaching and learning along with usability criteria to address the learner's needs. First, we have presented learning theories that relate to the four elements of an eLearning environment: content, interface, assessments, and feedback. We incorporated the learning and teaching strategies into a theoretical framework of guidelines for learner-centered interaction design of eLearning modules for people with ID. Then, we used that framework to establish the guidelines for eLearning module design. Finally, we presented a concrete example of the application of the guidelines through a case study. This paper focuses on the content and interface design. That is, we have not addressed the learner-teacher interactions and the learner-peers interactions. In future work, we will further explore these interactions, and the role of on-site support people to determine how universal designs of eLearning platforms should account for their contributions and requirements.

Fig. 2 .

 2 Fig. 2. A functional model for eLearning design that integrate learning theories: a guide for the designer

Fig. 4 .Fig. 5 .

 45 Fig. 4. eLearning module screen

Table 1 .

 1 Guidelines for learner-centered design of an eLearning environment for learners with intellectual disability

	Interac-	Learner	Accessibility	Guidelines
	tion	Context	requirement
	Learner -	Attention	Minimised dis-	Without too many graphics, blinking, and anima-
	Interface		tractions	tions
				Small number of colours (<4)
				Font type and colours appropriate to the learner pref-
				erence
				Highlighting with colour codes instead of capitalisa-
				tion of letters
				Minimum Hyperlinks in the content pages
		Mobility	Easy to operate Icons and menus large enough to be pointed
				Prompts and cues to help the learner
		Cognitive	Readability &	Font size according to the user preference (>14
		capacity	Visualisation	point)
				Short sentences (<7 words)
				Minimum number of sentences in one screen (<4)
				Leave space between lines
				Use white background
				Multimedia, graphics, and images to make the con-
				tents familiar and descriptive
			Consistency	Every screen designed maintaining same format
				Consistent positioning of title, menus, forward, back-
				ward, print, and save buttons
				Consistency in use of font size and colours
			Feedback	Feedback with error messages and support
		Learner	Navigability Less than three levels structure
		abilities		Orientation support by means of logical arrangement,
				course map and menus
				Use known symbols
				Highlight and colour-code the current tasks
			Personalisation Possibility to personalise font size, colours and
				graphics
				Possibility to save pages and make bookmarks
				Allows learning at the learner's pace; self-regulated
				learning
	Learner -	Learning	Easy to under-	Content appropriately challenging
	content	needs and	stand,	Content organised around big ideas with holistic ap-
		interests,	Relevant	proach
		Student suppositions		Topics introduced in immerging relevance Content, examples and images linked to existing skills and knowledge
		Ability to	Learner	Content in easy to read and easy to understand termi-
		read and	friendly	nology
		memorise		Content presented on small chunks
				Explained with examples including images and or
				multimedia

Design for an eLearning Module for People with Intellectual Disability: a Case Study

Acknowledgements . The authors would like to thank the anonymous reviewers and editors from INTERACT 2017 for their very much helpful comments on the previous version of this paper. The authors wish to acknowledge the University Grant Commission, Sri Lanka, University of Colombo and Queensland University of Technology for their support for this research study.