Maria Laura Mele

Gaze and eye-tracking solutions for psychological research

Eye-tracking technology is a growing field used to detect eye movements and analyze human processing of visual information for interactive and diagnostic applications. Different domains in scientific research such as neuroscience, experimental psychology, computer science and human factors can benefit from eye-tracking methods and techniques to unobtrusively investigate the quantitative evidence underlying visual processes. In order to meet the experimental requirements concerning the variety of application fields, different gaze- and eye-tracking solutions using high-speed cameras are being developed (e.g., eye-tracking glasses, head-mounted or desk-mounted systems), which are also compatible with other analysis devices such as magnetic resonance imaging. This work presents an overview of the main application fields of eye-tracking methodology in psychological research. In particular, two innovative solutions will be shown: (1) the SMI RED-M eye-tracker, a high performance portable remote eye-tracker suitable for different settings, that requires maximum mobility and flexibility; (2) a wearable mobile gaze-tracking device—the SMI eye-tracking glasses—which is suitable for real-world and virtual environment research. For each kind of technology, the functions and different possibilities of application in experimental psychology will be described by focusing on some examples of experimental tasks (i.e., visual search, reading, natural tasks, scene viewing and other information processing) and theoretical approaches (e.g., embodied cognition).

A psychotechnological review on eye-tracking systems: towards user experience

Purpose: The aim of the present work is to show a critical review of the international literature on eye-tracking technologies by focusing on those features that characterize them as ‘psychotechnologies’. Method: A critical literature review was conducted through the main psychology, engineering, and computer sciences databases by following specific inclusion and exclusion criteria. A total of 46 matches from 1998 to 2010 were selected for content analysis. Results have been divided into four broad thematic areas. Results: We found that, although there is a growing attention to end-users, most of the studies reviewed in this work are far from being considered as adopting holistic human-computer interaction models that include both individual differences and needs of users. User is often considered only as a measurement object of the functioning of the technological system and not as a real alter-ego of the intrasystemic interaction. Conclusion: In order to fully benefit from the communicative functions of gaze, the research on eye-tracking must emphasize user experience. Eye-tracking systems would become an effective assistive technology for integration, adaptation and neutralization of the environmental barrier only when a holistic model can be applied for both design processes and assessment of the functional components of the interaction. Implications for Rehabilitation Eye-tracking methodologies facilitates communicative functions of gaze favoring a successful outcome in many areas of rehabilitation. Eye-tracking systems would be an effective assistive technology for integration, adaptation and neutralization of the environmental barrier. Successful rehabilitation outcomes are improved when a holistic and interactive model is applied for both design processes and assessment of the functional components of the interaction.

Web popularity: an illusory perception of a qualitative order in information

Using a psychotechnological perspective, this study discusses the current model of information ranking by search engines, based on quantitative Web Popularity (WP), which binds users to a cognitive adaptation to the rank-system restrictions. This phenomenon gives rise to a “rich-get-richer” effect on the Web. This paper claims that such an effect could be limited or reversed by the introduction of quality factors in ranking, and addresses the case of accessibility as a fundamental such factor. A study is reported which, through introducing an accessibility factor in a well-known popularity ranking algorithm, demonstrates that this transformation allows a qualitative rearrangement, without modifying or weighing on the properties of the rank. The overall approach is grounded on two development factors: the analysis of accessibility through specific tools and the employment of this analysis within all components used to build up the ranking. The results show that it is important to reconsider WP as including not only on the number of inbound and outbound links of a website, but also on its level of accessibility for all users, and on users’ judgment of the website use as efficient, effective, and satisfactory.

Usability evaluation with screen reader users : A video presentation of the PCTA's experimental setting and rules

In the study entitled “Web usability evaluation with screen reader users: Implementation of the Partial Concurrent Thinking Aloud technique” (Federici et al. 2010), we have proposed a modified protocol of usability evaluation technique for blind users, which integrates the features of the concurrent and the retrospective techniques. This new technique, called partial concurrent thinking aloud (PCTA), while respecting the properties of classic verbal protocols, overcomes the structural interference and the limits of concurrent and retrospective protocols when used with screen reader users. In order to facilitate understanding and acquisition of the PCTA’s technique for practitioners and researchers, we have video recorded three different verbal protocols by visualizing five experimental sections. In the first two videos, we have compared a concurrent with a retrospective’s verbal protocol of a sighted user, showing the difference of the verbalizations provided by the user in these two conditions. The third video shows the structural interference of the screen reader, during a blind user concurrent thinking aloud. In the last two videos, we show the difference of a blind user behaviour when PCTA or retrospective protocol is adopted. The videos clearly visualize the advantage of the PCTA use in respect of the two other protocols. In conclusion, the visualization of the PCTA technique confirms that this new verbal protocol promotes and guarantees a more user-driven usability assessment with disabled people, by better involving screen reader users, overcoming the structural interference and the limits of the concurrent and retrospective protocols.

From cognitive ergonomist to psychotechnologist: A new professional profile in a multidisciplinary team in a centre for technical aids

Objective The aim of this work is to introduce the professional figure of the psychotechnologist, with particular reference to the specific contexts of application of the assistive technology assignation process in a centre for technical aids. Main content The main differences between the role of psychotechnologists and the professional figures of cognitive ergonomists and clinical psychologists in a multidisciplinary team for assistive solution assignation are described. Psychotechnology is any ‘technology that emulates, extends, amplifies and modifies sensory-motor, psychological or cognitive functions of the mind’ [6, 20]. This definition highlights both the intrasystemic relation between any technology and the user and the interactive role of any artefact within the interaction process. Conclusion In this perspective, the role of the psychotechnologist in a centre for technical aids is to analyse and evaluate the components emerging from the dynamic relation between user and technology in order to facilitate better autonomy, interaction and participation for people with disabilities.

A visual sonificated web search clustering engine

Information Visualization is a widespread approach of the Information and Communication Technologies, and it facilitates the manipulation of abstract information by representing it by geometric models. It has been shown that spatial representation can be independent by the sensorial way in which it is perceived (Avraamides et al. 2004; De Vega et al. 2001), leading to the hypothesis of an amodal spatial representation (Bryant 1992). In light of these studies, an important alternative to Information Visualization methods appears to be the Sonification approach, an information representation method (Olivetti Belardinelli et al. 2009) that implements non-speech audio information to ‘‘represent data relations into perceived relations in an acoustic signal for the purposes of facilitating communication and interpretation’’ (Kramer et al. 1997). The main focus of the sonification approach is on the interactivity between the user and the data representation, since it allows user to manipulate complex data and their inner relations in a dynamic way. Currently, the information representation techniques of main search engines are based on a top-down hierarchic order, according to quantitative indexes of ranking. In a recent study (Borsci et al. 2008; Federici et al. 2009), it has been shown that high ranking values of web popularity (WP) do not match with high levels of accessibility. The top-down output of search engines leads users to assign a qualitative value to the hierarchy organization based on WP, although it is calculated without considering quality indexes (i.e., accessibility). Moreover, Andronico et al. highlighted the lack of qualitative ratings on WP, showing that the main search engines do not comply with W3C accessibility guidelines (Andronico et al. 2008). In this study, we aim to describe the redesign process of WhatsOnWeb (WoW) (Di Giacomo et al. 2007, 2008), a visual graph based search engine implemented by the Department of Electronic and Information Engineering of the University of Perugia. WoW is an autonomous application able to order indexed Web data using semantic nodes in a single page network diagram. In this way, WoW overcomes the page scrolling normally required by the reports of the traditional search engines (Search Engines Report Page), overpassing the limits of traditional Web information representation methods pointed out by Borsci et al. (2008).

Using Spatio-Temporal Saliency to Predict Subjective Video Quality: A New High-Speed Objective Assessment Metric

We describe a new Objective Video Quality Assessment (VQA) metric, consisting of a method based on spatio-temporal saliency to model human visual perception of quality. Accurate measurement of video quality is an important step in many video-based applications. Algorithms that are able to significantly predict human perception of video quality are still needed to evaluate video processing models, in order to overcome the high cost and time requirement for large-scale subjective evaluations. Objective quality assessment methods are used for several applications, such as monitoring video quality in quality control systems, benchmarking video compression algorithms, and optimizing video processing and transmission systems. Objective Video Quality Assessment (VQA) methods attempt to predict an average of human perception of video quality. Therefore subjective tests are used as a benchmark for evaluating the performance of objective models. This paper presents a new VQA metric, called Sencogi Spatio-Temporal Saliency Metric (Sencogi-STSM). This metric generates subjective quality scores of video compression in terms of prediction efficacy and accuracy than the most used objective VQA models. The paper describes the spatio-temporal model behind the proposed metric, the evaluation of its performance at predicting subjective scores, and the comparison with the most used objective VQA metrics.

Beyond a visuocentric way of a visual web search clustering engine: the sonification of WhatsOnWeb

It is widely accepted that spatial representation is processed by an amodal system. Recent studies show that blind subjects have a better motion ability than sighted people in performing spatial exploration guided only by auditory cues. The sonification method offers an effective tool able to transmit graphic information, overcoming the digital divide risen by a visuocentric modality in which contents are conveyed. We present a usability evaluation aiming at investigate the interaction differences between both blind and sighted users while surfing WhatsOnWeb, a search engine that displays the information by using graph-drawing methods on semantically clustered data. We compare the visual presentation of three different layouts with the sonificated ones, demonstrating both qualitatively and quantitatively that blind and sighted users perform with no significant differences the interaction. These results remark that the digital divide could be decreased by going beyond the visuocentric way of the commonly adopted visual content representation.

The Web-based Subjective Quality Assessment of an Adaptive Image Compression Plug-in.

Images are a key element for conveying information about visual systems. However, image-based representation and communication require large information bandwidth. Image compression is currently the leading methodology for reducing bandwidth/load problems thus improving User Experience. Synthetic objective metrics are often used to assess the quality of image compression models, but they often do not reliably predict subjective ratings. This work shows the end-users’ quality evaluation of a new compression plug-in fully compliant with all on-going image formats. The subjective quality assessment of jpeg pictures compressed by the plug-in followed a new Web-based Single Stimulus Continuous Quality Scale method, whose validity and reliability have been described in a previously published study. The results of this study show that pictures compressed by the proposed adaptive image compression plug-in have a 55% compression gain compared to jpeg images compressed by Facebook Mobile, with no loss in perceived

Validating a Quality Perception Model for Image Compression: The Subjective Evaluation of the Cogisen's Image Compression Plug-in

User experience has a fundamental role in determining the effectiveness of image compression methods. This work presents the subjective evaluation of a new compression plug-in for current compression formats developed by Cogisen. The quality of image compression methods is often evaluated by objective metrics based on subjective quality datasets, rather than by using subjective quality evaluation tests. Cogisens compression method follows an adaptive compression process that evaluates the saliency of any image and calculates the level of compression beyond which viewers shall be aware of image quality degradation. The Single Stimulus Continuous Quality Scale method was used to conduct the subjective quality evaluation of image compression. Pictures compressed by the Facebook Mobile lossy JPEG compression and by the Cogisen plug-in integrated in the Facebook Mobile compression settings were used. The results of the user quality evaluation of pictures show about a 45i¾?% compression improvement, with no loss in perceived image quality, for pictures compressed by the Cogisen plug-in compared to jpeg pictures as compressed by Facebook Mobile.