Jonathan Ling

The effect of text and background colour on visual search of Web pages

Usability and visual impact in Web pages are not necessarily compatible ideals. This paper investigates the effect of colour on the presentation of information in a navigation bar, and aims to contribute towards design guidelines for the use of colour on the Web. We studied the effect of the combination of text and background colour on visual search performance and subjective preference. Twenty-nine participants carried out a visual search task using mock Web pages. Analysis showed that higher contrasts between text and background colour led to faster searching and were rated more favourably. The results are discussed in terms of visual search processes and design recommendations are given.

Nonequivalence of on-line and paper-and-pencil psychological tests: The case of the prospective memory questionnaire

There is growing evidence that Internet-mediated psychological tests can have satisfactory psychometric properties and can measure the same constructs as traditional versions. However, equivalence cannot be taken for granted. The prospective memory questionnaire (PMQ; Hannon, Adams, Harrington, Fries-Dias, & Gibson, 1995) was used in an on-line study exploring links between drug use and memory (Rodgers et al., 2003). The PMQ has four factor-analytically derived subscales. In a large (N763) sample tested via the Internet, only two factors could be recovered; the other two subscales were essentially meaningless. This demonstration of nonequivalence underlines the importance of on-line test validation. Without examination of its psychometric properties, one cannot be sure that a test administered via the Internet actually measures the intended construct.

Differential experiences of the psychobiological sequelae of ecstasy use: quantitative and qualitative data from an internet study

Previous work provided preliminary evidence that different patterns of use among ecstasy users may impact on perceived side-effects. Participants recruited via an ecstasy-related bulletin board differed in their responses compared to those recruited via other means. The present investigation compares self-reports of psychobiological dif.culties among ecstasy users recruited either via a bulletin board or by alternative methods. Qualitative data included reports of any negative or positive changes attributable to ecstasy use and reasons for cessation of use. An Internet-based design was utilized and 209 volunteers completed the study, 117 of whom were recruited via a bulletin board devoted to discussion of ecstasy. Psychobiological dif.culties attributable to ecstasy use varied, with mood .uctuation the most common. Differences between the two groups in the extent to which these problems were reported was found. Bulletin board recruits were less likely to report anxiety or poor concentration, but more likely to report tremors/twitches. For the whole sample, lifetime use was associated more with psychobiologial problems, although this pattern was stronger and more pervasive for the nonbulletin board participants. Bulletin board recruits were more aware of possible negative psychological effects and were more likely to report adopting harm reduction strategies. From the qualitative data three negative consequences of use were identi.ed, the most common of which was ëpsychological problemsí. In support of the quantitative .ndings the likelihood of reporting psychological problems increased with lifetime exposure to ecstasy in both recruitment conditions but interestingly this did not appear to impact on reasons for cessation of use. Participants also reported a number of effects that they regarded as bene.cial. Future research should also take these aspects of use into account.

Using on-line surveys to measure three key constructs of the quality of human-computer interaction in web sites: psychometric properties and implications

On-line surveys are now an important tool for data collection on the World Wide Web (the Web). Determining the psychometric properties of key constructs such as disorientation, ease of use and flow is of paramount importance in establishing the quality of users interactions with web sites. The current study used techniques of experimental research and on-line surveys to investigate the psychometric properties of existing instruments for measuring these constructs using two response formats: visual analogue scale and Likert scale. A 2 × 2 design with response format and orientation support as independent variables was used. Ninety participants carried out an information retrieval task using an experimental on-line shopping site before completing the scales. Factor analysis confirmed the existence of three distinct scales that possessed high reliability. Evidence for validity, and to a lesser extent, sensitivity, was found. Although psychometric results generally converged, some differences between the two response formats were found. A framework for the comprehensive investigation of response formats of on-line questionnaires is proposed as a basis for future research. Practical implications for the on-line measurement of the quality of users interactions with web-based systems are discussed.

The effect of link colour on information retrieval in educational intranet use

Abstract One of the most important determinants of the success of intranet sites is their degree of usability. This study aims to contribute towards intranet design guidelines for usability through an empirical investigation using an existing ‘live’ site and realistic tasks. Employing an experimental design, the effect of link colour on both performance and subjective measures was studied. Eighty-six undergraduates carried out an information retrieval task using two versions of the same intranet site. Analysis showed an effect of link colour both on accuracy and rated display quality, with blue links on a white background resulting in better outcomes than black links on a white background. Analysis of navigation behaviour showed that the home page was used more frequently than either the site map or the search function; however, use of these three navigation support functions was associated with poor and inefficient task performance. The results are discussed in terms of schema theory [Norman, D. A. (1988). The psychology of everyday things . Basic Books; Norman, D. A. (1999). Internetworking, 2 (1)] and design recommendations are given.

The effects of graphical display and screen ratio on information retrieval in web pages

Abstract Although many web pages consist of blocks of text surrounded by graphics, there is a lack of valid empirical research to aid the design of this type of page [D. Diaper, P. Waelend, Interact. Comput. 13 (2000) 163]. In particular little is known about the influence of animations on interaction with web pages. Proportion, in particular the Golden Section, is known to be a key determinant of aesthetic quality of objects and aesthetics have recently been identified as a powerful factor in the quality of human–computer interaction [N. Tractinsky, A.S. Katz, D. Ikar, Interact. Comput. 13 (2000) 127]. The current study aimed to establish the relative strength of the effects of graphical display and screen ratio of content and navigation areas in web pages, using an information retrieval task and a split-plot experimental research design. Results demonstrated the effect of screen ratio, but a lack of an effect of graphical display on task performance and two subjective outcome measures. However, there was an effect of graphical display on perceived distraction, with animated display leading to more distraction than static display, t (64)xa0=xa02.33. Results are discussed in terms of processes of perception and attention and recommendations for web page design are given.

The effects of link format and screen location on visual search of web pages.

Navigation of web pages is of critical importance to the usability of web-based systems such as the World Wide Web and intranets. The primary means of navigation is through the use of hyperlinks. However, few studies have examined the impact of the presentation format of these links on visual search. The present study used a two-factor mixed measures design to investigate whether there was an effect of link format (plain text, underlined, bold, or bold and underlined) upon speed and accuracy of visual search and subjective measures in both the navigation and content areas of web pages. An effect of link format on speed of visual search for both hits and correct rejections was found. This effect was observed in the navigation and the content areas. Link format did not influence accuracy in either screen location. Participants showed highest preference for links that were in bold and underlined, regardless of screen area. These results are discussed in the context of visual search processes and design recommendations are given.

The impact of Eysenck's extraversion‐introversion personality dimension on prospective memory

Prospective memory (PM) is memory for future events. PM is a developing area of research (e.g., Brandimonte, Einstein & McDaniel, 1996) with recent work linking personality types and their utilisation of PM (Goschke & Kuhl, 1996; Searleman, 1996). The present study compared 28 extraverts and 28 introverts on their short- and long-term prospective memory using the Prospective Memory Scale developed by Hannon, Adams, Harrington, Fries-Dias & Gibson (1995). The main finding was that extraverts reported significantly fewer errors on short- and long-term PM than introverts, and this difference could not be explained in terms of the number of strategies used to support prospective remembering. These findings are discussed in relation to differences between the personality types.

The effects of movement of attractors and pictorial content of rewards on users' behaviour in virtual environments: an empirical study in the framework of perceptual opportunities

Abstract Technological developments in Virtual Reality (VR) appear to outpace progress in design methodology of VR. The theory of Perceptual Opportunities (POs) has previously been proposed as a basis of such a design methodology ( Blade and Padgett, 2002 ). This paper presents the first empirical study investigating the effect of representation of POs on users behaviour in Virtual Environments (VEs). The current study has a methodological focus, using POs as a framework and desktop VR as a experimental environment. The application of an experimental paradigm is illustrated with two experiments. Evidence was found for an effect of movement type on choice of objects in a simple VE. Implications for VE design and the methodology of empirical research in the framework of POs are discussed.

Further evidence for automatic encoding of colour by children and adults

Previous investigations of recall for colour have only examined colour recall over short delays. In the present experiments, children aged 4, 7 and 9 years and adults interacted briefly with objects in various colours under incidental conditions. Although participants were not asked to learn the colours of the objects, all age groups successfully recalled colour even after a delay of one day. In Expt 1, recall was above chance in all age groups, and in Expt 2, when preschoolers were given a non-verbal memory aid to prompt colour recall, there were no developmental differences. These findings support and extend previous research that has found evidence for automaticity in colour encoding.