Siné McDougall

Measuring symbol and icon characteristics: norms for concreteness, complexity, meaningfulness, familiarity and semantic distance for 239 symbols

This paper provides rating norms for a set of symbols and icons selected from a wide variety of sources. These ratings enable the effects of symbol characteristics on user performance to be systematically investigated. The symbol characteristics that have been quantified are considered to be of central relevance to symbol usability research and include concreteness, complexity, meaningfulness, familiarity, and semantic distance. The interrelationships between each of these dimensions is examined and the importance of using normative ratings for experimental research is discussed.

Icon Identification in Context: The Changing Role of Icon Characteristics With User Experience:

Objective: This research examined the relative importance of icon characteristics in determining the speed and accuracy of icon identification. Background: Studies to date have focused on the role of one or two icon characteristics when users first experience an icon set. This means that little is known about the relative importance of icon characteristics or how the role of icon characteristics might change as users gain experience with icons. Methods: Thirty participants carried out an icon identification task over a long series of trials to simulate learning through experience. Icon characteristics investigated included semantic distance, concreteness, familiarity, and visual complexity. Results: Icon characteristics were major determinants of performance, accounting for up to 69% of the variance observed in performance. However, the importance of icon characteristics changed with experience: Semantic distance is crucial initially while icon-function relationships are learned, but familiarity is important later because it has lasting effects on access to long-term memory representations. Conclusion: These findings suggest that icon concreteness may not be of primary importance when identifying icons and that semantic distance and familiarity may be more important. Application: Designers need to take into account icon characteristics other than concreteness when creating icons, particularly semantic distance and familiarity. The precise importance of the latter characteristics will vary depending on whether icons are rarely encountered or frequently used.

Brain training in older adults: Evidence of transfer to memory span performance and pseudo-Matthew effects

ABSTRACT In this study the effects of ‘brain training’ using the Nintendo DS Brain Training program were examined in two groups of older adults; the cognitive performance of an experimental group (n = 21) who were asked to use the Nintendo DS regularly over a 6-week period was compared with the control group (n = 20). Groups were matched on age (mean age = 74 years), education, computer experience, daily activities (time spent reading or watching television), and initial scores of Wechsler Adult Intelligence Scale. Analyses revealed that improvements were primarily in the Digit Span Test, specifically Digits Backwards. Although the Brain Training package appeared to have some efficacy, other factors such as perceived quality of life and perceived cognitive functioning were at least equally important in determining training outcomes. The implications of these findings for cognitive training are discussed.

Are dyslexics different? I. A comparison between dyslexics, reading age controls, poor readers and precocious readers

Four groups of children with matched reading ages of 7:03–8:06 were given a battery of tests assessing a range of skills related to reading, visual processing and phonological processing. The groups were: (i) dyslexics (mean age 10:03, mean IQ 118 with a minimum of 105); (ii) younger normal readers (conventional ‘reading age controls’ with a mean age of 7:11 and a mean IQ of 107); (iii) ordinary poor readers (mean age 10:04, mean IQ 80); (iv) precocious readers (mean age 6:02, mean IQ 126). The dyslexics were faster at some of the visual processing tasks, including object naming, and did not differ significantly from the other three groups on any of the phonological processing tasks. There was no indication of less use of phonology in reading on the part of the dyslexics: they were no less affected by spelling-sound regularity in lexical decision and naming than the other groups, showed a similar sensitivity to pseudohomophones in lexical decision, and were not significantly impaired in their reading of non-words. Dyslexic reading comprehension was superior to that of the reading age controls and precocious readers and their listening comprehension was better than that of the other three groups. The poor readers were similar to the reading age controls on the visual processing tasks. They were worse than the reading age controls at discriminating rhyme but not at phoneme deletion, non-word repetition or verbal memory span.

What’s in a name? The role of graphics, functions, and their interrelationships in icon identification

Communication using icons is now commonplace. It is therefore important to understand the processes involved in icon comprehension and the stimulus cues that individuals utilize to facilitate identification. In this study, we examined predictors of icon identification as participants gained experience with icons over a series of learning trials. A dynamic pattern of findings emerged in which the primary predictors of identification changed as learning progressed. In early learning trials, semantic distance (the closeness of the relationship between icon and function) was the best predictor of performance, accounting for up to 55% of the variance observed, whereas familiarity with the function was more important in later trials. Other stimulus characteristics, such as our familiarity with the graphic in the icon and its concreteness, were also found to be important for icon design. The theoretical implications of these findings are discussed, with particular emphasis on the parallels with picture naming. The icon identification norms from this study may be downloaded from brm.psychonomic-journals .org/content/supplemental.

Why do I like It? the Relationships between Icon Characteristics, user Performance and Aesthetic Appeal

Until recently the guiding tenet in human-computer interaction was that any interface must be easy to learn and use. However, it has been increasingly recognized that the appeal of the interface to the user and their enjoyment of it is also important. The aim of the current study was to examine the nature of the relationships between icon characteristics, user performance, and aesthetic appeal. When participants were asked to rate the appeal of a corpus of icons, it was found that the same icon characteristics predicted appeal as those predicting user performance. The theoretical and practical implications of the remarkable similarity in the factors determining appeal and usability are discussed.

Reading Ability and Memory Span: Long-Term Memory Contributions to Span for Good and Poor Readers.

A number of studies have shown that childrenwith reading difficulties perform poorly ontests of verbal memory span. The extent towhich differences in memory span for good andpoor readers can be explained by differences ina long-term memory component to span as well asby differences in short-term memory processeswas investigated in this study. Memory spanand rehearsal rate were measured for high andlow frequency words and nonwords. Althoughmemory span performance for high frequencywords was comparable for all reading abilitygroups, good readers had better memory spanperformance for low frequency words. This wasattributable to differences in both short-termand long-term memory contributions to spanperformance. Differences between readingability groups also emerged when memory spanfor nonwords was measured. In this case,differences between groups also appeared to bethe result of difficulties which poor readersencountered in learning newphonologically-based materials (i.e. nonwords). The nature of the inter-relationships betweenmemory span, reading and measures ofphonological awareness are discussed in thelight of these findings.

Searching for signs, symbols, and icons: Effects of time of day, visual complexity, and grouping.

Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual search were examined: the time of day at which search was carried out, the visual complexity of the icons, and the extent to which information features in the icon were grouped together. The speed with which participants searched icon arrays for a target was slower early in the afternoon, when icons were visually complex and when information features in icons were not grouped together to form a single object. Theories of attention that account for both feature-based and object-based search best explain these findings and are used to form the basis for ways of improving icon design.

Dynamic confidence during simulated clinical tasks

Objective: Doctors’ confidence in their actions is important for clinical performance. While static confidence has been widely studied, no study has examined how confidence changes dynamically during clinical tasks. Method: The confidence of novice (n = 10) and experienced (n = 10) trainee anaesthetists was measured during two simulated anaesthetic crises, bradycardia (easy task) and failure to ventilate (difficult task). Results: As expected, confidence was high in the novice and experienced groups in the easy task. What was surprising, however, was that confidence during the difficult task decreased for both groups, despite appropriate performance. Conclusions: Given that confidence affects performance, it is alarming that doctors who may be acting unsupervised should lose dynamic confidence so quickly. Training is needed to ensure that confidence does not decrease inappropriately during a correctly performed procedure. Whether time on task interacts with incorrect performance to produce further deficits in confidence should now be investigated.

The effects of the visual metaphor in determining icon efficacy

The visual metaphor lies at the heart of modern graphical user interfaces. The benefits ascribed to its use rest largely on the belief that pictorially realistic icons allow users to apply pre-existing world knowledge to the computer domain. Added visual realism, however, has also been associated with increased levels of visual complexity. This, in contrast, has been found to impair user performance. This paper discusses our recent investigations demonstrating that visually realistic icons can be designed without increasing their levels of visual complexity and attempts to provide an experimental basis for design practice.