The effects of age on symbol comprehension in central rail hubs in Taiwan

Abstract

The purpose of this study was to investigate the effects of age and symbol design features on passengers' comprehension of symbols and the performance of these symbols with regard to route guidance.

In the first experiment, 30 young participants and 30 elderly participants interpreted the meanings and rated the features of 39 symbols. Researchers collected data on each subject's comprehension time, comprehension score, and feature ratings for each symbol.

In the second experiment, this study used a series of photos to simulate scenarios in which passengers follow symbols to arrive at their destinations. The length of time each participant required to follow his/her route and his/her errors were recorded.

Older adults experienced greater difficulty in understanding particular symbols as compared to younger adults. Familiarity was the feature most highly correlated with comprehension of symbols and accuracy of semantic depiction was the best predictor of behavior in following routes.

Introduction

The Taiwan High Speed Rail (THSR) was established in 2007 to solve traffic problems in western Taiwan, and the Kaohsiung rapid transit system was completed in 2008. Following the completion of these two transportation systems, central rail hubs, which include a railway station, a THSR station, and a rapid transit station, have appeared in Taiwan. Many different people pass through these stations for different purposes. For example, local residents in the Kaohsiung rapid transit station may actually intend to take the train or high speed rail, and tourists in the THSR or railway station may intend to travel by rapid transit. Various systems of directional and informational symbols are used in these hubs to guide passengers, provide them with information, and help them identify directions according to their travel intentions. However, not only are these three systems of symbols in the central rail hubs different but many symbols have been modified and new symbols have been added.

Because the symbols in these transportation hubs are not standardized and some residents or foreign tourists may not have seen these symbols before, comprehension of symbols in such hubs is important for prospective users of transportation systems. It was hypothesized that detailed investigation of the comprehension of directional and informational symbols in central railway hubs was an important need. When the tourists can't understand the symbols of the central rail hubs, they experience confusion and are at a loss of what to do next. They are likely to feel even more lost in central rail hubs, and can easily become more flustered. These conditions could disrupt order and be a serious issue from a safety perspective (Building Research Establishment for Office of the Deputy Prime Minister, 2006).

The advantages of using symbols are: (a) symbols can quickly communicate instructions; (b) use of symbols avoids problems related to inadequate reading skills or linguistic unfamiliarity; and (c) passengers may remember symbols better than they remember text (Wogalter et al., 1997). Because symbols provide a language-free method of communicating, they can potentially be understood by diverse groups which vary in life experience and reading ability. However, studies have proved that many symbols currently in use are difficult to understand (Collins and Lerner, 1982; Davies et al., 1998; Wolff and Wogalter, 1993; Lesch, 2003).

Picha et al., 1995, Picha et al., 1997 conducted multiple evaluations of comprehension of different traffic symbols by more than 3000 drivers in Texas. They found that low comprehension levels existed for several symbols. Paninti (1989) compared several alternative symbols used to signify work zones, and found that symbols with good physical resemblance to what they were meant to signify were all well understood, even when the details of these symbols were different. In contrast, when the intended message was difficult to convey symbolically, all proposed alternative symbols were not clearly understood.

Measurement of symbol design is based on recognition rate. McDougall et al. (1999) measured characteristics of symbols or icons according to features like familiarity, concreteness, simplicity, meaningfulness, and accuracy of semantic depiction. Ng and Chan (2007) also used these same features to investigate the guessability of traffic symbols. These features have become central concerns in research on symbols and icons (Ng and Chan, 2008, Ng and Chan, 2009, Chan and Ng, 2010). Familiarity indicates the frequency with which icons have been encountered. Rosson (2002) also found that familiarity improves comprehension, a conclusion similar to that of Ben-Bassat and Shinar (2006). Concreteness indicates the degree to which something is material and genuine. Icons or symbols are concrete if they depict real objects, materials, or people; otherwise, they are abstract. Symbols with concrete design are more easily understood than those with ambiguous designs (Wolff and Wogalter, 1993; Foster and Afzainia, 2005; Passini et al., 2008; Rousek and Hallbeck, 2011). Symbols are regarded as complex if they are intricate or depict a lot of detail, and simple if they contain only few elements or details. Dewar (1999) noted that complicated symbols are more difficult to comprehend compared to simpler symbols. Meaningfulness refers to the degree of significance viewers attribute to icons and is seen as an important characteristic of symbol design (Huang et al., 2002; Lin, 1992). Accuracy of semantic depiction indicates how closely, accurately, and comprehensively the design of the symbol represents what the symbol is meant to signify.

Lesch (2008) suggested that positive symbol characteristics are easy to understand, and that using positive symbol characteristics is more effective in helping viewers to understand symbols as compared to symbol comprehension training. Shinar et al. (2003) found that ‘infrequent symbols are more likely to be miscomprehended and less likely to be correctly learned’ by drivers. It was hypothesized that users identify symbols more easily if the symbols are familiar to them. Another hypothesis of this study was that because concrete symbols provide a direct visual aid to help viewers comprehend the intended meaning of such depiction, users comprehend concrete symbols better than they do abstract symbols. It was expected that simple symbols to be easier to identify than complex symbols because complex symbols have the potential to confuse or complicate understanding (Bruyas et al., 1998). The meaningfulness of a symbol refers to the ability of a symbol to elicit attribution of meaning from users (Preece et al., 1994), so researchers expected higher comprehension scores for meaningful symbols. Higher ratings for accuracy of semantic depiction indicated that symbols given such ratings were clearly associated with the concepts they were meant to signify, and thus should lead to higher comprehension scores. Young and Wogalter (1990) indicated that users will better identify a symbol that precisely communicates the semantic meaning.

Statistics show that 20% of the population in most developed countries is older than 60, and that one third of the earth's population will be over 60 years old by 2050 (United Nations Population Division, 2009). In 2009, 2.45 million people (10.7% of the population) in Taiwan were over 65 years old (Statistical Yearbook of Interior, Taiwan, 2010), and the population of elderly adults will only continue to increase. According to population statistics forecast in the international database of the U.S. Census Bureau, 12.3% of the population in Taiwan will be older than 65 in 2015. The 65 + age group represents the fastest growing age group in Taiwan (U.S. Census Bureau, 2010).

Regarding the effect of aging, past studies have indicated that the use of symbols may pose special problems for the elderly (Collins and Lerner, 1982; Dewar et al., 1994; Easterby and Hakiel, 1981; Hancock et al., 1999; Jones, 1992; Lesch, 2003; Morrell et al., 1990; Shinar et al., 2003; Zwaga and Boersema, 1983; Al-Gadhi et al., 1994; Scialfa et al., 2008). Hancock et al. (1999) indicated that aging is generally associated with a decline in various perceptual and cognitive abilities—for example, vision and working memory. However, Al-Madani and Al-Janahi (2002) found that the differences between the different age groups showed that drivers in the younger age group (16–24 years) comprehend significantly less well than those in the older groups (35–44 and over 44 years). Ng and Chan (2008) also indicated that the poor performance of older subjects was not evident.

In related experimentation, Dewar et al. (1994) showed 85 color slides of standard US symbol symbols to 480 volunteer licensed drivers from the USA and Canada. Results showed that for 39% of the symbols examined, the understanding of older drivers was poorer than that of younger drivers. Regarding the remaining symbols, no difference in comprehension with regard to age was observed. Jones (1992) reported that a survey of older drivers in Illinois also showed that older drivers failed to understand some common traffic control signs. Shinar et al. (2003) evaluated levels of comprehension of highway traffic symbols used in different countries, and found that “older drivers tend to do less well at symbol comprehension than other drivers, including novice drivers and repeated violators”. Lesch (2003) examined the effectiveness of three different training conditions to improve comprehension and remembrance of warning symbols for younger (18–35 years old) and older (50–67 years old) participants. Results showed that although training improved participants' accuracy and speed of response on a comprehension test, the performance of older participants was significantly poorer than that of younger participants, both before (37% vs. 52% of correct answers, respectively, in the older and younger participant groups) and after training (68% vs. 88% of correct answers on the immediate post-test). Older participants also found it more difficult to reject incorrect meanings (55% vs. 68% of correct answers). According to the abovementioned research, the effects of aging significantly influence comprehension of symbols, and the design of symbols in central rail hubs should take elderly adults into account.

The aims of this study were as follows, and two experiments were used to assess the objectives.

• To evaluate the comprehension of symbols in Taiwanese central rail hubs by two user groups of different ages;

• To explore the correlation between symbol design features and symbol comprehension;

• To examine the differences among participants' symbol comprehension performance with regard to various categories of symbols