Adult Age Differences in Eye Movements During Reading: The Evidence From Chinese

Could driving help us to "see better"? A comparative assessment of saccadic efficiency, visual speed, and attention

BACKGROUND

This study aimed at comparing drivers' and non-drivers' results in the Adult Developmental Eye Movement with Distractors test (ADEMd) and the Useful Field of View test (UFOV).

METHODS

One hundred and twenty Spaniards (mean age 50.90 ± 17.32 years) without eye disease voluntarily participated in this cross-sectional descriptive study. Participants in a single experimental session completed a questionnaire on sociodemographic, health, eyesight, and driving information. They also performed the ADEMd and UFOV tests randomly following standardized protocols. The ADEMd is a visual-verbal test that measures saccadic efficiency and visual attention. Brown-Forsythe (B-F) tests with Games-Howell post-hoc adjustments were conducted to assess differences between groups. Groups were formed according to sex, age (young adults, adults, and older adults), and driver/non-driver for further analysis. Additionally, associations between dependent variables were assessed through Spearman's correlations.

RESULTS

Drivers obtained significantly better results in the ADEMd compared with non-drivers. Non-significant differences between drivers and non-drivers were encountered in the UFOV. Additionally, significant differences were observed between sexes and age groups. It is worth highlighting that non-driver's age significantly correlated with worse ADEMd performance (rho = .637 to .716). This correlation was non-significant in drivers. Similarly, reading hours significantly correlated with better ADEMd performance in non-drivers (rho = - .291 to - .363), but not in drivers. The only significant correlations between ADEMd and UFOV tests were found in drivers (rho = .307 to .410).

CONCLUSION

Considering all the discussed results, it could be hypothesized that the driving task promotes abilities, such as oculomotor and cognitive function, which are relevant for the performance in the ADEMd. However, this hypothesis is based on correlational outcomes and further studies should causally assess this possible relation.

A further look at ageing and word predictability effects in Chinese reading: Evidence from one-character words

Older adults are thought to compensate for slower lexical processing by making greater use of contextual knowledge, relative to young adults, to predict words in sentences. Accordingly, compared to young adults, older adults should produce larger contextual predictability effects in reading times and skipping rates for words. Empirical support for this account is nevertheless scarce. Perhaps the clearest evidence to date comes from a recent Chinese study showing larger word predictability effects for older adults in reading times but not skipping rates for two-character words. However, one possibility is that the absence of a word-skipping effect in this experiment was due to the older readers skipping words infrequently because of difficulty processing two-character words parafoveally. We therefore took a further look at this issue, using one-character target words to boost word-skipping. Young (18–30  years) and older (65+ years) adults read sentences containing a target word that was either highly predictable or less predictable from the prior sentence context. Our results replicate the finding that older adults produce larger word predictability effects in reading times but not word-skipping, despite high skipping rates. We discuss these findings in relation to ageing effects on reading in different writing systems.

Effects of Normative Aging on Eye Movements during Reading

Substantial progress has been made in understanding the mostly detrimental effects of normative aging on eye movements during reading. This article provides a review of research on aging effects on eye movements during reading for different writing systems (i.e., alphabetic systems like English compared to non-alphabetic systems like Chinese), focused on appraising the importance of visual and cognitive factors, considering key methodological issues, and identifying vital questions that need to be addressed and topics for further investigation.

Establishing a role for the visual complexity of linguistic stimuli in age-related reading difficulty: Evidence from eye movements during Chinese reading

Older adults experience greater difficulty compared to young adults during both alphabetic and nonalphabetic reading. However, while this age-related reading difficulty may be attributable to visual and cognitive declines in older adulthood, the underlying causes remain unclear. With the present research, we focused on effects related to the visual complexity of written language. Chinese is ideally suited to investigating such effects, as characters in this logographic writing system can vary substantially in complexity (in terms of their number of strokes, i.e., lines and dashes) while always occupying the same square area of space, so that this complexity is not confounded with word length. Nonreading studies suggests older adults have greater difficulty than young adults when recognizing characters with high compared to low numbers of strokes. The present research used measures of eye movements to investigate adult age differences in these effects during natural reading. Young adult (18-28 years) and older adult (65+ years) participants read sentences that included one of a pair of two-character target words matched for lexical frequency and contextual predictability, but composed of either high-complexity (>9 strokes) or low-complexity (≤7 strokes) characters. Typical patterns of age-related reading difficulty were observed. However, an effect of visual complexity in reading times for words was greater for the older than for the younger adults, due to the older readers experiencing greater difficulty identifying words containing many rather than few strokes. We interpret these findings in terms of the influence of subtle deficits in visual abilities on reading capabilities in older adulthood.

Aging and Pattern Complexity Effects on the Visual Span: Evidence from Chinese Character Recognition

Research suggests that pattern complexity (number of strokes) limits the visual span for Chinese characters, and that this may have important consequences for reading. With the present research, we investigated age differences in the visual span for Chinese characters by presenting trigrams of low, medium or high complexity at various locations relative to a central point to young (18–30 years) and older (60+ years) adults. A sentence reading task was used to assess their reading speed. The results showed that span size was smaller for high complexity stimuli compared to low and medium complexity stimuli for both age groups, replicating previous findings with young adult participants. Our results additionally showed that this influence of pattern complexity was greater for the older than younger adults, such that while there was little age difference in span size for low and medium complexity stimuli, span size for high complexity stimuli was almost halved in size for the older compared to the young adults. Finally, our results showed that span size correlated with sentence reading speed, confirming previous findings taken as evidence that the visual span imposes perceptual limits on reading speed. We discuss these findings in relation to age-related difficulty reading Chinese.

Effects of word length on eye guidance differ for young and older Chinese readers

Effects of word length on where and for how long readers fixate within text are preserved in older age for alphabetic languages like English that use spaces to demarcate word boundaries. However, word length effects for older readers of naturally unspaced, character-based languages like Chinese are unknown. Accordingly, we examined age differences in eye movements for short (2-character) and long (4-character) words during Chinese reading. Word length effects on eye-fixation times were greater for older than younger adults. We suggest this age difference is due to older adults’ saccades landing more rarely at optimal intraword locations, especially in longer words.

Adult Age Differences in Effects of Text Spacing on Eye Movements During Reading

Large-scale changes in text spacing, such as removing the spaces between words, disrupt reading more for older (65+ years) than younger (18–30 years) adults. However, it is unknown whether older readers show greater sensitivity to simultaneous subtle changes in inter-letter and inter-word spacing encountered in everyday reading. To investigate this, we recorded young and older adults’ eye movements while reading sentences in which inter-letter and inter-word spacing was normal, condensed (10 and 20% smaller than normal), or expanded (10 or 20% larger than normal). Each sentence included either a high or low frequency target word, matched for length and contextual predictability. Condensing but not expanding text spacing disrupted reading more for the older adults. Moreover, word frequency effects (the reading time cost for low compared to high frequency words) were larger for the older adults, consistent with aging effects on lexical processing in previous research. However, this age difference in the word frequency effect did not vary across spacing conditions, suggesting spacing did not further disrupt older readers’ lexical processing. We conclude that visual rather than lexical processing is disrupted more for older readers when text spacing is condensed and discuss this finding in relation to common age-related visual deficits.

The "risky" reading strategy revisited: New simulations using E-Z Reader

Eye-movement studies have demonstrated that, relative to college-aged readers, older readers of alphabetic languages like English and German tend to read more slowly, making more frequent and longer fixations and longer saccades, and skipping more words, but also making more frequent regressions. These findings have led to suggestions that older readers either adopt a "risky" strategy of using context to "guess" words as a way of compensating for slower rates of lexical processing, or have a smaller and more asymmetrical perceptual span. Unfortunately, neither of these hypotheses seemingly explains more recent observations that older readers of Chinese seem to adopt a more "conservative" strategy, making shorter saccades and skipping less often. In this paper, we use the E-Z Reader model of eye-movement control to examine several possible accounts of the differences between college-aged and older readers of both alphabetic and non-alphabetic languages. These simulations re-confirm that the "risky" strategy may be sufficient to explain age-related differences in reader's eye movements, with older readers of English versus Chinese being, respectively, more versus less inclined to guess upcoming words. The implications of these results for aging, reading, and models of eye-movement control are discussed.

Effects of adults aging on word encoding in reading Chinese: evidence from disappearing text

The effect of aging on the process of word encoding for fixated words and words presented to the right of the fixation point during the reading of sentences in Chinese was investigated with two disappearing text experiments. The results of Experiment 1 showed that only the 40-ms onset disappearance of word n disrupted young adults' reading performance. However, for old readers, the disappearance of word n caused disruptions until the onset time was 120 ms. The results of Experiment 2 showed that the disappearance of word n + 1 did not cause disruptions to young adults, but these conditions made old readers spend more time reading a sentence compared to the normal display condition. These results indicated a reliable aging effect on the process of word encoding when reading Chinese, and that the encoding process in the preview frame was more susceptible to normal aging compared to that in the fixation frame. We propose that sensory, cognitive, and specific factors related to the Chinese language are important contributors to these age-related differences.