Age Differences In Saccadic Averaging. Psychology: Fill & Download for Free

Most authors, including those mentioned in the excellent overview of blink rate research from Stern et al. (1994), conclude that blink rate is a robust measure that increases with time on task and fatigue. Blink rate exhibits average values of 3–7 blinks per minute during reading and 15–30 during most nonreading tasks. The following effects on blink rate can be found in the literature:Dry eyes. Montes-Mico et al. (2005) concluded that the need to moisten the eyeball is not a major determinant of blinking. However, Montes-Mico et al. (2005), amongst others, reported that ‘the typical interblink interval in normal patients is approximately 4 to 5 seconds and in those with dry eyes is approximately 1 to 2 seconds in normal conditions’ (p. 1618). It is intuitive that a function of blinking is to keep the eyeball moist, and the results of the latter authors support this.Air pollutants such as those resulting from cigarette smoking, increase blink rate (Stern et al., 1994).Contact lenses. Blink rates initially increase when wearing lenses, but may return to base values following long-term wear (Collins, Seeto, Campbell, & Ross, 1989).Monitors Patel, Henderson, Bradley, Galloway, and Hunter (1991) reported that blink rate dropped on average by 20% during the use of monitors by normal, healthy participants, although Chu, Rosenfield, and Portello (2014) reported higher blink rates when reading from monitors versus reading from paper.Time on task The vast majority of earlier studies (before 1990) were conducted using prolonged reading tasks, which could be up to six hours in length. Blink rate generally increases with time on task (i.e. length of time of reading), but intermediate pauses with comprehension questions have been found to eradicate this effect.Time of day Blink rate appears to be higher during late afternoon than during the morning (Stern et al., 1994).Saccade amplitude Blinks are more likely to co-occur with large amplitude than with small amplitude saccades. Evinger et al. (1994) observed that activation of the lid closing muscle occurred with 97% of saccadic gaze shifts larger than 33 degrees. Williamson, Zivotofsky, and Basso (2005) found less blinks during saccades to the target as compared to saccades back to the centre of the screen.The dopaminergic system There are indications from pharmacological studies that blink rate re- flects the participant’s dopamin levels. Medication that increases dopamin increases blink rate (Bologna, Fasano, Modugno, Fabbrini, & Berardelli, 2012). Parkinson patients (who have lost dopaminergic cells) have markedly lower blink rate, while Tourettes syndrom and schizophre- nia patients (with elevated dopaminergic levels) instead have higher blink rate. Eckstein et al. (2016) argues that blink rate could be a reliable indicator of dopamin levels also for non- patients.Mental workload Several studies associate the rate of blinks with mental workload (Wolkoff et al., 2005). In a study where car drivers had simultaneous auditory tasks, Tsai, Viirre, Strychacz, Chase, and Jung (2007) found an increase in blink rate compared to the driving only task. van Orden et al. (2000) found that blink rate increased as a function of tracking error in a human factors tracking task. Brookings et al. (1996) showed a positive correlation between blink rate and mental workload in air traffic controllers. However, Veltman and Gaillard (1996) came to the conclusion that blinking is independent of mental workload. This conclusion was based on physiological observations from a flight simulator study, where participants experienced in aviation had a concurrent auditory memory task, as well as the primary task of controlling and landing the simulated aircraft. Veltman and Gaillard (1996) found that during landing, when pilots had to process more visual information, the number and duration of blinks decreased, irrespective of the demands of the auditory task. The authors suggested that this decrease is reflective of a strategy to maximize the time available for visual processing when visual demands are highest. It is possible that the differences in findings for blink rate and mental/visual work- load reflect the different types of task. One can easily envisage, for example, a situation where blinks are infrequent owing to maintained concentration when visual (and cognitive) demands are high. However, when the requirements of the task exceed available cognitive resources, concentration may falter, and blink rate may increase due to mental workload.Psychoticism Participants with higher scores on the psychoticism scale have shown higher blink rates (Colzato, Slagter, Van Den Wildenberg, & Hommel, 2009).Anxiety The psychophysiology studies by Tecce (1992) gave rise to the ’blink-hedonia hypothesis’ which states that decreased blink frequency is related to pleasant feelings, whereas an increased blink frequency accompanies unpleasant mood states such as nervousness, stress, and fatigue. Empirical support for this hypothesis was indeed found by Harrigan and O’Connell (1996).Individual differences Using a cluster analysis, Doughty and Naase (2006) grouped their partici- pants into two groups: normal blinkers, with around 10 blinks per minute, and frequent blink- ers, with more than 20 blinks per minute.Age Young children blink significantly less frequently than adults. When younger than two months, infants barely blink at all (Stern et al., 1994).From pages 557–560 in our book on Eye-tracking: Eye tracking: A comprehensive guide to methods, paradigms, and measures: Prof Kenneth Holmqvist, Dr Richard Andersson: 9781979484893: Amazon.com: Books