Eye-Blink Behaviors in 71 Species of Primates

Abstract

The present study was performed to investigate the associations between eye-blink behaviors and various other factors in primates. We video-recorded 141 individuals across 71 primate species and analyzed the blink rate, blink duration, and “isolated” blink ratio (i.e., blinks without eye or head movement) in relation to activity rhythms, habitat types, group size, and body size factors. The results showed close relationships between three types of eye-blink measures and body size factors. All of these measures increased as a function of body weight. In addition, diurnal primates showed more blinks than nocturnal species even after controlling for body size factors. The most important findings were the relationships between eye-blink behaviors and social factors, e.g., group size. Among diurnal primates, only the blink rate was significantly correlated even after controlling for body size factors. The blink rate increased as the group size increased. Enlargement of the neocortex is strongly correlated with group size in primate species and considered strong evidence for the social brain hypothesis. Our results suggest that spontaneous eye-blinks have acquired a role in social communication, similar to grooming, to adapt to complex social living during primate evolution.

Half-Blind to the Risk of Predation

“…Blinks associated with head movements are known in other species (Zeigler et al, 1980;Kirsten and Kirsten, 1983;Evinger et al, 1994;Tada et al, 2013;Yorzinski, 2016), and many species of birds are also known to peck at very high rates (Gillings et al, 2007;Kuwae et al, 2008). In other species, head movements can occur when looking for food (Ochs et al, 2016) or when scanning for predators (Butler et al, 2016).…”

“…In addition, blinking aids vision through a series of processes including a reduction in photoreceptor image fading (Kinsbourne and Warrington, 1963). Blinking can occur spontaneously but in birds and mammals it tends to be associated with gaze shifts caused by eye or head movements (Kirsten and Kirsten, 1983;Evinger et al, 1994;Tada et al, 2013). Blinking during such gaze shifts might serve several purposes.…”

Psychophysiology-Based QoE Assessment: A Survey

“…For example, reading, particularly on video terminals, is associated with a decrease in blink rate which may in turn cause dry eyes [72], while active social conversation can lead to increased blink frequency [73]. In fact, blinking behaviour across primate species is correlated with social factors such as group size, indicating a role in vigilance and visual awareness [74]. Further, the physical motions of the eye, and movements of the eyelid, are closely related for spontaneous, voluntary and reflexive behaviours [75].…”

Blink and wink detection as a control tool in multimodal interaction

“…The closing of the eyelids blocks (in fact significantly reduces) the amount of light during sleep. The physiology of the eye and the blinking mechanism have been well known for a long time and have been documented [9,16,30,36]. Depending on individual predispositions and external conditions, a human being blinks approximately 6-30 times/min (on average, approximately 16 times/min) [20].…”