Sustained vigilance and animal performance

Abstract

Abstract. Psychological studies have established that the central nervous system cannot sustain vigilance for an extended period of time. The consequent vigilance decrement implies a gradual reduction in the ability to process information effectively. This may result in a reduced ability to detect hidden predators, locate cryptic food items or make successful behavioural decisions. A model incorporating parameters of vigilance decrement during foraging and vigilance recovery during rest predicts first, the optimal allocation of time between foraging activity and rest, and second, the optimal length of each foraging episode. For a given rate of vigilance recovery, the model predicts that both the optimal proportion of time devoted for foraging activity and the optimal length of a foraging bout should be decreasing functions of the rate of vigilance decrement. Because the rate of vigilance decrement is larger for more difficult tasks, both the total time spent foraging and the duration of each foraging episode should be smaller for more demanding foraging activities. It is suggested that vigilance decrement is a dominant factor determining temporal patterns of animal behaviour.

Dolphin continuous auditory vigilance for five days

“…The dolphins detected 94.2±2.26% (SAY) and 94.36±6.33% (WEN) of the target stimuli throughout all sessions with little vigilance decrement as indicated by target response time and accuracy (Fig.·2). When the 24·h before the start of the vigilance session was compared with the 24·h following the vigilance sessions (Fig.·3) there was not a substantial increase in sleep behaviors (McCormick, 1969;Flanigan, 1974;Goley, 1999) or signs of sleep deprivation (Oleksenko et al, 1992;Dinges et al, 1994;Dukas and Clark, 1995).…”

“…The dolphins' lack of a significant vigilance decrement over the 120·h sharply contrasts both field observations and laboratory studies of other species (Dukas and Clark, 1995;Siegel, 2005). It is an almost universal finding that prolonged periods of sleep deprivation cause a reduction in vigilance performance (Davies and Parasuraman, 1982;Beaumont et al, 2001;Horne and Pettitt, 1985;Gillberg and Akerstedt, 1998).…”

Dolphins maintain cognitive performance during 72 to 120 hours of continuous auditory vigilance

“…A reduced amount of sleep resulted in a degradation of human response time (Lim and Dinges, 2008) and performance on a response time task. The dolphins' lack of a significant decrement in auditory vigilance or in a cognitive task over 72 h or 120 h sharply contrasted with both field observations and laboratory studies of other species (Dinges et al, 1997;Dukas and Clark, 1995;Liberman et al, 2006;Siegel, 2005). It is an almost universal finding that prolonged periods of continuous vigilance or sleep deprivation of even shorter periods than our dolphin trials cause a reduction in vigilance performance (Beaumont et al, 2001;Davies and Parasuraman, 1982;Gilberg and Akerstedt, 1998;Horne and Pettitt, 1985).…”

“…6) there was not a substantial increase in sleep behaviors (Flanigan, 1974;Goley, 1999;McCormick, 1969) or signs of sleep deprivation (Dinges et al, 1994;Dukas and Clark, 1995;Oleksenko et al, 1992); however, dolphin SAY did show a slight increase in 'sleep' time after one of the 120 h vigilance sessions (S03). In contrast to NAY's night time behavior, SAY floated less and usually continued to circle the enclosure.…”

Substrate selection and use of protective cover by juvenile Atlantic cod Gadus morhua in inshore waters of Newfoundland

“…Such antipredator behaviours require that fish (especially those which are small and, presumably, more vulnerable) must be ever vigilant to predatory attack. However, such vigilance has metabolic (Lima & Dill 1990) and neurological (Dukas & Clark 1995) costs Simply stated, it 1s not always possible to be in a constant state of vigilance It may be more efficient, and perhaps 'safer' in the long run, to adopt predator averse behaviours which require less vigilance and, therefore, a minimum expenditure of energy. One way fish can achieve this objective is to select appropriate substrate.…”