There's been some debate about how the highly popular Survivor contestant Hein happened to lose the tie-breaking challenge in which he had to guess a duration of 30 seconds.
Some thought he had nobly sacrificed himself for Lorette's sake and had deliberately waited far too long, to ensure she won. Others were sure he had actually fallen asleep.
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I spoke to an eye-witness who was there during the filming of this tribal council and challenge and she was convinced that Hein had indeed nodded off to sleep at the most crucial time.
And Dyke, who had been chatting to Hein throughout most of the night (for technical reasons, filming the tribal council was delayed until after midnight), said that Hein was drowsy and nodded off during their conversations. He said he was sure Hein had fallen asleep, however briefly, at a crucial time.
Hein didn't tell us his version in public. But I believe the sleep theory is a powerful one and if, as I suspect, it involved a micro sleep, even Hein himself might not be aware that he drifted off.
What is a microsleep?
Anyone who has sat through any form of lecture will have experienced that irresistible moment when, despite the best intentions of looking interested, you nod off into brief into a deep sleep, before jerking back awake.
A microsleep is a brief and unintentional episode of sleep, which includes a momentary loss of attention and usually occurs in someone who has a significant sleep debt, related to sleep deprivation, or general mental fatigue. Or, in even more pathological conditions such as sleep apnoea, hypersomnia, or narcolepsy.
The microsleep can last from a fraction of a second up to several seconds and the sleeper is usually not aware that this has happened. They either feel certain they were fully awake the entire time, or at most feel rather 'spaced out'.
But short term memory is generally affected, too, so one's own memory of what one thinks happened may be highly unreliable.
Clearly such events can be very dangerous when clear alertness is needed, such as when someone is driving, flying a plane, or using heavy machinery.
Tests for microsleepers
It can be very difficult to decide with any certainty when such an episode has occurred, even when the person was wired up to an EEG machine measuring brain-wave activity which is known to reflect some aspects of sleep.
Some experts prefer to rely on common sense signs such as drooping and closing eyelids (we saw Hein's eyes close) or a head nod. Even a blank stare, as microsleeps often occur with the person's eyes remaining open; or the common experience of seeing the head jerk back upright after a brief droop.
Other symptoms include eyelids blinking slowly but more often, the pupils tend to become smaller and there may be yawning and mild shivering. These have been seen in monotonous experimental situations, for instance, when someone is watching a computer screen, even when highly motivated to scan for important signs on it.
Some research has looked into the effects of sleep deprivation on junior doctors, in which very tired young doctors were asked to closely watch a heart monitor screen for occasional abnormalities in the patient's heart rhythm.
Even when they could win money for each minor anomaly they correctly spotted, it was found that even after quite modest amounts of sleep deprivation, their ability to notice and recognise the occasional abnormalities on the screen was dramatically affected.
What happens during a microsleep?
During such a microsleep, a person often doesn't notice or respond to relevant information from outside stimuli. A driver may not notice a curve in the road, or a red light and a pilot may not recognise flashing alarm lights among his instruments.
The more one has been deprived of sleep, the more likely these occurrences happen - perhaps more so at times when the brain is used to being asleep.
In time we'll probably hear what Hein is prepared to say about the incident. But I think he had a brief sleep at exactly the most significant moment in the series.
Sources: www.wikipedia.org
(Professor M. A. Simpson, aka CyberShrink, November 2007)
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