1956). The exertion of effort is associated with significant heart rate deceleration (Coles,
1972; Kramer & Spinks, 1991; cf. Kagan, 1965; Lewis, Kagan, Campbell, & Kalafat,
1966). The EEG becomes desynchronized (Boiten, Sergeant, & Geuze, 1992; Sergeant et
al., 1999; van Winsum, Sergeant, & Geuze, 1984), and rhythmic theta waves associated
with hippocampal activity can be observed (Pribram & McGuinness, 1975).
Effort is closely linked to arousal. Kahneman (1973) sometimes equated the two
processes, but further research has suggested that they should be regarded as intimately
related rather than inseparable (Pribram & McGuiness, 1975; Sanders, 1983). During an
episode of physiological arousal, the heart rate surges (Obrist, Wood, & Perez-Reyes,
1965), arterial blood pressure increases (Abrahams & Hilton, 1964), and then the heart
rate abruptly decelerates (Pribram & McGuinness, 1975). The eyes may dart back and
forth briefly, as has been frequently noted in arousals associated with deceptive behavior
(Ekman, 2001; Moore, Petrie, & Braga, 2003). Respiratory activity fluctuates, and
electrodermal activity momentarily increases (Tursky, Shapiro, Crider, & Kahneman,
1969). Blood flow is altered (Abrahams & Hilton, 1964), and the amygdala becomes
active (Pribram & McGuiness, 1975).
4. Analysis
Table 1 summarizes the physiological similiarities between tonic REM sleep and
effort and between phasic REM sleep and arousal. Although it is currently challenging to
make an exhaustive comparison because of the piecemeal and often imprecise nature of
preliminary draft (9/24/2006)