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normal and pathological laughter. Note that in the mesencephalic
encyclopaedia.
and pontine regions the ®bres from the PAG, which probably
Although operational de®nitions of `laughter,' `humour'
transmit the signal to laugh, are located dorsally/tegmentally,
whereas the ®bres from the frontal motor areas run ventrally, and `funny' have been formulated for individual studies, a
probably inhibiting facial emotional expressions. BASAL TEMP =
broad consensus on their exact meanings has yet to be
basal temporal lobe including amygdala; CB = cerebellum; CMN
reached. This is not a trivial handicap: it is obvious that what
= cervical motor neurons; BG = basal ganglia; HYPOTHAL =
one means by humour and laughter will in¯uence what kinds
hypothalamus; MOTOR = motor area; N.X = vagal nerve nucleus;
of experiments one designs for their analysis. The relation-
PREFRONTAL = medial and dorsolateral prefrontal cortex;
PREMOTOR = premotor area; THAL = thalamus. ships between the subjective feelings of an emotion (in this
case, exhilaration) and its motor expressions (in this case,
smiling and laughter) have been discussed for over a century
be formed voluntarily; it is, however, not possible for most
(James, 1950) and continue to be the subject of lively
people to imitate convincingly the genuine facial expressions
discourse (Damasio, 2003).
of felt emotion. This is particularly dif®cult with laughter, or
There is a goodly number of theories on why things are
as Gowers (1887, cf. Ironside, 1956) formulated it, `The will
funny. Inasmuch as all the experiments described below are
is needed not to effect it, but to restrain it'.
based on only one of these theories, howeverÐthe incongru-
We thus propose that genuine, emotionally driven laughter
ity theory of Kant (1972)Ðother theories, such as the
is not normally initiated in the motor cortex but rather that,
superiority theory of Plato (1941) and Aristotle (1941) and
during such laughter, cortical frontal inhibition ceases. In this
the psychoanalytic theory of Sigmund Freud (1976), will not
context, it is interesting that laughing gas, an N-methyl-D- be discussed.
aspartate antagonist, probably exerts its in¯uence by inhib- According to the incongruity theory, humour involves the
ition of neurons in the premotor and motor cortex (Franks and
perception of incongruity or paradox in a playful context
Lieb, 1998). We consider the occurrence of pathological
(Forabosco, 1992). For something to be funny, two stages can
laughter to be the result of damage to this inhibitory system.
be distinguished in the processing of humorous material
Pathological laughter, then, would have a neural substrate of
(Suls, 1972). In the ®rst stage, `¼ the perceiver ®nds his
subcortical disinhibition similar to the disinhibition observed
expectation about the text discon®rmed by the ending of the
in patients with spasticity of the extremities or of the bladder,
joke. ¼ In other words, the recipient encounters an incon-
in which the micturition re¯ex can be triggered by normally
gruityÐthe punch-line. In the second stage, the perceiver
inadequate stimuli. It further seems possible that, in patients
engages in a form of problem-solving to ®nd a cognitive rule
with ventrally lying tumours of the brainstem, pressure- which makes the punch-line follow from the main part of the
induced disruption of inhibitory tracts results in forced facial
joke and reconciles the incongruous parts'. Other researchers
expressions.
have called these stages `surprise' and `coherence' (Brownell
et al., 1983).
To some psychologists, however, these two stages are
insuf®cient to account for differences between the perception
Humour and the brain
of humour and a similar situation, the perception that a
Humour: overview problem has been solved. It has been suggested that the two-
Reasons for the complexity of research on humour are legion. step model should be expanded to include a third stage (Ruch
What was funny 20 years ago may not be funny today and the and Hehl, 1998): that of detecting that what actually makes
2132 B. Wild et al.
sense (given the ability to perceive humour) is pleasant 1975 (Gardner et al., 1975). Until then, scattered references to [ Pobierz całość w formacie PDF ]