Discoveries are sometimes made through the establishment of connections between ideas or theories that appear unrelated. There is currently a booming field of study investigating Theory of Mind and its relationship to mental illness. The study of humour has the potential to provide meaningful insights into this relationship. Not only could humour assist in connecting Theory of Mind and mental illness, but it could assist mental health professionals in connecting with those whom they are treating.
Theory of mind is generally described as the ability to attribute feelings and thoughts to oneself and make inferences with respect to the same in others. The term, first coined by Premack and Woodruff Reference Premack and Woodruff(1), is also referred to as ‘mentalizing’. Over the years, interesting hypotheses have been developed that attempt to explain the symptoms of schizophrenia as an impairment of Theory of Mind, in particular, to adequately internalise the thoughts of others. For instance, delusions of persecution and reference can be conceptualised as a misinterpretation of another person's behaviour or intentions. Furthermore, thought disorder can be regarded as a failure of partitioning assignment of ideas and thoughts. Similarly, negative symptoms of schizophrenia have also been investigated through the lens of a loss of the ability to make appropriate social inferences.
But where is the humour amongst such hypotheses? The first clue is a hint. Indeed, a study conducted involving patients with schizophrenia and a hinting task highlighted the deficits in social inferences in this population Reference Corcoran, Mercer and Frith(2). Those with schizophrenia found hints difficult to understand and often required many clues, compared with a control group. A husband stating to his wife that the shirt he wants to wear to work is creased may not result in the wife ironing the shirt. There may be nothing to read between the lines other than perhaps the implied gender stereotype that is slowly dissolving.
From hints, one can increase complexity to jokes and specifically “Theory of Mind Jokes”. In the latter, understanding humour requires the attribution of ignorance, false belief or deception to one of the characters in the joke, in other words an analysis of the character's mind Reference Marjoram, Tansley, Miller, Macintyre, Cunningham Owens, Johnstone and Lawrie(3). Without Theory of Mind, Figure 1 could be interpreted as a couple waiting for a bus with a man next to them reaching for something. In fact, a more negative interpretation with a persecutory connotation has the couple attempting to push the man over to get onto the bus first. Introduce Theory of Mind and inferences can be made of both the thoughts of the man and the couple, and the joke is explained. The man thinks that someone is putting a gun to his back. The couple do not realise (have not thought) that they are making the man feel like he is being robbed. Explaining a joke is often a lesson in humility, but highlights our ability to mentalize in order to ‘get the joke’. Imagine watching the reactions of Basil Fawlty's patrons without Theory of Mind. Sadly, Mr Fawlty and his towers would not be funny at all.
‘Theory of Mind’ joke. Used with permission from www.cartoonstock.com© Vahan Shirvanian.
There are several theories attempting to explain humour processing from neuropsychological, affective and neurobiological perspectives, which shed light on the underpinnings of deficits observed in schizophrenia. The cognitive element incorporates humour detection that is regarded as a two-step task based on incongruity resolution theory, where incongruity is detected and then resolved. The incongruity is a conflict between what is expected and what actually occurs in the joke. A mother is told by her children on her birthday that she can stay in bed and wait for a surprise. The mother waits for some time and eventually gets out of bed and enters the kitchen to find the children making their own breakfast, for the first time (that is the surprise). Theory of Mind enables an observer to firstly detect the conflict between what was expected by the mother (breakfast in bed) and what actually occurred (the children making their own breakfast): the incongruence. Incongruence resolution is the process by which one gets the joke. With Theory of Mind, the children may escape the wrath of their mother and instead hear the chortles of their mother's laughter.
Martin Reference Martin(4) further elaborated on the cognitive elements of humour using the idea of schema. When facing a humorous situation, a schema is invoked that enables us to make sense of the incoming information. If the information in the humorous situation does not fit with this schema, we search for an alternative schema that matches. This second schema, in turn, allows for an alternative interpretation of the situation. If this second schema is invoked simultaneously with the initial schema, then humour results. Hence, simultaneous activation of two incompatible schemata is the essence of incongruity in humour.
The affective element of the humour experience refers to humour appreciation. This element often involves experiencing different emotions including positive and negative ones Reference Tsoi, Lee, Gee, Holden, Parks and Woodruff(5).
Neuroimaging studies in healthy volunteers (Reference Goel and Dolan6–Reference Moran, Wig, Adams, Janata and Kelley8) suggest that the inferior frontal gyrus and temporo-occipital junction are involved in the cognitive aspect of humour, whereas the mesolimbic reward system (e.g. amygdala, ventral striatum, nucleus accumbens) is involved in humour appreciation. As both sets of brain regions are known to be altered in schizophrenia Reference Shenton, Dickey, Frumin and McCarley(9), these individuals display impairment in understanding jokes, in particular when these require inferences to be made about others' mental states Reference Corcoran, Cahill and Frith(10).
With particular emphasis on the role of frontal regions in the cognitive aspect of humour (Reference Goel and Dolan6–Reference Moran, Wig, Adams, Janata and Kelley8), executive dysfunction in schizophrenia correlates with deficits observed in tasks of humour recognition. For example, the ability to recognise humour has been found to negatively correlate with the perseveration error score of the Wisconsin Card Sorting Test (WCST) Reference Tsoi, Lee, Gee, Holden, Parks and Woodruff(5,Reference Brüne, Abdel-Hamid, Lehmkamper and Sonntag11), suggesting difficulties in shifting response strategies such as holding different concepts simultaneously. Shifting response strategies is required for humour recognition according to the schema-based cognitive theory of humour, proposed by Martin Reference Martin(4). Furthermore, the negative correlation between WCST perseverative errors and ToM total scores support the idea that difficulties in holding two schemata together in schizophrenia may contribute to the impairment in mental state attribution Reference Tsoi, Lee, Gee, Holden, Parks and Woodruff(5).
The relationship between humour and Theory of Mind extends well beyond the mental illness of schizophrenia. Studies have explored these phenomena with depression Reference Corcoran, Cahill and Frith(10), traumatic brain injury Reference Shammi and Stuss(12), alcohol-related cognitive deficits Reference Uekermann, Channon, Winkel, Schlebusch and Daum(13) and developmental delay Reference Martin and MacDonald(14). Without doubt, the role of humour processing in mental illness and other neurological conditions could be explored to deepen our understanding of how individual minds think. An important subset of this understanding is how individual minds find humour funny, and with that, truly funny jokes could be shared between patient and doctor.
