There is now a large body of evidence showing that many different conditions related to impaired fronto-executive functioning are associated with the enhancement of some types of creativity. In this paper, we pursue the possibility that the central mechanism associated with this effect might be a reduced capacity to exert inhibition. We tested this hypothesis by exhausting the inhibition efficiency through prolonged and intensive practice of either the Simon or the Eriksen Flanker task. Performance on another inhibition task indicated that only the cognitive resources for inhibition of participants facing high inhibition demands were impaired. Subsequent creativity tests revealed that exposure to high inhibition demands led to enhanced fluency in a divergent thinking task (Alternate Uses Task), but no such changes occurred in a convergent task (Remote Associate Task; studies 1a and 1b). The same manipulation also led to a hyper-priming effect for weakly related primes in a Lexical Decision Task (Study 2). Together, these findings suggest that inhibition selectively affects some types of creative processes and that, when resources for inhibition are lacking, the frequency and the originality of ideas was facilitated.
The ability most frequently said to reflect human uniqueness is creativity. Human beings are able to create and this ability is expressed in a variety of different domains such as art, technology, or science. At the same time, our uniqueness is also characterized by higher cognitive functions which have emerged with the growth of the human prefrontal cortex (PFC) (Deacon, 1997 and Ruff et al., 1997). These executive functions are composed of three main components: mental-set shifting, inhibitory control, and updating working memory (Miyake et al., 2000).
From this, one might infer that creativity comes from our ability for executive functioning. However, one of the most intriguing finding in psychology and psychiatry is that many kinds of mental states that are associated with impaired executive functioning can lead to positive consequences in terms of creative performance (Dietrich, 2004). For example, White and Shah (2006) showed that ADHD individuals outperformed non-ADHD individuals on a divergent creativity task which requires participants to find multiple ideas. Interestingly, Healey and Rucklidge (2006) noted that 40% of highly creative children met criteria for ADHD. Keri (2009) indicated that a specific gene (i.e., neuregulin 1; T/T), which has been previously associated with fronto-executive disfunctioning and schizophrenia (Hall et al., 2006), is positively associated with real-life creative achievements. In a neurological study, Reverberi, Toraldo, D’Agostini, and Skrap (2005) showed that patients with lateral frontal lesions were better than normal participants at solving hard insight problems. Similarly, a recent study showed that a decrease in cortical excitability of the lateral frontal cortex, induced by transcranial magnetic stimulation, improved performance on a divergent creativity task (Chrysikou et al., 2013). A psycho-pharmacological study by Morgan, Rothwell, Atkinson, Mason, and Curran (2010) showed that cannabis intoxication elicited a hyper semantic priming effect. Under marijuana, the perception of a stimulus generated the activation of a greater network of distantly related concepts, which is considered an important aspect of creativity (Martindale, 1995). Also, enhanced problem solving was found when individuals worked at a non optimal time of the day compared to an optimal time of the day (Wieth & Zachs, 2011). This raises the question of why all these different conditions lead to the same positive effect. In the present research, we propose that they might all in fact be linked to the same process. That is, we do not assume that a reduced executive functioning in general is at work but rather a reduced capacity to exert inhibition. Indeed, it is known that the capacity to exert the inhibition function is impaired by cannabis use (Skosnik, Spatz-Glenn, & Park, 2001) and tends to be affected by the circadian rhythm (May, 1999). Impaired inhibition is also a suspected symptom in ADHD (Barkley, 1997) and schizophrenia patients (Beech, Powell, McWilliam, & Claridge, 1989). In addition, dysfunction of the lateral frontal cortex is typically related to reduced inhibition as this function is mainly located in this region, especially the inferior frontal cortex (e.g., Aron, Robbins, & Poldrack, 2004). Given that impaired inhibition is the common denominator of all these various conditions, we suggest that this dysfunction can have a paradoxical effect, favoring some types of creativity while being detrimental to others.
