Aha, εὕρηκα, insight, illumination…

Several anecdotal descriptions of big and small inventions mention the “aha” experience, a sudden unpredictable discovery following prolonged unsuccessful solution attempts. The Nobel laureate and occasional Feynman (also a Nobel laureate) collaborator,  Murray Gell-Mann (leaning against the blackboard) described the magic solution process of Feynman to his student: “Dick’s method is this. You write down the problem. You think very hard. (Gell-Mann shuts down his eyes and presses his knuckles periodically to his forehead.) Then you write down the answer.” In Seyfert’s (Seyfert et al., 1994, p. 72-73) opinion this description is an example of the “wizard Merlin” perspective on insight.

Beside the unexpected appearance of the solution, anecdotal reports of insight have also revealed that the answers were most often experienced in a dream[1], or in a state of day-dreaming and mind wondering characterized by diminished consciousness. The discovery of the benzene ring by Kekulé represents such an example (Seyfert et al., 1994, p. 115):

“I turned my chair to the fire and doze… Again the atoms gamboling before my eyes… My mental eye… could now distinguish larger structures, of manifold conformation; long rows, sometimes more closely fitted together; all twining and twisting in a snakelike motion. But look! … One of the snakes had seized hold of its own tail, and the form whirled mockingly before my eyes. As if by a flash of lightening I awoke.”

Yet another characteristic described was the immense emotional intensity of insight moments. For instance, in the almost archetypal story of the aha-moment,  Archimedes of Syracuse was so inspired by his discovery that he supposedly ran down the street shouting ‘‘Eureka!’’ without remembering to put on his clothes.  

Some reports point also to a coincidental event that triggered a mapping process with a previously unsolved problem – such as the famous Newton’s apple. As the legend goes, Newton went for a walk in the countryside. It was autumn and he happened to notice an apple fall from a tree. On seeing this, it suddenly occurred to him that the moon is like an apple towards Earth, which let him to formulate his gravitational law.

From a historical perspective, the first who were attracted by the insight phenomenon were Gestaltists. Graham Wallas (1926), for example, proposed four stages involved in the creative solution process:  preparation, incubation, illumination or insight, and verification. Especially the processes of incubation and illumination were in the focus of research interest. As stressed by Davidson and Sternberg (2003), the gestalt analysis of insight was later followed by approaches that did not recognize that insight problems are something special and those who tried to study insight in the lab by employing different puzzle problems. Recent research shows a preference for neurobiological and genetic explanations of the insight experience.  Davidson and Sternberg (2003) further concluded that insightful problem solving differs from working out solutions of interpolation and logic problems. Insight involves searching for overlooked relevant encodings, combinations, and comparisons of information and the restructuring of one’s mental representation of the problem. Highly intelligent individuals are better at this process than individuals of average intelligence.

For the incubation phase preceding illumination, several functions have been suggested. Selective forgetting, which eliminates false leads and hampering assumptions, is thought to occur during this process. Recent review papers suggested that during the incubation period unconscious processes contribute to creative thinking (e.g., Gilhooly, 2016; Ritter and Dijksterhuis, 2014). It was further suggested that in this unconscious thinking process a joint effect of spreading activation (unusual associations) and subconscious goal activation (rising train of associations) subserves creative solutions.

Sio and Ormerod (2009) included 117 (n = 3606) independent studies in their meta-analysis of incubation. The unweighted mean of the unbiased effect size estimate was 0.41, suggesting moderate incubation effects. The main subconscious processes identified were activation of new knowledge, or restructuring, and forgetting carried out either by switching the strategy used, or by relaxing inappropriate self-imposed constraints on the problem representation. For creative problem solving, longer incubation periods were more beneficial than for linguistic problems, for which a low cognitive load task during the incubation gave the strongest effects.

Neurocognitive explanations

Kuonious and Beeman (2014) in a recent review on the neurocognitive underpinnings of incubation and insight identified several characteristics of brain activity that can be nicely integrated into a neuro cognitive theory of insight (selective forgetting, or restructuring of problems). The main conclusion put forward was that coarse semantic coding in the right hemisphere subserves the insight process. It was further suggested that in association cortices of Wernicke’s and Broca’s areas, and the anterior temporal cortex, right hemisphere neurons have larger input fields than left hemisphere neurons do, which physiologically enhances wider spreading of activity. EEG studies in the right hemisphere revealed bursts of gamma and alpha band activity, a pattern that suggests intense mental work (gamma-band) accompanied by suppression of distracting environmental stimuli (alpha band activity in the right occipital lobe). This switching process between inwardly and outwardly directed attention was accompanied with high/low anterior cingulate activity. Inwardly directed attention and high anterior cingulate activity heightens sensitivity to weakly activated remote associations and long-shot solution ideas and vice versa. Individuals also differed in their tendency to solve verbal anagram puzzles either analytically or by insight. Furthermore their thinking style was related to the level of arousal prior to task presentation (2 s). Insightful individuals showed greater right hemisphere activity at rest, relative to analytic individuals.

The authors concluded (Kuonious and Beeman, 2014; p.83): “Thus, the notion that insight is associated with diffuse attention appears to be an oversimplification. Insightful individuals may generally have more diffuse and outwardly directed attention, but successful insight solving involves transiently redirecting attention inwardly during the preparation for and solving of a problem. It therefore appears that the tendency to solve problems insightfully is associated with broad perceptual intake as the default mode of resting-state attention deployment, coupled with the tendency to focus inwardly in preparation for, and during, solving. In contrast, analytical people’s resting-state attention is less outwardly focused during the resting state and less inwardly directed during preparation and solving.”

A similar explanation was also provided for the beneficial influence of non-rapid eye movement (NREM) sleep on incubation, insight and creativity observed in several studies (e.g., Drago et al., 2011; Landmann et al., 2014; Llewellyn, 2016). It was proposed that sleep promotes the qualitative reorganization of memories. Low levels of cortical arousal during NREM sleep may enhance the ability to access remote associations that are critical for creative innovations. Cyclic Alternating Patterns (CAP) during NREM also play a role in this process. They are characterized by periodic transient events (phase A of CAP) arising from background activity (phase B). The A phase is subdivided into A1-3 subtypes based on the relative proportions of slow wave and fast EEG oscillations. The A1 subtype  (most common) is characterized by a prevalence of high-voltage slow waves in the frontal brain areas, which have been identified to be important for divergent thinking and creativity. These explanations  are also in line with findings suggesting the importance of slow-wave sleep on other forms of cognitive functions, such as learning and processing speed (Ferri et al., 2008). The main mechanisms of these effects are explained by the synaptic homeostasis hypothesis and the spreading activation theory which complement each other. The former proposes a global downscaling of synaptic strength during slow-wave sleep that improves the signal-to-noise ratio, whereas the latter suggest that similar memory traces are linked together to form a novel network subserved by occurring changes in synaptic connectivity in localized neuronal circuits (Landmann et al., 2014).

Recent advances in molecular genetics have made it possible to analyze the underlying genetic architectures of individual differences in the tendency to solve problems analytically or via insight. Zhang and Zhang (2016) explored the association of dopamine D2 receptor gene (DRD2) with insight problem solving. The study provided evidence for a positive association between genotyped SNPs, rs1800497 and rs6278 with spatial insight problem solving. Because for verbal insight problems this relation was not so prominent it was suggested that the findings lend support for the domain-specific theory of insight, rather than a unitary category of creative problem solving.

It seems that neuroimaging and genetic research step by step uncover the mystery of the “aha moment” so often mentioned in anecdotal reports of great discoveries and inventions.

References

Davidson, J. E., & Sternberg, R. J. (2003). The psychology of problem solving. Cambridge, UK; New York: Cambridge University Press. Retrieved from http://www.books24x7.com/marc.asp?bookid=8963

Drago, V., Foster, P. S., Heilman, K. M., Aricò, D., Williamson, J., Montagna, P., & Ferri, R. (2011). Cyclic alternating pattern in sleep and its relationship to creativity. Sleep Medicine, 12(4), 361–366. https://doi.org/10.1016/j.sleep.2010.11.009

Ferri R, Huber R, Aricò D, et al. The slow-wave components of the cyclic alternating pattern (CAP) have a role in sleep-related learning processes. Neurosci Lett 2008; 432: 228–31.

Gilhooly, K. J. (2016). Incubation and Intuition in Creative Problem Solving. Frontiers in Psychology, 7. https://doi.org/10.3389/fpsyg.2016.01076

Haider, H., & Rose, M. (2007). How to investigate insight: A proposal. Methods, 42(1), 49–57. https://doi.org/10.1016/j.ymeth.2006.12.004

Kounios, J., & Beeman, M. (2014). The Cognitive Neuroscience of Insight. Annual Review of Psychology, 65(1), 71–93. https://doi.org/10.1146/annurev-psych-010213-115154

Landmann, N., Kuhn, M., Piosczyk, H., Feige, B., Baglioni, C., Spiegelhalder, K., … Nissen, C. (2014). The reorganisation of memory during sleep. Sleep Medicine Reviews, 18(6), 531–541. https://doi.org/10.1016/j.smrv.2014.03.005

Llewellyn, S. (2016). Crossing the invisible line: De-differentiation of wake, sleep and dreaming may engender both creative insight and psychopathology. Consciousness and Cognition, 46, 127–147. https://doi.org/10.1016/j.concog.2016.09.018

Ritter, S. M., & Dijksterhuis, A. (2014). Creativity: the unconscious foundations of the incubation period. Frontiers in Human Neuroscience, 8. https://doi.org/10.3389/fnhum.2014.00215

Seifert, C. M., Meyer, D. E., Davidson, N., Patalano, A. L., & Yaniv, I. (1994). Demystification of cognitive insight: Opportunistic assimilation and the prepared-mind hypothesis. In R. Sternberg, & J. Davidson (Eds.), The nature of insight (pp. 65-124). Cambridge, MA: MIT Press.

Sio, U. N., & Ormerod, T. C. (2009). Does incubation enhance problem solving? A meta-analytic review. Psychological Bulletin, 135(1), 94–120. https://doi.org/10.1037/a0014212

Wallas, G. (1926). The art of thought. New York: Harcourt, Brace.

Zhang, S., & Zhang, J. (2016). The Association of DRD2 with Insight Problem Solving. Frontiers in Psychology, 7. https://doi.org/10.3389/fpsyg.2016.01865

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[1] Beatle Paul McCartney announced that he came up with the melody for “Yesterday” in a dream.