What do the great historical inventors such as Leonardo Da Vinci, Thomas Edison, and Nikola Tesla have in common? While we may be tempted to define their extraordinary abilities as a reflection of their IQ, it may be more accurate to say that they were exceptional divergent thinkers. Divergent thinking is defined as “open ended thinking involving a large number of potential solutions and no correct answer” (Goldstein, 2011). This can be contrasted with convergent thinking, which involves finding a solution to a specific, defined problem that usually has a correct answer (Goldstein, 2011). While both forms of thinking are essential to human intelligence, divergent thinking, which is closely associated with creativity, is highly valued in many Westernized societies. However, one common assumption that many people make about creative people is that they possess a dominant right hemisphere (Eby, 2013). I remember a popular quiz shared on Facebook several years ago that supposedly measured how “left-brained” or “right-brained” you were based on a series of questions, and then suggested an occupation based on these results. The suggestions for left-brained people were logic and science-based, and the suggestions for right-brained people were oriented towards art, music, and other realms associated with creativity. Another example of this oversimplification can be seen in this fairly recent Mercedes-Benz ad: http://adsoftheworld.com/sites/default/files/styles/media_retina/public/images/paint-72dpi.jpg?itok=LqT-7MiU . One technique that may help dispel this common assumption is through neuroimaging research. In this post, I will examine the results of a recent meta-analysis of studies involving fMRI and creativity to show that the creative process cannot be boiled down hemispheric specificity.

Current research suggests that divergent thinking does not appear to have a specific neuroanatomical localization, partially because it is multidimensional process involving different cognitive domains (Boccia, Piccardi, Palermo, Nori, & Palmiero, 2015). Boccia et al. (2015) conducted a meta-analysis using an Activation Likelihood Estimation (ALE), which assessed the overlap in activated areas of the brain in each study and developed a probability distribution associated with the coordinates for each area. Their results showed that creativity that involves executive functions is strongly related to the activation of the Dorsolateral Prefrontal Cortex (DLPFC). The activation of the DLPFC is specifically associated with effortful problem solving, monitoring, and focused attention, and may be linked to increased working memory load (Boccia, Piccardi, Palermo, Nori, & Palmiero, 2015). When assessing three different domains of creativity, the DLPFC was found to be consistently activated in all three, including the Musical domain, the Visual-spatial domain, and the Verbal domain.

Other mechanisms behind divergent thinking appear involve domain-specific activations. For example, verbal creativity was consistently associated with activation of the left interior frontal gyrus, while musical and visual-spatial creativity was associated with the right supplementary and the left premotor cortices (Boccia, Piccardi, Palermo, Nori, & Palmiero, 2015). In general, Boccia et al. (2015) showed that the creativity process seems to heavily involve three separate areas of the brain, including the aforementioned prefrontal cortex, and the posterior temporal, and the parietal areas. This has also been confirmed through studies with dementia patients, who experienced a progressive decline in artistic creativity and divergent thinking when these specific areas of the brain were damaged (Palmiero, Di Giacomo, & Passafiume, 2012). Furthermore, Boccia et al. (2015) showed that interaction between both hemispheres of the brain occurred during all three domains of creativity, suggesting once again that creativity is not lateralized in the right hemisphere.

While the neurological underpinnings of creativity are complex and warrant further depth than is covered in this post, one consistent finding is that many different areas of the brain are activated during divergent thinking, and the majority of them seem to involve inter-hemispheric interaction. Further research is needed on this subject, particularly involving people who possess extraordinary creative capabilities, such as the historical figures mentioned above. The question of why some people may be more creative and inclined towards divergent thinking has yet to be answered, but neuroimaging has allowed us to have a glimpse into this multifaceted process – one that does not appear to be solely dependent upon the right hemisphere.

References

Boccia, M., Piccardi, L., Palermo, L., Nori, R., & Palmiero, M. (2015, August). Where do bright ideas occur in our brain? Meta-analytic evidence from neuroimaging studies of domain-specific creativity. Frontiers in Psychology, 6(1195), 1-12. doi:doi: 10.3389/fpsyg.2015.01195

Eby, D. (2013, September 6). Left Brain, Right Brain – Creativity And Innovation. Retrieved from PsychCentral: http://blogs.psychcentral.com/creative-mind/2012/02/left-brain-right-brain-creativity-and-innovation/

Goldstein, E. B. (2011). Cognitive Psychology: Connecting Mind, Research, and Everyday Experience (3rd ed.). Belmont, CA: Wadsworth.

Palmiero, M., Di Giacomo, D., & Passafiume, D. (2012). Creativity and dementia: a review. Cognitive Processes, 13(3), 193-209. doi:10.1007/s10339-012-0439-y.

Nelson Dellis claims to be an average guy with an average memory. The current 2015 U.S. National Memory Champion is able to recall 339 digits given 5 minutes of preparation, can correctly memorize the order of a pack of 52 playing cards in 40.52 seconds, and when given 15 minutes to study, can recall 255 random words (World Memory Sports Council, 2015). Are these statistics indicative of a brain with savant-like qualities, or do we underestimate the human brain’s ability to memorize? Working memory is defined as “a limited-capacity system for temporary storage and manipulation of information for complex tasks, such as comprehension, learning, and reasoning” (Goldstein, 2011). Why is it that some of us struggle to remember our own phone number, while others like Dellis are able to achieve extraordinary feats such as the speed card memorization task mentioned above? According to many World Memory Champions, it’s all about attention and technique. Memory athletes claim to hone these techniques through so-called memory training, using a combination of visual imaging, mnemonic devices, and other retrieval cues in order to maximize their capacity and recall for both working and long term memory (Foer, 2011).

One study by Olesen, Westerberg, & Klingburg (2003) investigated the effects of memory training on the brain. Using fMRI technology, they compared a group of mental athletes to a group of control subjects. Little difference was found between the general cognitive ability and anatomical structure. However, when engaged in memorizing tasks, there was remarkably more activity in the prefrontal and parietal regions of the mental athletes brains, the latter of which is heavily involved in spatial memory (Olesen, Westerberg, & Klingberg, 2003). What is interesting about this is that a great deal of memory athletes claim to rely on spatial visualization as one of their memory aiding devices. In particular, many of them create what they call a “memory palace” in which they actually visualize an imaginary building and fill it with imagery that is connected to what they are attempting to remember. This is derived from an ancient Greek mnemonic strategy called the Method of Loci (MOL), which involves navigating an imaginary environment and placing items that need to be remembered in specific locations (Legge, Madan, Ng, & Caplan, 2012). From an evolutionary perspective, our memory is thought to have evolved to fit our need for survival, which would have favored spatial and visual imagery in order to aid us in remembering things such as the best places to find food and how to find our way home (Foer, 2011). Although the mechanisms underlying the effectiveness of this technique are poorly understood, it is still one of the most often used mnemonic techniques even centuries after it was first introduced.

In addition to the memory palace, memory champions use retrieval cues in order to enhance memory capacity. Joshua Foer, a New York Times journalist turned memory athlete, advises creating images associated with the item that you are trying to remember – the more bizarre, funny, or lewd the better (Foer, 2011). He claims that our brains are not primed to remember the detail of mundane or ordinary experiences, but when we create these bizarre images that are associated with the item, we are much more likely to recall it. Using these retrieval cues are a large part of the memory athlete’s game, and many claim that they can significantly alter the ability to correctly recall a large number of items in a short period of time.

Although it could be argued that some people are more gifted than others when it comes to the “art” of memory, training in mnemonic strategies and retrieval cues appears to drastically increase the ability of the human brain to recall large amounts of information (Olesen, Westerberg, & Klingberg, 2003; Legge, Madan, Ng, & Caplan, 2012). People like Nelson Dellis, who claim to have started out with an average working memory capacity, further support the idea of memory’s neural plasticity. While the assumption that working memory is limited may be well founded, the extraordinary achievements of World Memory Champions serve to make this issue more complex. Baddeley’s proposal of the episodic buffer may serve to explain how people may increase their working memory storage through an interchange mechanism between working and long term memory (Goldstein, 2011). In addition, it is thought that attention is strongly associated with working memory, and that increasing attention through mindfulness will thus increase one’s ability to remember (Goldstein, 2011; Foer, 2011). While these theories are still a work in progress, one thing that is clear is that we have not yet found this limit on human working memory capacity.

For a short clip showing Nelson Dellis explain some of his memorization techniques, please click here: https://www.youtube.com/watch?v=KxD_XQ7ItyA

References

Foer, J. (2011, February 15). Secrets of a Mind Gamer. The New York Times. New York, NY, United States. Retrieved from http://www.nytimes.com/interactive/2011/02/20/magazine/mind-secrets.html?_r=0#commentsContainer

Goldstein, E. B. (2011). Cognitive Psychology: Connecting Mind, Research, and Everyday Experience (3rd ed.). Belmont, CA: Wadsworth.

Legge, E., Madan, C., Ng, E., & Caplan, J. (2012, November). Building a memory palace in minutes: Equivalent memory performance using virtual versus conventional environments with the Method of Loci. Acta Psychologica, 141(3), 380-390. doi:10.1016/j.actpsy.2012.09.002

Olesen, P. J., Westerberg, H., & Klingberg, T. (2003). Increased prefrontal and parietal activity after training of working memory. Nature Neuroscience, 7, 75-79. doi:10.1038/nn1165

World Memory Sports Council. (2015). Nelson Dellis GMM- Grand Master. Retrieved from World Memory Statistics: http://www.world-memory-statistics.com/competitor.php?id=691

Most students are familiar with the dilemma created by a deadline to take a test when there are not enough hours left in the day; should I push through the exhaustion and study until I am finished, or should I sleep? While we might be tempted to choose the former, we are also familiar with the consequences of taking an exam after a night of little to no sleep. We wonder what happened to the information we were just reading five minutes before taking the test, which now seems impossible to recall. One possible answer is that interference of some sort did not allow for memory consolidation of this newly acquired information. Memory consolidation is defined as “the process by which experiences or information that has entered the memory system becomes strengthened so it is resistant to interference caused by trauma or other events” (Goldstein, 2011). So what does this have to do with sleep? Research has repeatedly shown that sleep can alter the consolidation of memories (Gais & Born, 2004). The specific type of memory we are most concerned with while taking an exam is called declarative memory, which involves the recollection of previously experienced events or facts (Goldstein, 2011). Because the mechanisms of memory acquisition, consolidation, and retrieval are quite complex, I will choose to focus on the relationship between the hippocampus, slow wave sleep, and declarative memory in our investigation into why lack of sleep might affect our memory during exams.

Although many structures are activated during memory consolidation, the hippocampus appears to be the most pronounced and most studied brain structure with regards to sleep and declarative memory (Marshall & Born, 2007). One proposed mechanism of declarative memory consolidation is believed to involve reactivation of newly acquired information in the hippocampal networks during slow wave sleep (SWS), which stimulates the transfer of these memory representations into neo-cortical networks (Gais & Born, 2004). One study that supports this theory involves neuroimaging in humans subsequent to learning a declarative task, which showed reactivation in the hippocampus during SWS (Marshall & Born, 2007). The amount of reactivation that was shown in the hippocampus was directly correlated with the participants’ performance on a recall task the following day. The increased activation of the hippocampus during SWS is part of the reason that researchers have continued to focus on the link between these stages of sleep and declarative memory.

Research has shown that declarative memory benefits specifically from an increase of slow wave sleep (Gais & Born, 2004). Slow wave sleep, characterized by slow delta waves, is often referred to as non-REM sleep stages 3 and 4, and dominates the first few hours of sleep we get each night (Freberg, 2010). One important study that showed the effects of stages of sleep and type of memory was performed by Plihal and Born (1997). The researchers assessed recall of paired-associative lists (declarative) and mirror-tracing skills (procedural) after two different retention intervals consisting of either early nocturnal sleep or late nocturnal sleep. They found that the participants’ recall of paired-associative lists improved more during the early sleep retention interval, which coincides with the time period that contains the bulk of our SWS (Plihal & Born, 1997). Recall of mirror-tracing skills improved more during the late sleep retention interval. Another study suggests that the decline in declarative memory recall that may occur during aging can be directly correlated with the decline of early nocturnal SWS during aging (Backhaus, et al., 2007). While slow wave sleep is not the only mechanism involved in improved consolidation and recall of declarative memories, it can certainly be claimed that it is a necessary component for optimal performance during an event that requires a high amount of recall of acquired facts, such as taking an exam.

The hippocampus-SWS link is an important component of memory consolidation with regards to declarative memory. Studies such as Plihal and Born (1997) have shown a direct link between improved declarative memory and SWS that occurs during early nocturnal sleep. In addition, hippocampal reactivation during SWS has been seen in neuroimaging studies, and greater activation was correlated with higher performance on recall tasks the following day (Marshall & Born, 2007). How does this apply to our original dilemma: stay up and study or get a good night’s rest before taking an exam? Based on the information that I have just described, I would say that early nocturnal sleep appears to be crucial to declarative memory consolidation, and consequently, recall during the exam. Perhaps this would mean that going to bed early the night before and waking up early to study would be a better solution than staying up late and getting only a few hours of sleep before a test. While more research would be needed to confirm this hypothesis, I certainly am going to consider this information when faced with another late night of studying.

References

Backhaus, J., Born, J., Hoeckesfeld, R., Fokuhl, S., Hohagen, F., & Junghanns, K. (2007). Midlife decline in declarative memory consolidation is correlated with a decline in slow wave sleep. Learning Memory, 14, 336-341. doi:10.1101/lm.470507

Freberg, L. A. (2010). Discovering Biological Psychology (2 ed.). (J. Potter, Ed.) San Luis Obispo, CA, USA: Wadsworth.

Gais, S., & Born, J. (2004). Declarative memory consolidation: mechanisms acting during human sleep. Learning Memory, 11, 679-685. doi:10.1101/lm.80504

Goldstein, E. B. (2011). Cognitive Psychology: Connecting Mind, Research, and Everyday Experience (3rd ed.). Belmont, CA: Wadsworth.

Marshall, L., & Born, J. (2007, November). The contribution of sleep to hippocampus dependent memory consolidation. Trends in Cognitive Science, 11(10), 442-450. doi:http://dx.doi.org/10.1016/j.tics.2007.09.001

Plihal, W., & Born, J. (1997). Effects of early and late nocturnal sleep on declarative and procedural memory. Journal of Cognitive Neuroscience, 9(4), 534-547. doi:10.1162/jocn.1997.9.4.534