What is the most important finding in Psychology? By Hildie Leyser

The most important finding in psychology can be gauged by how much it changes how we evaluate past research and shapes how we approach future research. Does it reveal crucial insights which unlock unexplored avenues of psychological principles? Does it force us to reassess and reimagine core psychological mechanisms? Does it inform the next questions we ask and how we go about answering them? Does it determine what can be extrapolated from psychological research for applied and therapeutic purposes? ‘Mirror Neurons’ create irreconcilable contradictions with previous theories whilst also proposing an alternate set of assumptions to orientate novel methodologies.

In 1992 researchers at the University of Parma first discovered a class of neurons in ventral premotor area F5 that fired both when the subject was observing and executing an action. This finding came out of experimental paradigms of reaching and grasping with Macaque monkeys (Di Pellegrino et al., 1992). The term ‘Mirror Neurons’ was coined 4 years later in a subsequent publication (Gallese et al., 1996). This concept has not only caught the public imagination with features on ‘Mirror Neurons’ in all major news outlets including Time magazine and The New York Times, and programs about ‘Mirror Neurons’ broadcast by CNN and the BBC, but also attracted huge scientific interest with over 1678 articles academic articles on the subject of ‘Mirror Neurons’ in the 30 years since their debut (Bonini et al., 2022; Heyes & Catmur, 2022).

The core contribution of ‘Mirror Neurons’ is how the idea disrupts our understanding of the nature of thought and feelings and the relationship between them. Since Plato and Aristotle psychological discourse has separated thinking and feeling and identified ‘higher level cognition’ as what sets us apart from other species. ‘Mirror Neurons’ however supports the concept of simulation promoting that thinking in fact involves feeling. In order to build an understanding of the actions of another agent, these same actions are simulated internally, reflecting the notion that the brain uses feeling to create understanding, rather than extrapolating actions into abstract higher-level concepts.

‘Mirror Neurons’ provide an anomaly to the established mechanisms of dual stream processing. Traditionally the ventral stream has been thought to recognise size and features using abstract concepts engaging the prefrontal cortex and other areas of ‘higher level cognition’ whilst a dorsal stream tracks the orientation of stimuli. On this model, the dorsal stream engages less evolved areas of the brain and does not involve processes of understanding or meaning making. These two types of processing have been considered to very differently functional characteristics; understanding and cognitive evaluation has been associated with higher cognition whilst reflexive and affect driven judgements with lower brain areas. Variants of this idea have been popularized by Daniel Kahneman’s system 1 and system 2 and the public fascination with ‘the reptile brain’ vs ‘the evolved brain’ (Kahneman, 2011). ‘Mirror Neurons’ pose a challenge to this dichotomy. They become active in order to perceive and understand but use the vehicle of feeling to achieve this. These challenges established frameworks as it ruptures the idea that cognitive and somatic perceptions and processes can be neatly separated.

Before concluding it is relevant to acknowledge the large degree of controversy that ‘Mirror Neurons’ have sparked. Well supported claimants have asserted important objections and argue ‘Mirror Neurons’ that have been given overstated credit. In speech perception for example Gregory Hickok points out that people with damaged motor systems can still perceive speech, thus we do not need the capacity to enact actions in order to understand them: Patients with cerebral palsy who are not able move or are born with motor deficits still understand the movements of others (Hickok, 2009). Similarly understanding of motor movements between species with different motor systems is possible (Hickok, 2014). Hickok argues that ‘Mirror Neurons’ may play an augmenting role but cannot be attributed as the core mechanism at play in action understanding or speech perception (Lotto et al. 2009). Meanwhile behavioral and neurological evidence for a ‘Broken Mirror Hypothesis’ to explain conditions like autism remain elusive and inconclusive (Iacoboni & Dapretto, 2006; Sowden et al., 2016). In fact the idea that ‘mirror-neurons’ are a specific class of neuron has been disproven as Heyes argues they are merely ordinary motor-cortex neurons that have been adapted to take on special roles through learning (Heyes, 2013). Most broadly they have given rise to a debate between researchers who understand the experience of embodiment as integral to human cognition and conceptual processing (embodied cognition – Gallese & Sinigaglia, 2011), and those who understand cognition as computational and probabilistic (disembodied cognition – Chatterjee, 2009).

Given that the extent of contribution of ‘Mirror Neurons’ to complex systems and neural functions is up in the air and that their unique nature as a specific class of neuron is itself in question, does this mean that the significance no longer stands? In fact, the contrary is true: regardless of the specific neurobiological role that they play, the assessment of ‘Mirror Neurons’ has become ever more central as a path for research. The challenge that ‘Mirror Neurons’ are not a specific class of neuron, but a feature further supports dynamic functionality as the guiding principle of neural structure as opposed to specialized and localized characteristics which proposes an entirely different perspective from which to define neural mechanisms. The more complexity the question of ‘Mirror Neurons’ reveal the more insight the findings have been able to uncover. Moreover, the finding supports psychology in its role arbitrate archetypal questions between science and humanities such as nature vs nurture. ‘Mirror Neurons’ show the importance of cultural learning as embodied sensorimotor processes and reevaluate other neurocognitive mechanisms, once thought to be genetically inherited but simultaneously show fundamental similarities between mammalian brains. The work that ‘Mirror Neurons’ have done in psychology can’t be taken back even if they are not what they thought we were.

 

References

Bonini, L., Rotunno, C., Arcuri, E., & Gallese, V. (2022). Mirror neurons 30 years later: Implications and applications. Trends in Cognitive Sciences, 26(9), 767–781. https://doi.org/10.1016/j.tics.2022.06.003

Chatterjee A. (2010). Disembodying cognition. Language and cognition, 2(1), 79–116. https://doi.org/10.1515/LANGCOG.2010.004

di Pellegrino, G., Fadiga, L., Fogassi, L., Gallese, V., & Rizzolatti, G. (1992). Understanding motor events: a neurophysiological study. Experimental brain research, 91(1), 176–180. https://doi.org/10.1007/BF00230027

Gallese, V., & Sinigaglia, C. (2011). What is so special about embodied simulation?. Trends in cognitive sciences, 15(11), 512–519. https://doi.org/10.1016/j.tics.2011.09.003

Gallese, V., Fadiga, L., Fogassi, L., & Rizzolatti, G. (1996). Action recognition in the premotor cortex. Brain : a journal of neurology, 119 ( Pt 2), 593–609. https://doi.org/10.1093/brain/119.2.593

Heyes C. (2013). A new approach to mirror neurons: Developmental history, system-level theory and intervention experiments. Cortex, 49(10), 2946–2948.

Heyes, C., & Catmur, C. (2022). What Happened to Mirror Neurons? Perspectives on Psychological Science, 17(1), 153–168. https://doi.org/10.1177/1745691621990638

Hickok G. (2009). Eight problems for the mirror neuron theory of action understanding in monkeys and humans. Journal of cognitive neuroscience, 21(7), 1229–1243. https://doi.org/10.1162/jocn.2009.21189

Hickok, G. (2014). The myth of mirror neurons: The real neuroscience of communication and cognition. W W Norton & Co.

Iacoboni, M., & Dapretto, M. (2006). The mirror neuron system and the consequences of its dysfunction. Nature reviews. Neuroscience, 7(12), 942–951. https://doi.org/10.1038/nrn2024

Kahneman, D. (2011). Thinking, Fast and Slow. http://ci.nii.ac.jp/ncid/BB2184891X

Lotto, A. J., Hickok, G. S., & Holt, L. L. (2009). Reflections on mirror neurons and speech perception. Trends in cognitive sciences, 13(3), 110–114. https://doi.org/10.1016/j.tics.2008.11.008

Sowden, S., Koehne, S., Catmur, C., Dziobek, I., & Bird, G. (2016). Intact Automatic Imitation and Typical Spatial Compatibility in Autism Spectrum Disorder: Challenging the Broken Mirror Theory. Autism research : official journal of the International Society for Autism Research, 9(2), 292–300. https://doi.org/10.1002/aur.1511