There Is Only Weak Evidence That Mirror Neurons Underlie Human Empathy – New Review And Meta-Analysis

GettyImages-1080455448.jpgBy Christian Jarrett

It is not too long ago that mirror neurons were touted as one of the most exciting discoveries in neuroscience (or most hyped, depending on your perspective). First discovered in monkeys, these brain cells fire when an individual performs a movement or when they see someone else perform that movement. This automatic neural mirroring of other’s actions was interpreted by some scientists as the seat of human empathy. The cells’ most high-profile champion, US neuroscientist Vilayanur Ramachandran, described them as “the neurons that shaped civilisation” and, in 2000, he (in)famously said they would do for psychology what DNA did for biology. Nearly 20 years on, what evidence do we have that mirror neurons provide the basis for human empathy? According to a new meta-analysis and systematic review released as a preprint at PsyArXiv, the short answer is “not a lot”.

The research team, led by Soukayna Bekkali and Peter Enticott at the University of Deakin, searched the literature for all English language studies conducted in humans that had investigated whether mirror neuron activity was correlated with empathy.

This search led to the identification of 52 relevant papers involving over 1000 participants. These studies had used a range of methods to measure mirror neuron activity (including fMRI brain scanning, EEG recording of brain activity and TMS –  magnetic stimulation typically applied to the motor cortex, to check how much it had already been activated by witnessing movement by others). There were also various measures of empathy: mostly self-report questionnaires, but also measures of “motor empathy” (the automatic mimicry of other people’s movements) and the recognition of other’s facial emotions.

There was a notable lack of objective measures of empathy, such as looking at participants’ heart rate or skin conductance (the involuntary production of sweat as part of an emotional response). Overall, participant samples were small and there was great inconsistency in methods.

Bekkali and her colleagues broke down the literature according to whether the papers had investigated motor empathy, emotional empathy (feeling what someone else is feeling), and/or cognitive empathy (knowing what someone else is feeling or thinking).

Regarding motor empathy, the accumulated evidence pointed to no association with mirror neuron activity. Regarding emotional empathy, there was no evidence for a link with mirror neuron activity in one key brain region where these cells are thought to reside (the inferior parietal lobule; IPL) and only weak evidence for an association with postulated mirror neuron activity in another key brain area, the inferior frontal gyrus (IFG). “It remains unclear how the mirror neuron system relates to the experience of emotional empathy,” the researchers said.

In terms of cognitive empathy, there was no evidence for a mirror neuron link in the IPL and weak evidence of a link with activity in the IFG. “The current results suggest mirror neuron activity may play a role in cognitive empathy,” the researchers said, adding that “the mirror neuron system may potentially be one neurophysiological mechanism subserving cognitive empathy.”

One problem with interpreting the existing evidence base is that the results tended to vary according to the methods used, not only in terms of how mirror neuron activity and empathy were measured, but also according to the stimuli presented to participants, such as whether they viewed real images of people performing actions, or cartoons, and whether the images were dynamic or static. There is no currently accepted “gold standard” measure of mirror neuron activity in humans, the review authors also noted, and some evidence of a file-drawer problem in the literature, in which positive results are more likely to be published.

Finally, although this thorough investigation of the existing evidence base uncovered some modest evidence that mirror neurons may be involved in empathy – especially cognitive empathy (or understanding other people’s perspectives) – to date there is no evidence that mirror neurons play a causal role in empathy or are necessary for empathy.

When excitement about mirror neurons was at its peak, it was common for newspaper columnists and media commentators to reference these cells with confidence when discussing empathy. “It’s thanks to these cells that we are willing to help strangers in need”; “the best rom coms trigger our mirror neurons”; “altruists have more mirror neurons”, and so on. We were getting ahead of ourselves. After more than two decades of research, this new review provides a sober reminder that our understanding of the neural basis of empathy, and especially the role played by mirror neurons, remains far from complete.

Is the Putative Mirror Neuron System Associated with Empathy?A Systematic Review and Meta-Analysis [this paper is a preprint meaning it has not yet been subjected to peer review and the final published version may differ from the version that this report was based on]

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest

8 thoughts on “There Is Only Weak Evidence That Mirror Neurons Underlie Human Empathy – New Review And Meta-Analysis”

  1. Thomas Nagel wrote 1974 his essay ´What is it like to be a bat?´ – with the statement that we can not understand how another being (animal, human) might perceive, or feel.
    When we can not understand others – then we can not ´mirror´ it ! Therefore the idea of ´mirror neurons´ was already a bad/wrong idea when it was invented in the mid-1990s.

    The brain works much more effective:
    When we perceive a stimulus (or when we observe others) – then we RE-ACTIVATE immediately a comparable/identical own experience from the memory. By the RE-ACTIVATION of our OWN experience – we do understand what we perceived (based on our own experience: Therefore the first reaction is very quick and this can be a prejudice)
    This working procedure is a survival mechanism of the brain – the first reaction has to be quick (accurracy is not important for survival)

    Our brain does process a new stimulus in a pattern-matching-activity
    1) when we perceive a new stimulus – a comparable/identical own experience is reactivated = this is our new ´reality´ which allow a quick reaction
    2) in a second step – the new stimulus and the reactivated experience are compared. When the compare fit together then both merge into a new experience which is stored as a ´new´experience into the memory
    3A) then go back to 1): a new stimulus will processed
    3B) when the comparison in 2) went wrong – then the brain will change the focus of its attention/perception and compare the new stimulus against the content of the memory in ascending or descending order. Step by step experiences from the memory will now be reactivated – and thus perceived as a consious experience
    In descending order we can recognize experiences from the actual age, back to the 4th-2nd year of childhood. This limitated access to our memory is known as ´Infantile Amnesia´.
    In ascending order we can recognize experiences since the 5th month of foetus age – in the same order as the senses develop (touch > acoustic > optical sense > birth(indirect >…)
    This Life Review is known very well as ´Near-Death Experience´!

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  2. off topic: additional information to my first comment

    How we recall our memories is ´state dependent´: This does mean that the content of a recall is influenced by two states
    A) by our intellectual, physical and emotional abilities – which we have when we make an experience and store it INTO the memory
    B) by our intellectual, physical and emotional abilities – when we RECALL an experience OUT OF the memory
    This does mean: our memories will/might be changed at a recall (A) > B) )

    An example from foetus age:
    When our optical system develop step-by-step, the we have different experiences – each with a different (and increasing) number of working optical cells. These rexperiences are stored in the memory
    When the experiences with the development of the optical sense are recalled in a very quick speed – then we have the optical illusion: to be in a dark tunnel and to move towards an increasing area of light (This is similar like in the cinema: The movie is made of single photos – but when we see it in a very high speed – we can ´see´ movement.)

    When the perception of the light change from DIM to BRILLIANT – then is this the light perception bevore(dim) and after the birth(brilliant)

    A newborn baby is almost blind but all senses are working. When a baby receive the loving care, tenderness, affection of its family – then this experience will be stored in the memory. BUT – when an adult person does recall this experience OUT OF the memory, then it will be changed in a STATE DEPENDENT RETREVAL:
    The we have the experience to have met a being of light from which we get unlimited love and affection. >> This is one of the most impressive experience which is reported from Near-Death Experiences !!!

    AND – all these experiences are perceived, stored and re-activated in PRESENT TENSE: Thus we have the impression, that this experience is REAL

    (I have developed the first complete explanation model of the phenomenon ´Near-Death Experience´(NDE): In a NDE we can perceive as a conscious experience how a single stimulus/thought is processed by the brain. That´s all – so simple is it to explain NDEs)

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  3. DOI: 10.1523/JNeurosci.22418.09.2009 ´Do you feel my pain? Racial group membership modulates emphatic neuronal responses´

    This paper showed, that the reaction was depending on the individual ethnic background knowledge: Empathy was bigger for members of the own ethnic group. A mirror-neuron-reaction should have been independent from an ethnic background.

    DOI: 10.1016/j.toxocon.2016.04.044 ´Deeper than skin deep – the effect of botulinum toxin A on emotion processing
    http://www.sciencedaily.com/releases/2016/05/160512085113.htm ´Emotions in the age of botox´

    This paper show that a (by botox) disturbed function of muscles in the face – can influence our empathic reaction: because the complete re-activation of own experiences is disturbed (motor reaction). Here we can recognize too, that mirror-neurons were not at work – because with mirror-neurons already a mental-reaction should have triggered an emotional response

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