Within the depth-psychology corpus, Left Hemisphere Dominance occupies a contested and increasingly critiqued position. The classical neuroscientific assumption — that the left hemisphere, as the seat of language, analytic reasoning, and serial processing, constitutes the ‘dominant’ hemisphere — is systematically interrogated by Iain McGilchrist across both The Master and His Emissary (2009) and The Matter with Things (2021). McGilchrist argues that this presumed dominance is itself a symptom of cultural pathology: a ‘left-hemisphere chauvinism’ that has occluded the more foundational, integrative capacities of the right hemisphere. Julian Jaynes offers a complementary genealogy, locating left-hemisphere analytic function in the ‘man side’ of the bicameral mind — the part that operates on parts rather than wholes. Allan Schore’s developmental neurobiology traces a right-hemisphere primacy in early emotional organization, implicitly qualifying any simple narrative of left dominance. A.D. Craig’s ethological evidence situates left-hemisphere control within routine, familiar-environment approach behaviors across vertebrates, counterposed to right-hemisphere governance of arousal and danger. The central tension across the corpus is not whether the left hemisphere specializes in language and serial analysis — that is broadly conceded — but whether such specialization constitutes dominance in any meaningful sense, or whether it represents a historically and developmentally derivative usurpation of right-hemisphere primacy.
There would seem to be a partisanship amongst scientists in the left hemisphere’s favour, a sort of ‘left-hemisphere chauvinism’ at work.
McGilchrist argues that the scientific presumption of left hemisphere dominance is itself a cultural and ideological bias rather than a neutral empirical finding.
, The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009thesis
The left or dominant hemisphere, like the man side of the bicameral mind, looks at parts themselves.
Jaynes identifies left hemisphere dominance with analytic, part-focused cognition and links it to the human, non-divine side of his bicameral model of ancient consciousness.
, The Origin of Consciousness in the Breakdown of the Bicameral Mind, 1976thesis
attentional dominance lateralises even more strongly to the right hemisphere than speech does to the left; and left-handers still display right-hemispheric attentional dominance in 81% of cases
McGilchrist demonstrates that the conventional identification of the left hemisphere as dominant is undermined by the superior lateralization of attentional control to the right hemisphere.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021thesis
attentional dominance lateralises even more strongly to the right hemisphere than speech does to the left; and left-handers still display right-hemispheric attentional dominance in 81% of cases
McGilchrist demonstrates that the conventional identification of the left hemisphere as dominant is undermined by the superior lateralization of attentional control to the right hemisphere.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021thesis
when the left hemisphere is stimulated, both artistic creativity and appreciation are reduced. When the left hemisphere DBS is switched off, patients’ creativity and artistic appreciation scores are relatively enhanced.
McGilchrist marshals deep brain stimulation evidence to argue that left hemisphere activation actively suppresses creativity by inhibiting the right hemisphere.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021thesis
when the left hemisphere is stimulated, both artistic creativity and appreciation are reduced. When the left hemisphere DBS is switched off, patients’ creativity and artistic appreciation scores are relatively enhanced.
McGilchrist marshals deep brain stimulation evidence to argue that left hemisphere activation actively suppresses creativity by inhibiting the right hemisphere.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021thesis
There is active inhibition of right hemisphere language by the left hemisphere, which comes to light when the left hemisphere is suppressed; if the inhibitory effect of the left hemisphere is attenuated or suppressed, the right hemisphere proves to have a considerable vocabulary
McGilchrist argues that left hemisphere dominance in language is maintained through active inhibition of the right hemisphere rather than any intrinsic linguistic superiority.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021thesis
There is active inhibition of right hemisphere language by the left hemisphere, which comes to light when the left hemisphere is suppressed; if the inhibitory effect of the left hemisphere is attenuated or suppressed, the right hemisphere proves to have a considerable vocabulary
McGilchrist argues that left hemisphere dominance in language is maintained through active inhibition of the right hemisphere rather than any intrinsic linguistic superiority.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021thesis
they found genes that acted on the right hemisphere to prevent its expansion … ‘it may just be normally repressed in the right hemisphere and allowed to take place in the left.’
Genetic research cited by McGilchrist suggests that left-hemisphere language dominance arises from suppression of the right hemisphere rather than from a positive developmental endowment of the left.
, The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009supporting
the left hemisphere controls routine, oft-practiced approach behaviors in a safe, familiar environment, whereas the right forebrain controls sudden, arousing avoidance behaviors and responses to unexpected stimuli
Craig’s ethological evidence situates left-hemisphere dominance within the narrow domain of routine approach behavior, relativizing any general claim of left hemisphere superiority.
, How Do You Feel? An Interoceptive Moment with Your Neurobiological Self, 2014supporting
high creativity – right>left; average creativity – left>right; and low creativity – no hemisphere difference.
McGilchrist reviews EEG data showing that left hemisphere dominance characterizes average rather than exceptional cognitive performance, reversing the cultural valuation of analytic dominance.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021supporting
high creativity – right>left; average creativity – left>right; and low creativity – no hemisphere difference.
McGilchrist reviews EEG data showing that left hemisphere dominance characterizes average rather than exceptional cognitive performance, reversing the cultural valuation of analytic dominance.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021supporting
‘our left hemisphere – the one that typically speaks to others – may be more adept at lying and constructing a social masquerade’
McGilchrist cites Panksepp to argue that left hemisphere verbal dominance is associated with social confabulation rather than authentic truth-telling.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021supporting
‘our left hemisphere – the one that typically speaks to others – may be more adept at lying and constructing a social masquerade’
McGilchrist cites Panksepp to argue that left hemisphere verbal dominance is associated with social confabulation rather than authentic truth-telling.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021supporting
repeated preference for one hemisphere helps to entrench still further an advantage that may start out by being relatively marginal … ‘Small initial differences between the hemispheres could compound during development, ultimately producing a wide range’
McGilchrist explains how left hemisphere dominance, once established, self-reinforces through winner-takes-all developmental dynamics rather than reflecting an intrinsic biological superiority.
, The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009supporting
Living in an isolated, left-mode-dominated internal world, however, can be experienced as filled with highly categorized routines or top-down processes that lack a feeling of spontaneity and vitality.
Siegel identifies left hemisphere dominance as a potential developmental pathology when it becomes dissociated from right-hemisphere integrative processes.
, The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020supporting
we can even have, as personalities, characteristic and consistent biases towards one or other hemisphere … This phenomenon is known as ‘hemispheric utilisation bias’ or ‘characteristic perceptual asymmetry’.
McGilchrist notes that individual personalities may exhibit sustained left or right hemisphere dominance as a trait-level cognitive bias rather than only a task-specific phenomenon.
, The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009supporting
Even verbal problems, which classically engage the left hemisphere more than the right, rely on the right hemisphere if they require insight.
McGilchrist argues that even within the left hemisphere’s ostensible domain of language, genuine insight depends on right hemisphere engagement, limiting the scope of left-hemisphere dominance.
, The Matter With Things: Our Brains, Our Delusions and the Unmaking of the World, 2021supporting
Even verbal problems, which classically engage the left hemisphere more than the right, rely on the right hemisphere if they require insight.
McGilchrist argues that even within the left hemisphere’s ostensible domain of language, genuine insight depends on right hemisphere engagement, limiting the scope of left-hemisphere dominance.
, The Matter with Things: Our Brains, Our Delusions, and the Unmaking of the World, 2021supporting
when you give comparable bad news to a patient with the mirror-image damage in the left hemisphere, the reaction is entirely normal.
Damasio’s clinical observations indicate that left hemisphere damage does not produce the anosognosic denial characteristic of right hemisphere lesions, implying distinct functional roles rather than a simple dominance hierarchy.
, The Feeling of What Happens: Body and Emotion in the Making of Consciousness, 1999supporting
The right cortex has a greater metabolic activity … and is larger … and heavier than the left.
Schore’s neurobiological developmental account establishes that the right hemisphere’s early structural and metabolic precedence qualifies any assumption of left hemisphere dominance in human psychological development.
, Affect Regulation and the Origin of the Self: The Neurobiology of Emotional Development, 1994supporting
the input from the body … is more highly integrated in the right hemisphere than in the left, as known in the field of neurology and taught to medical students for decades.
Siegel notes the clinical commonplace of right hemisphere body-integration superiority as contextual evidence that left hemisphere dominance is domain-specific rather than global.
, The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020aside
Global attention, courtesy of the right hemisphere, comes first, not just in time, but takes precedence in our sense of what it is we are attending to; it therefore guides the left hemisphere’s local attention
McGilchrist establishes a temporal and structural hierarchy in which right hemisphere global processing precedes and orients left hemisphere local analytic processing.
, The Master and His Emissary: The Divided Brain and the Making of the Western World, 2009aside