Skip to main content

Or 34,00 After 66% tax deduction

I make a monthly donation I make an IFI donation
Research, science & health

The unconscious under conscious influence

Published on: 01/09/2016 Reading time: 1 min
Un journal ouvert

In a study published in the new international scientific journal Neuroscience of Consciousness, Benjamin Rohaut, Inserm researcher, and Lionel Naccache, team leader of the " Picnic lab : Physiological Investigation of Clinically Normal and Impaired Cognition ", both being also clinicians attached to the Pitié-Salpêtrière hospital neurology department, AP-HP, provide evidence that the unconscious semantic processing of a word genuinely exists, but that it is subject to very strong conscious influences. A work conducted in collaboration with their colleagues from the Brain and Spine Institute – AP-HP/CNRS/Inserm/UPMC.

Experimental psychology is full of situations allowing to explore the depth and diversity of mental operations performed without our knowledge, in other words, unconsciously. For example, using the techniques of subliminal visual presentation, it is possible to" inject " a word in the brain of a volunteer, and then explore his psychological and cerebral fate using behavioural measures and functional brain imaging. Since the end of the 90s, several high impact studies have thus shown that the meaning of an image, a number or a "subliminal" word could be unconsciously represented in our mind/brain.

In the study led by Lionel Naccache, researchers provide evidence that the unconscious semantic processing of a word certainly exists, but that it is subject to very strong conscious influences.

To do so, they used French words such as : "band, crane, ice, lawyer, pitcher, second, letter, agreement, time, bar, cup ... ". These words share a common semantic property, have you noticed ?

In reality, each of these words is " polysemous ", and is thus associated with two (or more) different meanings. Each time such a word is presented to you, you can thus understand it in two different ways. Consciously, we perceive only one meaning at a time, as Descartes told, as early as 1649 in Passions of the soul : "we only have one single thought of a same thing at the same time ". The meaning of the word we consciously get to at any time, is likely to be influenced.

Therefore, if you read : SORBET then ICE, you are very likely to get to the culinary sense of the word ice : " sweetened and flavoured product obtained by icing a pasteurised mixture made of milk, cream or butter and eggs (ice cream made with eggs), syrup and fruit (ice cream made with syrup, sorbet)" (Larousse Dictionary), while the MIRROR – ICE pair will strongly guide your semantic analysis towards the " homogeneous and properly reheated glass sheet, with both perfectly flat and parallel sides with which mirrors and window glasses are made".

The authors have presented word triplets to the volunteers of this experience while recording their brain activity using a headset of electrodes placed on their head. Each trial started with the presentation of a first word which was always visible, and allowed to define a specific semantic context (e.g. SORBET). Then the second word was flashed on screen, and was either subliminal or consciously visible. The third word then appeared and was always consciously visible. It was used as a target stimulus to which the subjects had to answer by pressing a button in order to indicate whether it was a real word (ex : WINDOW GLASS) or a pronounceable chain of letters which did not correspond to a word in the lexicon, referred to as a pseudo-word, such as "DRAIE" (scrape). When the middle word was semantically related to the target word, the subjects answered more quickly. It is referred to as priming effect. This priming effect was also revealed in the analysis of brain activities.

When the polysemous word (middle word of the triplet) was consciously visible, a priming effect was found only for consistent meaning with the contextual word introduced at the beginning of each trial (word 1). For example, when we introduced the triplet : TRACTOR – CRANE – SHIPYARD, we could find the priming effect of the word SHIPYARD with the word CRANE, whereas this effect was absent in triplets such as : BIRD – CRANE – SHIPYARD. Analysing electrical brain activity confirmed and clarified this result. The absence of priming effect for the non-contextualised meaning of the polysemous word indicates that it was simply not analysed by the subjects. Conscious semantic processing is therefore influenced by conscious context.

The main result of this work lies in the discovery that the same applies to polysemous words unconscious perception . When the polysemous word (word 2) was subliminally presented, the authors found semantic priming effects comparable to those observed in conscious reading condition : only the meanings of the subliminal polysemous word consistent with the contextual word were unconsciously analysed.

This series of experiments demonstrates that unconscious cognition is not only very complex, since it can reach the level of semantics (the meaning of words), but also that it is extremely sensitive to conscious influences. At every moment, our conscious posture influences the nature of mental operations occuring unconsciously in us.

"This work, which brings together neuroscience with psycholinguistics of the French language also illustrates the potential of scientific multi-disciplinary approaches", conclude Lionel Naccache and his colleagues.

Sources

Unconscious semantic processing of polysemous words is not automatic.
Benjamin Rohaut, F.-Xavier Alario, Jacqueline Meadow, Laurent Cohen, Lionel Naccache, Neuroscience of Consciousness, 6 Août 2016.
http://nc.oxfordjournals.org/content/2016/1/niw010

Our news on the subject

Tiré de New Theory of Colours de Mary Gartside, 1808
Aphantasia Might Be Linked to Alterations in Brain Connectivity
Thanks to 7T fMRI, researchers from Paris Brain Institute and NeuroSpin, the CEA's neuroimaging centre, are exploring the neural substrate of visual imagery at very high resolution for the first time. Their results, publiés [i] in Cortex, pave the...
06.06.2025 Research, science & health
Le développement du cerveau a une part d’aléatoire
The stochastic aspect of brain development
Although every person’s personality is the result of genetic and environmental factors, these are not the only factors at play. Bassem Hassan and his team at Paris Brain Institute have discovered that, in fruit flies (drosophila), individuality also...
05.12.2025 Research, science & health
Analyse MERSCOPE
New treatment pathways for brain malformation-linked focal epilepsy?
A study by Stéphanie Baulac’s team has revealed somatic mutations in different cell types in patients with type 2 focal cortical dysplasia. This disease causes drug-resistant epileptic seizures, for which the main treatment option is currently...
05.12.2025 Research, science & health
Un iceberg
The ICEBERG cohort, 10 years of collective scientific and medical mobilization
The ICEBERG cohort, initiated 10 years ago, is interested in studying factors predictive of the onset and progression of Parkinson’s disease.
05.15.2025 Research, science & health
La huntingtine est une protéine indispensable au développement embryonnaire, à la formation et au maintien du tissu cérébral.
Huntington's Disease: The Energy Hypothesis Gets Traction
Huntington's disease, a rare hereditary neurological disorder, is associated with an energy deficit that precedes the onset of symptoms and is closely linked to their progression. At Paris Brain Institute, Fanny Mochel and her colleagues are testing...
02.11.2025 Research, science & health
À la recherche de marqueurs d’imagerie dans la démence frontotemporale
Searching for Imaging Markers in Frontotemporal Dementia
Could exploring the relationships between different brain networks help us understand frontotemporal dementia (FTD)? This neurodegenerative disease, which progresses at varying rates, is often diagnosed late—when clinical signs are already severe. At...
01.07.2025 Research, science & health
See all our news