Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Evidence that subliminal is not so 'sub'

10.11.2006
The popular notion of subliminal information is that it streams into an unguarded mind, unchecked and unprocessed. However, neurobiologists' experiments are now revealing that the brain does consciously process subliminal information and that such processing influences how that subliminal information is perceived.

In an article in the November 9, 2006, issue of the journal Neuron, published by Cell Press, Kimihiro Nakamura and colleagues report experiments with human volunteers demonstrating such "top-down" processing of subliminal information.

Their findings also shed light on the neural mechanism by which reading a printed word evokes the representation of the spoken form. This "lexical-phonological" linkage is critical to learning to read and is disrupted in some forms of reading disorders.

In the researchers' experiments, they showed volunteers either words or pronounceable nonwords and asked them to perform either a lexical task or a pronunciation task on the words. The lexical task was to identify whether the word they saw was a real word or a nonsense word.

... more about:
»TMS »neural »perceived »subliminal

However, unbeknownst to the subjects, they had been first presented with a subliminal word that either matched or didn't match the target word. Such subliminal words were "masked" with nonsense characters that would render the presentation subliminal. The researchers' initial experiments showed that presenting subliminal words identical to the target word produced a "priming" effect in which subjects responded faster on the lexical or pronunciation tasks.

The researchers next applied a harmless magnetic pulse--called transcranial magnetic stimulation (TMS)--to two key regions of the brain involved in such perception, before presenting the priming word. The two regions were known to be involved in either converting visually perceived words to phonological representations or to integrating perceived words across visual and auditory modes. TMS is known to transiently affect neural function in a target area.

Nakamura and colleagues found that TMS applied to one brain area or the other could selectively disrupt the priming effect for either the lexical or pronunciation task. The researchers concluded that the conscious task instruction for either of the tasks caused a different neural network to be engaged for generating the appropriate behavioral response.

They concluded that their results "provide direct evidence for the proposal that even the unconscious processing of incoming stimuli operates under the strong influence of the conscious task instructions." They also concluded that "results further suggest that such top-down, strategic control modulates the bottom-up neural activation produced by unconsciously perceived words to set up a different neural circuit for generating the intended behavioral response."

In a preview of the Neuron paper, Stanislas Dehaene and Lionel Naccache commented that "perhaps the most important implications of the Nakamura et al. study concern our concept of automaticity. Many theories of human cognition postulate that nonconscious cognitive processes are automatic and independent of attention. Recently, however, experimental reports using the masked priming paradigm have revealed that subliminal processing is affected by several top-down effects. By showing that repetition priming can be suppressed by applying TMS to distinct locations depending on the task, the present results strongly support this point of view."

Dehaene and Naccache concluded that the results "support the idea that a whole chain of processing defined by the task, once prepared consciously, can be applied to nonconsciously perceived stimuli. Thus, 'subliminal' is not synonymous with 'automatic' or 'task-independent.' Our expectations shape our processing of subliminal stimuli."

Heidi Hardman | EurekAlert!
Further information:
http://www.neuron.org

Further reports about: TMS neural perceived subliminal

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>