Consciousness and the Brain

Deciphering How the Brain Codes Our Thoughts

By: Stanislas Dehaene

Published: 2014

Read: 2016


A theoretical exploration of what goes on in the brain as conscious and non-conscious processes unfold.

Exploring questions such as when do we become aware of information, how do we make decisions and how is information processed and disseminated across the brain. 

Worth Reading:

Great read. Dense, thorough and well researched. Particularly enjoyed the chapter on what consciousness is good for.

Goes into many interesting elements of network theory, such as the importance of long distance connections (in the brain) in disseminating information (across various brain sections) and self-organization (see also “Linked“).

Practical Takeaways:

  • Brain autonomy.
    • The brain generates its own goals thanks to spontaneous activity.
    • These patterns evolve and shape brain activity in a top-down matter.

Key Concepts


  • Consciousness = conscious access.
  • The ability to become aware of selected sensory stimuli.

The importance of memory

  • Provides a workspace to think about the past and the future.
    • Ability to hold information in mind long after the stimulus is gone.
    • Capacity to synthesize information over time and space.
    • Rethink it at any time in the future,
  • Fundamental component of the conscious mind.
    • Likely to have been positively selected for during evolution.

Conscious decision making, confidence and judgment

  • In order to be useful, conscious thoughts must be earmarked with a confidence level.
    • Optimal decision making demands that each source of information, internal or external, is weighted by an estimate of its reliability.
  • Judgments of confidence occupy a central location in conscious minds.
    • We consistently evaluate the reliability of our own thoughts and the thoughts of others (gossip).
  • By comparing our knowledge with that of others, we achieve better decisions.

Knowing yourself

  • We spend our life monitoring our behavior as well as that of others.
  • Having spent a lifetime with ourselves, we reach a view of our own character, which is only slightly more refined that our views of others.
  • We remain largely ignorant of the unconscious determinants of our behavior.
  • Our “self” is a database that gets filled in through our social experiences and is likely to include gaps, misunderstandings and delusions.

Random thoughts

  • Even when we rest and “think of nothing”, our brain constantly produces complex and ceaselessly changing arrays of neuronal activities.
  • Ceaseless neuronal discharges create our ruminating thoughts.
  • By spontaneously generating fluctuating patterns of activity, even in the absence of of external stimulation, the brain allows us to generate new plans, try them out, and change them at will.
  • A Darwinian generator of diversity, constantly sculpted by the brain’s evaluation of future rewards.
    • [This turns randomness into potentially purposeful behavior; see “The Genius Within.]

Consciousness emerging

  • Any face that we see, any word that we hear, begins in an unconscious manner.
    • Information diluted in the firing of myriad unrelated neurons.
    • Each sensing only a miniscule part of the overall event.
  • We become aware of the latent information only once higher level brain areas categorize the information.
    • Once it is encoded as an organized pattern of neuronal activity in higher cortical regions.
    • Activation of long distance connections across the brain.
  • One of the ways to detect a conscious reaction to a sensory input is a slow wave of neuronal firing across the top of the brain.
    • About 0.3 seconds after the stimulus input.
    • Serves to inhibit all other neuronal activity not relevant to the specific input.

Leave a Reply