David Eagleman: Dreaming protects the visual cortex, the Ulysses contract enhances self-discipline, and brain plasticity supports lifelong learning | The Diary of a CEO

Dreams protect the brain's visual cortex, revealing the complex interplay of perception and neural networks.

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Add us on Google by Editorial Team Apr. 23, 2026

Key takeaways

• Dreaming serves to protect the brain’s visual cortex from being overtaken by other sensory inputs.
• The brain’s peak development occurs at age two, transitioning from fluid to crystallized intelligence as we age.
• Competing neural networks in the brain construct our perception of reality, influencing decision-making.
• The Ulysses contract is a strategy to curb future bad behavior by making present decisions.
• Humans are not a singular entity but a collection of internal voices influencing decisions.
• Brain plasticity allows for lifelong learning and adaptation, impacting how we learn and remember.
• Lack of emotional and social interaction during critical periods can lead to cognitive deficits in children.
• The brain’s adaptability is contingent on sufficient environmental input for proper development.
• As we age, crystallized intelligence makes learning new things more challenging.
• Seeking novelty and challenges is essential for maintaining brain health and cognitive resilience.
• The brain’s ability to model the world can be hindered by insufficient input, affecting development.
• Engaging in new tasks and seeking novelty promotes cognitive function and resilience.
• Brain plasticity is a fundamental aspect of neuroscience with significant implications for education.
• Internal conflicts within the brain reflect the complexity of human decision-making.
• Social interaction plays a critical role in cognitive development, particularly in early childhood.

Guest intro

Dr. David Eagleman is a neuroscientist at Stanford University, co-founder of Neosensory and BrainCheck, and director of the Center for Science and Law. He previously directed a neuroscience research laboratory at Baylor College of Medicine for 10 years. He is an international bestselling author of Livewired: The Inside Story of the Ever-Changing Brain, exploring brain plasticity and perception.

The purpose of dreaming in brain function

• Dreaming defends the visual territory from being overtaken by other senses.

• The purpose of dreaming is to defend the visual territory from takeover from the other senses

  — David Eagleman

• Understanding sensory experiences is crucial for grasping brain function.
• Dreaming highlights the brain’s plasticity and its role in maintaining sensory balance.
• The visual cortex relies on dreaming to maintain its dominance over other senses.
• Dreaming is a protective mechanism against sensory takeover.
• The brain’s adaptation through dreaming underscores its dynamic nature.
• Dreaming is essential for preserving the visual cortex’s function.

Brain development and intelligence

• The brain peaks at age two, shifting from fluid to crystallized intelligence.

• Your brain peaked at the age of two… you’ve got crystallized intelligence meaning you know how to drive a car

  — David Eagleman

• Crystallized intelligence reduces the need for change in the brain.
• Fluid intelligence is prominent in early development, facilitating learning.
• As we age, crystallized intelligence makes learning new things more difficult.
• The transition from fluid to crystallized intelligence impacts cognitive development.
• Understanding brain development stages is key to understanding learning processes.
• Crystallized intelligence supports routine tasks, reducing cognitive flexibility.

Neural networks and perception of reality

• The brain constructs reality through competing neural networks.

• You can actually get competing networks… you are arguing with yourself

  — David Eagleman

• Internal neural conflicts influence human behavior and decision-making.
• Competing networks create a dynamic perception of reality.
• Understanding neural networks is crucial for grasping human behavior.
• The complexity of decision-making is rooted in internal neural conflicts.
• Neural networks drive different conclusions about behavior.
• The brain’s perception of reality is a result of internal competition.

The Ulysses contract and behavioral psychology

• The Ulysses contract prevents future bad behavior through present decisions.

• A Ulysses contract is where you do something now to prevent yourself from behaving badly in the near future

  — David Eagleman

• This strategy helps manage future behaviors by setting constraints.
• Understanding self-control is key to applying the Ulysses contract.
• The Ulysses contract is a proactive approach to behavior management.
• Behavioral psychology benefits from the application of the Ulysses contract.
• Setting up constraints aids in preventing undesirable future actions.
• The Ulysses contract is a tool for enhancing self-discipline.

The concept of multiple selves in decision-making

• Humans are a collection of internal voices influencing decisions.

• That tussling with himself implies different political parties that are all battling it out

  — David Eagleman

• Internal conflicts reflect the complexity of human decision-making.
• The concept of multiple selves challenges the idea of a unified self.
• Decision-making involves a dynamic interplay of internal voices.
• Understanding multiple selves is crucial for grasping human behavior.
• Internal “political parties” drive different behavioral outcomes.
• The brain’s internal conflicts shape decision-making processes.

Brain plasticity and learning

• Brain plasticity allows for lifelong learning and adaptation.

• Our whole lives our brains are changing every moment

  — David Eagleman

• Plasticity influences how we learn and remember information.
• Understanding brain plasticity is crucial for education and cognitive development.
• The brain’s adaptability is a fundamental aspect of neuroscience.
• Plasticity supports cognitive resilience and learning capacity.
• Lifelong learning is facilitated by the brain’s plastic nature.
• Brain plasticity underscores the dynamic nature of cognitive processes.

The impact of social interaction on cognitive development

• Lack of emotional and social interaction can lead to cognitive deficits.

• We’re not gonna hold them we’re not gonna talk to them and all these children grew up with real cognitive deficits

  — David Eagleman

• Early social interactions are crucial for cognitive development.
• Neglect during critical periods impacts cognitive outcomes.
• Social interaction plays a critical role in brain development.
• Understanding the effects of neglect is crucial for child development.
• Cognitive deficits highlight the importance of early social engagement.
• Emotional and social interactions are vital for healthy cognitive growth.

The relationship between brain adaptability and environmental input

• The brain’s adaptability is contingent on sufficient environmental input.

• Mother nature drops human brains into the world kind of half baked

  — David Eagleman

• Insufficient input can hinder brain development and modeling of the world.
• Environmental input is crucial for proper cognitive development.
• The brain’s adaptability relies on absorbing external stimuli.
• Understanding environmental input is key to grasping brain development.
• The brain’s modeling of the world depends on adequate input.
• Cognitive science emphasizes the importance of environmental factors.

The importance of seeking novelty for brain health

• Challenging oneself is crucial for brain health and resilience.

• The key is seeking challenge… you wanna take on new tasks

  — David Eagleman

• Novelty promotes cognitive function and resilience.
• Engaging in new tasks supports brain health.
• Seeking novelty is essential for maintaining cognitive flexibility.
• Brain health benefits from active engagement and challenges.
• Understanding the relationship between challenge and brain health is crucial.
• Cognitive resilience is enhanced through novelty and challenges.

Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.