November 15, 2021 • 1hr 11min

Time Perception & Entrainment by Dopamine, Serotonin & Hormones

Huberman Lab

In this episode, Dr. Andrew Huberman discusses the science of time perception and how it fundamentally shapes our experience of life. He explores how our perception of time is linked to neurochemical states that control mood, stress, happiness, and excitement. The episode covers how time perception frames our evaluation of past experiences, our sense of the present moment, and our outlook on the future. Huberman explains various forms of entrainment - how our internal biology and psychology are linked to external cues like light-dark cycles. He discusses circannual (yearly), circadian (daily), and ultradian (90-minute) cycles and how they impact our physiology and time perception. The role of key neurotransmitters like dopamine, norepinephrine, and serotonin in modulating our sense of time is examined in depth. The episode provides insights into how time perception varies throughout the day and how this affects our ability to perform different types of tasks. Huberman also explores interesting phenomena like how fun experiences feel fast in the moment but are remembered as longer, while boring experiences have the opposite effect. Practical tools and protocols are provided throughout for leveraging our understanding of time perception to enhance productivity, creativity, and overall life experience.

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Key Takeaways

Time perception is fundamentally linked to neurochemical states that control mood, stress, happiness, and excitement. It frames how we evaluate our past, present, and future.
Entrainment is how our internal biology and psychology are linked to external cues like light-dark cycles. This occurs on circannual (yearly), circadian (daily), and ultradian (90-minute) cycles.
Dopamine and norepinephrine increase our perception of time passing by increasing our "frame rate" and leading us to overestimate time intervals. Serotonin has the opposite effect, slowing our perception and causing underestimation of time.
Our perception of time varies throughout the day based on natural fluctuations in dopamine, norepinephrine and serotonin levels. This impacts when we may be best suited for different types of tasks.
Cold exposure can increase dopamine levels by 2.5x, altering time perception during the experience.
Fun, varied experiences feel fast in the moment but are remembered as longer in retrospect. Boring experiences feel slow in the moment but are remembered as shorter.
Dopamine release serves as a marker for how we parse time, allowing us to segment our day into functional units through habits and routines.

Introduction

In this episode, Dr. Andrew Huberman discusses the science of time perception and how it fundamentally shapes our experience of life. He explores how our perception of time is linked to neurochemical states that control mood, stress, happiness, and excitement. The episode covers how time perception frames our evaluation of past experiences, our sense of the present moment, and our outlook on the future.

Huberman explains various forms of entrainment - how our internal biology and psychology are linked to external cues like light-dark cycles. He discusses circannual (yearly), circadian (daily), and ultradian (90-minute) cycles and how they impact our physiology and time perception. The role of key neurotransmitters like dopamine, norepinephrine, and serotonin in modulating our sense of time is examined in depth.

The episode provides insights into how time perception varies throughout the day and how this affects our ability to perform different types of tasks. Huberman also explores interesting phenomena like how fun experiences feel fast in the moment but are remembered as longer, while boring experiences have the opposite effect.

Practical tools and protocols are provided throughout for leveraging our understanding of time perception to enhance productivity, creativity, and overall life experience.

Topics Discussed

Circannual Entrainment (9:25)

Circannual rhythms refer to how our biology is matched to the 365-day journey of Earth around the sun. This entrainment occurs primarily through changes in day length and light exposure throughout the year.

Melatonin plays a key role, with levels inversely related to light exposure
Longer days in spring/summer lead to less melatonin release, shorter days in fall/winter lead to more melatonin
This impacts energy levels, mood, and other physiological processes

Seasonal Oscillations in Hormones (13:20)

Research shows testosterone and estrogen levels vary across the year, correlating with day length:

Longer days associated with higher testosterone and estrogen
Impacts desire for romantic interactions, energy levels, and mood
Skin exposure to light (about 2 hours/day) can significantly increase these hormones

Circadian Timing and Entrainment (16:06)

Our 24-hour circadian rhythm is controlled by a "clock" in the brain that regulates gene expression cycles in every cell of the body. This internal clock is entrained to the external light-dark cycle.

Tool 1: View bright light (ideally sunlight) for 10-30 minutes within an hour of waking
Tool 2: Get bright light exposure again in the late afternoon/evening
Tool 3: Avoid bright light exposure at night

Additional Circadian Entrainment Tools (21:13)

Tool 4: Time physical activity consistently, ideally within +/- 2 hours each day
Tool 5: Maintain a consistent eating window each day

Ultradian Cycles and Focus (25:00)

90-minute ultradian cycles govern our ability to focus intensely. These cycles are linked to the release of acetylcholine, dopamine, and norepinephrine.

Tool 6: Leverage 90-minute focus blocks for intense work, separated by at least 2-4 hours
Most people can handle 1-2 such blocks per day
Unlike circadian rhythms, you can initiate these cycles at will

Three Types of Time Perception (31:42)

Huberman outlines three main forms of time perception:

Present: How we perceive the passage of time in the moment
Prospective: How we estimate future time intervals
Retrospective: How we recall the duration of past events

Dopamine and Time Overestimation (34:40)

Higher levels of dopamine and norepinephrine in the brain lead to overestimation of time intervals:

Causes "fine slicing" of time, increasing our mental "frame rate"
Makes experiences feel like they're happening in slow motion
Can lead to "overclocking" during traumatic events, causing vivid, persistent memories

Serotonin and Time Underestimation (37:18)

Higher levels of serotonin have the opposite effect of dopamine:

Causes underestimation of time intervals
Decreases our mental "frame rate"
Makes time seem to pass more quickly

Daily Fluctuations in Neurotransmitters (39:10)

Levels of dopamine, norepinephrine, and serotonin naturally fluctuate throughout the day:

First half of day: Higher dopamine and norepinephrine
Second half of day: Higher serotonin

Tool 7: Leverage these fluctuations for optimal task timing:

Morning: Better for tasks requiring precision, rigid rules, high resolution
Afternoon/Evening: Better for creative work, brainstorming, flexible thinking

Trauma and Time Perception (44:38)

Traumatic experiences can lead to "overclocking" due to extreme dopamine/norepinephrine release:

Causes events to be perceived in ultra-slow motion
Creates vivid, persistent memories that are difficult to shake
Trauma treatments often involve adjusting the "playback rate" of these memories

Blinking and Time Perception (51:03)

Research shows a link between spontaneous blinking, dopamine, and time perception:

Increased arousal leads to increased blink rate
Each blink causes a slight dilation of perceived time
Tool 8: Consciously adjusting blink rate may influence time perception

Cold Exposure and Dopamine (53:38)

Cold exposure (e.g., ice baths, cold showers) can significantly increase dopamine levels:

Can boost dopamine by 2.5x
Alters time perception during the experience
Tool 9: Use mental tactics to adjust perceived frame rate during discomfort

Perception of Fun vs. Boring Experiences (56:30)

An interesting paradox exists in how we perceive fun vs. boring experiences:

Fun, varied experiences feel fast in the moment but are remembered as longer
Boring experiences feel slow in the moment but are remembered as shorter
This relates to how dopamine influences time perception and memory formation

Context Variation and Bonding (1:00:54)

Experiencing varied contexts with people or places impacts our perception of time spent:

More novel experiences in a place make us feel we've been there longer
Varied experiences with a person make us feel we know them better and have spent more time with them

Dopamine as a Time Marker (1:03:00)

Research shows dopamine release serves as a marker for how we parse time:

Dopamine pulses help segment our perception of experiences
This occurs regardless of whether the dopamine release is from positive or surprising events

Habits and Time Perception (1:07:40)

Tool 10: Use habits to create functional units in your day:

Regular habits trigger dopamine release
This dopamine release serves as a time marker
Strategically placed habits can help segment your day for optimal performance

Conclusion

Dr. Huberman concludes by emphasizing the profound impact that understanding time perception can have on our daily lives. By leveraging our knowledge of circannual, circadian, and ultradian rhythms, along with the role of neurotransmitters like dopamine and serotonin, we can optimize our performance, creativity, and overall life experience.

The tools and protocols discussed provide practical ways to apply this knowledge, from optimizing our daily routines to enhancing our ability to focus and be productive. Understanding how our perception of time is influenced by factors like novelty, arousal, and habits allows us to consciously shape our experiences and memories.

Ultimately, this episode underscores the importance of aligning our behaviors with our biology to create a more fulfilling and effective approach to life. By becoming aware of how our brains process time, we can take greater control over our subjective experience and make the most of every moment.