Dr. Andrew Huberman, Ph.D. is a Professor of Neurobiology and Ophthalmology at Stanford University School of Medicine. His lab focuses on neural regeneration, neuroplasticity, and brain states such as stress, focus, fear, and optimal performance.
In this episode, Andrew Huberman describes the neural mechanisms that activate and control aggressive states and behaviors, the effects of alcohol and caffeine, and the role of hormones in mediating violent and/or competitive aggression. He also reviews tools that can be used to modulate the factors that have been shown to ‘prime’ an individual for aggression, including sunlight, estrogen sensitivity, competition within social settings, overall stress levels, and the hormone cortisol.
Host: Andrew Huberman (@hubermanlab)
The context of aggression matters: some are ok – think of a mother protecting her child; while others are not acceptable – such as picking a fight unprovoked
Sadness and aggression are not one in the same thing
There are neural circuits that work together to engage a pattern of behaviors
“Aggression has a beginning, middle, and an end. That means it’s a process, not an event.” ­Dr. Andrew Huberman
Certain hormones and neurotransmitters will drive people to different levels of aggression, but a buildup of pressure is the real driver
A collection of neurons in a part of the brain called the ventromedial nucleus hypothalamus (VMH) evokes aggressive responses
The neurons responsible for making estrogen receptors in the VMH are specifically responsible for generating aggressive behavior
Stimulation of the VMH in mice evokes almost instantaneous aggressive behavior
Types of aggression: (1) reactive aggression – triggered by a fight for life; (2) proactive aggression – activation of ‘go’ pathways and leaning in to overcome a certain state
Dispelling a myth: testosterone does not cause aggression – it causes proactivity and the willingness to lean into the effort in competitive scenarios and makes effort feel good
Testosterone increases natural tendencies:  if you are already aggressive, it will make you more aggressive; if you are competitive, it will make you more competitive, etc.
The activation of estrogen receptor containing neurons makes people more aggressive
Testosterone can be converted into estrogen through aromatase
Aggression levels vary on short days versus long days: on short days the melatonin signal goes up, dopamine is lower, and stress hormones circulate more
Under conditions where serotonin is reduced, estrogen is more likely to trigger aggression
If cortisol is higher, there’s a tilt toward aggression
Genetic bias exists but it’s rare that aggression will boil down to one specific gene – there is almost always an interplay between genetics and the environment
There is a strong correlation between season and aggression
Caffeine increases autonomic arousal and creates a sense of readiness in the brain and body
Alcohol decreases activity in the sympathetic arm of the autonomic nervous system and ultimately makes us less alert
Caffeine & alcohol are on opposite ends of the spectrum
The more alcohol you consume, the more likely you are to engage in indirect aggressive behaviors
The combination of caffeine and alcohol biases people toward impulsivity and less self-regulation
Omega-3 can reduce impulsivity and aggression for predisposed individuals by modulating hormone systems
Omega-3 dose: 1g or more per day
Get sunlight in your eyes early in the day
Hot baths and sauna can reduce cortisol (20 minutes)
Ashwagandha may reduce cortisol – but cycle about 2 weeks on, 2 weeks off
L carnitine can reduce aggressive tendencies – and can be supplemented or found in food but isn’t very bioavailable; you can find injectable L carnitine – try 500mg-1g per day
Photoperiod reverses the effects of estrogens on male aggression via genomic and nongenomic pathways (PNAS)
Testosterone and occupational choice: actors, ministers, and other men (Journal of Personality and Social Psychology)
Age, Testosterone, and Behavior Among Female Prison Inmates (Psychosomatic Medicine)
Testosterone Rapidly Increases Neural Reactivity to Threat in Healthy Men: A Novel Two-Step Pharmacological Challenge Paradigm (Biological Psychiatry)
Caffeinated and non-caffeinated alcohol use and indirect aggression: The impact of self-regulation (Addictive Behaviors)
Efficacy of carnitine in the treatment of children with attention-deficit hyperactivity disorder (Prostaglandins, Leukotrienes and Essential Fatty Acids)
Functional identification of an aggression locus in the mouse hypothalamus (See “Supplementary information” for movies)
An Introduction to Behavioral Endocrinology 5th Edition
The Nature of the Beast: How Emotions Guide Us