Dr Diana Fleischman04 March 2021

How Catching Covid Can Change Your Personality - Dr Diana Fleischman - #290

0Frameworks

10Insights

Insights & moments

The myth-busts, hot takes, explainers, and tools worth keeping.

Myth Buster· 1

Myth Buster02:00

Fever Is Not the Enemy — It’s a Defense

Contrary to common practice, fever is a beneficial immune response that helps fight infection. Suppressing it with medication may prolong illness, as higher body temperature creates an environment hostile to pathogens.

Fever is an evolved defense mechanism, not a symptom to eliminate.
Taking anti-fever medication can interfere with the body’s natural healing process.
Pathogens are less likely to survive in a hotter internal environment.

“The virus and the bacteria... does not want you to have a fever because a fever is really optimal for you.”
Dr. Diana Fleischman · 02:30

#immune system#fever#health

Hot Take· 1

Hot Take53:30

Modern Dualism: Why We Deny Biology’s Influence on Behavior

People resist biological explanations for personality and behavior, clinging to the idea of a 'soul' untouched by hormones or disease—what the guest calls 'modern-day dualism.'

People accept psychological influences but reject biological ones.
This denial extends to how hormones, illness, and physiology shape identity.
It reflects a desire to feel free from evolutionary and physiological constraints.

“People are really averse to the idea that these biological effects really have an influence on their personality. I think it's like modern-day dualism.”
Dr. Diana Fleischman · 53:30

#evolutionary psychology#dualism#self-perception

Explainer· 6

Explainer03:30

What Lassitude Is and Why It Matters

Lassitude is the evolved emotional state of being sick, encompassing fatigue, malaise, chills, and emotional sensitivity. It's not just a symptom but an adaptive mechanism that helps conserve energy and signal vulnerability to prompt caregiving from others.

Lassitude is a distinct emotion evolved to optimize behavior during illness.
It includes fatigue, sensitivity to pain, and emotional vulnerability.
It encourages rest and signals others to provide care, increasing survival chances.

“Lassitude is the whole thing... feeling of malaise, feeling of fatigue, but also feeling chills.”
Dr. Diana Fleischman · 04:30

#evolutionary psychology#illness behavior#emotion

Explainer07:00

Why We Crave Familiar Foods When Sick

When ill, people prefer familiar foods like toast or lemon water not just for comfort, but because the body avoids novel foods that could carry unknown pathogens, conserving immune resources.

Unfamiliar foods pose a higher risk of additional pathogens.
Digestion consumes significant energy, so appetite suppression is adaptive.
Familiar foods are perceived as safer due to past exposure.

“You really have a preference for incredibly familiar food... it's food that we know is safe.”
Dr. Diana Fleischman · 08:00

#nutrition#immune response#evolution

Explainer01:00

How Inflammation Changes Behavior and Mood

High inflammation during illness triggers behavioral changes like fatigue, social withdrawal, and emotional sensitivity. Even chronic inflammation from obesity can mimic these 'sickness behaviors.'

Inflammation signals the brain to shift priorities toward rest and recovery.
Chronic inflammation from obesity can cause similar behavioral changes.
Anti-inflammatory drugs can reduce emotional sensitivity, showing a direct link.

“When your body doesn't know the difference between I have too much weight on me and I'm actively fighting off an infection, you're going to…”
Dr. Diana Fleischman · 34:00

#inflammation#mental health#behavior

Explainer34:00

The Smoke Detector Principle in Immune Response

The immune system errs on the side of caution—like a smoke detector that overreacts—because it's safer to falsely detect an infection than to miss a real one.

The body prioritizes false alarms over missing a real threat.
This explains prolonged inflammation even after infection clears.
It's an evolutionary trade-off favoring survival over comfort.

“It's less costly for it to make the mistake of carrying on with inflammation than it is for it to stop.”
Dr. Diana Fleischman · 34:30

#evolutionary psychology#immune system#inflammation

Explainer18:30

How Pathogen Load Shapes Cultural Conservatism

Societies with higher historical pathogen exposure tend to be more conservative and conformist, as traditional practices reduce the risk of disease transmission.

High pathogen load increases preference for tradition and conformity.
Cooking methods and food taboos (like avoiding pork) may have evolved as disease prevention.
This extends to social behaviors, including openness to outsiders.

“Countries with high pathogen loads... it's much more important for them to stick to traditional ways of doing things.”
Dr. Diana Fleischman · 18:30

#cultural evolution#pathogens#conservatism

Explainer37:00

Why Women Are More Sensitive to Infection Than Men

Due to the high biological cost of reproduction, women are evolutionarily tuned to avoid infection more than men, leading to greater behavioral changes when sick.

Pregnancy and breastfeeding make women more vulnerable to pathogens.
Women reduce libido more than men in response to illness.
This reflects differing reproductive energy budgets between sexes.

“For women, mating is much more costly... you have to maintain your body better in order to carry a child.”
Dr. Diana Fleischman · 38:00

#sex differences#evolution#immunity

Story· 1

Story13:30

How Catching COVID Changed My Personality

After recovering from COVID, the guest experienced heightened social anxiety, emotional sensitivity, and increased contact with her mother—changes she attributes to the body’s evolved sickness response.

Post-COVID, she felt more anxious around strangers.
She became emotionally sensitive and called her mother daily, unlike before.
These shifts reflect lassitude and the evolutionary drive to seek care.

“I was much more socially anxious and I was much more emotionally sensitive.”
Dr. Diana Fleischman · 14:00

#long covid#personality change#mental health

Q&A· 1

Q&A09:30

How Sickness Makes Us Needy and Socially Sensitive

Illness increases emotional sensitivity and neediness as a way to elicit caregiving. This behavior aligns with evolutionary strategies to signal vulnerability to trusted allies.

Sickness increases sensitivity to social rejection and emotional neediness.
This signals vulnerability to prompt care from kin and close relationships.
It shifts focus from novelty to familiar, trusted relationships.

“You want to signal to the people that you know... 'I'm vulnerable and I need help.'”
Dr. Diana Fleischman · 10:00

#social behavior#evolutionary psychology#illness