Snapshot · Stuff You Should Know
Deoxygenated blood is not actually blue — veins appear blue because blue light cannot penetrate as deeply as red light, so blue light is reflected back to the eye.
Where this was said
At 17:50 · chapter starts 16:00
Chuck and Josh tackle hemangiomas, the raised reddish 'strawberry marks' that alarm new parents but are usually benign. Only about 30% are visible at birth; most appear between 4–6 weeks and are gone by the time a child reaches double digits. Large ones near the eyes or ears can pose medical risks, and hemangiomas can extend internally to organs in rare cases. The discussion of why deeper hemangiomas look blue rather than red triggers a wonderfully entertaining detour: the hosts debunk the playground myth that deoxygenated blood is blue [1] — Josh Clark "Blood is never blue — not even when deoxygenated. Veins appear blue because blue light can't penetrate as deeply as red light, so it reflec…" 17:20 . Josh explains the actual physics — blue light reflects off shallow tissue while red light penetrates deeper and is absorbed — a fact Chuck swears he didn't know until that very morning.
Blood is never blue — not even when deoxygenated. Veins appear blue because blue light can't penetrate as deeply as red light, so it reflects back to the surface. Red light goes deeper and gets absorbed, making deep tissue appear blue to the eye.
The widely cited ego-depletion model — the idea that willpower is a finite resource that gets depleted — failed to replicate in follow-up studies.
Humans are estimated to have 5,000–7,000 thoughts per day, yet can recall essentially none of them afterward, highlighting why in-the-moment emotional tracking matters.
A large Harvard study found that a wandering mind is an unhappy mind — people report greater happiness when their attention is tethered to the present, even if the task is unpleasant.
A key study finding that we have a 'credit card's worth of plastic' in our bodies was likely skewed because researchers used nitrile gloves that shed plastic particles onto the microplastic detector.
Emotionally sensitive people have a hyperactive amygdala, an underactive prefrontal cortex, and a frayed connection between the two — making emotional regulation structurally harder.
Rejection sensitivity can be observed as early as age 2 or 3, suggesting it has strong developmental and likely genetic roots.
A Yale study found that non-judgmental observation of emotions — without rushing to resolve them — reduces activation in the brain, making it a powerful regulation tool.
Dan Gilbert's research found that the psychological immune system — the brain's ability to justify and find satisfaction in choices — activates most powerfully when a decision is perceived as irreversible.
Barry Schwartz's research found that maximizers — people who try to optimize every decision — tend to achieve objectively better outcomes but report lower happiness than satisficers who choose 'good enough.'
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