“Neuroscience of human sexual attraction triggers (3 hypotheses)” by Steven Byrnes

tl;dr

There's a stereotype that male sexual attraction is triggered mainly by appearance, and female sexual attraction is triggered mainly by status.

…Yes I know, this stereotype is grossly oversimplified, and is only valid on the margin, and really there's overlapping distributions, etc. etc. (+ even more caveats in §1.2 below). But it does have a kernel of truth.[1]

Now, this post is not mainly about sex differences per se. What I actually care about is the more basic observation that “appearance-based sexual attraction” is a thing that exists in humans, and so is “status-based sexual attraction”. These stem from innate reflexes in the brain. My goal in this post is to speculate on how those innate reflexes might work, focusing on the neuroscientific “symbol grounding problem”.

For appearance-based sexual attraction (§2), I suggest two possible hypotheses. One involves innate sensory heuristics calculated in the brainstem, including visual processing [...]

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Outline:

(00:12) tl;dr

(01:43) 1. Introduction

(01:47) 1.1 Why am I writing this post?

(03:24) 1.2 A bunch of caveats

(06:13) 1.3 Relation to prior literature on the neuroscience of human sexual attraction triggers

(06:54) 2. Part A: Appearance-based sexual attraction

(08:36) 2.1 Hypothesis 1: Sexual attraction triggered by direct innate sensory heuristics in the brainstem

(09:17) 2.2 Hypothesis 2: Sexual attraction triggered by transient empathetic simulations of somatosensory inputs

(10:18) 3. Part B: Sexual attraction from phasic physiological arousal (esp. in women)

(10:30) 3.1 Terminology

(11:12) 3.2 Headline hypothesis

(12:03) 4. Central examples

(12:07) 4.1 Tall guys

(13:17) 4.2 Guys with fame, power, and status

(14:14) 5. Details, neuroscience, and evolution

(14:44) 5.1 More on the neuroscience

(16:51) 5.2 Evolutionary plausibility

(18:59) 6. Other everyday things that the phasic physiological  arousal \[coincident with paying attention to a person\] → sexual attraction theory might incidentally explain

(19:15) 6.1 Friend zone / Nice guys finish last

(19:34) 6.2 Reduction of female sex drive in long-term relationships

(20:06) 6.3 Women are less likely to make the first move

(20:33) 6.4 Women tend to feel attracted to guys who make them laugh

(21:51) 6.5 Sexual fetishes

(23:03) 6.6 The Lisa Feldman Barrett flu anecdote

(25:16) 6.7 Heterosexuality?

(25:26) 7. Conclusion

The original text contained 13 footnotes which were omitted from this narration.

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First published:

August 25th, 2025

Source:

https://www.lesswrong.com/posts/ktydLowvEg8NxaG4Z/neuroscience-of-human-sexual-attraction-triggers-3

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Narrated by TYPE III AUDIO.