---
layout: post
title: "Bandwidth between Brain and Computer"
date: 2026-07-06
---

A few years ago I was watching "[Some Reflections on Early
History](https://www.youtube.com/watch?v=SN--t9jXQc0)" by J.C.R. Licklider, the
author of "[Man-Computer
Symbiosis](https://ieeexplore.ieee.org/document/4503259)" (please excuse the
anachronisms, and read "Man" as "Human"). Licklider was one of the key players
developing the concept of "networked computers" and the personal computer. He's
credited as one of the "fathers of the internet," directly writing memos while
working at the Pentagon. So as a military guy talking about an "Intergalactic
Computer Network" where "anyone could access data and programs from anywhere,"
he was seen as a loony by his coworkers, because back then computers were used
for just calculating salaries and census data and missile trajectories.

In that boring talk, he describes that his biggest disappointment
with personal computers, and people in general, was that they won't take the
time to learn to use a new device, and the keyboard is boring and slow. He
thought that we should have better ways to type stuff, and that the QWERTY
keyboard is an unhappy coincidence. That we could get "more bits of information
out of every key press"; like how fast, how hard, or where you type; or maybe
use different phalanges to input different keys, or have gauntlets with
accelerometers in there to type faster.

Based on that, through 2020 and 2021, my pandemic project was using my computer
only from the terminal. I started to use a Matrix server with a WhatsApp
bridge, so I could chat through the terminal with friends and family, browsed
the internet with `lynx`, and overall wanted to have the computer make the
least amount of compute necessary, so that the bits flowing from the network,
to my machine, to my screen, to my eyes stayed as close to 1:1 as I could get
them.

The bandwidth from "brain-to-computer" (what I type in) shall be minimized, so
I get the exact behavior I want out of as few keystrokes as possible. The
bandwidth from "computer-to-brain" (what I read on the screen) was also to be
minimized: no extra pixels, only the letters conveying the exact information
that I requested.

Funny, that made me practice a lot of "how to maximize conciseness," very
useful for talking to a language model. They have a similar bandwidth problem:
the quality of LLMs depends a lot on how much signal you can pack into a
prompt. Too much context, too many pictures, anything over 200k tokens makes
the LLM much dumber. Bandwidth can be measured, and the
[[a_mathematical_theory_of_communication|signal-to-noise]]
ratio matters a lot.