Profile picture
John Allspaw @allspaw
, 13 tweets, 4 min read Read on Twitter
Contrary to popular belief (tooling marketing and some SRE/Ops/Infra writings) the “substitution myth” continues to hold and I think it requires repeating. @courtneynash summed it up best (more than 3 years ago now!) in this way...

(oreilly.com/ideas/ghosts-i…)
Another way of putting this is:
This means that every time you read promises that a tool will genuinely *relieve* people of doing some task, flip your skepticism bit HARD. The reason this marketing tends to be effective is that it fits with a common belief in what’s known in the field as “functional allocation”
Functional allocation is more commonly known as the “HABA-MABA” perspective. These lists of activities that “humans-are-better-at, machines-are-better-at” sits at the core of assumptions behind many designs and even predictions about technology’s effects in the future (AI, etc.)
(Aside: you’ll find searching around that this was also known as MABA-MABA, with the gendered ‘men-are-better-at’ - thankfully this bit has evolved.)
Anyway, the idea of course is to give each (people and machines) the parts that they’re good at, and “voilà!” - efficiency! Here’s the 1951 representation of this...
The substitution myth flies in the face of this idea and has been replicated in multiple studies in multiple domains across *decades* of research. To run with these antiquated ideas is akin to building a database while ignoring the fundamental concepts of distributed systems.
(Aside: I believe that this stance — belief that HABA-MABA is a productive design director — is commonly applied when people look to reduce so-called “toil.” That is a different topic.)
Here’s an accessible description of how belief in the substitution myth can play out:
I think we can imagine other examples in software. Take k8s — the benefits of implementing it may bring benefits or “relieve” engineers from specific tasks or concerns, but introduces new ones that were not present before: new failure paths, new mental models & dependencies, etc.
I urge folks who read this entire thread - read @courtneynash’s article above, then read the references she points to.
As to the most productive reaction to the HABA-MABA and substitution myth: it’s called Joint Cognitive Systems and centers on making automation a “team player” - much has been written about this, and I’ll share two things to consider. One is @ddwoods2’s “patch” for HABA-MABA:
And the other is a paper that outlines the fundamentals necessary in order to make software a “team player” jeffreymbradshaw.net/publications/1… <- this has all the basic concepts to address

Question is: can you make the leap from those concepts to implementing designs in *your* context? FIN
Missing some Tweet in this thread?
You can try to force a refresh.

Like this thread? Get email updates or save it to PDF!

Subscribe to John Allspaw
Profile picture

Get real-time email alerts when new unrolls are available from this author!

This content may be removed anytime!

Twitter may remove this content at anytime, convert it as a PDF, save and print for later use!

Try unrolling a thread yourself!

how to unroll video

1) Follow Thread Reader App on Twitter so you can easily mention us!

2) Go to a Twitter thread (series of Tweets by the same owner) and mention us with a keyword "unroll" @threadreaderapp unroll

You can practice here first or read more on our help page!

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just three indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member and get exclusive features!

Premium member ($30.00/year)

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!