Trails A-B is a more nuanced storyline than you might think

For my thesis work rather than to finish off my proposal I am procrastinating by going down the rabbit hole of attention and the origins of the Trail Making task.

At first it seems like a relatively simple task, trace a continuous line where you alternate between letters and numbers with an increasing order of both. So A>1>B>2 etc..

This task can be used to assess cognitive dysfunction pretty well - it's a task that's pretty common place, so common place that I started to wonder where it came from. So far when it came to neuroscience anything we've learnt about the brain came from the oddest possible storylines, just consider that some of the first axons we've ever worked with came from squids, and that most things to do with vision research came from cats.

So of course there's a pretty substantive and silly story when it comes to Trails A-B. For one, it was first sold as Partington's Pathway test.

This was right around 1949, just after the Second World War when the American military was getting ready for its broad takeover of the globe with more military bases than reasonable. (As of Dec 2024 it's up to 280 military bases globally)

There aren't many records of this period, so if you or someone you know is an archivist with spare time, please CC me in your findings!

This assessment was quickly bought up and reused in the American Military as an assessment that was used to standardize attention and cognitive capacities in their folk. This makes sense and this is when it starts to be called The Trails test that we know today.

What I found really silly is how little information there is about this assessment prior to the "The Relation of the Trail Making Test to Organic Brain Damage" published in 1955 by Ralph M. Reitan. In this paper, they literally tested it on people with brain tumors, penetrating head injuries, and cerebral abscesses - when they said "organic brain damage," they meant it in the most literal sense possible.

You would think that records for this kind of this would be better kept, but mostly all we know is that this assessment worked well enough for the army to figure out how smart someone was that it was just used.

I don't know about you but I wanted to figure out just where this idea comes from and who the creator was so me and Claude (from Anthropic) started to work through public records.

Our conclusions on how we came to Trails A-B is the connect the dots game.

The speculative story of our mystery man is that he graduated in Iowa and became a teacher and principal before working in the Office of Alien Property Custodian during WWII (though we're not entirely sure if this is the same Partington - archival detective work is hard!).

I don't quite know what it is but I love that the origins of one of the most used neuro-cog assessments 70 years later can be broken down to teacher repurposing something they gave to bored kids with a twist to adults with organic brain damage.