Expanding the chord reaction time test

chord reaction time
Using a cog psych task to measure how fast I can play various chords on demand.

Matt Crump


January 21, 2024

cartoon thundercat scientist building a synthesizer. laboratory. science. 80s cartoon. space music.

I’ve been tinkering with a web-based “Chord Reaction Time” test to measure how fast I can play various chords on demand. The first version of the task had all the keys and three basic 7th chords (7, -7, ∆7). The newer version adds a selection screen, and more chords to practice. I don’t have a demo to share yet, but here’s a figure of what happens:

At the moment, whenever I play a chord in response to a name, I have to simultaneously press the space bar on a bluetooth keyboard. That keypress records my reaction time to the chord and triggers the next trial. This coming week I’ll look into using the laptop microphone to record reaction time by analyzing amplitude changes (and then later something similar using MIDI).

Yesterday afternoon I tried my hand at all the chords in all the keys. I haven’t looked at the data yet, but I’m sure it will tell me that I’m slow at the chords that I already know I’m slow on.

This graph averages over keys and shows mean chord reaction time for each type of tested chord form.

I should dedicate practice to all of the chords above the 2 second range.

One question I have is whether the performance on this kind of test would meaningfully predict my ability to fluently play through chord changes on lead sheets.

My experience right now is that I can often get through chord changes on a new song without too much trouble, but I’ll get tripped on the altered chords with flats and sharps. More like fall all over the place. I can’t dead reckon those chords. Instead, I’ll sit there and take 5 seconds or more to puzzle out the chord, which ruins the flow. If I’m feeling diligent I might work out a fingering pattern that makes it easy to play in that context. However, I don’t appear to retain any of that chord knowledge in a general way.

I assume that if I was able to play all my chords really well in the context of playing lead sheets then my reaction times in the above graph would be faster and more uniform. I could practice this test over and over, and I’m pretty confident that I would get faster on the slower chords. However, one possibility is that that this learning would be somewhat specific to the peculiar demands of this very non-musical chord production task. So, it’s not clear to me that improvements derived from practicing chording in this task would fully generalize to helping me play lead sheets. At the same time, If I can get all the chords down to under 2 seconds in all the keys, that’s gotta help.

Breakfast time.

I did practice some of the extended chords yesterday. This morning I did a round of practice/testing on the 7b9 chords.

Yesterday, 7b9 were initially excruciatingly slow. I couldn’t play any of them and had to construct them on the fly. As the graph below shows, I took over 12 seconds to produce some of the chords.

Practice felt very slow and I didn’t feel like I was locking in new patterns at a fingering level. For example, I can visualize a C7 chord immediately, and still can’t visualize a C7b9 (even after all this practice).

Nevertheless, the graph shows some substantial gains in chord production time. There were a few stages in learning to play this chord. Stage 1 was having no clue and working out each chord anew. In stage 2, I settled on a method to get to the 7b9: play the 7th chord in root position, go up 1 inversion, but instead of playing the root at the top, play 1 semitone above the root. Stage 2 was pretty slow also. At some point I realized that I already knew all of these chords as o7 chords. For example C7b9 without the root has E-G-Bb-Db, which are all the notes in Eo7, Go7, Bbo7, and Dbo7. In stage 3, I switched to translating the chord name, “C7b9”, and thinking play the o7 on the third (or, in this case Eo7). That helped a little bit in terms of speed, and I think it makes musical sense to build mental associations between the 7b9 and o7 anyway.