Manage your game's mental load

A concept I don't see discussed often when it comes to RPGs is that of a "mental load". To put it simply, there is a limit to how many things a human mind can keep track of, and the same is true for RPGs. Once that limit is reached, you tend to either forget things you should be doing, or slow down considerably. Ideally, you want your game to work under that limit, where you can reach the flow state.

Lets break things down into a few categories.

First of all, complicated rules take up a lot of our mental limit. Remembering all the rules for something like Contact would take a lot of effort, so you're most likely be going over it step by step each time you engage in combat. Fewer special cases, exceptions and so on are much less strenuous on the players and GMs alike.

Secondly, more rules means more mental strain, understandably. You can either start off with a system that has a lot of rules for everything, or gradually build up as PCs gain more powers and abilities (which often come with their own little special rules as discussed last time). An example of that from our group would be Exalted, where after a few seasons of Princes of the Universe our character sheets turned into character booklets, with everyone having too many incremental charms to use effectively. This problem was solved when we switched to Godbound where powers were bigger in scope, but smaller in number.

Just one of many of Exalted's charm trees.

Most of those nodes are incremental powers, a small rule to remember...

On a similar note, letting players have limited access to a really large pool of powers can also lead to choice paralysis and increased mental load. A good example of this would be the power Brilliant Invention from Godbound. It's a power that lets you mimic any Lesser Gift from almost any Word. That's over 300 different Gifts you can conjure at a moment's notice - good luck trying to remember the best thing to use for any given situation off the top of your head (then again, 90% of the time you just use Purity of Brilliant Law with this one and call it a day)...

You can use 60% of all Gifts.

Hope you remember them all!

Thirdly, GMs have to juggle more things than players, so it's easier for them to reach their limit. When it comes to NPCs, you ideally want them to be much simpler than PCs. Fellowship handles this pretty well - NPCs only have one to two powers that also serve as their HP. They are much simpler than PCs that take up at least two pages of stats, powers and what have you. It's much easier on the GMs.

Fourthly, context switching can help to compartmentalise the rules and alleviate the mental load. While trying to say, hold 50 different powers in mind at one time can be hard, having 5 distinct and separate game systems each with 10 different powers can be much simpler. You don't need to remember rules for investigation or hacking during a shootout, and bulk trading rules don't apply during space combat. Being able to switch context and only consider a smaller subset of rules and powers can let you handle bigger things. For example, in our Stars Without Number game we use the Suns of Gold expansion that features a big trading system. It's not the easiest thing to use, but since when we are doing the trading there isn't anything else going on, everyone can focus on just this one thing and it flows pretty smoothly.

Fifthly, game aides can help a lot. It's much easier to remember rules when you've trimmed off all the fat and put them on a simple cheatsheet. Having all the rules you need for something on one sheet is ideal - you can context switch to that single page whenever you need to use those rules and follow along to make sure you're not missing anything. For example, while playing Mage the Awakening, having a printout of the Spellcasting Quick Reference pages really made the magic flow, rather than getting bogged down whenever we'd try to engage with the core system of the game.

Page 3 of 4 of MtA's Spellcasting Quick Reference

Sixthly, changing numbers doesn't increase the load. As discussed last time, RPGs usually have powers that come with their own little rules, and stats, which just alter the numbers you roll. Changing the stats doesn't really change your mental load for dealing with them (unless you have to deal with some weird dice mechanics). So if you want to balance your own mental load in a point buy system like Chronicles of Darkness, you can do so by buying powers when things are too simple, and stats when you are reaching your own limits. It can be an interesting way to balance the system without hampering character growth.

So all in all, there are many ways a game can manage the mental load of their players - by keeping its rules simple, avoiding too many small extra rules, keeping things simple for the GM, segmenting systems from one another, providing concise game aides, and letting you buy into more powers or stats to adjust your own load.