"What's the Difference between a Terrorist and Two Year Old ?"
"You can negotiate with a Terrorist"
Although a joke a typical child does not START to develop the ability to reason until at least 3 1/2 years old and not start to make decisions based on conscious thought until they are around seven.
Until then they have two modes - Do or Do Not. There are no other thoughts in terms of decisions.
A lot of athletes are at the other end of the scale - they are constantly having 'discussions' with themselves trying to rationalise whether to keep going or not. Coming up with justifications, worrying about what-if, thinking about how, calculating times etc etc. I often see statements in race reports starting with "I thought...". I thought I was going too hard, I thought I was going to cramp.
Champions run like a two year old.
Understand (based on training/testing) what you can do, what pace you can hold, when you need to fuel etc. Even take this 'thought' away by setting zones, alters, autolap etc on your device
Then, to quote Nike, Just Do It.
If you find yourself negotiating with yourself then be conscious of this type of thought. This takes practise - to identify when your 'inner voice' is trying to rationalise/justify an outcome. But when you identify this put those thoughts to the side and be in the moment. There is a reason why, for most people, the last kilometre of an event (even a marathon) is their fastest - they stop negotiating and 'just run'.
When training, try doing some longer runs without an MP3 player. Music can often drown out the inner voice which detracts from developing the skill of identifying and 'dealing' with it. Plus all triathlons and a lot of running events ban MP3 players anyway. The skills of identifying the inner voice and knowing how compartmentalise or respond to it is key in longer events.
So next time you are running practise Childlike Running - catch those thoughts and throw them away and just 'Do' like the 2 year old in the video below.