Another of the newest latest elements to the game are personalities...when you catch a Pokémon they all have a random personality, and most of them have a slight effect on your stats...when it makes the stats go up, it's by a small factor of between 1 and 1.15, so it is barely noticiable, and if it goes down it would be between 0.85 and 1, hardly noticiable so it stays within the set Pokémon's Perameters. You can find out the personality by looking at the bottom box on the 1st page of the Status Screen. Anyway, here's a table naming them and showing what the raise and lower:

Natures Name Raises Lowers
Hardy None None
Lonely Attack Defense
Brave Attack Speed
Adamant Attack Special Attack
Naughty Attack Special Defense
Bold Defense Attack
Docile None None
Relaxed Defense Speed
Impish Defense Special Attack
Lax Defense Special Defense
Timid Speed Attack
Hasty Speed Defense
Jolly Speed Special Attack
Naďve Speed Special Defense
Modest Special Attack Attack
Mild Special Attack Defense
Quiet Special Attack Speed
Bashful None None
Rash Special Attack Special Defense
Calm Special Defense Attack
Gentle Special Defense Defense
Sassy Special Defense Speed
Careful Special Defense Special Attack
Quirky None None

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