In the newer games such as ruby sapphire and everything since then, pokemon have natures. These increase the rate at which one stat grows and decrease the rate of another stat's growth. They also affect what type of pokeblock that pokemon likes. A bold pokemon, for example, would have an increase in attack, a decrease in defense, would like sour pokeblocks, and would dislike spicy pokeblocks. Note: Bashful, Docile, Hardy, Quirky, and Serious natures seem to have no effect on the pokemon. Also Note: Each Stat is increased by 4 natures and decreased by 4. Same with each
type of pokeblock.