Traits modify aspects of gameplay, granting a benefit in one area at the cost of hampering another. With the exception of Wild Wasteland, which has a less direct effect on gameplay, each trait modifies (and hampers) the Courier's statistics in some way; this can include Primary statistics, Derived statistics, or SPECIAL points and skills. During character creation the Courier may choose a maximum of two (with a minimum of none at all). The add-onOld World Blues makes it possible for them to re-pick the Courier's assigned traits.
Though Fast Shot and Trigger Discipline will at first appear to cancel each other out, the way the system calculates the statistics (as a multiplier effect with the base compounded as it is affected) means that both accuracy and fire speed decrease by 4% should both be selected (0.8*1.2=.96).
The Four Eyes trait is somewhat misleading in its description. The benefit it conveys is a status effect, similar to the bonus that would be granted by wearing a hat. The drawback, however, is directly subtracted from your base Perception, meaning a character with a Perception of 2 would have that value permanently reduced to 1 upon taking the trait. This can prevent the player from taking perks such as Sniper or Better Criticals, since Perks only take base stats into account when checking if the player meets the requirements. Having a Perception of one will not allow you to pick this trait.
Picking the Wild Wasteland trait allows you to obtain the alien blaster, but it comes at the cost of being unable to obtain the unique Gauss rifleYCS/186. The alien blaster is more powerful, but has limited ammunition, making the YCS/186 a better long-term weapon. This and the difference between finding the Holy Frag Grenades versus two mini nukes in Camp Searchlight is the only real difference that taking the trait makes.
Se o jogador selecionar logo de início o trait Skilled e depois decidir reconstruir o personagem antes de se aventurar Mojave adentro, selecionar Skilled novamente pode fazer com que seus efeitos "empilhem-se". Fazendo com que seja adquirido +10 pontos em cada habilidade, porém deve se destacar que as penalidades causadas pelo trait na experiência não se acumula.(Confirmado em todas as plataformas)
Como encontrado nos arquivos do jogo, um histórico médico era para ser preenchido pelo jogador; então se é possível sugerir que o menu seria em uma espécie textura do papel real, em vez de um menu convencional. O papel apresenta mais escolhas de traits do que os disponíveis na versão final do jogo. O histórico também não apresenta nada sobre o trait Wild Wasteland em si.