Humans tend to be right-hand or left-hand dominant and generally display greater dexterity and more refined fine motor skills with their dominant hand. Where possible, humans also tend to prefer to use their dominant hand.
Simon and Rudell (1967) showed that the location of stimuli directly influences response-selection due to a natural tendency to react towards the source of the stimulation. Their conclusion was that stimulus location produces interference in a response-selection process. Therefore where stimulus location and response-selection are congruent, rather than incongruent, accuracy is greater and reaction times are faster.
This is known as the Simon effect.