Relational responding (also known as a relational response) is when an organism's response due to a stimulus is not due to the situational context but responding as if due to another stimulus. Discrimination occurs because of relational responding in that stimuli are related to each other and conditioning can occur due to associations made by relating the stimuli. In a paper by Ian Stewart and John McElwee an example of relational responding is used. An animal is trained to pick a horizontal line when the color green is used and a vertical line when the color red is used. This produces two unidirectional relational responding: horizontal-green and vertical-red. This association is a result of relating the stimuli and responding based on the relationship.