According to Schiller (1966) this is due to the fact that reading a colour word triggers the brain to visualise the specific representation of colour. Reading is a highly practiced skill, which therefore makes it hard for the brain to ignore the meaning of the word as it is an automatic process. In contrast, specifying colours is not automatic but rather a controlled process since colour naming is a less practiced skill (Schiller, 1966). As a result, these two information contradict one another and makes it hard for the brain to respond quickly. It was also revealed by Schiller (1966) that people who go through this test displays different signs of tension such as awkward body movement and nervous laughter. Relatively, Klopfer's (1996) research in regards to this area of study declares that the total time of interference change according to varying incongruent stimuli. It was revealed that the more similar the colour-word stimuli is, the more amount of interference it would yield. For instance, the words orange and purple both printed in yellow would generate different reaction times. .
Since yellow and orange is visually more similar than yellow and purple, the interference of the first stimuli is therefore, greater than that of the second. Interference occur in this situation because reading a colour word stimulates a specific representation of colour without effort or awareness. During this type of task, participants were often observed to make errors in verbal response such as 'breen' or 'gred'. .
Schiller's (1966) and Klopfer's (1996) theory in relation to reading being a highly practiced skill was challenged by Brown's (1915) research regarding this field. Brown (1915) assessment suggests that the interference between colour naming and reading does not rely on practice but on the association process of the brain. This was further supported by Hollingworth (1915) who established that a person is only obliged to verbalise the words when reading whereas colour naming requires both verbalisation and association.
