Multiple elements of the retail environment can have an impact on a consumer's behaviour and purchase decisions. Much of the influence that the environment has on behaviour often goes unnoticed, as it affects internal processes that happen below the level of conscious awareness. This research aims to explore and quantify the effect a retail environment has on consumers' affective (emotional) and cognitive responses towards products. Priming is the influence of external stimuli on one's behaviour or response towards target stimuli. This research designed an experiment to prime participants with a particular coloured stimulus (pink, blue, or red) in order to measure the influence of this prime on the participants' purchase decisions. The participants entered a real-world simulated retail shop, and within a guided format they shopped through the available dresses, eventually picking out their three ranked favourites. The participants' physiological responses were measured using an eye-tracker and a portable Electroencephalogram (EEG) recording unit. The eye-tracking data were analysed using the Gaze Cascade Theory, testing for an increase in gaze bias towards preferred and primed products. The EEG data provided information about the participants' brain activity, and were analysed in accordance with Davidson's model of emotion, indicating an approach or withdrawal tendency towards different products. The results showed that with both eye-tracking and EEG it is possible to measure a difference between the participants' cognitive and affective responses towards the products that they preferred and chose as their favourites, compared with the products they did not choose. The EEG data provided evidence of a difference in neural responses between the prime matching coloured products and the non-prime matching products. However, the eye-tracking responses did not demonstrate a significant difference in eye-movements between the primed and not primed products. Technical innovation was required to allow the recording of EEG data in the semi-controlled shop environment, to allow data free of motion artefacts to be analysed. These results demonstrate the ability to measure consumers' physiological, neural, and subconscious responses in a real-world retail environment, whilst allowing the participants to move freely and unhindered. A novel methodology for analysing motion artefact free EEG data is presented. The results demonstrate a significant difference in emotional responses, as detected by EEG, in preference towards the prime coloured products, suggesting that priming has an influence in decision making in fashion retail environments.