Smell research examines the sensory attractiveness of fragrance-based products, such as cleaning supplies, detergents, cosmetics, and perfumes. The sense of smell is quite sensitive, compared to other human senses. Scientific studies indicate that smell can arouse emotional memories much stronger than visual or acoustic stimuli. Smell significantly affects our moods and our purchase and consumption habits. Smell research is a significant sub-category of sensory research, and requires professional and specialist knowledge and approach.