 In contrast, researchers, including Terry Bristol, have found teenagers to be generally unaffected by these advertisements due to the idea that repeat exposure can create an immunity to images and messages in advertisements.Moreover, some researchers, such as Paul Humphreys, have concluded that exposure to such advertisements can actually create higher self-esteem in teenagers.According to Medimark Research Inc., a marketing research company, teenagers are important to marketers because they "have significant discretionary income; spend family money, as well as influence their parents' spending on both large and small household purchases; establish and affect fashion, lifestyle, and overall trends; and provide a 'window' into our society – a view of how it is now and what it is likely to become."