Consumer market research company The NPD Group says Tween girls (ages 8-12) are increasing their usage of a number of beauty products. Their findings come in NPD’s latest report, “Insight into the Youth Beauty Market.”

The company notes that this finding comes at a time when teens (13-17) and young women (18-24) are reporting a drop in usage of beauty products. Regular usage of mascara among tween girls rose from 10 percent in 2007 to 18 percent in 2009 and eye liner use increased from 9 percent to 15 percent.

Overall, the report found, on average, tweens regularly use 4.5 different beauty products, an amount consistent with levels reported in 2007 (4.3).

The NPD Group defines “regular usage” as using at least once a month. The evolution in tween girls appears to have less to do with diminished self-esteem and a larger societal issue and more to do with mom and family, according to The NPD Group. The girls say that they “look to their parents and siblings to see what they are using to help decide what to buy and use.”

Meanwhile, the report also found that among teens (ages 13 to 17 years), skin care basics, like facial cleansers and acne-spot treatment products, and makeup products, like mascara and lip gloss, dropped significantly in reported regular usage versus 2007 levels. Among young women (ages 18 to 24 years), the pattern was similar. Foundation was the only product in the top 10 (ranked on overall reported usage) that showed no significant change in reported regular usage for this age segment.

“As tween girls using beauty has now become a family affair, it is our opportunity and responsibility to ensure that these girls, and their parents, are educated on the role of beauty in the most responsible way,” says Karen Grant, VP and global industry analyst for The NPD Group.