Despite the explosive popularity of sweet flavored electronic cigarettes, there is little empirical evidence regarding how "sweet" flavors interact with different levels of nicotine to reduce its perceived bitterness and harshness, and thereby increase its appeal and additive potential. This study will serve to fill this knowledge gap through empirical psychophysical data that will determine the association between sweet flavor and nicotine and its link to the acceptance and rejection of vaped nicotine.

We will recruit current, healthy e-cigarette users between the ages of 18-35.This study will require 1 visit to the Oregon State University campus to partake in a 1 hour (approximate) testing session. During the testing session, participants will be asked to puff commercial e-cigarettes containing 9 commercially available e-liquid preparations.

Inclusion Criteria:

• Healthy adults between 18-35 years of age; have been vaping for at least 1 month; currently use an e-cigarette that contains nicotine; have used an e-cigarette with medium (9-12 mg/mL) or high (18 to 36 mg/mL) nicotine strength at some point in their e-cigarette using history.

Exclusion Criteria:

• Do not have mouth or throat problems that would keep subject from vaping comfortably; do not have health problems that would keep subject from tasting or smelling normally; do not have any food ingredient allergies and have never had an allergic reaction to propylene glycol or vegetable glycerin; do not have any respiratory allergies (i.e., frequent sneezing, nasal congestion, nasal discharge); do not have a history of pulmonary disease or asthma; are not in the process of trying to quit vaping; are not pregnant, breast feeding, or trying to become pregnant.