Second, acetylcholine may in part underlie animals’ ability to select and/or update their choice behavior; cholinergic agonism would thus render animals behaviorally inflexible, whereas antagonism would lead to behavioral indifference. This is supported both by previous results and the current data: nicotine arguably exacerbated animals’ existing choice preferences and decreased sampling of animals’ less preferred option, whereas scopolamine drove all animals toward equivalent choice of LR versus HR and more greatly affected workers, whose preference was further from indifference. Third, acetylcholine may influence decision making via attentional processes, such as increasing the salience of the task’s objective and subjective properties. Such an interpretation could equally explain nicotine’s exacerbation of existing preferences on the rCET, when salience is increased, and scopolamine’s drive to indifference, when salience is decreased. Fourth, as cortical ACh efflux is known to track the amount of attentional effort exerted rather than attentional performance per se, nicotine may have artificially inflated the sense of total effort expended in a rCET session, independent of its actual effects on attentional performance. This theory would suggest that animals more sensitive to the attentional effort exertion would be more strongly affected by the drug, and indeed this is supported by the current data. Conversely, thereby leading to the observed decrease in effortful choice predominantly in this harder-working group. Further disentangling these putative contributions of acetylcholine to decision making, for example by elucidating cortical versus striatal cholinergic influence on choice at baseline and in response to drug challenge, will be a focus of future research utilizing the rCET. In sum, it appears that both nicotinic and muscarinic cholinergic systems contribute to cost/benefit decision making, and in part their contributions can be understood as a function of individual differences. While nicotine has been considered as a cognitive enhancer by both smokers and researchers, these data suggest that its modest benefits to attention may be coupled with impulsiveness and decreased willingness to work hard, especially in individuals who are particularly sensitive to effort costs. Nicotine may therefore produce a subjective feeling of increased output or task BKM120 abmole bioscience engagement, while actually producing a decrease in application. Novel therapeutic interventions may therefore be best understood by simultaneously studying multiple cognitive constructs such as decision making, attention, and impulsivity. Interleukin-35 is a member of the IL-12 cytokine family. It is produced in human cancer tissues such as in melanoma, B cell lymphoma, lung cancer, colon cancer, esophageal carcinoma, hepatocellular carcinoma, cervical carcinoma, and colorectal cancer.