Loss aversion, labor supply, and income taxation

We assume taxpayers are loss averse in reference to other taxpayers' consumption. Loss aversion implies that labor supply responses to taxation depend on the taxpayer's position in income distribution. Consistent with empirical evidence, we find the steeper the ascend on the curve of income distribution, the smaller the labor supply elasticity. In the standard problem of optimal income taxation, the role of income distribution is to aggregate the labor supply effects of taxation. We show that loss aversion can offset the aggregation role of income distribution resulting in a greater role for social concerns.