A research study has suggested that changes in hours worked over time are due, in part, to change in tax rates. "If taxes and [government expenditures] are high, that may lead to less work," said one of the researchers. Supporting this theory, since 2001, workers in the United States have increased their hours worked while tax rates have dropped. What theory or theories of motivation might support such a change? How have Indian workers reacted to changes in tax rates?