Bales said the major factors that have lead to modern slavery are a population explosion in developing countries, globalization and corrupt governments.

"This had led to a glut in impoverished, desperate people," he said. "Slaves are now much cheaper than they once were."

In the 1850s, the average slave was sold for about $1,000, Bales said. Today, he said, one slave can be sold for as little as $40.

"Imagine if you could buy a brand new car for $40," he said. "If you had a flat tire, you would just walk away. Sadly, that's what happens to human beings when the price gets so low -- they're a disposable item. "

Bales told students many things they could do to take action. One thing he said students could do is buy his book, Disposable People: New Slavery in the Global Economy, since all of the money goes toward anti-slavery organizations.

"If you buy the book and don't even read it, you have done something good," he said.

However, he added that slavery is a complex problem and calls for people to make sure they understand the problem in order to find creative solutions.

"We are living in the first moments of the [new] anti-slavery movement," Bales said. "You could be the generation that ends the problem."

Sociology lecturer Sam Richards, who uses Bales' book in SOC 119 (Race and Ethnic Relations), said slavery is an issue that affects everyone.

"The issue of slavery is something everyone can tap into because everyone disagrees with it," he said. "Even with the recent stuff going on with racism and homophobia -- everybody on either side of the issue still disagrees with slavery."

The speech was sponsored by Asha for Education, a student service group that works to provide education to underprivileged children in India.

Mona Vakil, co-coordinator for Asha for Education, said she hopes Bales makes people more aware of the problem.

"A lot of people think slavery has died out, but it's actually a really important issue that needs to be dealt with," she said.