There was a time, not too long ago, that tasks such as bagging groceries, pumping gas and booking flights was someone else's job.

A new book examines how consumers are now responsible for a growing number of unpaid tasks, and argues that this shift is eliminating jobs, curbing social interactions and eating into our free time.

Craig Lambert, author of "Shadow Work: The Unpaid, Unseen Jobs That Fill Your Day", said the idea for the book first came to him when he spotted a lawyer he knew, who was earning several hundreds of thousands of dollars a year, scanning and bagging her own groceries.

"I thought, that's an entry level, minimum wage job. But she's not even getting minimum wage, she's getting nothing," Lambert told CTV's Canada AM on Thursday.

Lambert said he began to think of the numerous jobs that consumers are doing on behalf of businesses and organizations that are unpaid.

"Things like officiating and coaching youth sports," Lambert said. "Adults have taken over and they're doing thousands and thousands of hours of shadow work organizing, officiating, finding sponsors and coaching."

In the office environment, smartphones have replaced executive assistants and airline agents and front desk staff at hotels have been replaced by kiosks, Lambert added.  

Beyond the loss of jobs, Lambert says there's also a social cost to shadow work.

"It kind of silos people," he said. "Instead of dealing with other humans, we're dealing with technology, we're dealing with screens. And that's one of the foundations of community, those small relationships we have with the cashier the supermarket."