Possibly, if we heed a recent group of studies from the University of Waterloo in Canada, involving 660 participants: “Reliance on smartphones linked to lazy thinking”:

The study, from researchers at the University of Waterloo and published in the journal Computers in Human Behavior, suggests that smartphone users who are intuitive thinkers -- more prone to relying on gut feelings and instincts when making decisions -- frequently use their device's search engine rather than their own brainpower. Smartphones allow them to be even lazier than they would otherwise be.

"They may look up information that they actually know or could easily learn, but are unwilling to make the effort to actually think about it," said Gordon Pennycook, co-lead author of the study, and a PhD candidate in the Department of Psychology at Waterloo. – Nathaniel Barr, Gordon Pennycook, Jennifer A. Stolz, Jonathan A. Fugelsang. The brain in your pocket: Evidence that Smartphones are used to supplant thinking. Computers in Human Behavior, 2015; 48: 473 DOI: 10.1016/j.chb.2015.02.029

Social media and entertainment applications did not correlate with lower cognitive abilities. But the specific habits described above did. Of course, no one knows whether not-so-smart smartphone use decreases intelligence, as opposed to simply identifying a less intelligent user. The usual chicken-and-egg problem, of course. With social media use growing rapidly (71% of adults online use Facebook), it is worth keeping an eye on this.
Hat tip: First Things, which mentions that their new senior editor Mark Bauerlein is the author of The Dumbest Generation: How the Digital Age Stupefies Young Americans and Jeopardizes Our Future; Or, Don’t Trust Anyone Under 30, (2008)
In the vid below, he addresses a reasonable objection which has doubtless occurred to our alert readers: Haven’t all new technologies induced dire predictions of doom, many of which were justified in some part but not all? Look what the printed word did to our ability to just memorize and recite epics and books of Scripture! Solzhenitsyn, for example, notes somewhere in Gulag that his memory greatly improved in the camps because there was nothing to read. But that didn’t make books a tool of ignorance
Wait, says Bauerlein, the smartphone introduces a quite separate problem: Teens are spending almost all of their communication time socializing with their friends—other teens.
Didn’t they always? Well, not quite. The way older media work, one must often interact with others of quite different ages and life experiences. Bauerlein’s concern is that increasing numbers of young people don’t know anything because their peers can’t teach them anything..
Reading led to an increase in general knowledge, but a technology that encourages self-segregation among the underinformed might reverse that trend

Denyse O’Leary is a Canadian journalist, author, and blogger.