Should I ban electronic devices (smartphones, tablets and laptops) from a course? TL;DR

In the coming semester,
I will be teaching a "seminar" type course with around 30 students.
I would like to disallow students in the course
to use any electronic devices (smartphones, tablets and laptops)?

Questions:


Is banning electronic devices in my course a good idea?
How do I enforce such a rule?


Background

In the coming semester, I will be teaching a "seminar" type course.
The course is fairly small, with fewer than 30 students.
We will spend most of the time in the course
listening to students presenting their ideas,
and the students critiquing and giving feedback
on other students' presentations.

I have had a few years of experience teaching
large lecture courses with more than 100 students per lecture.
In these courses, many of the students prefer
to type their notes on my Powerpoint slides,
rather than writing on a physical copy of the lecture notes.
Unfortunately, as I walk around the classroom,
I invariably notice that a significant proportion of the students
are distracted during the class by their electronic devices,
e.g., checking their Facebook, Instagram or playing games.
(I would estimate about 20% of students
are distracted at any given point of time.)

I have noticed that I work better without electronic devices
because I am less distracted and can focus better.
Consequently, I would hope to minimize the distractions faced by students
by disallowing students in the course to use any electronic devices.

Why do I want to ban electronic devices from the course?

The main goal of the course is to teach students
how to analyze and present business case studies.
The course is not one that is heavy on facts or memorization.
Instead, students need to use their powers of observation
to follow along presentations by their fellow students,
and to evaluate their presentation style, body language and slide design.

Consequently, for this type of course,
I do not see that electronic devices add any value.
In fact, there are many research studies which suggest that
electronic devices negatively affect students' learning.
For example, an article in Psychology Today writes the following:


  Cognitive capacity and overall brain power are significantly reduced when your smartphone is within glancing distance—even if it’s turned off and face down—according to a recent study. This new report from the University of Texas at Austin, “Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity” was published in the Journal of the Association for Consumer Research.
  
  During this study, the UT Austin researchers found that someone’s ability to hold and process data significantly improved if his or her smartphone was in another room while taking a test to gauge attentional control and cognitive processes. Participants who kept their phones in a pocket or bag also outperformed those who kept their phones on the desk while taking the same test. Again, even if the phone was turned off and face down on the desk, the mere sight of one's own smartphone seemed to induce “brain drain” by depleting finite cognitive resources.
(I'm a student)

Why do you want to ban the laptops?
Just because some students get distracted? If this is the only reason, that is almost a question of philosophy: Should you force the students into a situation that you think is best for them or should you assume them to be mature enough to decide what's best for them?
If your students were around the age of 12 years old, I'd agree that you should ban the laptops. But I'm assuming that your students have to be somewhat self-disciplied anyways to study for the courses in their 'free-time'.

I like writing my notes on the laptop. If you or the content of your course requires the students to take notes, please allow electronic devices. If the course is entirely focused on participation and taking notes would actually be useless, it might actually make sense to forbid using the devices because then the students would probably participate more.

In a class with only ~30 students, the following does not apply, but regarding your observation that some students are playing games during your lectures:
You will never be able to give the lecture in a tempo that fits every of the 100+ students perfectly. Some may be constantly bored and it suffices for them to listen with one ear while they are gaming or working on something else. Some are perfectly happy with your speed but get bored once somebody who was a bit slower asks a question.
In my experience, when I try to listen to a (to me) boring lecture, my thoughts just drift after a few minutes and I have not much to take away from the lecture. If I instead find a balance so that I can listen to you while it's interesting and keep myself awake and active by doing something else while it's not, I get more out of it.


  Is banning electronic devices in my course a good idea?


In general a big no from me, because students don't like to be told how they should behave. Why would you need to enforce something like that when they are here because they want to learn. However, I encourage you to mention your observations to them and that you think the electronic devices might be detrimental to their learning, so they can make an educated choice.

In your case however, with only 30 students where you expect them to actively participate instead of just listen and understand, it can make sense.
But if only one student is presenting and the rest are supposed to sit and listen (opposed to interactively asking questions and discussing) then I feel like it's a similar situation to my usual lectures.


  I have noticed that I work better without electronic devices because I am less distracted and can focus better. 


True. On the other hand, I can learn better with electronic devices because it is easy to look something up that I didn't understand without having to interrupt the lecture to ask a question. It's also imo better for note-taking because you can paste parts of the slides and freely rearrange them. 


  How do I enforce such a rule?


First of all, please provide a good reason to the students along with the statement that it is forbidden. Otherwise you will get a few of them on the wrong side and they will still try to use the devices. Without cooperation, enforcing this would be very hard I imagine.

Secondly, give them a good reason not to get distracted. If they are required to be present anyways, it might be an idea to give out grades for participation. Or ensure that the content of the lecture is really interesting.

Think also about when you want to make exceptions. What if somebody has special needs, e.g. does not see the screen from afar? What if some student has an important deadline incoming and wants to work on that during your class, but still came to not miss completely everything? Etc.

Alternative Solution:


  Some of the best instructors I had knew at which point of their lecture they should ask questions and took the time to learn students names. Then you can first ask the questions to people goofing off, and follow up with someone paying attention.  


This is a quote of DBB's answer, and it reminded me of a tutor we had who everybody considered to be really great. The thing that set him apart is that he noticed when somebody was getting bored, distracted or lost, and asked that person a question. It might be a really simple one just to get their focus back, or it might be one that tests whether they are bored because they already know the content or rather because they're getting tired. Often, when one student would not know the answer, a different student would know the answer (and could explain it to everybody who lost track) or nobody else knew it either and the tutor knew what he had to explain again.
Such questions make people who are zoning out focus again, even if they are not the ones who were asked. And if it is fine to say "I don't know", nobody is afraid of being asked either, so they can answer honestly and give the tutor information about what they got and what not.