We are designing an application for iPads that are stationed in tech support areas. We have implemented a facial recognition capability, so that when you tap a button it begins analysing your face and if after 3 seconds it can not recognise you, the option to login in with your username will appear.

One suggestion was to use a Face ID animation which indicated your face was being analysed, however another suggestion was that the fact the user's face is being scanned should be kept hidden and as a secret since this looks more impressive.

I'd love to gather some opinions on how to approach this.

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    "the fact the user's face is being scanned should be kept hidden and as a secret since this looks more impressive." That wouldn't look "impressive", it would look like "three seconds of lag". Commented Mar 22, 2018 at 14:34
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    @DanielBeck - It's also creepy. Facial recognition will expand to the point where there is no public privacy - unless we enact laws to prevent that. (Good luck on that happening.) Still the user ought to be informed how it is that he's being validated.
    – Mayo
    Commented Mar 22, 2018 at 14:43
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    I keep electrical tape over my mobile device's user-facing cameras. I might consider removing it if I knew the camera was in use (although I'd more likely wait the 3 seconds and be angry there's no option to type my credentials immediately.) Commented Mar 22, 2018 at 17:28
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    If I'm not aware that facial recognition is being attempted, I may not keep my face towards the camera, I'm likely to be multitasking, conversing, using my phone, or generally looking away from your device. Additionally, regular users (as opposed to novice users) may prefer the fastest way to do something rather than the coolest.
    – Pranab
    Commented Mar 22, 2018 at 20:17
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    If your application mistakes me for someone else, how would I recognize this? And if logging out just runs the auto-recognition again, how would I escape the loop? (By putting my hand in front of my face for three seconds?) Commented Mar 22, 2018 at 23:25

9 Answers 9


Based on Nielsen's 10 heuristics of interface design:

Visibility: Show system status, tell what's happening.

Following these guidelines you should show the status of interface and visualize that their face is being recognized. This will most likely avoid anxiety in the users.

Image showing Nielsen's 10 usability heuristics, viewable in text form at https://www.nngroup.com/articles/ten-usability-heuristics/

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    I agree. The fact that it's a relatively new technological process doesn't exclude it from the fundamentals. If anything, the fundamentals are more important when users are less familiar with what the system is doing.
    – Refe
    Commented Mar 22, 2018 at 13:57
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    What does "diagonize" mean? Should it say "diagnose"? Commented Mar 23, 2018 at 10:38
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    Freudian slip @CedricReichenbach :-D Commented Mar 23, 2018 at 12:16
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    Yeah, it's ironic that the error in the image comes from the error recovery section. Commented Mar 23, 2018 at 12:23
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    The answer is simple and this is it. Users should always know what's happening when the potential delay is ≥ 1 sec. Commented Mar 23, 2018 at 20:29

In my opinion, yes, users should be informed that the app uses face recognition for providing access. Whether this should be done each time or only upon installation, it's another issue.

Nevertheless, imagine you did inform the users about the face recognition functionality:

  • face recognition is never 100% safe and can be (easily) forged. If the user knows about this (security) issue, they can chose whether to use it for the ease running the risk of someone unwanted unlocking the app or revert to traditional username/password (I assume your app would allow it). They have a choice, they appreciate it.
  • the user may wear sunglasses or a hat, may have a beard or heavy makeup, will your face recognition algorithm be sufficiently reliable in those circumstances? If the users are aware of the face recognition, they are more willing to accept the inconvenience of sometimes not being recognised.

Imagine you didn't inform the users about the face recognition functionality:

  • someone gets the knowledge of it, forges the users' faces and breaks into their app. You try to explain the security breach by informing about the secret face recognition, the users get upset, to say the least...
  • for the users wearing hats, sunglasses, impressive facial hair, heavy makeup - face recognition is not perfect and sometimes the users are allowed into the app, sometimes they need to give their credentials. You start getting questions "why is that". You try to explain you have been using face recognition secretly, the users get upset they were filmed without permission, think what's next.
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    But 15 years in the future isn't now, which is what the OP wants to know about. (Ducks behind screen to remove beard and heavy makeup).
    – TripeHound
    Commented Mar 22, 2018 at 14:20
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    Another reason for showing some kind of "Facial scan in progress" message is that the user isn't left standing there for several seconds wondering why they are not being prompted to enter their username.
    – TripeHound
    Commented Mar 22, 2018 at 14:22
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    @TripeHound - you're right about the waiting time. Still, whatever the advancement of the facial recognition is at the moment, I don't see the reason to do it secretly.
    – Mike
    Commented Mar 22, 2018 at 14:23
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    @Mike I totally agree it shouldn't be done in secret even if it were instant (for reasons you rightly point out). But as it's not instant, that's yet another reason to show the user what's happening.
    – TripeHound
    Commented Mar 22, 2018 at 14:24
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    @TripeHound - clearly the user needs to be informed that he's being validated by facial recognition. There may be flaws but those flaws are quickly being remedied. (As a privacy advocate I find this more than a little disturbing.)
    – Mayo
    Commented Mar 22, 2018 at 14:45

Without going into any of the security/privacy concerns of this system...

Consider the failure rate of your face scanning. Let's assume it works 90% of the time. If you don't tell the user you've been doing face scanning, they're interacting with an app that, for no discernible reason, asks for a username and password randomly 10% of the times they use it. This is a horribly inconsistent experience.

  • It would be a similar experience to getting randomly logged out of long running sessions on websites. I'm not sure how many people would think it odd that they got prompted only 10% of the time. I would certainly think "I guess my session timed out." before "They're using secret facial recognition technology." Not saying that is the best experience but it's a common scenario.
    – Mike D.
    Commented Mar 23, 2018 at 4:40
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    @MikeD. 10% of the time is extremely frequent compared to (reasonably well engineered) website session time outs. Moreover, it could easily happen several times in a row.
    – Cubic
    Commented Mar 23, 2018 at 16:28
  • The 10% figure was just to illustrate a point, but the main point is that most of the user's interactions will, for reasons hidden from the user, not require a username/password log in, until randomly they do. A smart user would likely assume that it is a session time out, until it happens twice in a row/only when they wear sunglasses/on cloudy days/whatever. Eventually someone would figure it out anyway, humans are pretty good at finding patterns, so you should just inform them of what you're doing. Commented Mar 23, 2018 at 16:49

A delay during which the user has no idea what happens is likely to be seen as the application being slow. Keep in mind that an user unaware of facial recognition feature may simply hold their tablet in a way that prevents it from working successfully (i.e. the camera not capturing their face).

Also, some users may dislike the concept of facial scanning, so hiding it from them may lead them to believe that your application also does secretly other things that they dislike.

Some people have problems with camera being secretly turned on - how many people (who usually don't care about data security) tape their cameras? From what I've seen, a lot of them.


Please don't be a part of the problem we have with tech we cannot trust right now.

For one, as many people pointed out, your main argument for not informing the user about facial scanning i.e. the process being more "impressive", holds up only for the happy path: camera present, user facing the camera, scanning conditions ok, user not moving etc. That's far too many "happy" assumptions. What's the pessimistic path if you don't inform the user about it and it fails?

For the second, and more importantly: if you're not sure about your "should I do something with user sensitive data" questions, I'd say follow this simple rule: user data belongs to the user. It is up to them to decide how and if they want their data used in any way. If you require or collect any sort of data from users they should be informed upfront and have a clear possibility to opt out.

Yours is really a question on the intersection of ethics and UX, and I think that instead of wondering whether your design is a good UX, you should be reflecting whether it's ethical at all.

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    +1, also probably worth pointing out that not only is not informing people (and giving them a choice) about collecting personal data unethical in general, in many jurisdictions this is straight up a felony crime (asker never mentioned where this takes place, then again this is more a legal question than UX).
    – Cubic
    Commented Mar 23, 2018 at 16:30

I'm not sure of actual legal issues.

In my fortune 500 advertising company we just covered the information you can legally gather from clients in meetings throughout every employee in the company.

When you gather sensitive information from a client, the client must be clearly aware of the fact you are gathering it, the reason you are gathering and what it could potentially be used for, how long you will be holding on to that information, and how they contact you if they need to update or request removal of that information. The data center's we have have contract agreements whereby we need to know where every piece of sensitive data is stored (exactly which hard drive etc).

Policy aside, gathering sensitive information from someone without their knowledge could be seen as highly immoral and dangerous to the client even if you can't perceive it. (What if you were hacked per se). That could expose your users to security risks and your application creators up to hefty lawsuits I'd imagine.


Imagine logging into your bank website. If it was showing you the log in form, then suddenly (without explanation or input) logged you in. If that happened to me - I would think that the login form is bugged.

Likewise, if I was accessing a website I never used to have to log into and was presented with a login form, I would be just as confused, and think it was bugged (not to mention I'd probably have no clue what my credentials actually are).

You need to keep the user in the loop. Doing things that the user doesn't expect does not make people think your software is "more impressive". It makes it look buggy and inconsistent.


Instead of automatically scanning the users' faces without their approval, you should wait for them to indicate that they want to authenticate in that way.

If they don't wish to, they should have the option of entering their user name and password the old-fashioned way. But if they've specifically opted in to the face scan, then there's no surprise for them.

An example is shown below:

Login screen could look like this


Either is acceptable. However, the decision will be dictated by, and have the ripple effects causes by, you or your companies position on disclosure in regards to privacy concerns. There is no US Federal law, case precedent or even industry standard protocol with majority backing by private sector, public sector and privacy advocates, as of yet.

  • "There is no US Federal law" is hardly a UX-relevant answer. Also hardly rest-of-the-world relevant answer (and it seems like the OP is not in the US).
    – Frax
    Commented Mar 24, 2018 at 10:51

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