How does invisible reCaptcha widget works?

I'm trying to implement the Invisible reCaptcha widget on my forms. But, I'm not seeing much information about its use. And, I have these three questions:

1. How does the widget work if it doesn't require the user to interact with it?

2. Is the widget still actively working, even with its Properties set to "Hide Field"? And,

3. How do we test the widget if its invisible?

- Thanks for your reply 

Below are my response to your questions.

1. It uses the same analysis engine as reCaptcha widget. The only difference is that it is hidden and will only be triggered once it detects a bot (automated program accessing the form).

2. Yes, user won't have to interact unless the widget detects that the one accessing the form is not a human.

3. Again, it's similar to reCaptcha widget by Google. You can review more of this from here https://www.google.com/recaptcha/intro/index.html.

Let us know if you have any questions.

Not sure you understood my Question #2, Jed. The Invisible reCaptcha widget appears "invisible" even though its "Hide Field" property setting is set to "Off". However, in the past, widgets have taken up invisible space on my forms until I set their Hide Field to "On".

I don't want this widget to take up visible space on my form. And since we can't test it, I'm asking if this widget will work, even with its Hide Field setting set to "On", since "Off" appears to be the default setting? (I've been told that setting the Hide Field feature of a widget to Off or On has no affect on a widget's performance; only its visibility. Is this correct?)

Also, the link you sent talks about reCaptcha. I found a link from there which discusses the implementation of Invisible reCaptcha which I'm trying to use. However, it doesn't explain how their widget determines that its a bot interacting with it, instead of a human being, without a human Captcha response? If I read the reCaptcha documentation correctly, some humans will occasionally be queried for a traditional Captcha response, if their reCaptcha algorithms can't be sure whether or not its a bot. Is that the same with the Invisible reCaptcha widget?

Trying to be clear,
- Thanks

Not sure you understood my Question #2, Jed. The Invisible reCaptcha widget appears "invisible" even though its "Hide Field" property setting is set to "Off". However, in the past, widgets have taken up invisible space on my forms until I set their Hide Field to "On".

The widget will not be shown no matter if the "Hide field" property is set to yes or no, the block where the widget should be will not be shown either, example: 

I don't want this widget to take up visible space on my form. And since we can't test it, I'm asking if this widget will work, even with its Hide Field setting set to "On", since "Off" appears to be the default setting? (I've been told that setting the Hide Field feature of a widget to Off or On has no affect on a widget's performance; only its visibility. Is this correct?)

As explained above, the widget does not uses space on the form, it's hidden with a default "display:none;" CSS code that basically avoids to use the space even when the element is hidden. 

I don't want this widget to take up visible space on my form. And since we can't test it, I'm asking if this widget will work, even with its Hide Field setting set to "On", since "Off" appears to be the default setting? (I've been told that setting the Hide Field feature of a widget to Off or On has no affect on a widget's performance; only its visibility. Is this correct?)

I have been searching information about how it works, but there is not much information about it, due to security reasons I guess, I think the widget may be based on facts such as how many times you have submitted the form, the location where you're accessing to (if you're from a location with a lot of spammers), here are some links that I think may help you: 

https://developers.google.com/recaptcha/docs/invisible

https://www.google.com/recaptcha/intro/invisible.html

https://arstechnica.com/gadgets/2017/03/googles-recaptcha-announces-invisible-background-captchas/

I hope this helps.