Does Google capture microphone data to better target advertising?

Question

Recently several ads which I had never seen before started popping up. Most were related to products I had been talking about and thinking about buying as Christmas Gifts. Some of the most specific ads which popped up were "Dinosaur Books for Children" and "coffee machines". I never searched for these products online, but had mentioned many times in front of my computer while talking to friends.

Back in April Mark Zuckerberg was addressing Congress in the Senate in the United States, where he answered many questions about privacy and security. One question which kept coming up was whether or not Facebook listens to microphone data to better target advertising. He replied saying that this is not the case. Google was not there to answer on their behalf.

Is Google always listening with the microphone to better target advertising, or is this simply a conspiracy theory?

Is there any proof to support or deny this claim?

This could be the result of excellent Deep Learning algorithms which are capable of connecting many dots behind the scenes to predict results.

I find it highly unlikely that Google would be monitoring 1.17 Billion People who use their search to target advertising, however recent advertisements for products I never searched for but had talked about made me wonder.

Is Google always listening: Live Test

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EDIT:

I came across the video above after I saw the lucky ad targets. I agree that the experiment was flawed, mostly by clicking on the related ad. However, I hadn't seen the other video disproving the hypothesis. I still don't think this is conclusive enough. Were formal tests/security checks done on this issue? Are there official statistics from third parties regarding Google Ads?

To me (as someone with little to no information security expertise) something like this raises big questions, and would have thought that these serious claims would have been addressed before. I can't seem to find much information about this on Google (ironically).

Do you use Google Home or similar smart devices?

No, however I do have an Amazon Alexa which was not on during that time. I also have Whats app and backup to Google Drive.

I'm not necessarily talking about my particular case, which may or may not have been a coincidence, but if this serious claim has been looked into professionally.

Answer 1

Possible, but unlikely.

As others have stated Google (and others) could record your conversations and analyze them, but it would probably be very expensive and the return of investment not high enough. Presumably this is a manifestation of (self)-selection bias.

What does that mean? In a nutshell: If you would have mentioned a wide selection of products in front of your computer would you have seen advertisement for them? Probably not.

The far more likely scenario:

1. you already use some Google services so they have a pretty good idea of who you are and
2. you (like 99% of all people) live in relatively easy to approximate personal circumstances.

Thus follows that showing you ads for the mentioned books or a coffee machine is pretty reasonable. If the Internet as a whole taught humanity one thing it's that we are all very much alike.