What do companies benefit from investing in market research surveys?

Surveys benefit people like you and me because we get rewarded for completing them. We can have muliple accounts with the same survey site and lie through our teeth as much as we want. We can randomly click away without even knowing or caring which company we're defrauding.

What do companies get in return for their market research investment?

The costs of rolling out a new (or a new-and-improved [supposedly!]) product can be astronomical. Make one mistake, and your investment in the new product is wiped out. So it's far, far better to make a smaller investment to test-market a product first, before doing a huge regional or national product roll-out and potentially having it bomb.

As to your question about falsifying answers: It's difficult for someone who's clicking away, just posting bullsh*t, to also write CONSISTENT bullsh*t. (I mean, if you're going to be consistent, then why not just write what you really think--makes sense, no? Why try to be some big joke-meister, just 'cause you think it's "kewl"?) Computers pick up on "wack" answers, and those surveys get tossed out.

BTW, it's worthwhile to answer the question sincerely. When you do so, you often get to actually TEST OUT the product, in addition to getting paid whatever fee they're paying you to just fill out the survey. I've gotten free laundry detergent, steaks...lots of stuff, just for being a RELIABLE survey answerer.

i think a bad headache.

It tells them if there is interest in their product. One area of the country or a particular age group might be more likely to buy it than another.

They get information on their products and services even if a certain percentage lies through their teeth on a particular survey. There is a mathematical calculation that they will use to discount all bad information.

They can see how to screw Americans out of money. That is the point of Market Research, to trap people into buying their product, one way or another. they get richer every time they have a research, and we get a crappy product.

so they can check how their product is received by the market and then look to make any changes to operations as necessary

The main reason for a business to invest in a market researcher is to get an overview of the market and to see how well their product/service is doing and if the product/service needs to be improved or altered.