It's possibly the same reason people wear clothing with a large brand-name printed across the back/front. People often associate brands with their "tribe", and liking posts could be another way to signal that they are part of the in-group.

Disclaimer: I possibly don't know what I am talking about as I don't really know Instagram mechanics at all, but I am guessing they are similar to Facebook's.

Does Instagram broadcast a notification to your friends / followers when you like something? I don't use it, but I think it'd need something like that for a signaling theory to make sense.

There is no broadcast, but when you are scrolling your feed you will see a selection of friends who have liked each post.

Also if you view the activity feed (in a different corner of the app) you can see what your friends have been up to. This is where you will see more explicitly "Sally, Sue, John and Dave liked a post by Mr. Famous" (and similar activity).

> There is no broadcast,

Wrong.

In your notifications screen (who liked your stuff), you can change pane and instead see what your friends has liked.

Most people don’t know it, but yes, it means you can “spy” on your spouse or vica-verce.

It’s the sort of creepy most people wanted to avoid when they left Facebook, and unknown to them, Instagram still has it.

The "likes/comment" notification is still chronological. And if you follow around more than 300 accounts, then it's quite difficult to spy. But if you follow only selected few people(say <50), then yes, it is much easier to spy.

I’m getting downvoted and I’m not sure why. In case anyone misunderstood my comment, I didn’t encourage people to spy.

My comment was merely meant as a correction to an incorrect claim and making people aware that they can be spied upon, also on Instagram.

Maybe they think they're training their Instragram feed to show more content like that?

Also maybe it let's your keep a record of things you liked to go back to. Could be fun seeing your meme progression over a decade (Reddit).

Giving personal support to a company via a click may be the quintessential example of the west's cultural collapse.

I like things so I will see more like it. This works because of my follows liking similar things and thus those appearing in my feed, and I’m part of the network effect doing that for my followers.

This doesn’t apply to “sponsored” posts, which show up in my feed regardless of what I like (and are almost always about plane tickets or cell phone plans). They are so uncharacteristic as to be easy to spot, and if they were engaging, the brand wouldn’t have paid to distribute them.

Instagram is an interesting place. I don't feel this way, but my wife has told me that her activity feed is as important as her own post feed. So for her, liking posts of items or people that she likes are very important.