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Why Modern Life Makes Finding Love Feel Like Swimming Upstream

Can this fish explain why you’re still single?

Key points

  • Evolution is a game of use it or lose it, many species lose abilities when they don’t use them for a long time.
  • For centuries, humans have relied on input from friends and family for their mating decisions.
  • This might have caused our mate choice and courting “tools” to become blunt causing a singlehood epidemic in the West.
  • Input from friends and family on mate choice might help those who find it hard to find mates on their own.

Alright, I’m going to level with you, there is no fish that will impart deeply personal and sage advice about your love life. But I do know about one particular species that might serve as a useful analogy for thinking about why some of us struggle to find love. Today on Darwin Does Dating: Can this fish explain why you’re still single?

The blind cavefish

As its nickname suggests, the Mexican Tetra is a species of blind fish. Well, that’s not entirely accurate. Some are blind and others aren’t. The difference? Those who cannot see have lived in caves for many generations. Living a comfortable existence in total darkness, these fish find food and reproduce quite happily using an elaborate system of sensors on their scales that can detect even the smallest changes in the water around them.

These fish don’t need sight as their non-cave dwelling ancestors did. And because they haven’t needed sight for a long time, when cavefish were born with harmful random mutations that affected their eyes, these had very little impact on them. These mutant fish went on to survive and reproduce like any other, passing their eye mutations on to their offspring. Generation after generation, these mutations stacked up. Eyes became less and less useful and shriveled up until they all but disappeared.

There’s a principle here that’s worth remembering: If a species doesn’t use a tool (like eyesight) for generations, then it can become less sharpened, useless, and perhaps disappear entirely.

I am not a cavefish

Don’t say that; you just need to believe in yourself. But seriously, there is an interesting parallel to be drawn between Mexican Tetra and humans.

I argue that we too have tools that were once a highly sharpened set of adaptations designed to help us reproduce and that have become less “sharp” over the decades because we haven’t used them. Specifically, tools for helping us to attract and choose partners.

Most mammals choose mates all on their own. They have really refined sets of tools for searching and locating prospective mates, assessing their quality, and initiating courtship. For some, finding and securing mates is no more a challenge than finding and securing food.

Do humans choose mates all on their own? Well, that depends. In the Western world in 2021, sure. But if you look outside this bubble and consider what other human cultures do and likely have done for generations you find a different story. For a very long time, we have not chosen mates on our own. Our family and community have had a lot of say on who can and should be our mate, something which grew even more intense when we started farming land and hoarding property.

And this “help” might be considered our own cave. A situation where the need for our mate choice tools to be razor-sharp was lessened. Unnoticed by evolution, they could become blunter with little-to-no consequence. Until now.

Out of the darkness and into the light

The change in mating culture in the Western world means that men and women seek mates independently, perhaps hoping for parental approval of the chosen boyfriend or girlfriend after the fact.

This is a level of autonomy unseen by humankind for hundreds of thousands of years, plenty of time for our mate choice and courtship tools to become blunt. We are semi-blind cavefish thrust into the illuminated open waters of the large anonymous mating market.

It is no wonder that we see so much variability in mating success. Some people, no matter how hard they try, can’t seem to find or attract the long-term partner they desire. A singlehood pandemic that seems unique to the West.

Thanks for the analogy, I hate it

If this parallel is useful, then it might give us some potential inspiration for how to make things easier. An obvious one would be to go back into the cave. That doesn’t mean to hand over all of your mate choice autonomy to someone else. But for those of you who have good relationships with your friends and family, it may be worth drawing upon their expertise.

Instead of feeling like you need to meet someone and then bring them home to play “meet the parents,” try getting their input a bit earlier on. When a friend recommends setting you up with someone that they know, consider giving it a try. Your loved ones know a lot about you and might have a better sense of your compatibility with someone than a dating website algorithm. The mating marketplace isn’t somewhere you have to navigate alone.

This post was partially inspired by some of Professor Menelaos Apostolou’s work, which gives good insight into how the involvement of family in mate choice has changed considerably over the years (Apostolou, 2015). If you're interested in the evolutionary psychology behind singlehood then you might also be interested in some of our recent cross-cultural work on the issue (Apostolou et al., 2021).


Apostolou, M. (2015). "Past, present, and why people struggle to establish and maintain intimate relationships." Evolutionary Behavioral Sciences 9(4): 257.

Apostolou, M., Birkás, B., da Silva, C. S. A., Esposito, G., Hsu, R. M. C. S., Jonason, P. K., Thomas, A.G., ... & Wang, Y. (2021). Reasons of Singles for Being Single: Evidence from Brazil, China, Czech Republic, Greece, Hungary, India, Japan and the UK. Cross-Cultural Research, 10693971211021816.

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