Having A Sister Might Make You Less Competitive


Your siblings shape your development in all sorts of ways. You play with them, fight with them, learn from them, and probably ask them inane questions your parents are too tired to answer. They’re often the peers you spend the most time with growing up, and being the oldest or the youngest certainly plays a role in finding your place in the family dynamic. Your birth order and your sibling’s gender might also influence your personality. 

For men, having an older sister can decrease the likelihood of being a competitive person, according to a recent study in the journal Personality and Individual Differences by Okayama University economist Hiroko Okudaira. Compared to men who were only children, men who had older sisters (but no older brothers) weren’t as interested in competing for prizes and money in a series of tasks across two studies of Japanese students.

In the first study, 135 Japanese high school students solved mazes in exchange for points that could be traded for prizes. Before the task, they had to select whether they would rather get points according to the number of mazes they solved, or be entered into a tournament against other participants, in which you had to solve more mazes than the rest of the group to get points (a competitive environment). Only 38 percent of men who had an older sister entered the tournament, showing a lower preference for competition than men with no older sisters.

In a follow-up study, 232 university students solved math problems for cash, with the same tournament setup. Only 24 percent of men who had older sisters entered the tournament, compared to 48 percent of the rest of the men. 

The second study is limited by the fact that it studied only university students at Osaka University, a very selective college, thus increasing the likelihood that the participants would already have a preference for competition. However, psychologists have long speculated that having siblings of the opposite sex can affect the gender-stereotypical traits you exhibit, and this provides further evidence for that claim. 

Why would having a sister influence your personality? Having an older sibling of the opposite sex has been shown to decrease the stereotypical gender roles you inhabit. Competitiveness is a stereotypically male trait, influenced by testosterone, so having an older sister may mediate that characteristic in boys. However, women with older brothers were not significantly more competitive in either of the tests. Here, birth order may also play a role, as later-born kids are generally less dominant than their first-born siblings.

Sorry guys, but it seems like your bossy older sis will still be controlling you long after you outgrow childhood spats.

[h/t: BPS Research Digest]

Honey Bees Can Understand the Concept of Zero

The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.

A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.

The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.

Left: A photo of a bee choosing between images with black dots on them. Right: an illustration of a bee choosing the image with fewer dots
© Scarlett Howard & Aurore Avarguès-Weber

The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.

Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.

It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.

Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.

[h/t Vox]

Can You Solve This Ice Cream Cone Riddle?

How much is an ice cream cone worth? In this visual riddle by Budapest-based artist Gergely Dudás (who posts comics on, the answer requires a little math.

The riddle asks you to determine how much an ice cream cone, a scoop of white-colored ice cream (let’s call it vanilla), and a scoop of pink-colored ice cream (let’s call it strawberry) are worth, according to the logic of the puzzle.

Stare at the equations for a while, then scroll down for the answer.

A math riddle that asks you to figure out what numbers each ice cream cone or scoop represents
Gergely Dudás


Are you sure?

OK, let's walk through this.

Three ice cream cones multiplied together are equal to the number 27. Since 3 multiplied by 3 multiplied by 3 equals 27, each cone must be equal to 3.

Moving on to the next row, two ice cream cones each topped with a scoop of vanilla ice cream added together equal 10. So since each cone equals 3, the vanilla scoops must each equal 2. (In other words, 3 plus 3 plus 2 plus 2 equals 10.)

Now, a double scoop of vanilla on a cone plus a single scoop of strawberry on a cone equals 11. So if a double-scoop of vanilla equals 4 (2 plus 2) and each cone is equal to 3, the strawberry scoop must equal 1. (Because 4 plus 6 equals 10, plus 1 for the strawberry scoop equals 11.)

And finally, one vanilla scoop on a cone, plus one empty cone, plus a double-scoop of strawberry and a single scoop of vanilla on a cone, all together equals 15. One scoop of vanilla on a cone is equal to 5 (2 plus 3), and an empty cone is equal to 3. Two strawberry scoops plus one vanilla scoop plus one cone can be calculated as 1 plus 1 plus 2 plus 3 (which comes out to 7). So together, one vanilla scoop (5) plus one cone (3) plus a triple scoop with two strawberries and one vanilla on a cone (7) equals 15.

And there you have it.

A cartoon-style legend that shows that one cone equals 3, one white scoop equals 2, and one pink scoop equals 1.
Gergely Dudás

If frozen dairy-themed challenges are your thing, he also has a hidden image puzzle that challenges you to find the lollipop in a field of ice cream cones. Check out more of his work on his website and Facebook.


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