Marmosets are the only primates

Answer choices

1. A

   No Impact1% picked this

   A study conducted on adult marmosets revealed that many

   This is a real Nothingburger. We already knew that most marmosets were left handed, which allows space for many adults to be right-handed. This doesn't do anything to increase our belief that imitation is causing the handedness.

   1%
2. B

   Weakens2% picked this

   Right-handed marmosets virtually all have at least one sibling who

   Assuming these siblings grew up around the same parents, this would hurt the author's story. If the kids learn by imitating their parents, then kids from the same parents should have the same handedness.

   2%
3. C

   No Impact2% picked this

   According to the study, 33 percent of marmosets are ambidextrous, showing equal facility using either their left hand

   Neat. But we're interested in the marmosets who do have handedness, and trying to assess the causal story of how they got there. These ones that don't have handedness aren't illuminating that conversation at all.

   2%
4. D

   Too Weak7% picked this

   Ninety percent of humans are right-handed, but those who are left-handed are likely to have at

   This almost draws a parallel between the humans and marmosets, the only primates with handedness. If it said, "Humans also imitate a lot as parents, and even adopted children usually end up with the handedness of their parents", it would be compelling. The idea that left-handed kids are likely to have at least one left-handed parent is very muddy data that could just as easily mean that left-handedness is passed genetically, not through imitation.

   7%
5. E

   Correct88% picked this

   Marmosets raised in captivity with right-handed adult marmosets to whom they are not related are more likely to

   Why this is right

   This goes against the alternate explanation of handedness being genetically based. Kids end up matching the handedness of their adopted (unrelated) parents. It also plays off the fact that right-handedness in marmosets is rare, so it's not like the default trait we'd expect whether you live with your related parents or unrelated people. Raised in captivity means that they were there when they were young and still in their imitative phase. It sounds like they imitated their right-handed cellmates and became (atypically) right-handed as a result.

   Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

   88%