Humboldt’s squirrel monkey gets tricked into the “French drop” trick. Credit: E. Garcia-Pelegrin et al., 2023
The key to a successful sleight of hand magic trick is how well the magician can manipulate the audience’s perception, especially the hand movements. Researchers in the UK have examined whether three types of monkeys can be fooled using simple magic tricks to see how humans can go astray. They found that only species with at least partially contralateral thumbs were fooled. This suggests that having similar anatomy (and thus biomechanical capabilities) plays an important role in illusion.they the result new paper It was published in Current Biology.
“The magician uses complex techniques to mislead the observer into experiencing the impossible.” Co-author Elias Garcia-Pelegrin said:He conducted this study after practicing magic while completing his PhD at the University of Cambridge. We can understand more about the evolutionary roots of cognitive deficits exposed to witchcraft cunning by investigating whether to generate actions such as holding an item with fingers and thumbs Having the manual capability is necessary to anticipate the impact that action will have on others.”
The researchers focused on three species with different hand anatomy and associated biomechanical capabilities: the yellow-breasted capuchin, the Humboldt’s squirrel monkey, and the common marmoset. Capuchin monkeys, for example, are known for their manual dexterity. This is partly because the fingers can be controlled individually. So you can do a scissor grip (holding something between the sides of two fingers) or a precision grip (bringing your thumb to your index or middle finger). They can examine, pinch, encircle, and even use stone tools to crack nuts with their hands, just like humans do.
Squirrel monkeys are less dexterous by comparison, but have been known to use simple tools occasionally. The thumb is not fully opposable because there is a hinge-like joint that limits the rotation of the thumb. However, you can touch the side of your index finger on your middle finger (but not the pad). Marmosets, on the other hand, have evolved for vertical movements like climbing tree trunks, and do not have contralateral thumbs as they are not advantageous for that. . According to the authors, marmosets climb by spreading their five fingers as wide as possible to increase their surface area, bending all fingers at the same time and digging with their claws.
