No sticks can be discarded, an isolated slanted stick cannot be interpreted as I (one), and a V (five) symbol must always be composed of two slanted sticks. The only valid symbols are Roman numerals and "+", "-" and "=". OK, now try this one:
If you had trouble with that last puzzle, fear not - it means your frontal lobe is probably intact! Healthy adults are frequently outperformed by patients with frontal brain damage on that test, according to a 2005 study by Reverberi et al.
The authors tested 35 patients with focal brain lesions to the lateral or medial prefrontal cortex, along with 23 age- and education-matched healthy subjects, on a series of similar "matchstick arithmetic" problems, with 3 minutes to complete each problem. Whereas only 43% of healthy subjects completed the second problem, more than 80% of the patients with lateral prefrontal damage were able to do so!
So healthy adults might search for solutions that respect the rules of normal arithmetic, and assume that this constraint is implied. One might never even consider the mathematically ill-formed solution to the second problem:
2 comments:
I didn't time myself, but I think I got the second one in about 90 seconds. Perhaps I have brain damage.
*grin* Perhaps. Email me your answer. lrknapp - gmail
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