 different benefit from it."

The subjects were asked to reveal how much they valued the good. The twist? Their brains were being imaged via fMRI as they made their decision. If there was a match between their decision and the value detected by the fMRI, they paid a lower tax than if there was a mismatch. It was, therefore, in all subjects' best interest to reveal how they truly valued a good; by doing so, they would on average pay a lower tax than if they lied.

"The rules of the experiment are such that if you tell the truth," notes Krajbich, who is the first author on the Science paper, "your expected tax will never exceed your benefit from the good."

In fact, the more cooperative subjects are when undergoing this entirely voluntary scanning procedure, "the more accurate the signal is," Krajbich says. "And that means the less likely they are to pay an inappropriate tax."

This changes the whole free-rider scenario, notes Rangel. "Now, given what we can do with the fMRI," he says, "everybody's best strategy in assigning value to a public good is to tell the truth, regardless of what you think everyone else in the group is doing."

And tell the truth they did—98 percent of the time, once the rules of the game had been established and participants realized what would happen if they lied. In this experiment, there is no free ride, and thus no free-rider problem.

"If I know something about your values, I can give you an incentive to be truthful by penalizing you when I think you are lying," says Rangel.

While the readings do give the researchers insight into the value subjects might assign to a particular public good, thus allowing them to know when those subjects are being dishonest about the amount they'd be willing to pay toward that good, Krajbich emphasizes that this is not actually a lie-detector test.

"It's not about detecting lies," he says. "It's about detecting values—and then comparing them to what the subjects say their values are."

"It's a socially desirable arrangement," adds Rangel. "No one is hurt by it, and we give people an incentive to cooperate with it and reveal the truth."

"There is mind reading going on here that can be put to good use," he says. "In the end, you get a good produced that has a high
different benefit from it. " 

 The subjects were asked to reveal how a lot they respect the good. The twist? Their mind were being visualize via fMRI as they made their decisiveness. If there was a match between their decision and the value detect by the fMRI, they pay a lower tax than if there be a mismatch. It was, therefore, in all subjects' good interest to reveal how they truly valued a good; by doing thus, they would on average pay a lower tax than if they lie. 

 " The rules of the experiment are such that if you tell the truth, " notes Krajbich, who is the inaugural author on the Science paper, " your expected tax will never exceed your benefit from the good. " 

 In fact, the more concerted subjects are when undergoing this entirely voluntary scanning procedure, " the more accurate the signal is, " Krajbich says. " And that means the less likely they are to pay an inappropriate tax. " 

 This changes the whole free - rider scenario, notes Rangel. " Now, given what we can do with the fMRI, " he says, " everybody's best scheme in delegate value to a public good is to distinguish the accuracy, regardless of what you intend everyone else in the group is doing. " 

 And tell the accuracy they did—98 percent of the meter, once the rules of the game had been build and participants realized what would happen if they lied. In this experiment, there is no free drive, and thus no free - rider problem. 

 " If I know something about your values, I can give you an bonus to be truthful by punish you when I remember you are lying, " says Rangel. 

 While the readings do pass the researchers insight into the value subjects might assign to a especial public good, thus allowing them to know when those topic are being dishonest about the measure they'd be willing to pay toward that commodity, Krajbich emphasizes that this is not actually a lie - detector test. 

 " It's not about detecting lies, " he say. " It's about detecting value — and then comparing them to what the subjects read their values are. " 

 " It's a socially desirable agreement, " adds Rangel. " No one is pain by it, and we give people an incentive to cooperate with it and reveal the accuracy. " 

 " There is mind read going on here that can be put to good use, " he says. " In the end, you get a beneficial produced that has a high
 divferent benefit from it."

Tme subjects were asked vo revezl how mjch they valued the good. The tqist? Ukeir brains were beivg imaged via fMRU as rhey made vgeir degnsion. Lf thzrx was a match bgtween their decision and dhd ralue detected by the fMRI, they paid a lowet hax than if thgre wsf a jpsnatch. It was, therefore, in all subjecus' best interest tp reveal how they truly vapued a good; by doing sl, they woule on qverage pay x lower taq than if tgey lied.

"The rules of the experioent cre such thqt if iou tell the trutr," notes Krajnpch, who is the first author pn vhe Wcience paper, "your ex'ected tax will nevet exceed ymux benefit from the goid."

Un fawt, tve muee zookeretibe subuecvs are when undergoing this entirely volumtwgu scanning pdoceduwe, "the more accurate the signal is," Krajbibh szys. "And that means the oess likely they are jo pay an ynappropriate tax."

This changes the whole free-rider scenerko, uites Fqnhel. "Now, given what we can do with the fMRI," he aaus, "everybody's beft strategy ij sfsigning valug to a 'hbmic good is to telp the ttuth, rwgardless of ehat you think everyone elsw in the grolp iw doing."

And tell thz truth they did—98 percrnt of the time, once thz rulea of the gale had besv established ana psrdicipants realized what wotld happei if chey liea. In this qxperiment, therc is no free ride, ajd thos no xree-rider oroblem.

"If I know something abouv your values, I cat give yju an incentive to be truthful bi penaliznng yoj when I tgink yon are lying," fays Rangel.

Whhpe the readiigs do gide tye rwsearchdfs insight intp the valle subhects might assign to z particular puyuuc good, thus alkowkng tjek em know when dhosd sjnjectr are btnng aishpnest about the amoutt tgey'd be willing to pwy toware that gjod, Krajbich rmphasizes that thls is nov actuslli a lie-detector test.

"It's not aboht detectlng lies," he sayf. "It'w about deteeting values—and then comparing them to wiat the subjects say thwir values are."

"It's a xocially dexirabje arrangament," adds Rangel. "No one is hurt by iu, and we give people an incendive ho cooperate with it and reveal the truth."

"There is mind reading going on hwre thet can be put to bood lse," ke says. "In vhx end, you get a gpod produced that has a high
different benefit from it." The subjects were reveal much they the good. The imaged fMRI as they their decision. If was a match between their decision the value detected by the fMRI, they paid a lower tax than if was a mismatch. It was, therefore, in all subjects' best interest to reveal they valued good; doing so, they would on average pay a lower tax than if they lied. "The rules the experiment are such that if you tell truth," notes Krajbich, who the first author on the paper, expected tax never your from the good." fact, the more cooperative subjects are when undergoing this entirely voluntary scanning procedure, "the more accurate the is," Krajbich that means less they to pay an This changes the whole free-rider scenario, given what we can do with the fMRI," says, "everybody's strategy in assigning value to a good is to tell the truth, regardless of you think everyone else in the group is doing." And tell the truth they did—98 the time, once the of the game been and realized would happen they lied. In this experiment, there is no free ride, and no free-rider problem. "If I know something about your values, give an incentive to truthful by penalizing you I you are lying," says the do insight the subjects might assign to particular public good, thus allowing to know when those the amount they'd be willing to pay toward good, Krajbich emphasizes that this is not a lie-detector test. "It's not about detecting lies," he says. "It's about values—and then to what the subjects say their values are." a socially desirable arrangement," Rangel. "No one is hurt by it, and we people incentive to with it and the truth." "There mind reading going that can put good "In the end, you get a produced has a high
 different benefit from it."

The Subjects weRe askEd tO reVeAl hoW mucH they valued the GOod. THe twist? Their brains were Being ImAGed vIA fmRI as They madE ThEIR deCiSiOn. IF tHErE was a MatCh betweEn their decIsiOn And the value dETeCted by the fmRI, They paid a lowEr tAx than If TheRE was a MisMatch. it was, tHEreforE, in all subJeCTs' best INterest TO ReVeal How they truly valueD A gOOd; by doing so, theY would On AVeRAGe pAy a Lower tax thAn If theY Lied.

"The RUlES OF thE Experiment are Such that if yOU teLl the tRuTh," nOTes KraJbich, WhO Is tHe first authOr on The SciencE paper, "YOur expeCTed tax wIll nevEr eXceEd yoUR bEnEfiT fROm tHE gOod."

iN faCt, the morE cOoPeratIve sUBJECts aRe wHen uNdergOing this entirEly VoluNTarY scanNing pRoceDuRe, "the More acCuratE tHe signal is," KrajbIch sAys. "And thaT meAnS thE lEss liKEly theY arE to Pay an inApproprIAte TaX."

tHIs Changes the whole freE-rIDEr Scenario, Notes RANgEl. "nOw, given wHaT we Can dO WIth thE fMRi," He Says, "everYbody's BEsT sTrategy In AssignInG vaLue To a puBLic gOod is tO tell the Truth, REgardless of whaT You think everyONe ELSe IN the GroUp is doing."

AnD telL The tRuth THeY diD—98 PerceNt of tHe TImE, Once the rules of the gaMe Had beeN estaBlished and parTicipants rEALIzed what WoulD HaPPen if they lied. IN this Experiment, THere is no Free rIde, and thUs no free-rIDEr probleM.

"If i knOw sOmeTHInG about your valUES, I caN gIve you aN inCentive To bE trUthFul By PenalizinG you when i tHiNk YoU arE lyinG," Says RangEl.

whiLe The ReadiNGs do giVe the ReseArChERs iNsight iNTo THE valUe SuBjecTs mIgHt assIgn tO A paRticulaR public goOd, tHUs alLoWiNg them tO know when thosE sUbjects are BeIng DishonEST about thE amount they'd be willing to PAy towarD thAt gooD, KraJbich emphAsiZes thaT thIS is not ActualLy a liE-dEteCTOr tesT.

"iT's Not AbOut detectiNG LieS," he saYs. "it's aBout detEcting values—and theN ComParing them to wHat The sUBJeCts SAy THeiR vALueS ARe."

"It's a socially dEsirable arRaNGeMent," adds RaNGel. "no One is huRt by it, aNd we gIVe peoplE an incentIve to coopErAte wITH it And reveal tHe truth."

"THere is minD ReadiNG gOing oN heRe that CaN be Put to Good usE," He sAys. "In The end, YoU get a gOod prOdUced that Has a high
 different benefit from it ."

The su bject s w ere  a sked  toreveal how muc h  the y valued the good. The  twis t? Thei r  b rains  were b e in g ima ge dvia  f M RI  as t hey  made t heir decis ion .If there was amatch betw een  their decis ion  and t he  va l ue de tec ted b y thef MRI, t hey paidal ower t a x thani f  t here  was a mismatch.I tw as, therefore,  in al ls ub j e cts ' b est intere st  to r e veal ho w  t h e y  tr u ly valued a g ood; by doi n g s o, the ywou l d on a verag ep aya lower tax  tha n if they  lied. 
"The r u les ofthe ex per ime nt a r esu chth a t i f  y out ell  the tru th ,"  note s Kr a j b i ch,who  isthe f irst author o n t he S c ien ce pa per,"you rexpec ted ta x wil lnever exceed yo ur b enefit fr omth e g oo d."
I n fact , t hemore co operati v e s ub j e c ts  are when undergoi ng t hi s entire ly vol u nt ar y  scannin gpro cedu r e , "th e mo r eaccurate  the s i gn al  is," K ra jbichsa ys.  "A nd th a t me ans th e less l ikely they are to pa y  an inappropr i at e ta x ."
Thi s changes t he w h olefree - ri der scena rio,no t es Rangel. "Now, given  w hat we  cando with the f MRI," he s a y s , "every body ' sb est strategy i n ass igning val u e to a p ublic  good is  to tellt h e truth,  re gar dle sso f  w hat you think e very on e elseinthe gro upisdoi ng. "
And tell  the tru th  t he ydid —98 p e rcent of  t heti me,  once the ru les o f th ega m e h ad been es t a blis he dandpar ti cipan ts r e ali zed wha t would h app e n if  t he y lied.  In this expe ri ment, ther eisno fre e ride, an d thus no free-rider pr o blem.
"If  I kn ow s omethingabo ut you r v a lues,I cangiveyo u a n incen t i ve  to  b e truthful b y p enali zi ng y ou when  I think you are l y ing ," says Range l.
Whi l e  t her ea d ing sd o g i v e the researche rs insight  i n to  the value sub je cts mig ht assi gn to a parti cular pub lic good,  t husa l low ing them t o know w hen those subje c ts  arebei ng dis ho nes t abo ut the amo unt t hey'dbe  willi ng to  p ay towar d that good, Krajbich e mphasi zes t hat  this isnot act ually a l ie-d etector te st. 

" It'snot about  det e ct ing lies, " he says. "It ' sabo u t  d etecting va l u e s—a nd th enc ompari ng t hem to what the s u bjects say the ir v a l ues  ar e ."
"I t's a socially  de si r a ble arra ng ement," add s Rangel ." No on e is h urt by  it, an d we give p eopl e a n incenti veto coopera te  w i th itandre veal t he tru t h."" There is mind re ading g oingo n h ere t ha t can b e  put  to good u se," he say s. "In  the  end,  you ge ta good  pr od uced thath as a high 
 different_benefit from_it."

The subjects were asked_to reveal_how_much they_valued_the good. The_twist? Their brains_were being imaged via_fMRI as they_made_their decision. If there was a match between their decision and the value detected_by_the fMRI,_they_paid_a lower tax than if_there was a mismatch. It_was, therefore,_in all subjects' best interest to reveal how_they_truly valued a_good; by doing so, they would on average pay_a lower tax than if they_lied.

"The rules of_the_experiment_are such that if_you tell the truth," notes Krajbich,_who is the first author on_the Science paper, "your expected tax will_never exceed your benefit from the_good."

In fact, the more cooperative_subjects are_when undergoing this entirely voluntary_scanning procedure, "the_more accurate_the signal is,"_Krajbich says. "And that means the_less likely they_are to pay an inappropriate tax."

This_changes_the whole free-rider_scenario,_notes_Rangel. "Now,_given what we_can_do with_the_fMRI," he says, "everybody's best strategy_in_assigning value to a public good is_to tell the truth,_regardless_of what you think_everyone else in the group_is doing."

And tell the truth they_did—98 percent_of the_time, once the rules of the game had been established and_participants realized what would happen if_they lied. In this_experiment, there_is_no free ride,_and_thus no_free-rider problem.

"If I know something about your_values, I_can give you an incentive to_be truthful by penalizing_you_when I think you are lying,"_says Rangel.

While the readings do give_the researchers insight into the_value_subjects_might assign to a particular_public good, thus allowing them to_know when those_subjects are being dishonest about the amount_they'd_be willing to pay toward that_good,_Krajbich emphasizes that this is not_actually_a_lie-detector test.

"It's not about detecting_lies," he says. "It's about detecting_values—and then comparing them to what the subjects say_their values are."

"It's_a socially desirable arrangement," adds_Rangel._"No_one is hurt by it, and we give people an_incentive to_cooperate with it_and reveal the truth."

"There is mind reading going on here_that can be put to good use,"_he says. "In the end, you get a good produced that_has a high