科學天地：預測未來行為 腦掃描準過自己估

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　■外國研究發現，腦掃描預測人類行為的準確度頗高。 資料圖片

　腦部掃描可能比人更能預測自己下一步行為。

　研究員發現一個方法，介入「即時」的腦部影像，知道看到防曬用品訊息的人會否在之後一周使用該產品。

　加州大學洛杉磯分校的法爾科及其同僚發現，腦掃描的估計比人本身更準確。負責領導是次研究的心理學教授利伯曼說：「很多人決定做一些事情，但最後卻不去做。 」

　通過功能性磁振造影，法爾科和同僚能超越人們的意願，預測他們的實際行為。功能性磁振造影是通過磁場來測量腦部血的流量，從而顯示腦部哪些區域較為活躍。

　研究人員招募20名年輕男女志願者參加這次實驗。在進行腦部掃描時，他們都看到和聽到使用防曬用品的安全訊息，但同時亦混有其他內容，這樣他們便無法知道實驗的真正意圖。研究員表示：「在實驗的第一天，志願者回答上周使用防曬用品的情況、下周會否使用防曬用品、以及對防曬用品的看法等問題。在他們看到有關防曬用品的訊息後，又進一步回答有關防曬用品的問題。然後，他們就會領取一個包，裡面有很多東西包括防曬濕紙巾。」

　法爾科表示，一周後，研究人員作出突擊跟進調查。結果顯示，只有約一半的志願者言行一致。研究人員對磁振造影再作研究，於內側前額葉皮質中一個特定區域有發現。

　利伯曼說：「通過對人腦這一區域活動的研究，我們可準確預測約3/4志願者會否用更多防曬用品，比他們說的更準確。 」 　■路透社　■羅國偉 資深翻譯員

Scientists Read Your Mind Better Than You Can

　Brain scans may be able to predict what you will do better than you can yourself.

　They found a way to interpret "real time" brain images to show whether people who viewed messages about using sunscreen would actually use sunscreen during the following week.

　The scans were more accurate than the volunteers were, Emily Falk and colleagues at the University of California Los Angeles discovered.

　"Many people decide to do things, but then don't do them," Matthew Lieberman, a professor of psychology who led the studysaid.

　But with functional magnetic resonance imaging (FMRI), Falk and colleagues were able to go beyond good intentions to predict actual behavior. FMRI uses a magnetic field to measure blood flow in the brain. It can show which brain regions are more active compared to others.

　Falk's team recruited 20 young men and women for their experiment. While in the FMRI scanner they read and listened to messages about the safe use of sunscreen, mixed in with other messages so they would not guess what the experiment was about. "On day one of the experiment, before the scanning session, each participant indicated their sunscreen use over the prior week, their intentions to use sunscreen in the next week and their attitudes toward sunscreen," the researchers said. After they saw the messages, the volunteers answered more questions about their intentions, and then got a goody bag that contained, among other things, sunscreen towelettes.

　"A week later we did a surprise follow up to find out whether they had used sunscreen," Falk said. About half the volunteers had correctly predicted whether they would use sunscreen. The research team analyzed and re-analyzed the MRI scans to see if they could find any brain activity that would do better. Activity in one area of the brain, a particular part of the medial prefrontal cortex, provided the best information.

　"From this region of the brain, we can predict for about 3/4 of the people whether they will increase their use of sunscreen beyond what they say they will do," Lieberman said. 　■Reuters