在很多年裡，紐約市政部門逐步停用了該市控制人行橫道信號燈的大部分按鈕，但一直沒怎麼聲張。他們認定，計算機操控的計時器更好用，但是，市政府並沒有拆除已經沒用的那些按鈕，令無數手指白費一番力氣。
圖片來源：pexles
Initially, the buttons survived because of the cost of removing them. But it turned out that even inoperative buttons serve a purpose. Pedestrians who press a button are less likely to cross before the green man appears, says Tal Oron-Gilad of Ben-Gurion University of the Negev, in Israel. Having studied behaviour at crossings, she notes that people more readily obey a system which purports to heed their input.
一開始，按鈕被留下來是因為拆除的成本問題。但後來卻發現，即使無法控制信號燈的按鈕也仍有用處。以色列本·古裡安大學的塔勒·奧龍-吉拉德表示，按下按鈕的行人不太可能在綠色信號燈亮起前就橫穿馬路。研究過人們在路口的行為後，她注意到大家更傾向於服從一個聲稱會聽從他們的指令的系統。
Inoperative buttons produce placebo effects of this sort (the word placebo is Latin for 「I shall be pleasing」) because people like an impression of control over systems they are using, says Eytan Adar, an expert on human-computer interaction at the University of Michigan, Ann Arbor. Dr Adar notes that his students commonly design software with a clickable 「save」 button that has no role other than to reassure those users who are unaware that their keystrokes are saved automatically anyway. Think of it, he says, as a touch of benevolent deception to counter the inherent coldness of the machine world.
密西根大學安娜堡分校的人機互動專家埃坦·埃達表示，失效的按鈕之所以會產生這種安慰劑效應（placebo出自拉丁語，原意是「我會討人喜歡」），是因為人們喜歡對自己所使用的系統有掌控感。他指出，自己的學生在設計軟體時經常會加上一個可點擊的「保存」按鈕，但其實用戶的輸入都會自動保存，這個「保存」按鈕僅僅是為了讓對此不知情的用戶放心而已。他說，不妨將這視作對抗機器世界裡固有的冷漠的一種善意欺騙。
That is one view. But, at road crossings at least, placebo buttons may also have a darker side. Ralf Risser, head of factum, a Viennese institute that studies psychological factors in traffic systems, reckons that pedestrians』 awareness of their existence, and consequent resentment at the deception, now outweighs the benefits.
這是一種觀點。但是，安慰劑按鈕可能也有不利的一面，至少在過馬路的問題上是這樣。研究交通系統心理因素的維也納FACTUM研究所的負責人拉爾夫·裡瑟爾認為，行人意識到按鈕無效進而感到被騙的怨怒，如今已讓這種做法弊大於利。
Something which happened in Lebanon supports that view. Crossing buttons introduced in Beirut between 2005 and 2009 proved a flop. Pedestrians wanted them to summon a 「walk」 signal immediately, rather than at the next appropriate phase in the traffic-light cycle, as is normal. The authorities therefore disabled them, putting walk signals on a preset schedule instead. Word spread that button-pressing had become pointless. The consequent frustration increased the amount of jaywalking, says Zaher Massaad, formerly a senior traffic engineer for the Lebanese government.
黎巴嫩發生的情況可引為佐證。2005年至2009年間在貝魯特引入的過街按鈕最後被證明是失敗的。行人希望按鍵後能立刻亮起「步行」信號，而不是像通常那樣等待交通燈的周期性轉換。因此市政部門停用了這些按鈕，按預設的時間啟動步行信號。曾在黎巴嫩政府擔任高級交通工程師的查希爾·馬薩德說，過街按鈕無用的消息傳開，隨之而來的懊惱導致更多人亂穿馬路。
圖片來源：pexles
Beirut’s disabled buttons are, says Mr Massaad, now being removed. They should all be gone within three years. New York has similarly stripped crossings of non-functioning buttons, says Josh Benson, the city’s deputy commissioner for traffic operations, though it does retain about 100 working ones. These are in places where pedestrians are sufficiently rare that stopping the traffic automatically is unjustified. However, internet chatter about placebo buttons has become so common that doubt, albeit misguided, seems to be growing about even these functioning buttons』 functionality. This suspicion, says Mr Benson, has spread beyond New York, to include places such as Los Angeles, where almost all the crossing buttons have always worked, at least during off-peak hours.
馬薩德說，貝魯特正在拆除無效的過街按鈕，三年內應該能全部清理完畢。紐約市交通運營處副處長喬什·本森表示，紐約也拆除了無效的過街按鈕，但保留了大約100個有效的。這些按鈕都設置在行人稀少到已經不適合使用自動交通燈的地方。然而，網上對安慰劑按鈕的熱議，導致人們對有效的按鈕也開始懷疑起來，儘管這是受到了誤導。本森表示，這種懷疑已蔓延到了紐約以外的地方，包括幾乎所有過街按鈕都總是有效（至少在非尖峰時段是這樣）的洛杉磯。
Truth be told, though, the end may be nigh for all road-crossing buttons, placebo or real. At an increasing number of junctions, those waiting to cross can be detected, and even counted, using cameras or infrared and microwave detectors. Dynniq, a Dutch firm, recently equipped an intersection in Tilburg with a system that recognizes special apps on the smart phones of the elderly or disabled, and provides those people with 5 to 12 extra seconds to cross. That really will be pleasing.
但事實上，無論是安慰劑還是真的過街按鈕可能都會很快消亡。越來越多的道路交匯處配備了攝像頭或紅外和微波探測器，可探測甚至統計等待過馬路的行人。荷蘭科技公司Dynniq近年在蒂爾堡市的一個十字路口安裝了一套系統，能識別老年人或殘疾人智慧型手機上的專門應用，為他們提供額外5到12秒的過馬路時間。這的確會很討人喜歡。