Day­light sav­ing has dark side for so­ci­ety

Austin American-Statesman Sunday - - INSIGHT - By David Wag­ner

A train hur­tled around a cor­ner at 82 mph, even­tu­ally com­ing off the rails and killing four pas­sen­gers.

Decades ear­lier, faulty de­ci­sion-mak­ing re­sulted in the deaths of the seven-per­son crew of the space shut­tle Chal­lenger.

Years be­fore these events, a stuck valve reg­u­lat­ing the sup­ply of coolant to a nu­clear re­ac­tor nearly re­sulted in the melt­down of a nu­clear plant in Penn­syl­va­nia. In each of these cases, poor or in­ad­e­quate sleep was one of the fac­tors that con­trib­uted to the fail­ure.

Even if you are not an en­gi­neer work­ing in one of those con­texts, the odds are pretty good that you oc­ca­sion­ally get a poor night’s sleep. In fact, over one-third of Amer­i­can adults sleep less than the sug­gested min­i­mum seven hours a night, and two-thirds of Amer­i­can teens sleep less than their min­i­mum rec­om­mended eight hours. Even for those with good sleep hy­giene, there is one time of year when you are likely to be short on sleep: the an­nual shift to day­light sav­ing time.

As an or­ga­ni­za­tional psy­chol­o­gist at the Univer­sity of Ore­gon, I have ex­am­ined a va­ri­ety of ways in which sleep af­fects em­ploy­ees. In par­tic­u­lar, my col­leagues and I in­ves­ti­gate how cir­ca­dian mis­align­ment caused

by the shift to day­light sav­ing time leads to costly work and so­cial out­comes.

Shed­ding some ex­tra light on the facts

The Amer­i­can pub­lic has had a love-hate re­la­tion­ship with day­light sav­ing time since it first be­came law in 1918. Per­sonal pref­er­ences aside, the em­pir­i­cal ev­i­dence for the in­tended ben­e­fits of day­light sav­ing time are mixed at best, whereas the costs of the switch to day­light sav­ing time are be­com­ing in­creas­ingly ev­i­dent.

At the crux of these costs is the ef­fect of the time shift on our sleep pat­terns. When we spring for­ward, the clocks on the wall ad­vance, but our body clocks do not change so read­ily. It gen­er­ally takes a few days for us to adapt to the time change in a way that al­lows us to fall asleep at our typ­i­cal time. The up­shot is that Amer­i­cans sleep ap­prox­i­mately 40 min­utes less than usual on the Sun­day to Mon­day night fol­low­ing the switch.

Along with my col­league, I first ex­am­ined how the shift to day­light sav­ing time af­fected work­ers in blue-col­lar set­tings. Us­ing a data­base of min­ing in­juries from the Na­tional In­sti­tute of Oc­cu­pa­tional Safety and Health, we dis­cov­ered that the spring shift to day­light sav­ing time re­sulted in a 6 per­cent in­crease in min­ing in­juries and a 67 per­cent in­crease in work­days lost be­cause of these in­juries.

Haz­ards even if you work above­ground

Al­though these find­ings might raise some con­cern, you may have more ex­pe­ri­ence with com­put­ers than with min­ing equip­ment, and you are prob­a­bly read­ing this ar­ti­cle at work. It makes sense then to con­sider how the shift to day­light sav­ing time in­flu­ences work­ers in white-col­lar set­tings.

We set out to un­der­stand these pos­si­ble ef­fects by ex­am­in­ing how peo­ple were us­ing their in­ter­net ac­cess on the day fol­low­ing the time change. By ex­am­in­ing in­ter­net search pat­terns over six years in over 200 dif­fer­ent Amer­i­can metro ar­eas, we found that searches for en­ter­tain­ment or re­lated cat­e­gories were much more preva­lent (3.1 per­cent to 6.4 per­cent) on the Mon­day im­me­di­ately fol­low­ing the time change than they were on the Mon­days be­fore and af­ter the time change. Given that much of this search ac­tiv­ity was con­ducted at work, we con­cluded that work­ers are mis­us­ing their in­ter­net ac­cess when they should be work­ing — a be­hav­ior called cy­ber­loaf­ing. Such loaf­ing on the job fol­low­ing the time change sug­gests that peo­ple are less pro­duc­tive when mildly sleep de­prived due to the time change.

Based solely on the find­ings from our two stud­ies, along with a study show­ing that the time change pre­dicts a 5 per­cent in­creased in­ci­dence of heart at­tacks, econ­o­mists es­ti­mate that the an­nual spring time change costs the Amer­i­can econ­omy $434 mil­lion each year. Yet that is not where the costs end.

Time change also af­fects our judg­ment

Our re­search has also re­vealed that the shift to day­light sav­ing time in­flu­ences our abil­ity to per­ceive the moral fea­tures of a given sit­u­a­tion. We again ex­am­ined in­ter­net search be­hav­ior and fol­lowed up with our own ex­per­i­ment. In the ex­per­i­ment we kept half of our re­search par­tic­i­pants awake through­out the night and al­lowed the other half to get a full night of sleep. The next day we pre­sented them with sce­nar­ios that con­tained vary­ing lev­els of moral con­tent.

We found that the day fol­low­ing the shift to day­light sav­ing time, or fol­low­ing a night of sleep de­pri­va­tion, peo­ple were less able to dis­cern when a sit­u­a­tion in­volved is­sues of moral rel­e­vance than when they were well rested.

The time change also af­fects our judg­ment in for­mal set­tings. A re­cent study found that judges hand out harsher sen­tences — 5 per­cent longer in du­ra­tion — the Mon­day fol­low­ing the time change, as com­pared to other days of the year. This means that sleep and pub­lic pol­icy re­lated to sleep could be in­flu­enc­ing im­por­tant de­ci­sions that should be im­par­tial.

These stud­ies are only the tip of the ice­berg, with ad­verse con­se­quence of the time change rang­ing from stu­dent test scores to stock mar­ket re­turns.

No mat­ter your sen­ti­ment to­ward day­light sav­ing time, ac­cu­mu­lat­ing ev­i­dence re­veals that the costs of shift­ing to day­light sav­ing time cut across so­ci­ety. Al­though the neg­a­tive out­comes are var­ied, the sin­gu­lar so­lu­tion seems quite sim­ple: Rather than change the clocks, we should change pub­lic pol­icy. Many state leg­is­la­tures have taken up this cause, with state­houses coast to coast re­con­sid­er­ing the an­nual prac­tice.

As the re­search ev­i­dence is con­sid­ered, other states could end up join­ing Ari­zona and Hawaii in ab­stain­ing from the an­nual day­light sav­ing time mad­ness. As we move to­ward that pos­si­bil­ity, we may find it eas­ier to save lives and money rather than chase the day­light.


Ger­many was the first coun­try to adopt day­light sav­ing in 1916 to con­serve en­ergy in World War I. Other in­dus­tri­al­ized coun­tries, in­clud­ing the United States, quickly fol­lowed.

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