237sure at mid-latitudes and decreasedpressure at high latitudes (1).Increasing greenhouse gases haveprobably contributed to the ob-served Southern Hemispherewarming at mid- and lower latitudesand to the observed circulationchanges (strengthening of theSAM) in winter. However, the mag-nitude of the circulation response inthese climate models is not nearlyas strong as that found in the obser-vations or in the ozone-forced mod-el response in summer (3). The recent changes in theSouthern Hemisphere circulation athigh latitudes have clear impacts onAntarctica and the Southern Ocean. In ad-dition, there may be important links be-tween SAM variations and rainfall in south-ern Australia, New Zealand, and SouthAmerica (see the figure). Increases in theSAM, with increasing pressure at mid-lati-tudes, are associated with decreases in rain-fall between 35° and 50°S. There has beena substantial reduction (15 to 20%) in win-ter rainfall in southwest Western Australiaover the past 50 years, associated with asouthward shift in the winter rain-bearingweather systems (5). Fyfe has noted thissouthward shift in Southern Hemisphereextratropical cyclones in both observationaldata and model responses to increasinggreenhouse gases (6).The observed rainfall trends in southwestWestern Australia are much greater than ex-pected from most climate model simulationswith increasing greenhouse gases. Further-more, they occur in a season when there islikely to be little influence from stratosphericozone depletion. Hence, natural decadal cli-mate variations are likely to be an importantfactor in these rainfall decreases.Recent climate changes in the SouthernHemisphere are likely to result from acomplex combination of natural climateprocesses (associated with interactions be-tween the atmosphere, oceans, and sea ice)and human influences (including decreasesin stratospheric ozone and increases in at-mospheric greenhouse gases and aerosols).Untangling the separate contributions iscrucial for understanding recent regionalclimate variations, such as the rainfalltrends in Western Australia, and for pre-dicting how climate is likely to change inthe future. Gillett and Thompson (3) havetaken an important step in this direction inshowing that the recent summer circulationchanges in the Southern Hemisphere highlatitudes are likely to be caused by strato-spheric ozone depletion.References and Notes1. J. T. Houghton et al.,Eds.,Climate Change 2001: TheScientific Basis,Contribution of Working Group I tothe Third Assessment Report of the Intergov-ernmental Panel on Climate Change (CambridgeUniv. Press, Cambridge, UK, 2001).2. D. W. J. Thompson, S. Solomon,Science296, 895(2002).3. N. P. Gillett, D. W. J. Thompson,Science302, 273(2003).4. M. P. Baldwin, D. W. J. Thompson, E. F. Shuckburgh, W.A. Norton, N. P. Gillett,Science301, 317 (2003).5. Indian Ocean Climate Initiative Panel,ClimateVariability and Change in South West WesternAustralia(Department of Environment, WA, Australia,2002).6. J. C. Fyfe,J. Clim.16, 2802 (2003).7. W. Cai, P. H. Whetton, D. J. Karoly,J. Clim.16, 1525(2003).8. I thank W.-J. Cai, CSIRO Atmospheric Research,Australia, for his assistance with the preparation ofthe figure.0°60°W 60°E0.50.40.30.20.1–0.1–0.2–0.3–0.4–0.5120°W 120°E180°1950 19601970 1980 1990 2000Time (years)Rainfall (mm per day)Seasonal11-year running mean2345Climate connections. (Top) Relation betweenvariations of the southern annular mode (SAM)and rainfall in the Southern Hemisphere, basedon data from a long control climate model sim-ulation (7). Similar results are obtained withthe climate model of Gillett and Thompson (3).(Bottom) Time series of winter rainfall insouthwest Western Australia. The decrease inrainfall is consistent with the observed increas-ing trend in the SAM.The Greek philosopher Zeno of Citium(356 to 264 B.C.), the founder ofStoicism, considered pain to be oneof nine forms of grief. We often speakabout the loss of a loved one in terms ofpainful feelings, but it is still not clear towhat extent such metaphors reflect what isactually happening in the human brain?Enter Eisenberger and colleagues (1) onpage 290 of this issue with a bold neu-roimaging experiment that seeks to discov-er whether the metaphor for the psycholog-ical pain of social loss is reflected in theneural circuitry of the human brain. Usingfunctional magnetic resonance imaging(fMRI), they show that certain humanbrain areas that “light up” during physicalpain are also activated during emotionalpain induced by social exclusion. You might wonder how one measuresthe feeling of social exclusion while thesubject is lying in an MRI machine.Eisenberger et al. circumvented this obvi-ous problem in a clever way. In their study,the 13 participants observed a virtual ball-tossing video game while brain blood flowwas monitored by MRI. During a baselineperiod, subjects were led to believe thatthey were only observing the game. Duringthe experimental phase, however, they be-came active participants in the game.Within a few throws of the ball, the twoother “players” (actually computerizedstooges) stopped throwing the ball to thesubjects, leading them to feel excluded (2).The subjects experienced emotional dis-tress as indicated by substantial blood-flowchanges in two key brain areas. One ofthese areas, the anterior cingulate cortex,has been implicated in generating the aver-sive experience of physical pain.Eisenberger and colleagues demonstratethat the greater the feeling of social dis-tress, the more this brain area becomes ac-tivated. The other brain region, in the pre-frontal cortex, showed an opposite patternof activity, becoming more active when thedistress was least. In other words, the twobrain areas involved in the distressing feel-ings of social exclusion responded in op-NEUROSCIENCEFeeling the Pain of Social LossJaak PankseppThe author is at the J. P. Scott Center forNeuroscience, Mind and Behavior, Department ofPsychology, Bowling Green State University, BowlingGreen, OH 43403, USA, and at the Falk Center forMolecular Therapeutics, Department of BiomedicalEngineering, Northwestern University, Evanston, IL60201, USA. E-mail: [email protected] SCIENCE VOL 302 10 OCTOBER 2003P ERSPECTIVES238posite ways to the degree of social pain ex-perienced. This suggests that the anteriorcingulate is more important for elaboratingfeelings of emotional distress, whereas theprefrontal cortex, already implicated inemotional