Ralph Hertwig

Hertwig received his Ph.D. in Psychology from the University of Konstanz, Germany, in 1995. In the same year, he joined Gerd Gigerenzer's research group at the Max Planck Institute for Psychological Research in Munich; in 1997, the group moved to the Max Planck Institute for Human Development in Berlin. In 2000, Hertwig received a fellowship from the German Research Foundation, which supported his research at Columbia University for three years. Hertwig obtained his Habilitation qualification from the Free University of Berlin in 2003, and in the same year became Assistant Professor for Applied Cognitive Science at the University of Basel, Switzerland. In 2005, he was appointed Full Professor of Cognitive and Decision Sciences. In 2012, Hertwig was appointed Director of the Center for Adaptive Rationality at the Max Planck Institute for Human Development in Berlin.

Hertwig has been a key contributor to the study of bounded rationality, or how people search for information and make decisions with limited resources. His work investigates how decision making can be modeled in terms of fast and frugal heuristics—simple cognitive strategies that use little information and rely on just a few processing steps. Hertwig has examined, for instance, heuristics for making inferences (e.g., fluency heuristic{{cite journal|doi=10.1037/a0013025|pmid=18763900|title=Fluency heuristic: A model of how the mind exploits a by-product of information retrieval|journal=Journal of Experimental Psychology: Learning, Memory, and Cognition|volume=34|issue=5|pages=1191–1206|year=2008|last1=Hertwig|first1=Ralph|last2=Herzog|first2=Stefan M.|last3=Schooler|first3=Lael J.|last4=Reimer|first4=Torsten|hdl=11858/00-001M-0000-0024-FC25-9|hdl-access=free}}), choices (e.g., priority heuristic,{{cite journal|doi=10.1037/0033-295x.113.2.409|pmid=16637767|pmc=2891015|title=The priority heuristic: Making choices without trade-offs|journal=Psychological Review|volume=113|issue=2|pages=409–432|year=2006|last1=Brandstätter|first1=Eduard|last2=Gigerenzer|first2=Gerd|last3=Hertwig|first3=Ralph}} natural mean heuristic{{cite journal|doi=10.1016/j.cognition.2009.12.009|pmid=20092816|title=Decisions from experience: Why small samples?|journal=Cognition|volume=115|issue=2|pages=225–237|year=2010|last1=Hertwig|first1=Ralph|last2=Pleskac|first2=Timothy J.|hdl=11858/00-001M-0000-002E-5786-D|s2cid=15918980 |hdl-access=free}}), parental allocation decisions (e.g., equity heuristic{{cite journal|doi=10.1037/0033-2909.128.5.728|title=Parental investment: How an equity motive can produce inequality|journal=Psychological Bulletin|volume=128|issue=5|pages=728–745|year=2002|last1=Hertwig|first1=Ralph|last2=Davis|first2=Jennifer Nerissa|last3=Sulloway|first3=Frank J.|pmid=12206192 |hdl=11858/00-001M-0000-0025-913B-1|hdl-access=free}}), and medical decisions (e.g., first impression heuristic{{cite journal|doi=10.1097/MD.0000000000000374 |pmc=4554174 |title=Physicianʼs First Clinical Impression of Emergency Department Patients with Nonspecific Complaints is Associated with Morbidity and Mortality|journal=Medicine|volume=94|issue=7|pages=e374|year=2015|last1=Beglinger|first1=Bettina|last2=Rohacek|first2=Martin|last3=Ackermann|first3=Selina|last4=Hertwig|first4=Ralph|last5=Karakoumis-Ilsemann|first5=Julia|last6=Boutellier|first6=Susanne|last7=Geigy|first7=Nicolas|last8=Nickel|first8=Christian|last9=Bingisser|first9=Roland|pmid=25700307 |doi-access=free}}).

The rationality of a heuristic depends on whether it matches the structure of the environment in which it is applied. The notion of ecological, rather than logical, rationality challenges a core premise of the heuristics-and-biases program, namely, that intelligent processes must conform with the formal principles of logic, probability theory, and rational choice theory, irrespective of the decision context.{{cite journal|doi=10.1521/soco.2009.27.5.661|title=Fast and Frugal Heuristics: Tools of Social Rationality|journal=Social Cognition|volume=27|issue=5|pages=661–698|year=2009|last1=Hertwig|first1=Ralph|last2=Herzog|first2=Stefan M.|hdl=11858/00-001M-0000-002E-576B-B|hdl-access=free}} Hertwig does not uncritically accept these domain-general standards; rather, he asks which other context-specific concerns may be at play when such principles are violated. In his Ph.D. dissertation, he showed that the conjunction fallacy, a seemingly logical error often illustrated by the Linda problem,{{cite journal|doi=10.1037/0033-295X.90.4.293|title=Extensional versus intuitive reasoning: The conjunction fallacy in probability judgment|journal=Psychological Review|volume=90|issue=4|pages=293–315|year=1983|last1=Tversky|first1=Amos|last2=Kahneman|first2=Daniel}} reflects people's capacity to infer the meaning of polysemous terms like probability.Hertwig, R. (1995). Why Dr Gould's Homunculus doesn't think like Dr Gould: The "conjunction fallacy" reconsidered, Doctoral dissertation, Universität Konstanz: Germany. Konstanz: Hartung-Gorre Verlag.{{cite journal|doi=10.1002/(sici)1099-0771(199912)12:4<275::aid-bdm323>3.0.co;2-m|title=The 'conjunction fallacy' revisited: How intelligent inferences look like reasoning errors|journal=Journal of Behavioral Decision Making|volume=12|issue=4|pages=275–305|year=1999|last1=Hertwig|first1=Ralph|last2=Gigerenzer|first2=Gerd|hdl=11858/00-001M-0000-0025-9EBC-6|hdl-access=free}}

Another reason why fast and frugal heuristics can yield good decisions is that they take advantage of evolved cognitive capacities of the human mind. Together with Lael Schooler,{{cite web|url=http://thecollege.syr.edu/people/faculty/pages/psy/schooler-lael.html|title=Lael Schooler|website=www.thecollege.syr.edu|accessdate=9 September 2019}} Hertwig has shown that ecologically smart forgetting—the capacity to forget information that is unlikely to be needed—fosters the use of heuristics that rely on partial ignorance (e.g., recognition heuristic, fluency heuristic).{{cite journal|doi=10.1037/0033-295X.112.3.610|title=How forgetting aids heuristic inference|journal=Psychological Review|volume=112|issue=3|pages=610–628|year=2005|last1=Schooler|first1=Lael J.|last2=Hertwig|first2=Ralph|pmid=16060753 |hdl=11858/00-001M-0000-0025-838B-B|hdl-access=free}}

People can learn about the potential consequences of their decisions and the associated probabilities in two ways: by reading summaries of probability information (e.g., drug-package inserts) or by personally experiencing the consequences of their decisions, one at a time (e.g., going out on dates). Using monetary lotteries to compare these two learning modes, Hertwig and colleagues observed a "description-experience gap," a phenomenon by which rare events are given too much weight in decisions from description and too little weight in decisions from experience.{{cite journal|doi=10.1111/j.0956-7976.2004.00715.x|pmid=15270998|title=Decisions from Experience and the Effect of Rare Events in Risky Choice|journal=Psychological Science|volume=15|issue=8|pages=534–539|year=2004|last1=Hertwig|first1=Ralph|last2=Barron|first2=Greg|last3=Weber|first3=Elke U.|last4=Erev|first4=Ido|hdl=11858/00-001M-0000-002E-57CE-F|s2cid=12977034 |hdl-access=free}} This occurs partly because decisions from experience are based on small samples, where people are simply less likely to experience the rare event. The description–experience gap has been observed across thousands of choices and found to generalize beyond monetary gambles to domains including causal reasoning, intertemporal choice, consumer choice, investment decisions, medical decisions, and adolescent risk taking.{{cite journal|doi=10.1037/bul0000115|pmid=29239630|title=A meta-analytic review of two modes of learning and the description-experience gap|journal=Psychological Bulletin|volume=144|issue=2|pages=140–176|year=2018|last1=Wulff|first1=Dirk U.|last2=Mergenthaler-Canseco|first2=Max|last3=Hertwig|first3=Ralph|hdl=21.11116/0000-0000-AD63-E|hdl-access=free}}{{cite journal|doi=10.1177/0956797619858969|pmid=31318637|title=What the Future Holds and When: A Description–Experience Gap in Intertemporal Choice|journal=Psychological Science|volume=30|issue=8|pages=1218–1233|year=2019|last1=Dai|first1=Junyi|last2=Pachur|first2=Thorsten|last3=Pleskac|first3=Timothy J.|last4=Hertwig|first4=Ralph|hdl=21.11116/0000-0003-8E07-6 |s2cid=197663746 |url=http://psyarxiv.com/grwye/|hdl-access=free}}

People often deliberately choose not to know. For example, up to 55% of those who get tested for HIV do not return to pick up their results.{{cite journal|doi=10.1521/aeap.15.4.282.23826|pmid=12866839|title=Failure to Return for HIV Posttest Counseling in an STD Clinic Population|journal=AIDS Education and Prevention|volume=15|issue=3|pages=282–290|year=2003|last1=Hightow|first1=Lisa B.|last2=Miller|first2=William C.|last3=Leone|first3=Peter A.|last4=Wohl|first4=David|last5=Smurzynski|first5=Marlene|last6=Kaplan|first6=Andrew H.}} The conscious choice not to seek or use information has been called deliberate ignorance. In a theoretical article, Hertwig and Christoph Engel{{cite web|url=https://www.coll.mpg.de/engel|title=Christoph Engel|website=www.coll.mpg.de|accessdate=9 September 2019}} argued that deliberate ignorance is not necessarily an anomaly but can serve important functions.{{cite journal|doi=10.1177/1745691616635594|pmid=27217249|title=Homo Ignorans|journal=Perspectives on Psychological Science|volume=11|issue=3|pages=359–372|year=2016|last1=Hertwig|first1=Ralph|last2=Engel|first2=Christoph|hdl=11858/00-001M-0000-002A-C462-8|s2cid=27556679 |hdl-access=free}} One such function is to act as an emotion-regulation device: people may avoid potentially threatening health information because it compromises cherished beliefs, they anticipate mental discomfort, or they want to keep hope alive. Hertwig and Engel are also co-editors of an interdisciplinary book exploring manifestations of deliberate ignorance from the right not to know in genetic testing to collective amnesia in transformational societies; from blinding in orchestral auditions to "don't ask, don't tell" policies in the military and beyond; and from efforts to prevent algorithms feeding on discriminatory data to the strategic lack of funding for research into gun violence.Hertwig, R., & Engel, C. (Eds.) (in press). Deliberate ignorance: Choosing not to know. Strüngmann Forum Reports. Cambridge, MA: MIT Press.

To date, most public policy interventions informed by behavioral science evidence involve "nudges"; that is, non-fiscal and non-regulatory interventions that steer (nudge) people in a specific direction while preserving freedom of choice.Thaler, R., & Sunstein, C. R. (2008). Nudge: Improving decisions about health, wealth and happiness. New York, NY: Simon & Schuster. Hertwig's work has focused on "boosts," an alternative class of non-fiscal and non-regulatory policy interventions grounded in behavioral science. Boosts aim to improve people's decisional, cognitive, and motivational competences, making it easier for them to exercise their own agency. Instead of simply providing information, boosts offer a simple and sustainable strategy for successfully dealing with a given task. For instance, a boost with proven effectiveness in improving the quality of relationships is to imagine oneself as a third-party spectator when involved in a quarrel, and to mentally engage with this perspective-shifting strategy through quick writing exercises.{{cite journal|doi=10.1177/0956797612474938|pmid=23804960|title=A Brief Intervention to Promote Conflict Reappraisal Preserves Marital Quality over Time|journal=Psychological Science|volume=24|issue=8|pages=1595–1601|year=2013|last1=Finkel|first1=Eli J.|last2=Slotter|first2=Erica B.|last3=Luchies|first3=Laura B.|last4=Walton|first4=Gregory M.|last5=Gross|first5=James J.|s2cid=2254080 }}

In an article written in collaboration with Till Grüne-Yanoff,{{cite web|url=https://www.kth.se/profile/gryne|title=Till Grüne-Yanoff|website=www.kth.se|accessdate=9 September 2019}} Hertwig examined how boosts differ from nudges in terms of the psychological mechanisms through which they operate, as well as their normative implications for transparency and autonomy.{{cite journal|doi=10.1177/1745691617702496|pmid=28792862|title=Nudging and Boosting: Steering or Empowering Good Decisions|journal=Perspectives on Psychological Science|volume=12|issue=6|pages=973–986|year=2017|last1=Hertwig|first1=Ralph|last2=Grüne-Yanoff|first2=Till|hdl=11858/00-001M-0000-002E-8D6F-D|s2cid=25989965 |hdl-access=free}} For instance, while nudges can skirt conscious deliberation and therefore risk being manipulative, boosts require the individual's active cooperation, and thus need to be explicit and transparent. Other important publications by Hertwig tackle questions such as when boosts are more appropriate than nudges,{{cite journal|doi=10.1017/bpp.2016.14|title=When to consider boosting: Some rules for policy-makers|journal=Behavioural Public Policy|volume=1|issue=2|pages=143–161|year=2017|last1=Hertwig|first1=Ralph|doi-access=free|hdl=11858/00-001M-0000-002E-22B3-3|hdl-access=free}} how to boost nutritional health,{{cite journal|doi=10.1111/obr.12659|pmid=29334693|title=The frequency of family meals and nutritional health in children: A meta-analysis|journal=Obesity Reviews|volume=19|issue=5|pages=638–653|year=2018|last1=Dallacker|first1=M.|last2=Hertwig|first2=R.|last3=Mata|first3=J.|hdl=21.11116/0000-0001-5197-9|s2cid=4855616 |hdl-access=free}} how statistical information can best be communicated to improve risk literacy,{{cite journal|doi=10.1126/science.290.5500.2261|pmid=11188724|title=MEDICINE: Communicating Statistical Information|journal=Science|volume=290|issue=5500|pages=2261–2262|year=2000|last1=Hoffrage|first1=U.|last2=Lindsey|first2=S.|last3=Hertwig|first3=R.|last4=Gigerenzer|first4=G.|hdl=11858/00-001M-0000-0025-9B18-3|s2cid=33050943 |hdl-access=free}} and how collective intelligence can be harnessed to boost medical diagnostic decisions.{{cite journal|doi=10.1073/pnas.1601827113|pmid=27432950|title=Boosting medical diagnostics by pooling independent judgments|journal=Proceedings of the National Academy of Sciences|volume=113|issue=31|pages=8777–8782|year=2016|last1=Kurvers|first1=Ralf H. J. M.|last2=Herzog|first2=Stefan M.|last3=Hertwig|first3=Ralph|last4=Krause|first4=Jens|last5=Carney|first5=Patricia A.|last6=Bogart|first6=Andy|last7=Argenziano|first7=Giuseppe|last8=Zalaudek|first8=Iris|last9=Wolf|first9=Max|pmc=4978286 |bibcode=2016PNAS..113.8777K |doi-access=free}}

• {{cite journal|doi=10.1111/j.0956-7976.2004.00715.x|pmid=15270998|title=Decisions from Experience and the Effect of Rare Events in Risky Choice|journal=Psychological Science|volume=15|issue=8|pages=534–539|year=2004|last1=Hertwig|first1=Ralph|last2=Barron|first2=Greg|last3=Weber|first3=Elke U.|last4=Erev|first4=Ido|hdl=11858/00-001M-0000-002E-57CE-F|s2cid=12977034 |hdl-access=free}}
• {{cite journal|doi=10.1037/0033-2909.128.5.728|title=Parental investment: How an equity motive can produce inequality|journal=Psychological Bulletin|volume=128|issue=5|pages=728–745|year=2002|last1=Hertwig|first1=Ralph|last2=Davis|first2=Jennifer Nerissa|last3=Sulloway|first3=Frank J.|pmid=12206192 |hdl=11858/00-001M-0000-0025-913B-1|hdl-access=free}}
• {{cite journal|doi=10.1177/1745691616635594|pmid=27217249|title=Homo Ignorans|journal=Perspectives on Psychological Science|volume=11|issue=3|pages=359–372|year=2016|last1=Hertwig|first1=Ralph|last2=Engel|first2=Christoph|hdl=11858/00-001M-0000-002A-C462-8|s2cid=27556679 |hdl-access=free}}
• {{cite journal|doi=10.1002/(sici)1099-0771(199912)12:4<275::aid-bdm323>3.0.co;2-m|title=The 'conjunction fallacy' revisited: How intelligent inferences look like reasoning errors|journal=Journal of Behavioral Decision Making|volume=12|issue=4|pages=275–305|year=1999|last1=Hertwig|first1=Ralph|last2=Gigerenzer|first2=Gerd|hdl=11858/00-001M-0000-0025-9EBC-6|hdl-access=free}}
• {{cite journal|doi=10.1037/0033-295X.104.1.194|title=The reiteration effect in hindsight bias|journal=Psychological Review|volume=104|pages=194–202|year=1997|last1=Hertwig|first1=Ralph|last2=Gigerenzer|first2=Gerd|last3=Hoffrage|first3=Ulrich|hdl=11858/00-001M-0000-0025-A38B-2|hdl-access=free}}
• {{cite journal|doi=10.1177/1745691617702496|pmid=28792862|title=Nudging and Boosting: Steering or Empowering Good Decisions|journal=Perspectives on Psychological Science|volume=12|issue=6|pages=973–986|year=2017|last1=Hertwig|first1=Ralph|last2=Grüne-Yanoff|first2=Till|hdl=11858/00-001M-0000-002E-8D6F-D|s2cid=25989965 |hdl-access=free}}
• {{cite journal|doi=10.1521/soco.2009.27.5.661|title=Fast and Frugal Heuristics: Tools of Social Rationality|journal=Social Cognition|volume=27|issue=5|pages=661–698|year=2009|last1=Hertwig|first1=Ralph|last2=Herzog|first2=Stefan M.|hdl=11858/00-001M-0000-002E-576B-B|hdl-access=free}}
• {{cite journal|doi=10.1017/s0140525x01004149|title=Experimental practices in economics: A methodological challenge for psychologists?|journal=Behavioral and Brain Sciences|volume=24|issue=3|pages=383–403|year=2001|last1=Hertwig|first1=Ralph|last2=Ortmann|first2=Andreas|pmid=11682798 |hdl=11858/00-001M-0000-002E-5A37-B|s2cid=19346375 |hdl-access=free}}
• {{cite journal|doi=10.1037/0033-295X.112.3.610|title=How forgetting aids heuristic inference|journal=Psychological Review|volume=112|issue=3|pages=610–628|year=2005|last1=Schooler|first1=Lael J.|last2=Hertwig|first2=Ralph|pmid=16060753 |hdl=11858/00-001M-0000-0025-838B-B|hdl-access=free}}

• {{cite book | last=Gigerenzer | first=Gerd | title=Heuristics : the foundations of adaptive behavior | publisher=Oxford University Press | publication-place=Oxford New York | year=2011 | isbn=978-0-19-974428-2 | oclc=606053731}}
• {{cite book | last=Hertwig | first=Ralph | title=Deliberate ignorance : choosing not to know | publisher=The MIT Press | publication-place=Cambridge, Massachusetts | year=2020 | isbn=978-0-262-04559-9 | oclc=1202406773}}
• {{cite book | last=Hertwig | first=Ralph | title=Simple heuristics in a social world | publisher=Oxford University Press | publication-place=New York | year=2013 | isbn=978-0-19-538843-5 | oclc=757177366}}
• {{cite book | last=Hertwig | first=Ralph | title=Taming uncertainty | publisher=MIT Press | publication-place=Cambridge | year=2019 | isbn=978-0-262-03987-1 | oclc=1099683077}}

• Heckhausen Young Scientist Prize (1996){{cite web|url=https://www.dgps.de/index.php?id=95|title=DGPs: Frühere Jahre|website=www.dgps.de|accessdate=23 July 2019}}
• Charlotte and Karl Bühler Early Career Award (2006){{cite web|url=https://www.dgps.de/index.php?id=214|title=DGPs: Laudatio Prof. Dr. Ralph Hertwig|website=www.dgps.de|accessdate=23 July 2019}}
• Member of the German Academy of Sciences Leopoldina (elected 2010){{cite web|url=https://www.leopoldina.org/en/members/list-of-members/list-of-members/member/Member/show/ralph-hertwig/|title=List of Members|website=www.leopoldina.org|accessdate=23 July 2019}}
• Fellow of the Association for Psychological Science (nominated 2011){{cite journal|url=https://www.psychologicalscience.org/observer/a-conversation-with-ralph-hertwig|title=A Conversation with Ralph Hertwig|journal=Aps Observer|date=30 November 2017 |volume=30 |accessdate=23 July 2019}}
• Member of the Wilhelm-Wundt Society (elected 2012){{cite web|url=https://www.wilhelm-wundt-gesellschaft.de/mitglieder/|title=Wilhelm Wundt Gesellschaft – Mietglieder|website=www.wilhelm-wundt-gesellschaft.de|accessdate=23 July 2019}}
• Gottfried Wilhelm Leibniz Prize (2017), Germany's most important research prize, in recognition of Hertwig's pioneering work on the psychology of human judgment and decision making{{cite web|url=https://www.dfg.de/en/funded_projects/prizewinners/leibniz_prize/2017/hertwig/index.html|title=DFG, German Research Foundation – Prof. Dr. Ralph Hertwig|website=www.dfg.de|accessdate=23 July 2019}}

• {{cite news|url=https://www.nytimes.com/2018/07/19/well/parents-kids-sugar-food.html|title=Parents aren't good judges of their kids' sugar intake|work=The New York Times |date=19 July 2018 |accessdate=24 July 2019 |last1=Reynolds |first1=Gretchen }}
• {{cite web|url=https://www.geo.de/wissen/gesundheit/21342-rtkl-faustformeln-wie-wir-mit-einfachen-prinzipien-bessere-entscheidungen|title=Geo Wissen: Wie wir mit einfachen Prinzipien bessere Entscheidungen treffen|website=www.geo.de/magazine|accessdate=24 July 2019}}
• {{cite web|url=https://www.3sat.de/wissen/scobel/scobel-die-kunst-der-entscheidung-100.html#autoplay=true|title=Scobel: Die Kunst der Entscheidung|website=www.3sat.de|accessdate=13 August 2019}}
• {{cite web|url=https://www.3sat.de/wissen/scobel/interview-verantwortung-von-mensch-und-natur-100.html|title=Interview: Verantwortung von Mensch und Natur|website=www.3sat.de|accessdate=13 August 2019}}
• {{cite web|url=https://www.sueddeutsche.de/wissen/gespraech-ueber-entscheidungshilfen-allein-so-schlau-wie-viele-1.90811|title=Gespräch über Entscheidungshilfen – Allein so schlau wie viele|website=www.sueddeutsche.de/wissen|date=17 May 2010 |accessdate=23 July 2019}}
• {{cite web|url=https://www.welt.de/wirtschaft/article153176167/Es-sind-die-leisen-Killer-die-uns-toeten.html?wtrid=onsite.onsitesearch|title=Es sind die leisen Killer, die uns töten|website=www.welt.de|accessdate=6 September 2019}}
• {{cite web|url=https://www.welt.de/kmpkt/article190820841/Was-die-Reihenfolge-der-Geschwister-ueber-die-Persoenlichkeit-aussagt.html?wtrid=onsite.onsitesearch|title=Was die Reihenfolge der Geschwister über die Persönlichkeit aussagt|website=www.welt.de|accessdate=6 September 2019}}

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Category:1963 births

Category:People from Heilbronn

Category:21st-century German psychologists

Category:University of Konstanz alumni

Category:Academic staff of the University of Basel

Category:Living people

Category:Max Planck Institute directors