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Gerdes, Christer
Publications (10 of 19) Show all publications
Franke, A. G., Gränsmark, P., Agricola, A., Schühle, K., Ronnmel, T., Sebastian, A., . . . Lieb, K. (2017). Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial. European Neuropsychopharmacology, 27(3), 248-260
Open this publication in new window or tab >>Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial
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2017 (English)In: European Neuropsychopharmacology, ISSN 0924-977X, E-ISSN 1873-7862, Vol. 27, no 3, p. 248-260Article in journal (Refereed) Published
Abstract [en]

Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2 x 200 mg modafinil, 2 x 20 mg methylphenidate, and 2 x 200 mg caffeine or placebo in a 4 x 4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.

Keywords
Cognitive enhancement, Chess, Stimulants, Methylphenidate, Modafinil, Caffeine
National Category
Sociology (excluding Social Work, Social Psychology and Social Anthropology) Neurology Pharmaceutical Sciences
Identifiers
urn:nbn:se:su:diva-142704 (URN)10.1016/j.euroneuro.2017.01.006 (DOI)000396971100005 ()28119083 (PubMedID)
Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2022-02-28Bibliographically approved
Gerdes, C. & Wadensjö, E. (2016). Post-enlargement migration and adjustment in a receiving country: the case of Sweden. In: Martin Kahanec, Klaus F. Zimmermann (Ed.), Labor migration, EU enlargement, and the great recession: (pp. 123-138). Berlin: Springer Berlin/Heidelberg
Open this publication in new window or tab >>Post-enlargement migration and adjustment in a receiving country: the case of Sweden
2016 (English)In: Labor migration, EU enlargement, and the great recession / [ed] Martin Kahanec, Klaus F. Zimmermann, Berlin: Springer Berlin/Heidelberg, 2016, p. 123-138Chapter in book (Refereed)
Abstract [en]

Sweden’s immigration policy has changed drastically on several occasions over time. Immigration policy was very liberal from the 1860s until WW1, with no requirements regarding passports, visas or work permits, although international migration mainly involved emigration during this period in the context of Sweden, with wages lower than in neighboring countries. The policy changed in 1914 after the start of WW1, and the controls became gradually more stringent during the war, with a work permit compulsory and difficult to attain for those who wanted to move to Sweden for work. While the immigration regulation remained after the war, the requirements for those coming from other Nordic countries were made slightly less stringent. The work permit requirement in the interwar-period was motivated by the high unemployment rate, based upon the notion that jobs should be reserved for natives.

Place, publisher, year, edition, pages
Berlin: Springer Berlin/Heidelberg, 2016
National Category
Economics
Identifiers
urn:nbn:se:su:diva-126652 (URN)10.1007/978-3-662-45320-9_6 (DOI)9783662453193 (ISBN)
Available from: 2016-02-10 Created: 2016-02-10 Last updated: 2022-02-23Bibliographically approved
Gerdes, C. (2014). A Comparative Study of Net Transfers for Different Immigrant Groups: Evidence from Germany. International migration (Geneva. Print), 52(4), 175-208
Open this publication in new window or tab >>A Comparative Study of Net Transfers for Different Immigrant Groups: Evidence from Germany
2014 (English)In: International migration (Geneva. Print), ISSN 0020-7985, E-ISSN 1468-2435, Vol. 52, no 4, p. 175-208Article in journal (Refereed) Published
Abstract [en]

In the wake of immigration to Western welfare states, certain aspects, such as the financial cost of providing social welfare, have become a subject of debate. The net amount of costs and tax payments, sometimes referred to as net transfers, has been used as a measure for evaluating the sustainability of welfare state systems. The present study analyses determinants of the volume of net transfers in Germany in 2002 with reference to immigrants from Poland, Turkey, former Yugoslavia, Lebanon and Iran. The study focuses on the differences and similarities between their outcomes. In line with previous research, the results below suggest that employment situation and family composition explain a large part of the differences in net transfers. One outcome that has not previously been adequately addressed, however, is that the legal immigration status granted on arrival in Germany is of considerable importance.

National Category
Economics
Identifiers
urn:nbn:se:su:diva-106880 (URN)10.1111/j.1468-2435.2009.00573.x (DOI)000339959300014 ()
Available from: 2014-08-26 Created: 2014-08-26 Last updated: 2022-02-23Bibliographically approved
Gerdes, C. & Wadensjö, E. (2014). Utvidgningen av EU och arbetskraftsinvandringen: de svenska erfarenheterna. Multiethnica. Meddelande från Centrum för multietnisk forskning, Uppsala universitet (35), 3-8
Open this publication in new window or tab >>Utvidgningen av EU och arbetskraftsinvandringen: de svenska erfarenheterna
2014 (Swedish)In: Multiethnica. Meddelande från Centrum för multietnisk forskning, Uppsala universitet, ISSN 0284-396X, no 35, p. 3-8Article in journal (Other academic) Published
National Category
Economics
Identifiers
urn:nbn:se:su:diva-104497 (URN)
Available from: 2014-06-11 Created: 2014-06-11 Last updated: 2022-02-23Bibliographically approved
Dreber, A., Gerdes, C. & Gränsmark, P. (2013). Beauty queens and battling knights: Risk taking and attractiveness in chess. Journal of Economic Behavior and Organization, 90(June), 1-18
Open this publication in new window or tab >>Beauty queens and battling knights: Risk taking and attractiveness in chess
2013 (English)In: Journal of Economic Behavior and Organization, ISSN 0167-2681, E-ISSN 1879-1751, Vol. 90, no June, p. 1-18Article in journal (Refereed) Published
Abstract [en]

We explore the relationship between attractiveness and risk taking in chess. We use a large international panel dataset on high-level chess competitions which includes a control for the players’ skill in chess. This data is combined with results from a survey on an online labor market where participants were asked to rate the photos of 626 expert chess players according to attractiveness. Our results suggest that male chess players choose significantly riskier strategies when playing against an attractive female opponent, even though this does not improve their performance. Women's strategies are not affected by the attractiveness of the opponent.

Keywords
Risk taking, Attractiveness, Chess, Gender differences
National Category
Economics and Business
Identifiers
urn:nbn:se:su:diva-89833 (URN)10.1016/j.jebo.2013.03.006 (DOI)000320414000001 ()
Note

AuthorCount: 3;

Available from: 2013-05-13 Created: 2013-05-13 Last updated: 2022-02-24Bibliographically approved
Gerdes, C. (2013). Does immigration induce native flight from public schools?. The annals of regional science, 50(2), 645-666
Open this publication in new window or tab >>Does immigration induce native flight from public schools?
2013 (English)In: The annals of regional science, ISSN 0570-1864, E-ISSN 1432-0592, Vol. 50, no 2, p. 645-666Article in journal (Refereed) Published
Abstract [en]

For more than a century, parents in Denmark could enroll their children into privately operated free schools. Results from this study indicate an increase in native Danes' propensity to enroll their children in free schools as the share of children with immigrant background becomes larger in their municipality of residence. The effect is most pronounced in small, and medium-sized municipalities, while it seems absent in larger municipalities. The study explores changes in the immigrant population in Danish municipalities 1992-2004, a period marked by a substantial influx of refugees, where a state-sponsored placement policy restricted their initial choice of residence.

National Category
Economics Environmental Sciences Economic Geography
Identifiers
urn:nbn:se:su:diva-89704 (URN)10.1007/s00168-012-0514-4 (DOI)000316823200014 ()
Note

AuthorCount:1;

Available from: 2013-05-08 Created: 2013-05-06 Last updated: 2022-02-24Bibliographically approved
Dreber, A., Gerdes, C., Gränsmark, P. & Little, A. C. (2013). Facial masculinity predicts risk and time preferences in expert chess players. Applied Economics Letters, 20(16), 1477-1480
Open this publication in new window or tab >>Facial masculinity predicts risk and time preferences in expert chess players
2013 (English)In: Applied Economics Letters, ISSN 1350-4851, E-ISSN 1466-4291, Vol. 20, no 16, p. 1477-1480Article in journal (Refereed) Published
Abstract [en]

In this study, we examine the relationship between risk-taking, impatience and facial masculinity in expert chess players. We combine a large panel data set from high-level chess games with measures of both risk-taking and impatience in chess with facial masculinity, a proxy for testosterone exposure in puberty. We find that male players with high pubertal testosterone exposure are more impatient by playing shorter chess games. For female players, we find that facial masculinity is negatively correlated with risk-taking.

Keywords
risk preferences, time preferences, chess, gender differences
National Category
Sociology
Identifiers
urn:nbn:se:su:diva-94017 (URN)10.1080/13504851.2013.826861 (DOI)000323632600007 ()
Note

AuthorCount:4;

Available from: 2013-09-27 Created: 2013-09-24 Last updated: 2022-02-24Bibliographically approved
Almenberg, J. & Gerdes, C. (2012). Exponential growth bias and financial literacy. Applied Economics Letters, 19(17), 1693-1696
Open this publication in new window or tab >>Exponential growth bias and financial literacy
2012 (English)In: Applied Economics Letters, ISSN 1350-4851, E-ISSN 1466-4291, Vol. 19, no 17, p. 1693-1696Article in journal (Refereed) Published
Abstract [en]

The tendency to underestimate the future value of a variable growing at a constant rate, an example of exponential growth bias, has been linked to household financial decision-making. We show that exponential growth bias and standard measures of financial literacy are negatively correlated in a representative sample of Swedish adults. Since financial literacy is linked to household decision-making, our results indicate that examining the relationship between exponential growth bias and household finance without adequate controls for financial literacy may generate biased results.

Keywords
exponential growth bias, financial literacy, household finance, survey data
National Category
Sociology Economics and Business
Identifiers
urn:nbn:se:su:diva-79705 (URN)10.1080/13504851.2011.652772 (DOI)000302502800008 ()
Note

AuthorCount:2;

Available from: 2012-09-14 Created: 2012-09-11 Last updated: 2022-02-24Bibliographically approved
Gerdes, C., Schultz-Nielsen, M. L. & Wadensjö, E. (2011). Indvandringens betydning for de offentlige finanser i Danmark. Danmark: The Rockwool Foundation Research Unit
Open this publication in new window or tab >>Indvandringens betydning for de offentlige finanser i Danmark
2011 (Danish)Report (Refereed)
Place, publisher, year, edition, pages
Danmark: The Rockwool Foundation Research Unit, 2011. p. 32
Series
University Press of Southern Denmark, Odense ; 24
National Category
Economics
Identifiers
urn:nbn:se:su:diva-60093 (URN)978-87-90199-58-6 (ISBN)
Available from: 2011-08-08 Created: 2011-08-08 Last updated: 2022-02-24Bibliographically approved
Gerdes, C. & Wadensjö, E. (2011). Is immigration challenging the economic sustainability of the Nordic welfare model?. In: Jon Kvist, Johan Fritzell, Björn Hvinden, Olli Kangas (Ed.), Changing social equality. The Nordic welfare model in the 21st century (pp. 187-199). Bristol: The Policy Press
Open this publication in new window or tab >>Is immigration challenging the economic sustainability of the Nordic welfare model?
2011 (English)In: Changing social equality. The Nordic welfare model in the 21st century / [ed] Jon Kvist, Johan Fritzell, Björn Hvinden, Olli Kangas, Bristol: The Policy Press , 2011, p. 187-199Chapter in book (Refereed)
Place, publisher, year, edition, pages
Bristol: The Policy Press, 2011
National Category
Economics
Identifiers
urn:nbn:se:su:diva-64179 (URN)9781847426604 (ISBN)
Available from: 2011-11-14 Created: 2011-11-14 Last updated: 2022-02-24Bibliographically approved
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