Normal Curves: Sexy Science, Serious Statistics

Wear red and drive men wild with lust – or so says scientific research on color’s role in human mating. But can a simple color swap really boost a woman’s hotness score? In this episode, we delve into the evidence behind the Red Dress Effect, from a controversial first study in college men to what the latest research says about who this trick might work for (and who it might not). Along the way we encounter red monkey butts, old-Internet websites, the Winner’s Curse in scientific research, adversarial collaborations, and why size (ahem, sample size) really does matter. Statistical topicsReproducibility crisis in psychologySample sizeSelection biasWinner’s curseCohen’s d standardized effect sizeAdversarial collaborationMeta-analysisPreregistrationPublication biasStatistical moderatorsMethodological morals“The smaller the sample, the flashier the result, the less you should trust it.”“Good scientists learn from their statistical mistakes and fix them.”ReferencesClarke, G. How to Be Sexy: 7 Weird (But True) Rules of Attraction. Allure. January 23, 2013.Nuzzo, R. Vying for a soul mate? Psych out the competition with science. Los Angeles Times. December 8, 2008. Vying for a Soul Mate on the Today Show, December 30, 2008.Elliot, A.J. and Niesta, D. Romantic red: red enhances men's attraction to women.  Journal of personality and social psychology. 2008; 95: 1150 – 1164. Lehrer, J. The Truth Wears Off. The New Yorker, December 5, 2010. MacMahon, B., Yen, S., Trichopoulos, D., Warren, K. and Nardi, G. Coffee and cancer of the pancreas. New England Journal of Medicine. 1981; 304: 630-633.Ioannidis, J.P. Why most published research findings are false. PLoS medicine. 2005; 2(8), e124 Lehmann, G.K., Elliot, A.J. and Calin-Jageman, R.J. Meta-analysis of the effect of red on perceived attractiveness. Evolutionary Psychology. 2018; 16: 1474704918802412. Pazda, A.D., Thorstenson, C.A. and Elliot, A.J. The effect of red on attractiveness for highly attractive women. Curr Psychol. 2023; 42: 8066–8073Kristin and Regina’s online courses: Demystifying Data: A Modern Approach to Statistical Understanding  Clinical Trials: Design, Strategy, and Analysis Medical Statistics Certificate Program  Writing in the Sciences Epidemiology and Clinical Research Graduate Certificate Program Chapters(00:00) - Introduction (06:04) - Red Dress Effect on TV (10:01) - Red Monkey Butts (12:56) - 2008 Study on Romantic Red (16:04) - HotOrNot.com (20:10) - 2008 Study Results (26:04) - Cohen’s d Standardized Effect Size (31:46) - Problems with Small Sample Sizes (35:06) - Winner’s Curse and Publication Bias (39:34) - Reproducibility Crisis (44:57) - Adversarial Collaboration (49:55) - Meta-Analysis and Pre-Registration (56:17) - Adversarial Discussion Sections and Updates (01:03:49) - Latest Red Study (01:07:20) - Wrap-Up

Can vitamin D really boost your athletic performance while slashing cancer risks? The hosts delve into claims of this miracle vitamin, discussing studies that tease out the truth. They tackle the challenges of observational studies and ecological fallacies, revealing how misleading correlations can be. Even promising trials, like VITAL, show no major benefits after rigorous testing. Their journey underscores that while vitamin D is essential for bones, more doesn't always mean better health, urging caution in supplementation.

Is America really facing an epidemic of vitamin D deficiency? While this claim is widely believed, the story behind it is packed with twists, turns, and some pesky statistical cockroaches. In this episode, we’ll dive into a study on Hawaiian surfers, expose how shifting goalposts can create an epidemic, tackle dueling medical guidelines, and flex our statistical sleuthing skills. By the end, you might wonder if the real deficiency lies in the data.Statistical topicsdichotomizationnormal distribution standard deviationresearcher biasesconflicts of intereststatistical sleuthingMethodologic morals“Arbitrary thresholds make for arbitrary diseases.”“Statistical errors are like cockroaches: Where there’s one, there’s many.”Note that all blood vitamin D levels discussed in the podcast are 25-hydroxyvitamin D levels given in units of ng/ml. To convert from ng/ml to nmol/L, use the formula: nmol/L=2.5*ng/ml. For example, a vitamin D level of 30 ng/mL corresponds to 75 nmol/L.CitationsDr. Rhonda Patrick: Micronutrients for Health & Longevity. Huberman Lab Podcast. May 1, 2022Noh CK, Lee MJ, Kim BK, et al. A Case of Nutritional Osteomalacia in Young Adult Male. J Bone Metab. 2013; 20:51-55.Binkley N, Novotny R, Krueger D, et al. Low vitamin D status despite abundant sun exposure. J Clin Endocrinol Metab. 2007;92:2130-5. Malabanan A, Veronikis IE, Holick MF. Redefining Vitamin D Insufficiency. Lancet. 1998;351:805-6. Dawson-Hughes B, Heaney RP, Holick MF, et al. Estimates of optimal vitamin D status. Osteoporos Int. 2005;16:713-6. Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266-81. Cui A, Xiao P, Ma Y, et al. Prevalence, trend, and predictor analyses of vitamin D deficiency in the US population, 2001-2018. Front Nutr. 2022;9:965376. Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011;96:53-8. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011;96:1911-30. Manson JE, Brannon PM, Rosen CJ, et al. Vitamin D deficiency-is there really a pandemic. N Engl J Med. 2016;375:1817-20. Conti G, Chirico V, Lacquaniti A, et al. Vitamin D intoxication in two brothers: be careful with dietary supplements. J Pediatr Endocrinol Metab. 2014;27:763-7.Holick, Michael, et al. The UV Advantage. Ibooks, 2004.Holick, Michael F. The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems. Penguin Publishing Group, 2011.Szabo, Liz. Vitamin D, the Sunshine Supplement, Has Shadowy Money Behind It. The New York Times. August 18, 2018.Lee JM, Smith JR, Philipp BL, Chen TC, Mathieu J, Holick MF. Vitamin D deficiency in a healthy group of mothers and newborn infants. Clin Pediatr. 2007;46:42-4. Holick MF. Vitamin D deficiency: what a pain it is. Mayo Clin Proc. 2003;78:1457-9.Passeri G, Pini G, Troiano L, et al. Low Vitamin D Status, High Bone Turnover, and Bone Fractures in Centenarians. J Clin Endocrinol Metab. 2003;88:5109-15. Armstrong, David. The Child Abuse Contrarian. ProPublica. September 16, 2018.Irwig MS, Kyinn M, Shefa MC. Financial Conflicts of Interest Among Authors of Endocrine Society Clinical Practice Guidelines. J Clin Endocrinol Metab. 2018;103:4333-38. Demay MB, Pittas AG, Bikle DD, et al. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2024;109:1907-47.McCartney CR, McDonnell ME, Corrigan MD, et al. Vitamin D Insufficiency and Epistemic Humility: An Endocrine Society Guideline Communication. J Clin Endocrinol Metab. 2024; 109:1948–54.See our detailed notes hereKristin and Regina’s online coursesDemystifying Data: A Modern Approach to Statistical Understanding Clinical Trials: Design, Strategy, and AnalysisMedical Statistics Certificate Program Writing in the SciencesEpidemiology and Clinical Research Graduate Certificate ProgramPrograms that we teach in:Epidemiology and Clinical Research Graduate Certificate Program Find us on:Kristin -  LinkedIn & Twitter/XRegina - LinkedIn & ReginaNuzzo.comChapters:(00:00) - Introduction (02:55) - Sources of Vitamin D (05:43) - What is Vitamin D & Why Do We Need It? (07:07) - Vitamin D Deficiency & Rickets (10:03) - Defining Vitamin D Deficiency – Changing the Goalposts ...

Sweaty t-shirt dating parties, sex pheromone dating sites, choosing your dating partner by sniffing them up — wacko fringe fads or evidence-based mating strategies? And what does your armpit stain have to do with your kids’ immune systems, or hormonal contraceptive pills, or divorce rates? In this episode of Normal Curves, Kristin and Regina reach back into the 1990s and revisit the scientific paper that started it all: The Sweaty T-Shirt Study. They bring a sharp eye and open mind, critically examining the study and following the line of research to today. Along the way, they encounter interesting statistical topics—including correlated observations, within-person study design, and bar-chart blasphemy—with a short, surprising detour into Neanderthal sex. Statistical topicsCorrelated observationsWithin-person study designBar charts Data and methodological transparencyCherry-pickingMeta-analysisMultiple testingPost-hoc analysesMethodological morals“Repeat after me: Bar charts are not for numerical data.”“Those who ignore dependencies in their data are destined for flawed conclusions.”ReferencesNuzzo, R. Ah, Love at first whiff. Los Angeles Times. May 19, 2008.Papamarko, S. Pheromone parties attempt to match singles by scent. Yahoo!life. April 12, 2012.Sainani, K. Stone Age Gene Swap. Stanford Magazine. November/December 2011.Aldhous, P. Darling, You Smell Wonderfully Different. New Scientist. 6 May 1995.Wedekind C, Seebeck T, Bettens F, Paepke AJ. MHC-dependent mate preferences in humans. Proc Biol Sci. 1995; 260(1359):245-249. doi:10.1098/rspb.1995.0087Hedrick P, Loeschcke V. MHC and mate selection in humans?. Trends Ecol Evol. 1996;11(1):24. doi:10.1016/0169-5347(96)80237-0Wedekind C, Seebeck T. Reply from C. Wedekind and T. Seebeck. Trends Ecol Evol. 1996;11(1):24-25. doi:10.1016/0169-5347(96)81061-5Wedekind C, Füri S. Body odour preferences in men and women: do they aim for specific MHC combinations or simply heterozygosity?. Proc Biol Sci. 1997;264(1387):1471-1479. doi:10.1098/rspb.1997.0204Havlíček J, Winternitz J, Roberts SC. Major histocompatibility complex-associated odour preferences and human mate choice: near and far horizons. Philos Trans R Soc Lond B Biol Sci. 2020;375(1800):20190260. doi:10.1098/rstb.2019.0260Kristin and Regina’s online courses: Demystifying Data: A Modern Approach to Statistical Understanding  Clinical Trials: Design, Strategy, and Analysis Medical Statistics Certificate Program  Writing in the Sciences Epidemiology and Clinical Research Graduate Certificate Program Programs that we teach in:Epidemiology and Clinical Research Graduate Certificate Program Find us on:Kristin -  LinkedIn & Twitter/XRegina - LinkedIn & ReginaNuzzo.com(00:00) - Introduction (02:27) - Pheromone Dating Parties (06:57) - Pheromone Dating Sites and Genetic Matching (10:47) - The Science of HLA Genes and Mate Selection (18:08) - Breaking Down the Original Sweaty T-Shirt Study (24:02) - Study Design Flaws and Data Transparency Issues (28:25) - Statistical Flaws: Correlated Observations Explained (36:16) - Analyzing the Study's Questionable Results (39:12) - The Pill's Influence on Scent Preferences (42:20) - Overstated Conclusions and Wandering Discussions (47:47) - Media Reactions and the Study’s Public Impact (54:00) - Other Studies and their results (56:39) - Conclusion

Join a vibrant discussion where science meets fun! Discover how two professors forged a lasting friendship during their PhDs. They dive into the art of evaluating scientific studies and the importance of clear communication. Reflect on personal health journeys and how they faced biases in research. Hear a heartfelt story about cochlear implants and the transformative power of clinical trials. Plus, get a glimpse into their engaging teaching styles and the provocative topics that shape their lively conversations.

Dive into the captivating world where science meets statistics! The hosts create a lively atmosphere, breaking down complex research with humor and relatable anecdotes. With a focus on demystifying academic papers, they empower listeners to think critically about data. Expect engaging conversations filled with irreverent fun, while gaining tools to assess scientific studies like a pro. Perfect for anyone curious about the truth behind the numbers!