All posts by Amy Alkon

About Amy Alkon

Amy Alkon is the irreverent purveyor of “science news you can use.” Her most recent book is the science-based and bitingly funny "Good Manners for Nice People Who Sometimes Say F*ck” (St. Martin’s Griffin, 2014). Her award-winning, science-based syndicated column runs in about 100 newspapers. She is the 2015 president of the Applied Evolutionary Psychology Society and hosts her own weekly radio show, “ Nerd Your Way to a Better Life,” featuring the luminaries of behavioral science.

Evolutionary Psychiatry Group Started

It’s the Evolutionary Psychiatry Special Interest Group (EPSIG) at the Royal College of Psychiatrists in the UK.

They list their objectives:

  1. Raise awareness of the value of understanding the contribution of evolutionary theory to psychiatry.

  2. Encourage research into the evolutionary psychiatry.

  3. Provide a forum for psychiatrists and others to discuss evolutionary models, research ideas and data with fellow evolutionists.

  4. Facilitate networking with academic institutions and evolutionary scientists, biologists, psychotherapists, psychologists and other disciplines such as philosophy.

  5. Keep members and supporters of the SIG informed via a webpage and newsletter.

  6. Organise workshops, symposia and conferences on Evolutionary Psychiatry and related subjects.

  7. Organise sessions at the WPA and the RCPsych’s International Congress as well as with other college Faculties and Divisions.

Via psychiatrist and researcher @RandyNesse, whose own work applying evolutionary theory to psychiatry and medicine can be seen here.

The Evolution Of “Creepiness”

Evolutionary social psychologist Francis T. McAndrew has a new paper out in on “creepiness.” The abstract:

Surprisingly, until now there has never been an empirical study of “creepiness.” An international sample of 1341 individuals responded to an online survey. Males were perceived as being more likely to be creepy than females, and females were more likely to associate sexual threat with creepiness. Unusual nonverbal behavior and characteristics associated with unpredictability were also predictors of creepi- ness, as were some occupations and hobbies. The results are consistent with the hypothesis that being “creeped out” is an evolved adaptive emotional response to ambiguity about the presence of threat that enables us to maintain vigilance during times of uncertainty.

Smithsonian.com’s Linda Rodriguez McRobbie quotes McAndrew:

“[Creepy is] about the uncertainty of threat. You’re feeling uneasy because you think there might be something to worry about here, but the signals are not clear enough to warrant your doing some sort of desperate, life-saving kind of thing,” explains McAndrew.

 

Being creeped out is different from fear or revulsion, he says; in both of those emotional states, the person experiencing them usually feels no confusion about how to respond. But when you’re creeped out, your brain and your body are telling you that something is not quite right and you’d better pay attention because it might hurt you.

 

This is sometimes manifest in a physical sensation: In 2012, researchers from the University of Groningen in the Netherlands found that when subjects felt creeped out, they felt colder and believed that the temperature in the room had actually dropped. (Dickens might not have used the word in quite the way it soon came to mean, but he did get the chills part right.)

 

That physical response further heightens your senses, and, continues McAndrew: “You don’t know how to act but you’re really concerned about getting more information … It kind of takes your attention and focuses it like a laser on this particular stimulus, whatever it is.”

 

Whatever it is can be things, situations, places and, of course, people. Most creepy research has looked at what makes people seem creepy. For example, the 2012 study successfully creeped people out by exposing them to others who didn’t practice normal non-verbal behavior.

 

…Perhaps the biggest predictor of whether someone was considered creepy was unpredictability. “So much of [what is creepy] is about wanting to be able to predict what’s going to happen, and that’s why creepy people creep us out – because they’re unpredictable,” explains McAndrews, noting that the 2012 study also seemed to underscore that point. “We find it hard to know what they’re going to do next.”

 

Creepiness in people is also related to individuals breaking certain tacit social rules and conventions, even if sometimes that rule breaking is necessary. This becomes more evident when we look at the kinds of jobs a majority of respondents found creepy. However unfairly, taxidermists and funeral directors  were among the creepiest professions listed in McAndrew and Koehnke’s survey, likely because these people routinely interact with macabre things that most other people would avoid.

 

“If you’re dealing with somebody who’s really interested in dead things, that sets off alarm bells. Because if they’re different in that way, what other unpleasant ways they might be different?” says McAndrew.

The Evolution Of Shame: Why Shame Is Adaptive

In The Boston Globe, Megan Scudellari reports on recent research by UCSB evolutionary psychologist Daniel Sznycer and his colleagues on shame:

In a new study published in the Proceedings of the National Academy of Sciences, researchers argue that shame evolved as a defense to prevent individuals from damaging important social relationships.

 

“When people find out negative things about you — say, that you steal or are physically weak or sexually unfaithful — this causes them to be less helpful and more exploitative toward you,” says study author Daniel Sznycer, an evolutionary psychologist at the University of California Santa Barbara.

 

That could be a threat to one’s welfare and success in life — especially back in early human hunter-gatherer social groups. It is possible therefore that humans evolved shame as a way to defend themselves by avoiding or concealing things that would make others devalue them.

 

To test this “defense” hypothesis of shame, Sznycer and colleagues recruited over 900 adults across the US, India, and Israel to answer questions about two dozen fictional scenarios. Each scenario depicted traits expected to invoke shame, such as stinginess, infidelity, and physical weakness.

 

They asked one set of participants to report — on a scale of 1 to 7 — how much shame they would feel if they themselves were committing the act in the scenario, such as stealing money from another person. People in a second group were asked to be observers, and to rate how negatively they would view the offending person. How would they feel, for example, about a person they spotted stealing money?

 

In similar experiments, the team gauged individuals’ feelings of sadness and anxiety in response to each scenario.

 

If shame is, in fact, a defense against the judgment of others, the researchers expected the intensity of shame felt in the first group to match up with the intensity of negative perception, or “devaluation,” of the second group. Such a match would suggest shame evolved to deal with the threat of being devalued by one’s peers.

 

That is exactly what they found. “The shame scores in each of the three countries were very highly correlated with the magnitude of devaluation of those in the audience situation,” says Sznycer. Morever, feelings of anxiety and sadness did not match up, supporting the idea that shame evolved as a defense against being devalued.

 

The findings suggest that shame is an innate emotion that evolved across different cultures, and that it is an evolved, rational trait designed to protect the individual.

Supplemental information about the study is here.

More from Daniel Sznycer about his research and thinking on shame (from his UCSB page):

The psychology of shame.

Ancestrally, the degree to which other people valued one’s welfare would have affected one’s access to resources such as food, mates, and support in times of conflict. Becoming less socially valuable would have entailed fitness costs. This adaptive problem is expected to have shaped adaptations for decreasing the likelihood and the costs of being socially devalued. We proposed that one such adaptation is the emotion of shame. Using this basic functional framework, and in collaboration with John Tooby and Leda Cosmides, I developed a theory of shame—the information threat theory of shame (ITTS)—and tested predictions derived from it.

 

Failing to deploy countermeasures against devaluation when one is devalued is a costly mistake. Deploying shame measures when one is not devalued is another type of mistake. Thus, effective shame countermeasures require an understanding of what does and does not elicit devaluation. In fact, we found a strong match between the extent to which a particular situation elicits devaluation on one hand (audience’s perspective) and shame on the other (discredited individual’s perspective).

 

According to the ITTS, what counts as socially valuable differs from domain to domain. For example, in the domain of cooperation, a track record of reciprocating is viewed favorably. In the domain of mating, value is indexed by things such as cues of fertility and pathogen-resistance. Consistent with this, we obtained evidence that both the elicitors and the motivational responses of shame vary across domains.

 

The more a discrediting piece of information becomes widely known, the stronger the shame response is expected to be. Supporting this ITTS prediction, we discovered that the extent of publicity of a discrediting behavior modulates the intensity of shame—but not the intensity of guilt.

 

The ITTS was also instrumental in making functional sense of cultural differences in shame. The cost of being devalued by an existing relationship partner can be attenuated by forming alternative relationships. Therefore, cultures where opportunities to build new relationships are perceived as being scarce are expected to also display higher proneness to shame—and vice versa. In collaboration with Kosuke Takemura, Andy Delton, Kosuke Sato, Tess Robertson, Leda Cosmides, & John Tooby, we found evidence supporting this prediction among American, English, and Japanese subjects.

How Understanding Evolution Can Help Us Treat Cancer

Evolutionary scientists Athena Aktipis, Randolph Nesse, and their colleagues and grad students are doing fascinating and important research in evolutionary medicine, and — the topic of this post — they have been applying an evolutionary framework to cancer, in order to think about it and treat it more effectively.

Athena’s post-doctoral fellows, Amy Boddy and Helen Wasielewski, pulled together these exciting examples just below of the work they’re all doing in this area (and are surely researchers to keep an eye on for more exciting work to come).

 

How Understanding Evolution Can Help Us Treat Cancer 
This is a foundational paper in the field of cancer evolution and explains how cancer progression is an evolutionary process and how understanding this evolutionary process can change how we think about and treat cancer.

Aktipis, C.A., Nesse, R. (2013). Evolutionary foundations for cancer biology. Evolutionary Applications. 6(1) 144-159. DOI: 10.1111/eva.12034 Open access.

Abstract: New applications of evolutionary biology are transforming our understanding of cancer. The articles in this special issue provide many specific examples, such as microorganisms inducing cancers, the significance of within-tumor heterogeneity, and the possibility that lower dose chemotherapy may sometimes promote longer survival. Underlying these specific advances is a large-scale transformation, as cancer research incorporates evolutionary methods into its toolkit, and asks new evolutionary questions about why we are vulnerable to cancer. Evolution explains why cancer exists at all, how neoplasms grow, why cancer is remarkably rare, and why it occurs despite powerful cancer suppression mechanisms. Cancer exists because of somatic selection; mutations in somatic cells result in some dividing faster than others, in some cases generating neoplasms. Neoplasms grow, or do not, in complex cellular ecosystems. Cancer is relatively rare because of natural selection; our genomes were derived disproportionally from individuals with effective mechanisms for suppressing cancer. Cancer occurs nonetheless for the same six evolutionary reasons that explain why we remain vulnerable to other diseases. These four principles—cancers evolve by somatic selection, neoplasms grow in complex ecosystems, natural selection has shaped powerful cancer defenses, and the limitations of those defenses have evolutionary explanations—provide a foundation for understanding, preventing, and treating cancer.

 

Applying Life History Theory At The Cancer Cell Level
This paper applies evolutionary life history theory at the cancer cell level and describes the likely tradeoffs between cell proliferation and cell survival and how these tradeoffs may affect the tumor’s response to different treatment strategies.

Aktipis, C. A., Boddy, A., Brown, J., Gatenby, R, Maley C. C. (2013). Life history tradeoffs in cancer evolution. Nature Reviews Cancer, 13, 883-892. DOI: 10.1038/nrc3606

Abstract: Somatic evolution during cancer progression and therapy results in tumour cells that show a wide range of phenotypes, which include rapid proliferation and quiescence. Evolutionary life history theory may help us to understand the diversity of these phenotypes. Fast life history organisms reproduce rapidly, whereas those with slow life histories show less fecundity and invest more resources in survival. Life history theory also provides an evolutionary framework for phenotypic plasticity, which has potential implications for understanding ‘cancer stem cells’. Life history theory suggests that different therapy dosing schedules might select for fast or slow life history cell phenotypes, with important clinical consequences.

 

Treating Cancer Like an Infectious Disease
Chemotherapy resistance is a major problem in cancer biology, yet we have no strategies to target resistance. Similar to resistance to antibiotics in infectious diseases, this paper describes costs and benefits of controlling a tumor population instead of attempting to kill all the cancer cells.

Jansen, G., Gatenby, B., Aktipis, C.A. (2015). Control vs. eradication: Adopting strategies from infectious disease treatment to cancer. Proceedings of the National Academy of Sciences of the United States of America 112.4 937. DOI: 10.1073/pnas.1420297111

Abstract: Clinical treatment for metastatic cancer has traditionally entailed administering the highest possible dose in the shortest period, a strategy known as high-dose density therapy. The implicit goal is complete eradication. Unfortunately, a systemic cure for most metastatic cancers remains elusive, and the role of chemotherapy has been reduced to prolonging life and ameliorating symptoms.

 

Cancer is Common to Multicellular Life
This paper is a review of cancer in species across the tree of life. It shows cancer or cancer-like phenomena are found in almost all multicellular organisms.

Aktipis, C. A., Boddy, A., Jansen, G., Hochberg, M., Maley, C., Hibner, U., Wilkinson, G. (2015). Cancer across life: Cooperation and cheating in multicellularity. Philosophical Transactions of the Royal Society B. Published online June 8 DOI: 10.1098/rstb.2014.0219 Open access.

Abstract: Multicellularity is characterized by cooperation among cells for the development, maintenance and reproduction of the multicellular organism. Cancer can be viewed as cheating within this cooperative multicellular system. Complex multicellularity, and the cooperation underlying it, has evolved independently multiple times. We review the existing literature on cancer and cancer-like phenomena across life, not only focusing on complex multicellularity but also reviewing cancer-like phenomena across the tree of life more broadly. We find that cancer is characterized by a breakdown of the central features of cooperation that characterize multicellularity, including cheating in proliferation inhibition, cell death, division of labour, resource allocation and extracellular environment maintenance (which we term the five foundations of multicellularity). Cheating on division of labour, exhibited by a lack of differentiation and disorganized cell masses, has been observed in all forms of multicellularity. This suggests that deregulation of differentiation is a fundamental and universal aspect of carcinogenesis that may be underappreciated in cancer biology. Understanding cancer as a breakdown of multicellular cooperation provides novel insights into cancer hallmarks and suggests a set of assays and biomarkers that can be applied across species and characterize the fundamental requirements for generating a cancer.

 

Reproducing versus Maintaining the Body is Important to Cancer Risk
All species vary in the investment of cancer defense mechanisms. Why certain species are more susceptible to cancer, while others are cancer resistant is an open question. This paper explore whether reproductive tradeoffs cancer influence an organism’s risk for getting cancer.

Boddy, A., Kokko, H., Breden, F., Wilkinson, G. Aktipis, C. A., (2015). Cancer susceptibility and reproductive tradeoffs: A model of the evolution of cancer defenses. Philosophical Transactions of the Royal Society B. Published online June 8 Open access. DOI: 10.1098/rstb.2014.0220

Abstract: The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction.

 

Cancer as an Evolutionary Process
Cancer is an evolutionary process, yet this concept is overlooked in cancer research.

Aktipis, C. A., Kwan, V.S.Y., Johnson, K. A., Neuberg, S.L., Maley, C.C. (2011) Overlooking evolution: A systematic analysis of cancer relapse and therapeutic resistance research. PLoS ONE 6(11): e26100. doi:10.1371/journal.pone.0026100 Open access.

Abstract: Cancer therapy selects for cancer cells resistant to treatment, a process that is fundamentally evolutionary. To what extent, however, is the evolutionary perspective employed in research on therapeutic resistance and relapse? We analyzed 6,228 papers on therapeutic resistance and/or relapse in cancers and found that the use of evolution terms in abstracts has remained at about 1% since the 1980s. However, detailed coding of 22 recent papers revealed a higher proportion of papers using evolutionary methods or evolutionary theory, although this number is still less than 10%. Despite the fact that relapse and therapeutic resistance is essentially an evolutionary process, it appears that this framework has not permeated research. This represents an unrealized opportunity for advances in research on therapeutic resistance.

 

How Do Elephants Avoid Cancer?
Larger, long-lived species have more cells and more time to accumulate mutations. This should make them more cancer prone than small, short lived species. However, larger, long-lived species typically get much less cancer than expected (known as Peto’s Paradox). This paper explore the elephant genome and finds that elephants have an extra 19 copies of P53, an important tumor suppressor gene.

Abegglen, Lisa M., et al. Potential mechanisms for cancer resistance in elephants and comparative cellular response to DNA damage in humans. JAMA 314.17 (2015): 1850-1860. DOI: 10.1001/jama.2015.13134

Abstract: Importance Evolutionary medicine may provide insights into human physiology and pathophysiology, including tumor biology.

Objective: To identify mechanisms for cancer resistance in elephants and compare cellular response to DNA damage among elephants, healthy human controls, and cancer-prone patients with Li-Fraumeni syndrome (LFS).

Design, Setting, and Participants: A comprehensive survey of necropsy data was performed across 36 mammalian species to validate cancer resistance in large and long-lived organisms, including elephants (n = 644). The African and Asian elephant genomes were analyzed for potential mechanisms of cancer resistance. Peripheral blood lymphocytes from elephants, healthy human controls, and patients with LFS were tested in vitro in the laboratory for DNA damage response. The study included African and Asian elephants (n = 8), patients with LFS (n = 10), and age-matched human controls (n = 11). Human samples were collected at the University of Utah between June 2014 and July 2015.

Exposures: Ionizing radiation and doxorubicin.

Main Outcomes and Measures: Cancer mortality across species was calculated and compared by body size and life span. The elephant genome was investigated for alterations in cancer-related genes. DNA repair and apoptosis were compared in elephant vs human peripheral blood lymphocytes.

Results: Across mammals, cancer mortality did not increase with body size and/or maximum life span (eg, for rock hyrax, 1% [95% CI, 0%-5%]; African wild dog, 8% [95% CI, 0%-16%]; lion, 2% [95% CI, 0%-7%]). Despite their large body size and long life span, elephants remain cancer resistant, with an estimated cancer mortality of 4.81% (95% CI, 3.14%-6.49%), compared with humans, who have 11% to 25% cancer mortality. While humans have 1 copy (2 alleles) of TP53, African elephants have at least 20 copies (40 alleles), including 19 retrogenes (38 alleles) with evidence of transcriptional activity measured by reverse transcription polymerase chain reaction. In response to DNA damage, elephant lymphocytes underwent p53-mediated apoptosis at higher rates than human lymphocytes proportional to TP53 status (ionizing radiation exposure: patients with LFS, 2.71% [95% CI, 1.93%-3.48%] vs human controls, 7.17% [95% CI, 5.91%-8.44%] vs elephants, 14.64% [95% CI, 10.91%-18.37%]; P < .001; doxorubicin exposure: human controls, 8.10% [95% CI, 6.55%-9.66%] vs elephants, 24.77% [95% CI, 23.0%-26.53%]; P < .001).

Conclusions and Relevance: Compared with other mammalian species, elephants appeared to have a lower-than-expected rate of cancer, potentially related to multiple copies of TP53. Compared with human cells, elephant cells demonstrated increased apoptotic response following DNA damage. These findings, if replicated, could represent an evolutionary-based approach for understanding mechanisms related to cancer suppression.

 

Making Cancer Go Extinct
One goal of cancer therapies is to drive tumors to extinction. What can we learn from species extinction in the paleontological record that can help us improve cancer therapy and prognosis?

Walther, V., Hiley, C.T., Shibata, D., Swanton, C., Turner, P.E., and Maley C.C.: Can oncology recapitulate paleontology? Lessons from species extinctions. Nature Reviews Clinical Oncology, Published online: 17 February 2015 | doi:10.1038/nrclinonc.2015.12

Abstract: Although we can treat cancers with cytotoxic chemotherapies, target them with molecules that inhibit oncogenic drivers, and induce substantial cell death with radiation, local and metastatic tumours recur, resulting in extensive morbidity and mortality. Indeed, driving a tumour to extinction is difficult. Geographically dispersed species of organisms are perhaps equally resistant to extinction, but >99.9% of species that have ever existed on this planet have become extinct. By contrast, we are nowhere near that level of success in cancer therapy. The phenomena are broadly analogous—in both cases, a genetically diverse population mutates and evolves through natural selection. The goal of cancer therapy is to cause cancer cell population extinction, or at least to limit any further increase in population size, to prevent the tumour burden from overwhelming the patient. However, despite available treatments, complete responses are rare, and partial responses are limited in duration. Many patients eventually relapse with tumours that evolve from cells that survive therapy. Similarly, species are remarkably resilient to environmental change. Paleontology can show us the conditions that lead to extinction and the characteristics of species that make them resistant to extinction. These lessons could be translated to improve cancer therapy and prognosis.

 

The Use of Common Pain Medications Could Slow Cancer Growth
This paper explores the potential for slowing down the evolution of cancer cells through the use of NSAIDS.

Kostadinov, R.L., Kuhner, M.K., Li, X., Sanchez, C.A., Galipeau, P.C., Paulson, T.G., Sather, C.L., Srivastava, A., Odze, R.D., Blount, P.L., Vaughan, T.L., Reid, B.J., Maley, C.C.: NSAIDs modulate clonal evolution in Barrett’s esophagus. PLOS Genetics, 9:e1003553, 2013. DOI: 10.1371/journal.pgen.1003553 Open access

Abstract: Cancer is considered an outcome of decades-long clonal evolution fueled by acquisition of somatic genomic abnormalities (SGAs). Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce cancer risk, including risk of progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA). However, the cancer chemopreventive mechanisms of NSAIDs are not fully understood. We hypothesized that NSAIDs modulate clonal evolution by reducing SGA acquisition rate. We evaluated thirteen individuals with BE. Eleven had not used NSAIDs for 6.2±3.5 (mean±standard deviation) years and then began using NSAIDs for 5.6±2.7 years, whereas two had used NSAIDs for 3.3±1.4 years and then discontinued use for 7.9±0.7 years. 161 BE biopsies, collected at 5–8 time points over 6.4–19 years, were analyzed using 1Million-SNP arrays to detect SGAs. Even in the earliest biopsies there were many SGAs (284±246 in 10/13 and 1442±560 in 3/13 individuals) and in most individuals the number of SGAs changed little over time, with both increases and decreases in SGAs detected. The estimated SGA rate was 7.8 per genome per year (95% support interval [SI], 7.1–8.6) off-NSAIDs and 0.6 (95% SI 0.3–1.5) on-NSAIDs. Twelve individuals did not progress to EA. In ten we detected 279±86 SGAs affecting 53±30 Mb of the genome per biopsy per time point and in two we detected 1,463±375 SGAs affecting 180±100 Mb. In one individual who progressed to EA we detected a clone having 2,291±78 SGAs affecting 588±18 Mb of the genome at three time points in the last three of 11.4 years of follow-up. NSAIDs were associated with reduced rate of acquisition of SGAs in eleven of thirteen individuals. Barrett’s cells maintained relative equilibrium level of SGAs over time with occasional punctuations by expansion of clones having massive amount of SGAs.

 

Cancer Evolves, Yet Treatment Often Doesn’t
Another foundational paper that describes the Darwinian nature of cancer and discussing the reason for this therapeutic failure. Greaves, M. & Maley, C.C.: Clonal evolution in cancer. Nature. 481:306-313, 2012. PMCID: PMC3367003. DOI: 10.1038/nature10762 Open access

Abstract: Cancers evolve by a reiterative process of clonal expansion, genetic diversification and clonal selection within the adaptive landscapes of tissue ecosystems. The dynamics are complex, with highly variable patterns of genetic diversity and resulting clonal architecture. Therapeutic intervention may destroy cancer clones and erode their habitats, but it can also inadvertently provide a potent selective pressure for the expansion of resistant variants. The inherently Darwinian character of cancer is the primary reason for this therapeutic failure, but it may also hold the key to more effective control.

 

Human Microbiome Papers

Microbes are Tiny Yet Powerful: Can They Change Human Behavior?
Explores novel possibilities for microbial manipulation of host behavior in humans.

Alcock, J., Maley, C.C., Aktipis, C.A. (2014). Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. BioEssays 36(10). DOI:10.1002/bies.201400071 Open access

Abstract: Microbes in the gastrointestinal tract are under selective pressure to manipulate host eating behavior to increase their fitness, sometimes at the expense of host fitness. Microbes may do this through two potential strategies: (i) generating cravings for foods that they specialize on or foods that suppress their competitors, or (ii) inducing dysphoria until we eat foods that enhance their fitness. We review several potential mechanisms for microbial control over eating behavior including microbial influence on reward and satiety pathways, production of toxins that alter mood, changes to receptors including taste receptors, and hijacking of the vagus nerve, the neural axis between the gut and the brain. We also review the evidence for alternative explanations for cravings and unhealthy eating behavior. Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating.

 

What We Eat Affects Whether Our Body’s Microbes Help or Harm Us
Considers diet as a fundamental source of cooperation or conflict between the gut microbiome and its human host, with important implications for health and disease.

Alcock, J., Wasielewski, H., Aktipis, C.A. (accepted pending revision). Conflict and cooperation between host and gut microbiota: Implications for nutrition and human health. Annals of the New York Academy of Sciences.

No link yet available. Not yet published.

 

For More in Evolutionary Medicine: Tweets and other references to the Evolutionary Medicine Symposium at the AAAS, The American Association for the Advancement of Science conference, February, 2016.

Follow: @RandyNesse, @AthenaAktipis@amy_boddy— and check out their papers posted on their sites linked at the top of this post.

Gossip Is An Evolved Social Skill, Not A Character Flaw

Evolutionary psychologist Frank T. McAndrew explains at The Conversation:

Let’s face it: gossips get a bad rap.

 

Smugly looking down from a moral high ground – and secure in the knowledge that we don’t share their character flaw – we often dismiss those who are obsessed with the doings of others as shallow.

 

Indeed, in its rawest form, gossip is a strategy used by individuals to further their own reputations and interests at the expense of others. Studies that I have conducted confirm that gossip can be used in cruel ways for selfish purposes.

 

…When disparaging gossip, we overlook the fact that it’s an essential part of what makes the social world tick; the nasty side of gossip overshadows the more benign ways in which it functions.

 

In fact, gossip can actually be thought of not as a character flaw, but as a highly evolved social skill. Those who can’t do it well often have difficulty maintaining relationships, and can find themselves on the outside looking in.

We are, in fact, “hardwired to gossip,” McAndrew continues:

Like it or not, we are the descendants of busybodies. Evolutionary psychologists believe that our preoccupation with the lives of others is a byproduct of a prehistoric brain.

 

According to scientists, because our prehistoric ancestors lived in relatively small groups, they knew one another intimately. In order to ward off enemies and survive in their harsh natural environment, our ancestors needed to cooperate with in-group members. But they also recognized that these same in-group members were their main competitors for mates and limited resources.

 

Living under such conditions, our ancestors faced a number of adaptive social problems: who’s reliable and trustworthy? Who’s a cheater? Who would make the best mate? How can friendships, alliances and family obligations be balanced?

 

In this sort of environment, an intense interest in the private dealings of other people would have certainly been handy – and strongly favored by natural selection. People who were the best at harnessing their social intelligence to interpret, predict – and influence – the behavior of others became more successful than those who were not.

 

The genes of those individuals were passed along from one generation to the next.

Yes, so the fact that you exist today, suggests that you had ancestors mumbling on to each other about the Kardashians of their day.

More on what fuels our thirst for gossip about celebrities at the link.

Sexual Harassment Is About Wanting Sex, Not Wanting Power Over Women

A 2012 paper in Evolution and Human Behavior by Leif Edward Ottesen Kennair and Mons Bendixen takes a much-needed evolutionary look at the issue of sexual harassment. They write in their paper:

While traditional social science theories have explained harassment as male dominance of females, the evolutionary perspective has suggested that sex differences in the desire for sex are a better explanation.

And their finding, in brief, was that an “unrestricted” sexuality “motivates people to test whether others are interested in short-term relations in ways that sometimes might be defined as harassment.”

The competing prediction suggesting that male dominance over females is the primary motivation for harassment was largely unsupported in this study. Not only was female harassment of males quite prevalent, so too was same-sex peer harassment. In addition, other competing social factors did not outweigh the importance of sociosexual orientation in explaining variations in sexual harassment for either of the sexes.
They further explain:
The main idea behind our predictions was the hypothesis that harassment is an unrestricted sociosexual style of behavior, aimed at testing out whether a potential sexual partner is available for a short-term sexual encounter, and that perceived harassment behavior to a large degree is motivated by a desire for sex. However, many instances of harassment in our study were cases of same-sex harassment. This may be understood from a similar perspective. It is an example of sexual surgency or dominance, and sexual competitiveness (Campbell, 2004). Thus, the logic of the evolved psychology of derogation (Schmitt & Buss, 1996) is relevant for understanding this behavior.
And their conclusion:
While more boys sexually harass and coerce than girls, both sexes commit sexual harassment and coercive acts. And while many different negative precursors and correlates have been suggested, it would seem that the main motive is an interest in short-term sex indicated by an unrestricted sociosexuality. This same characteristic also causes behavior that advertises an interest in sex, increasing the attraction of nonattractive partners. Furthermore, these individuals probably have an increased interest in sexual competition, thus both being subject to and partaking in same-sex derogation. Thus, an unrestricted sociosexual orientation is related to both harassing behavior and being a victim of harassment in high school.

The Evolutionary Ecology Of Cancer

Theoretical evolutionary biologist Athena Aktipis, a co-founder of the Center for Evolution and Cancer at UCSF, talks to David Sloan Wilson about how cancer is evolution that’s taking place inside an organism, but a perversely adaptive form of it, since it ends in the death of both the organism and the cancer.

Aktipis explains the selection pressures on cancer cells:

Let’s say that a tumor has evolved and grown so much that the interior is totally absent of nutrients, like you see in some cities, where the slums are totally absent of resources and filled with garbage. There is intense selection for cells to survive better in those conditions, which we call hypoxic conditions. These cells become pre-adapted to live in regions that are far away from blood vessels, so when you give chemotherapy, they are able to hide out, a phenomenon called “refugia” in cancer treatment. There are some really important aspects of the environment, ecology, and diversity of ecological niches that get created in the course of cancer progression and changed during treatment that haven’t been fully considered from an evolutionary perspective. There’s a lot of opportunities.

A particular cancer therapy can make sense — that is, until it’s viewed from an evolutionary perspective. Aktipis gives the example of the medical bias toward going with the most aggressive treatment possible:

For a long time it was almost a moral imperative to use the highest dose and most aggressive treatment possible, but now that’s being reexamined and many top cancer treatment hospitals in the country and the world are backing off from that. Not all of them are backing off because of an explicitly evolutionary framework, but some of the work that has been done over the last decade has helped to show why an overly aggressive approach can be problematic. As for drug-resistant infectious agents and resistance to pesticides in agriculture, high doses in cancer treatment imposes the highest selective-pressure on a population of cancer cells. If you have a small population that’s not very diverse, then using a high dose can make sense. But if you have a large and diverse population of cancer cells then the higher the dose, then the greater the selection pressure for resistant cells. That’s one of the really important insights that comes from taking an evolutionary approach to treatment. We shouldn’t just think about killing cells; we should be more strategic about what we want to select for and against.

Dr. Aktipis is also the author of the forthcoming book from Princeton University Press, “Evolution in the flesh: Cancer and the transformation of life.”

The Mating Crisis Among Educated Women

David Buss at Edge:

Every year, more women than men become college-educated. The disparity is already prevalent across North America and Europe, and the trend is beginning to spread across the world more widely. At the University of Texas at Austin where I teach, the sex ratio is 54 percent women to 46 percent men. This imbalance may not seem large at first blush. But when you do the math it translates into a hefty 17 percent more women than men in the local mating pool. Speculations about reasons range widely. They include the gradual removal of gender discrimination barriers and women’s higher levels of conscientiousness (relative to men’s) that translate into better grades and superior college app qualifications. Whatever the causes turn out to be, the disparity is creating a dramatic and unintended mating crisis among educated women.

 

…Most women are unwilling to settle for men who are less educated, less intelligent, and less professionally successful than they are. The flip side is that men are less exacting on precisely these dimensions, choosing to prioritize, for better or worse, other evolved criteria such as youth and appearance. So the initial sex ratio imbalance among educated groups gets worse for high achieving women. They end up being forced to compete for the limited pool of educated men not just with their more numerous educated rivals, but also with less educated women whom men find desirable on other dimensions.

 

…What are the potential solutions to the mating pool shortage for educated women? Adjust their mate preferences? Expand the range of men they are willing to consider as mates? Mating psychology may not be that malleable. The same mating desires responsible for the skewed gender imbalance to begin with continue to create unfortunate obstacles to human happiness. As successful women overcome barriers in the workplace, they encounter new dilemmas in the mating market.

The Evolution of Music as Medicine: Improving Mood Regulation, Focus, and Well-Being

Psychologist Michael Hogan asks at Psychology Today, “What are the adaptive functions of music listening?” He explains:

Research has highlighted mood regulation to be the most important function of music listening, but people also listen to music for its cognitive benefits, such as increased focus and attention, the experience of cognitive complexity, to facilitate social interaction and bonding, and reinforce social identity. More recently, research has started to focus on how music promotes wellbeing, which we can think of as simply the hedonic balance of positive and negative emotions, or more broadly in terms of our life engagement, meaning, and overall psychological and social well-being. It seems that beyond hedonic well-being, the broader, so-called “eudaimonic” aspects of wellbeing become more important as we age, but we know very little about how music interacts with these aspects of wellbeing. Research does suggest, however, that music brings about not only pleasure but also absorption and transcendence in listeners, so it is worth considering how music enhances wellbeing in the fullest possible sense, drawing upon the rich collective intelligence of experienced listeners.

Referencing his research with Jenny Groarke, he writes:

While both younger and older adults emphasized the importance of music in bringing about strong emotions, these emotions had a more positive, transcendent quality for older adults, who consistently spoke about music taking them to “another world”, “a different dimension”, and “transcending the mundane”. Transcendent experiences are functionally significant and have been related to benefits such as increased happiness and meaning in life, higher life satisfaction, and reduced loneliness in older adults.  Indeed, for the older adults in our study it seems that listening to music plays an important role in easing feelings of loneliness. At the same time, while older adults spoke about using music to reduce feelings of isolation, younger adults spoke about how music allowed them to carve out a personal space where they could limit social connection. As one young woman described it, “When I’m listening to music, I can escape sort of, even though there’s people around… I can escape that stress,” (Female, 24). It seems that while younger adults may be using music to ease the stresses associated with their active social lives, older adults may listen to music to compensate for their feelings of social isolation.

Both age groups discussed using music to aid reminiscence. Analysis of the collective intelligence transcripts revealed that reminiscence is linked to personal growth and empathy for older adults, whereas for younger adults reminiscence may serve self-regulatory functions that facilitate coping with life. For example, while older adults spoke about listening to music to bring back fond memories such as “lovely memories of a particular person that may have passed on” (Female, 65), younger adults described using music to consciously remember significant others, for example when feeling homesick, and even for less adaptive reasons such as “break-up songs, just to torture yourself” (Female, 22). In relation to personal growth, older adults described music as enhancing reflection which, in turn, helped them to foster feelings of compassion for themselves and others.

Our study was the first to use Interactive Management to explore the connections between music listening and wellbeing, and consider how the functions of music listening may differ between younger and older adults. It appears that both older and younger adults believe that music has an effect on their wellbeing. A meta-analysis of the systems thinking of younger and older adults highlighted the importance of intense emotional experiences, reminiscence, and eudaimonic experiences such as meaning and transcendence in driving all other adaptive functions of music listening. These aspects of music listening function adaptively to enhance feelings of wellbeing across the lifespan, in old and young alike.

Read the full version of their paper here. And check out their site, The Adaptive Functions of Music Listening.

 

Are You Rolling On Dubs? The Evolutionary Psychology Of Vehicle Mods

Post by Jessica S. Kruger, a University of Toledo Health Education doctoral student with a cognate in Psychology, who did the research with her husband, evolutionary social psychologist Dr. Daniel J. Kruger, a Research Assistant Professor at the University of Michigan.

 

“ARE YOU ROLLING on dubs?” Not long ago, I only knew this as a tag line in a rap song.

Rims1 

Rims2

Two years ago, we moved to a historic neighborhood in an urban area. As evolutionary researchers, we were fascinated by what we saw there. One thing we noticed was the high proportion of vehicles with large and shiny rims (wheels). There is even a store just a few blocks from where we live that sells these rims. After driving by so many times, I decided to stop in and investigate. I was stunned to learn how expensive they could be, and intrigued that we would often see very fancy vehicles parked in front of houses that were in various states of decay.

We understand these patterns through the framework of Life History Theory:

Life history theory … is a branch of evolutionary theory which predicts behavior based upon people’s [potential lifespans, vis a vis how stable or risky their environment is]. It suggests that as people believe they are likely to live longer, decisions related to certain milestones such as marriage, having babies, and divorce may be delayed in favor of other activities such as education. … Life history theory can help us understand how we make important decisions that affect our lives.

Some researchers describe life history as a continuum from slow to fast. This is because relatively “faster” species and individuals tend to reproduce earlier and more prolifically, but also tend to die earlier. In evolutionary terms, neither fast nor slow life histories are inherently good or bad. An individual’s life history is shaped in part by the environment in which it grows up. When conditions are unpredictable and the chance of early death is high, individuals seize opportunities when they can, before it is too late. If conditions are predictable and the chance of early death is low, individuals take a less risky, long-term approach.

Each individual has a limited amount of time and energy, so one has to make “trade-offs” in how much effort to invest in each aspect of life. One of these trade-offs is between mating effort (getting new sexual partners) and parenting effort (investing in offspring). For example, a male peacock has a big and beautiful tail. Charles Darwin was puzzled by peacock tails and wondered how they could have evolved, as they are cumbersome and could attract predators. He later realized that peacock tails did not evolve because they helped peacocks survive, but rather that this costly trait served as a signal of the male’s quality. The more brilliant the plumage, the more attractive it is to potential mates.

We concluded that the extravagant wheels we saw were a function of mating effort, a costly signal analogue to the peacock’s tail, used to gain status and attract partners. We decided to conduct a study to confirm this idea. We searched the Internet for before and after pictures of cars that had rim upgrades. We found suitable pictures of a Jeep Rubicon and a Chrysler 300. We predicted that people would rate a male owner of a car with upgraded rims as higher in mating effort, lower in parental effort, more interested in brief sexual affairs, and less interested in long-term committed relationships than men with stock vehicles.
RubiconPre

RubiconPost

The results from ratings of 339 college students generally confirmed our predictions. The patterns were stronger for male participants, and both cars seemed to be associated with a high mating effort (and lower parental effort, etc.) life history regardless of the wheels they had.

I am on the board of a grassroots non-profit inner-city gym for local youth. I was talking with people there about the project, and they were incredulous that we needed to do a study to figure this out; to them it was so obvious.

Rims can be thought of jewelry for your car and, in evolutionary terms, a display of resources to attract potential mates.

We are glad to shed more light on conspicuous consumption and explain an apparent paradox (why people in resource-scarce environment would spend so much on these products) with the strongest theoretical framework in the human sciences.

Screen Shot 2015-09-06 at 8.32.12 PM copy

 

 

 

 

 

 

 

 

I like to get into my research.

 

This research was presented by Jessica Sloan Kruger at NEEPS 2015, the NorthEastern Evolutionary Psychology conference. Dates and info on NEEPS 2016 and other the 2016 ev psych (and related) conferences here.