Tuesday, February 9, 2021

People with adverse childhood conditions had faster life history strategies and higher Dark Triad traits, and were more prone to be inflamed (i.e., sexually transmitted infections)

Childhood adversity is associated with adulthood white blood cell count through narcissism. Yaoguo Geng  et al. Personality and Individual Differences, Volume 174, May 2021, 110662. https://doi.org/10.1016/j.paid.2021.110662

h/t David Schmitt Childhood adversity is associated with adulthood white blood cell count through narcissism 

Abstract: The immune system's response to threat is to amass protective white blood cells. We investigated (N = 234) individual differences in white blood cell (WBC) through the lens of life history theory by examining individual differences in (self-reported) childhood threats (i.e., unpredictability and harshness), life history speed, and the Dark Triad traits (i.e., Machiavellianism, narcissism, and psychopathy). People with adverse childhood conditions had faster life history strategies and higher Dark Triad traits, and were more prone to be inflamed (i.e., sexually transmitted infections). In addition, men reported more childhood harshness, Machiavellianism, psychopathy, and a faster life history strategy and a higher WBC count than women did. Moreover, we revealed, through structural equation models, that the effects of childhood adversity on adult WBC count were mediated by narcissism especially in women. Results are discussed in terms of the mechanism underlying the association between childhood environments and physiological health.

Keywords: Childhood harshnessChildhood unpredictabilityLife history strategyDark TriadWhite blood cell count

No differences in subjective well-being & limited differences in personality traits between childfree individuals & parents, not-yet-parents, or childless individuals; politically, childfree individuals were more liberal than parents

Neal, Jennifer W., and Zachary Neal. 2021. “Who Are the Childfree?.” PsyArXiv. February 9. doi:10.31234/osf.io/57bjr


Objective: This study examines how childfree individuals differ from parents and other types of non-parents in subjective well-being, political ideology, and personality, and examines whether childfree individuals are a stigmatized outgroup.

Background: Childfree individuals choose not to have children. Most research on parental status and psychosocial characteristics has not distinguished childfree individuals from other non-parents or has relied on non-representative samples.

Method: This study uses a representative sample of 981 Michigan adults to estimate the prevalence of childfree individuals. The study also estimates a series of multiple regressions to examine differences between childfree individuals, parents, and other types of non-parents and to examine whether childfree individuals are perceived by others as an outgroup.

Results: Over a quarter of Michigan adults identified as childfree. After controlling for demographic characteristics, we found no differences in subjective well-being and limited differences in personality traits between childfree individuals and parents, not-yet-parents, or childless individuals. However, childfree individuals were more liberal than parents. Additionally, individuals who have or want(ed) children felt substantially less warm toward childfree individuals than childfree individuals felt toward each other.

Conclusions: Given the prevalence of childfree individuals, the risks of their outgroup status, and their potential role in politics as a uniquely liberal group, it is important for demographic research to distinguish the childfree from others and to better understand these individuals.

Self-Reported Symptoms of COVID-19, Including Symptoms Most Predictive of SARS-CoV-2 Infection, Are Heritable In Some Degree

Self-Reported Symptoms of COVID-19, Including Symptoms Most Predictive of SARS-CoV-2 Infection, Are Heritable. Frances M. K. Williams. Twin Research and Human Genetics, February 9 2021. https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/abs/selfreported-symptoms-of-covid19-including-symptoms-most-predictive-of-sarscov2-infection-are-heritable/316C6D3F18A25A99B11572BA777606CC

Abstract: Susceptibility to infection such as SARS-CoV-2 may be influenced by host genotype. TwinsUK volunteers (n = 3261) completing the C-19 COVID-19 symptom tracker app allowed classical twin studies of COVID-19 symptoms, including predicted COVID-19, a symptom-based algorithm to predict true infection, derived from app users tested for SARS-CoV-2. We found heritability of 49% (32−64%) for delirium; 34% (20−47%) for diarrhea; 31% (8−52%) for fatigue; 19% (0−38%) for anosmia; 46% (31−60%) for skipped meals and 31% (11−48%) for predicted COVID-19. Heritability estimates were not affected by cohabiting or by social deprivation. The results suggest the importance of host genetics in the risk of clinical manifestations of COVID-19 and provide grounds for planning genome-wide association studies to establish specific genes involved in viral infectivity and the host immune response.

Keywords: SARS-CoV-2 COVID-19 heritability twins anosmia

Superintelligence Cannot be Contained: Lessons from Computability Theory

Superintelligence Cannot be Contained: Lessons from Computability Theory. Manuel Alfonseca et al. Journal of Artificial Intelligence Research, vol 70, Jan 5, 2021. https://doi.org/10.1613/jair.1.12202

Abstract: Superintelligence is a hypothetical agent that possesses intelligence far surpassing that of the brightest and most gifted human minds. In light of recent advances in machine intelligence, a number of scientists, philosophers and technologists have revived the discussion about the potentially catastrophic risks entailed by such an entity. In this article, we trace the origins and development of the neo-fear of superintelligence, and some of the major proposals for its containment. We argue that total containment is, in principle, impossible, due to fundamental limits inherent to computing itself. Assuming that a superintelligence will contain a program that includes all the programs that can be executed by a universal Turing machine on input potentially as complex as the state of the world, strict containment requires simulations of such a program, something theoretically (and practically) impossible.

More terrible than either of these tales is the fable of the monkey’s paw (Jacobs, 1902), written by W. W. Jacobs, an English writer of the beginning of the [20th] century. A retired English working-man is sitting at his table with his wife and a friend, a returned British sergeant-major from India. The sergeant-major shows his hosts an amulet in the form of a dried, wizened monkey’s paw... [which has] the power of granting three wishes to each of three people... The last [wish of the first owner] was for death... His friend... wishes to test its powers. His first [wish] is for 200 pounds. Shortly thereafter there is a knock at the door, and an official of the company by which his son is employed enters the room. The father learns that his son has been killed in the machinery, but that the company... wishes to pay the father the sum of 200 pounds... The grief-stricken father makes his second wish -that his son may return- and when there is another knock at the door... something appears... the ghost of the son. The final wish is that the ghost should go away. In these stories, the point is that the agencies of magic are literal-minded... The new agencies of the learning machine are also literal-minded. If we program a machine... and ask for victory and do not know what we mean by it, we shall find the ghost knocking at our door.

Moreover, they believe that propaganda reduces other citizens’ willingness to protest, which in turn reduces their own willingness to protest; propaganda's power may lie more in the social perceptions & uncertainty it creates

Propaganda, Presumed Influence, and Collective Protest. Haifeng Huang & Nicholas Cruz. Political Behavior, Feb 8 2021. https://rd.springer.com/article/10.1007/s11109-021-09683-0

Abstract: Political propaganda can reduce citizens’ inclinations to protest by directly influencing their preferences or beliefs about the government. However, given that protest is risky in authoritarian societies and requires collective participation, propaganda can also reduce citizens’ inclination to protest by making them think that other citizens, rather than themselves, may have been influenced by propaganda and are, as a result, unwilling to protest. We test this indirect mechanism of propaganda using a survey experiment with Chinese internet users from diverse backgrounds and find that they do believe propaganda affects other citizens’ support for and beliefs about the government more than their own support and beliefs. Moreover, they believe that propaganda reduces other citizens’ willingness to protest, which in turn reduces their own willingness to protest. Therefore, the power of propaganda may sometimes lie more in the social perceptions and uncertainty it creates than in its direct individual effects.

Discussion and Conclusion

This study experimentally shows that people often believe that propaganda increases other people’s support for a regime or their beliefs about a regime’s capacity to maintain stability. In fact, the presumed influence of propaganda on other people’s support for and beliefs about a regime are usually stronger than propaganda’s actual influence on oneself. Consequently, propaganda can reduce people’s perceptions of other people’s willingness to protest, which in turn dilutes their own propensity to protest due to its risky nature under authoritarian regimes. Thus, propaganda can stave off dissent not by directly changing individuals’ own attitudes and intentions but, instead indirectly, by altering people’s perceptions of other people’s attitudes and behavioral intentions.

These findings imply that, due to the complementarity of participation in mass protest, authoritarian regimes have a special advantage by being the agenda setters in the propaganda game. Propaganda does not have to directly change individuals’ own willingness to protest to be effective. As long as propaganda reduces individuals’ perceptions of other people’s willingness to protest, or just makes them uncertain if other citizens have been influenced by it, they will be more timid in challenging the regime. Propaganda can achieve much of its function for the regime simply by sowing uncertainty among citizens about what they think others think and will do. Different from what conventional wisdom often assumes, the power of propaganda may sometimes lie more in the social perception and uncertainty it creates than in changes it induces in individuals’ own political attitudes and beliefs.

The study thus enriches theories of authoritarian propaganda, which have so far focused on propaganda’s direct effect on individuals’ themselves. The results also contrast with findings in the existing literature that in democratic and semi-democratic societies, where basic rights of expression and association are guaranteed, stronger perception of other people’s willingness to participate in protest or voting, or perceptions of protest news’s effects on other people, are associated with a lower willingness to participate (Banning 2006; Cantoni et al. 2019; Lo et al. 2017). In these societies, participation is more of a public good that demands a threshold level of contribution: Perception of other people’s participation reduces the need for oneself to participate in order to meet the threshold and, thus, could drive down one’s own willingness to participate. In other words, these are games of substitutes. Collective protests in authoritarian settings, however, are strategic games of complements (Chwe 2003; Edmond 2013; Gehlbach et al. 2016): The more/less willing other people are to participate, the more/less willing are individuals themselves. It is in this strategic setting that propaganda can inhibit people’s willingness to protest by reducing their perceptions of other people’s willingness to protest. And it is this mechanism that contributes to preference falsification, pluralistic ignorance, and the breakdown of common knowledge (Chwe 2003; Havel 1985; Kuran 1991).

Besides enriching our understanding of authoritarian propaganda, this study also contributes to the literature on the influence of presumed media influence. The standard literature on the influence of presumed influence focuses on people’s perceptions of media’s influence on others, without comparing the influence on others with influence on oneself. The third-person effect literature, on the other hand, focus on the discrepancy between media’s presumed influence on oneself and on others, without considering wither the presumed effect on oneself is accurate, or whether the presumed influence of media is really stronger than its actual influence on oneself. We show that propaganda’s presumed effects on others can be stronger than its actual effects on oneself, not just stronger than its presumed effects on oneself. It is this “real” presumed influence of propaganda that leads to one’s perceptions of propaganda’s influence on other people’s behavior, which in turn affects one’s own behavior.

One limitation of the study is that the propaganda messages had negative effects on the respondents’ perceptions of other people’s protest willingness, hence negative indirect effects on their own protest willingness, but the messages had either null or positive direct effects on the respondents’ protest willingness. As discussed above, the positive direct effect is likely because the propaganda messages about the greatness of China and its leader encouraged the respondents to express willingness to dissent against injustice and government malfeasance, which were holding China back. Self-other perceptual discrepancies have always been recognized in the third-person effect literature as a kind of inconsistency or bias. Our study suggests the self-other discrepancies may be larger than typically understood: A media message’s self and other effects may differ not just in magnitude but also in direction. Understanding the causes and/or prevalence of the directional divergence goes beyond the scope of this study, but it is potentially an important issue for future research.

A general theory about how sexual desires develop is provided that may explain how something, including another person, becomes an object of sexual desire

High and Tight, Please: Self-explanations for Experiencing Short Haircuts as Erotic. Robert W. Mitchell. Sexuality & Culture, Feb 9 2021. https://rd.springer.com/article/10.1007/s12119-021-09815-y

Abstract: Sexologists have infrequently asked individuals to describe what led them to their sexual desires. In this study, 264 men and 7 women answered a questionnaire about their sexual interest in short haircuts on men, part of which asked them about any events or ideas they had that might explain their sexual desires. Surprisingly, a substantial minority of the men desired women as sexual partners. Almost 80% of the participants provided responses, which were examined for themes related to what might have caused their sexual interest in short haircuts on men, resulting in 16 themes, most of which help explain why short haircuts became objects of interest and fascination. The 10 most common themes are presented in detail, and a general theory about how sexual desires develop is provided that may explain how something, including another person, becomes an object of sexual desire.

Sharing food can reduce the perceived fattening potential of a consumption episode without biasing caloric estimates, even when explicit caloric information is provided

Your Fries are Less Fattening than Mine: How Food Sharing Biases Fattening Judgments Without Biasing Caloric Estimates. Nükhet Taylor  Theodore J. Noseworthy. Journal of Consumer Psychology, December 17 2020. https://doi.org/10.1002/jcpy.1214

Abstract: Food sharing has become quite popular over the last decade, with companies offering food options specifically designed to be shared. As the popularity has grown, so too has concerns over the potential negative impact on consumer health. Despite companies’ explicit claims to the contrary, critics maintain that food sharing may be encouraging excessive caloric intake. The current article provides the first systematic exploration of why this may be happening. Three main and two supplementary studies suggest that food sharing reduces perceived ownership, which, in turn, leads people to mentally decouple calories from their consequence. Thus, sharing can reduce the perceived fattening potential of a consumption episode without biasing caloric estimates. This phenomenon persists even when explicit caloric information is provided, and it applies to both healthy and unhealthy foods. Importantly, we establish a relevant downstream consequence by illustrating that people tend to subsequently select calorie‐dense foods after underestimating the fattening potential of a shared consumption episode. A roadmap for future research and practical implications are discussed.

General Discussion

The current work investigated how food sharing impacts health‐related judgments. Our findings revealed that sharing is not biasing caloric estimates but is biasing how consumers construe the consequence of their caloric intake. Specifically, food appears less fattening when it is shared (study 1). We replicated these findings with both healthy and unhealthy food and with explicit calorie information (study 2). Thus, rather than a motivational mechanism that hinges on unhealthy food, sharing is causing a general decoupling of calories and their consequence. Importantly, reduced fattening judgments also reduced the possibility that consumers will correct for the extra caloric intake in subsequent choice (study 3). All studies confirmed that reduced perceived ownership underscored these results. Thus, elevating perceived ownership elevated fattening judgments (study 3). Two supplementary studies supported these conclusions (MDA: Appendix S1 pp. 14–20). Finally, a Bayesian SPM provided strong evidence in favor of sharing impacting fattening judgments and not caloric estimates.

This work represents a cautionary note for public policymakers and for companies promoting food sharing. When introducing share‐size snacks, Mars‐Wrigley claimed that food sharing may help weight maintenance by facilitating portion control (Mars, 2017). Our findings suggest that food sharing may be encouraging excessive caloric intake by leading consumers to underestimate the fattening potential brought on by shared food consumption.

Exploration and Future Research

In the spirit of a research report, we explored other ways in which sharing may impact perceptions. Specifically, while caloric estimates were not impacted, related factors such as perceived size and/or healthiness may have been impacted. However, we were not able to support these possibilities (MDA: Appendix S1 pp. 4–7). We also considered that people may feel less responsible over their consumption when sharing food. We did not find this to be the case either (MDA: Appendix S1 p. 4). Nevertheless, researchers can build on these attempts. For instance, although sharing did not bias the perceived healthiness of stereotypically healthy/unhealthy foods, it could bias perceptions of a health‐ambiguous food (e.g., pasta salad). Similarly, although sharing did not alter size perceptions, it may be that sharing elevates the desire for larger food options (Taylor, Noseworthy, & Pancer, 2019).

Future work can pinpoint why lower perceived ownership makes caloric intake seem inconsequential. One possibility relates to mental accounting. Extant work has shown that consumers use mental accounts to keep track of both monetary expenses (Thaler, 1985) and daily caloric budgets (Khare & Innman, 2009). Thus, it may be that consumers do not include calories from shared consumption in their caloric budget because they believe these calories do not belong to them. A related principle in categorization theory that fits the mental accounting lens could be how psychological budgets interact. If consumers see calorie budgets similar to financial budgets, sharing in one may lead people to compensate for a biased shortfall in the other—re: fluid compensation (Taylor & Noseworthy, 2020). Another possibility relates to egocentric categorization theory (Weiss & Johar, 2016), which shows that people assimilate to products they own, and contrast products they do not own. This may explain why people decouple calories from their consequences to the self. A final possibility is how people mentally construe (un)owned objects. People perceive things to be of lesser consequence when they are psychologically distant (Polman et al., 2018). A similar mindset mechanism could be contributing to our findings.

Future work can investigate the implications of our findings for other collaborative consumption domains. One area is household consumption, whereby typically one person purchases the food consumed by others (Belk, 2010).

Future work may also explore how external cues influence the tendency to share food. One intriguing question is how sharing is impacted when consumers are faced with cues of contagious disease, such as during flu season or during a health pandemic (e.g., Covid‐19). Extant work suggests two plausible accounts. The first one is that contagious disease cues elicit disgust and a desire to self isolate (Galoni & Noseworthy, 2015; Lerner & Keltner, 2000), which may dampen food sharing in general. The second one is that disease cues reduce the desire to interact with the unfamiliar, but elevate the desire to interact with the familiar (Galoni, Carpenter, & Rao, 2020). The end result may be a lower tendency to share with distant others such as acquaintances and colleagues, but greater tendency to share with close others such as family members and significant others. Future work may expand on these possibilities.

Finally, a major limitation of the current work is that the consequences of food sharing were examined via vignettes. We strongly encourage future research to examine actual consumption in a real‐world setting. This would not only establish the ecological validity of the current findings but would also provide a richer understanding of the social dynamics behind food sharing. Certainly, more work is needed in this area.

Self-perceived smile attractiveness: The increased strength of the effect in females provides support to the notion that females are overall more aware of their smile and the impact it has on their public image

Smile dimensions affect self-perceived smile attractiveness. Simone Horn, Natalia Matuszewska, Nikolaos Gkantidis, Carlalberta Verna & Georgios Kanavakis. Scientific Reports volume 11, Article number: 2779. Feb 2 2021. https://www.nature.com/articles/s41598-021-82478-9

Rolf Degen's take: (17) Rolf Degen on Twitter: ""Females are overall more aware of their smile and the impact it has on their public image." https://t.co/enAWpkRG5S https://t.co/tAWOBdc5VQ" / Twitter

Abstract: Facial expressions play a leading role in human interactions because they provide signaling information of emotion and create social perceptions of an individuals’ physical and personality traits. Smiling increases socially perceived attractiveness and is considered a signal of trustworthiness and intelligence. Despite the ample information regarding the social importance of an attractive smile, little is known about the association between smile characteristics and self-assessed smile attractiveness. Here we investigate the effect of smile dimensions on ratings of self-perceived smile attractiveness, in a group of 613 young adults using 3D facial imaging. We show a significant effect of proportional smile width (ratio of smile width to facial width) on self-perceived smile attractiveness. In fact, for every 10% increase in proportional smile width, self-perceived attractiveness ratings increased by 10.26%. In the present sample, this association was primarily evident in females. Our results indicate that objective characteristics of the smile influence self-perception of smile attractiveness. The increased strength of the effect in females provides support to the notion that females are overall more aware of their smile and the impact it has on their public image.


The purpose of this study was to explore the effect of smile dimensions on self-assessment of smile attractiveness in a large young adult population, using three-dimensional data. To our knowledge this is the first assessment of the association of self-perceived smile attractiveness to smile dimensions. The findings demonstrated that self-perceived smile attractiveness was affected by smile dimensions, with proportionally wider smiles perceived as more attractive. This effect was primarily evident in females.

As the societal esthetic demands influence interpersonal relationships heavily, medical and dental disciplines studying the human face continue to shift their focus on treatment trajectories that optimize facial and smile esthetics. Following an intervention in the face, self-perceived esthetic outcomes comprise important components of patient satisfaction with treatment28,29. Smiling can trigger a variety of emotions and biases during human interactions8,10,11 and it may be the most important factor controlling judgments of overall facial attractiveness30. Thus, the identification of factors that affect self-perceived smile attractiveness is important to set treatment goals that meet patients’ needs and demands, when treatment is expected to affect smile.

We were able to identify only one previous study associating smile characteristics to self-perceived smile attractiveness12. This was conducted on a sample of white adult men, who were asked to evaluate their smiles according to tooth size and color, tooth visibility, and upper lip position, while viewing their smiling image. The results indicated that tooth size and color appeared to have a larger effect on attractiveness ratings, however, smile dimensions were not evaluated and therefore no direct comparisons to our results are possible.

Considering external ratings, in growing individuals, a thicker upper lip was shown to influence observers’ judgements of an attractive smile31; while another study on young adult females reported that only smile height was related to smile attractiveness18. On the other hand, Schabel et al.32 were not able to identify any dimensional smile characteristic with a direct effect on smile attractiveness. Apart from the external ratings, the above studies had samples much smaller to ours (48–60 subjects), tested 2D images, and had different designs. Thus, no direct comparison to our study findings can be made.

No previous study has assessed smile dimensions in relation to face dimensions (proportional smile dimensions). During social interactions, attention is primarily shifted between the mouth and the eyes33; and thus, in real life, dimensional characteristics of facial structures are mostly viewed in relation to others. Therefore, it is safe to assume that quantitative assessments, which take the variability in facial size and shape into consideration are more likely to provide realistic information about smile dimensions. Here, we show that smile width, as related to facial width, has a significant effect on self-perceived smile attractiveness; participants with proportionally wider smiles, found their smiles more attractive. No such effect was evident for the original smile width.

Our sample population exhibited significant sexual dimorphism in smile dimensions, with males presenting wider smiles and faces than females. This is in agreement with previous studies that have explored smile dimensions using three-dimensional data34,35,36,37. However, it can be attributed to males exhibiting overall larger facial dimensions, since in our sample females had higher proportional smile widths. Our findings also allow for speculation that young adult women are more influenced by their objective smile appearance when evaluating their own smile attractiveness. Although smiling kindles an equally favorable response in females and males during social encounters6, females are consistently found to smile more38. This might be an inherent sexual characteristic of females or they may pay more attention or even be more aware of the positive responses generated during smile, and thus, exert a more conscious effort to smile. The latter might be supported by our finding that in contrast to young adult females, in males, smile dimensions had an undetectable effect on self-perceived smile attractiveness. There are numerous social and cultural causes for women being more conscious of their objective smile characteristics, since they are often expected to be friendlier and more emotionally expressive than men39,40,41. In addition, smiling frequency and intensity has been associated to hormonal changes during physical development; high testosterone levels, for example, have an inhibitory role in social smiling42,43. As a result, males may either have an intrinsic hesitation to smile or may very well not consider it an important feature of their social image. This could potentially lead them to rate their smile less favorably compared to females, which was clearly evident from our results and, thus, also supports the above thought process.

Special considerations and limitations

The results of this investigation should be assessed within the context of the applied methodology. Our study population was limited to a group of highly educated young adults, in order to control for the potential confounding effect of educational status44,45 and age46. The findings may thus not represent the general population.

In addition, participants were not allowed to look at their own pictures prior to evaluating their attractiveness. Being exposed to one’s own photograph tends to alter self-perception of appearance47, therefore this could have led to different results. However, it was preferred to obtain a more “genuine” response in order to avoid the effect of the instantaneous stimulus generated from the exposure to their facial images. In addition, some participants may have been influenced when smiling by the presence of a person in the research area to whom they wanted to appear attractive. Although this could potentially affect our results, it is unlikely given the large sample size and the minimal measurement error found.

The present study focused solely on smile dimensions. However, there are various other smile components that might affect smile attractiveness, but they were not considered in our study. Such factors could have been expected to confound ratings and affect the study outcomes, but we think that the large sample size adequately addresses this issue.

Anatomical landmark variability could also be a possible source of error in this study since the labial commissures of the mouth tend to not displace consistently upon smiling, between different image acquisitions of the same individual48. However, this confounder is not expected to have influenced our results due to the large sample population and the high standardization of image acquisition.

Moderate, naturally occurring ethanol concentration of 4% results in increased Drosophila larval fitness; but higher concentrations of 10% & 20% ethanol, which rarely or never appear in nature, increase mortality

Ethanol-guided behavior in Drosophila larvae. Isabell Schumann et al. bioRxiv, Feb 8 2021. https://doi.org/10.1101/2021.02.07.430116

Rolf Degen's take: The larvae of fruit flies are not only strongly attracted to alcohol, it also gives them a greater life expectancy

Abstract: Chemosensory signals allow vertebrates and invertebrates not only to orient in its environment toward energy-rich food sources to maintain nutrition but also to avoid unpleasant or even poisonous substrates. Ethanol is a substance found in the natural environment of Drosophila melanogaster. Accordingly, D. melanogaster has evolved specific sensory systems, physiological adaptations, and associated behaviors at its larval and adult stage to perceive and process ethanol. To systematically analyze how D. melanogaster larvae respond to naturally occurring ethanol, we examined ethanol-induced behavior in great detail by parametrically reevaluating existing approaches and comparing them with new experiments. Using behavioral assays, we confirm that larvae are attracted to different concentrations of ethanol in their environment. This behavior is controlled both by olfactory and contact cues. It is independent of previous exposure to ethanol in their food. Moreover, moderate, naturally occurring ethanol concentration of 4% results in increased larval fitness. On the contrary, higher concentrations of 10% and 20% ethanol, which rarely or never appear in nature, increase larval mortality. Finally, ethanol also serves as a positive teaching signal in learning and memory and updates valence associated with simultaneously processed odor information. Since information on how larvae perceive and process ethanol at the genetic and neuronal level is limited, the establishment of standardized assays described here is an important step towards their discovery.