The present research investigates the social transmission of food preferences in small colonies of domestic rats. In Experiment 1, four demonstrator rats were poisoned for consumption of a particular flavored diet and placed in a floor enclosure with a choice between the averted diet and an alternative diet. These original demonstrators were replaced one by one each 24-hr over a period of 4 days with naive subjects. The original demonstrators effectively transmitted a preference for the alternative diet to the naive replacements, as these replacements exhibited a preference for the alternative diet for a period of 4 days following the departure of the final demonstrator. Employing essentially the same methodology as that used in Experiment 1, videotape analysis of the feeding behavior of subjects on the sixth day (zero original demonstrators, four naive replacements) of Experiment 2 revealed no significant difference in the food choices of the first, second, third and fourth replacement subjects, indicating that naive replacements became effective demonstrators following interaction with original demonstrators. Random placement of the food bowls each day during Experiment 3 revealed that the social transmission of food preferences from original demonstrators to naive replacements can persist in the absence of excretory cues around a particular feeding site. In Experiment 4, removal of demonstrators from the floor enclosure during periods in which foods were available there for replacement subjects to choose between revealed that naive observers could obtain sufficient information from demonstrators during non-consumption periods to guide their food choices. Observers in Experiment 4 exhibited a preference for their respective demonstrators' diets when presented a choice between their demonstrators' diet and an alternative diet in the absence of demonstrators. In the General Discussion, variables were discussed that might modify the strength of socially transmitted food preferences in rats and could be examined in future research using the present paradigm. / Thesis / Master of Science (MSc)

No description available.

An observer rat that interacts with a conspecific, a demonstrator that has eaten a flavoured food, is subsequently more likely to eat that food than an alternative, novel food (Galef & Wigmore, 1983). In the first part of this thesis, four experiments were undertaken to determine the influence of unreliable demonstrators on observer food preference. In the first three experiments, observers were poisoned after interaction with demonstrators; a demonstrator that demonstrated a food that led to poisoning was considered an unreliable demonstrator. The first experiment compared the influence of an unreliable demonstrator and an unfamiliar demonstrator on observers' food preferences. Experiment 2 compared the influence of demonstration from an unreliable conspecific and a familiar conspecific that had only provided irrelevant information. The third experiment compared the influence of an unreliable and a reliable demonstrator. Experiment 4 compared the influence for protein-deficient observers of a demonstrator that had previously demonstrated a protein-deficient diet and a demonstrator that was unfamiliar. None of the first four experiments showed a significant difference in effectiveness of social transmission due to demonstrator quality. In the second part of the thesis I investigated the influence of familiarity on demonstrator effectiveness. In Experiment 5, the influence of local sisters was compared with that of unfamiliar non-relatives as demonstrators. Sisters were not better demonstrators than unfamiliar non-relatives. / Thesis / Master of Science (MSc)

There is much evidence that mate-choice decisions made by humans are affected by social/contextual information. Women seem to rate men portrayed in a relationship as more desirable than the same men when portrayed as single. Laboratory studies have found evidence suggesting that human mate choice, as in other species, is dependent on the mate choice decisions made by same-sex rivals. Even though non-independent mate choice is an established and well-studied area of mate choice, very few field studies have been performed. This project aims to test whether women’s evaluation of potential mates desirability is dependent/non-independent of same-sex rivals giving the potential mates sexual interest. This is the first field study performed in a modern human’s natural habitat aiming to test for non- independent mate choice in humans. No desirability enhancement effect was found. The possibilities that earlier studies have found an effect that is only present in laboratory environments or have measured effects other than non-independent mate choice are discussed. I find differences in experimental design to be the most likely reason why the present study failed to detect the effect found in previous studies. This field study, the first of its sort, has generated important knowledge for future experimenters, where the most important conclusion is that major limitations in humans ability to register and remember there surrounding should be taken in consideration when designing any field study investigating human mate choice.

Doctor of Philosophy / Department of Psychological Sciences / Jerome Frieman / Spotted hyenas (Crocuta crocuta) live in highly-complex, female-dominated groups called “clans.” Due to their social arrangement, spotted hyenas were a logical species on which to test the social complexity hypothesis. In the present study, they were presented with a series of puzzle boxes designed to test problem-solving behavior. The five puzzles varied in difficulty. All spotted hyenas solved the puzzle with the lowest difficulty level, five out of six solved the medium puzzles at least once, and one out of six solved the high difficulty puzzle. Some decreases in behavior diversity and time working on the puzzles were observed over successful trials; however, the decreases were only significant for successful trials of one medium-level puzzle. Decreases in work time were observed for some unsuccessful trials and the decrease was statistically significant for the highest difficulty puzzle. Overall, spotted hyenas were proficient at problem solving in the present study. Social learning is an important component of a lengthy juvenile period for spotted hyenas, and they have also been shown to influence one another’s feeding behavior. Furthermore, spotted hyenas participate in scramble competition when feeding and forage for and hoard food. In light of these behaviors, social learning was examined using the social transmission of a flavor preference (STFP) procedure. STFP was not observed overall. The sex of the subjects did not significantly influence the results; however, subjects that interacted with each other longer were significantly more likely to show STFP. The STFP procedure may not be sensitive enough to detect social learning in spotted hyenas. Perhaps spotted hyenas have no need to learn STFP due to their digestive and/or immune systems. The results of the current experiments make important contributions to existing knowledge. Data from other species like spotted hyenas are vital for evaluating the generality of the social complexity hypothesis since support thus far has come from data on primates. This study was the first to investigate STFP in a species from the Feliformia suborder. Additionally, finding more evidence that spotted hyenas have advanced cognitive abilities is essential for researchers and zoo personnel who work with spotted hyenas in captivity.

Le succès remarquable -écologique et démographique- de l'espèce humaine est largement attribué à notre capacité pour la culture cumulative, i.e. l'accumulation d'innovations culturelles à travers le temps. L'absence ou du moins la rareté de la culture cumulative chez les autres animaux a conduit à de nombreuses spéculations à propos des facteurs nécessaires à son émergence. La culture cumulative dépend étroitement de processus permettant de générer de l'information, et de mécanismes permettant à cette information d'être fidèlement transmise entre les individus. A l'aide d'une approche expérimentale basée sur l'utilisation de jeux sur ordinateur, nous montrons que la capacité d'imitation des patrons comportementaux peut grandement faciliter la fidélité de transmission des informations culturelles. De même, une grande taille de population contribue à la stabilisation des informations culturelles, particulièrement dans le cas d'informations complexes. Cependant, la culture cumulative requiert également la production d'innovations qui ne peut résulter de ces seuls facteurs. D'un point de vue théorique, les innovations sont généralement plus coûteuses à produire qu'à copier, de sorte que la sélection peut difficilement opérer au profit des innovateurs. Nos résultats nous permettent cependant d'avancer que l'émergence d'objets culturels technologiquement opaques pourrait permettre aux innovateurs de bénéficier plus largement de leurs innovations. L'émergence de l'opacité technologique pourrait ainsi constituer un pivot dans l'évolution de la culture cumulative, permettant de favoriser à la fois l'innovation et les mécanismes fidèles de transmission d'information. Les capacités à hiérarchiser et planifier ses actions étant essentiel à la production d'objets culturels technologiquement opaques, il est possible que l'absence apparente de culture cumulative chez les animaux non-humains soit due à un moindre développement de ces capacités cognitives. Finalement nous proposons que la complexité de la culture humaine repose sur quatre facteurs principaux : capacité à hiérarchiser et planifier ses actions, capacité à imiter, collaboration interindividuelle et grande taille de population. / The remarkable success – both ecological and demographic- of the human species is widely attributed to our capability for cumulative culture, i.e. the accumulation of innovations over time. The lack or at least the rarity of cumulative culture in non-human animals has led to much speculation about factors enabling its emergence. Cumulative culture strongly depends on processes allowing generating information, and mechanisms allowing information to be efficiently transmitted between individuals. Using a computer-based experimental approach, we show that process-copying ability improves the fidelity of cultural information transmission. Also, population size contributes to the stability of cultural information, especially for complex information. However, cumulative culture also requires the creation of new innovations, which cannot be the outcome of these factors. From a theoretical point of view, innovations are generally costlier to produce than to copy, so that selection hardly favours innovators. From our results, we propose that the emergence of technologically opaque cultural traits may allow innovators to more widely benefit from their innovations. Thus, the emergence of technological opacity could be pivotal in the rise of cumulative culture, allowing favouring innovation and faithful copying mechanisms. Because the ability to plan actions in a hierarchical way is pivotal to produce technologically opaque cultural artefacts, the lack of cumulative culture in non-human animals could be due to limitations of these cognitive skills. Finally, we propose that human cultural complexity depends on four main factors: the ability to plan actions in a hierarchical way, the ability to process-copy, inter-individual collaboration and large population size.

This thesis investigates estrogens' modulation of three aspects of social cognition (aggression and agonistic behaviour, social learning, and social recognition). Sex-typical agonistic behaviour (males: overt attacks, females: more subtle dominance behaviours) was increased in gonadectomized mice by estrogen receptor alpha (ERα) agonist 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT), while non-overt agonistic behaviour was increased in male and female gonadally intact mice by ERβ agonist 7-Bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY-200070). Estrogens also affected the social transmission of food preferences (STFP). Acute estrogen and ERβ agonists WAY-200070 and 2,3-bis(4-hydroxyphenyl)propionitrile (DPN) prolonged the preference for the demonstrated food when administered pre-acquisition, likely by affecting motivation or the nature of the social interaction, while acute PPT blocked the STFP. All mice receiving any of the three treatments chronically showed a prolonged demonstrated food preference, suggesting a loss of ER specificity. Individual differences in social recognition may relate to increased oxytocin (OT) and vasopressin (AVP) mRNA, and ERα and ERβ gene activation, in the medial preoptic area, and decreased mRNA for ERs, OT receptor (OTR), AVP and AVP receptors 1a and 1b in the lateral amygdala. Additionally, dorsolateral septum ERs, progesterone receptor, and OTR may relate to social interest without affecting social recognition. Our and others' results suggest that estrogens, OT and AVP are all involved in social behaviours and mediate social recognition, social learning, social interactions, and aggression. ERs differently modulate the two types of social learning investigated here: ERα is critical for social recognition, but impairs social learning, while ERβ is less important in social recognition, and prolongs the demonstrated food preference in the STFP. This may be due to differences in receptor brain distributions or in downstream neurochemical systems that mediate these behaviours. The results of this thesis suggest that estrogens, through the various systems they modulate, have a key role to play in social behaviour. Further investigations of how estrogens effect change in these systems at the molecular and cellular level, as well as the critical brain areas and downstream effectors involved in these complex behaviours, are needed, and could contribute to therapeutic interventions in socially-based, sexually dimorphic disorders, like the autism spectrum disorders, and women receiving hormone replacement therapy for negative peri- or post-menopausal symptoms. / National Science and Engineering Research Council (PGS-D, CGS-M)

Submitted by Maria Santos (mariajoaosantos26@gmail.com) on 2018-07-20T11:46:18Z No. of bitstreams: 1 2018_DISSERATION_MARIAJOAO_FINAL (1).pdf: 985094 bytes, checksum: ae65eaf60f5eb75bcd74e76b10b71d79 (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2018-07-27T18:45:46Z (GMT) No. of bitstreams: 1 2018_DISSERATION_MARIAJOAO_FINAL (1).pdf: 985094 bytes, checksum: ae65eaf60f5eb75bcd74e76b10b71d79 (MD5) / Made available in DSpace on 2018-08-08T13:19:44Z (GMT). No. of bitstreams: 1 2018_DISSERATION_MARIAJOAO_FINAL (1).pdf: 985094 bytes, checksum: ae65eaf60f5eb75bcd74e76b10b71d79 (MD5) Previous issue date: 2018-06-20 / Objetivo – O objetivo desta tese é examinar a influencia que gênero e diferentes estímulos emocionais exercem sobre as intenções de partilha online das pessoas: (1) se os indivíduos partilham mais conteúdos positivos ou negativos; (2) quem, de entre homens ou mulheres, reage mais fortemente a estímulos emocionais; e (3) se a valência emocional e o género têm algum tipo de correlação. Metodologia - Esta dissertação utiliza um estudo experimental: 2 (valência emocional: positiva vs. negativa) x 2 (género: masculino vs. feminino) entre sujeitos. Resultados – Os resultados mostram que a valência emocional afeta, de facto, as intenções de partilha de conteúdo online e, mais importante, que as emoções negativas levam a uma maior predisposição para partilhar. Além disso, os resultados demonstram que as mulheres partilham mais conteúdos online quando comparadas com os homens, contudo, não foram observados efeitos heterogêneos de valência emocional. Limitações- A principal limitação desta pesquisa é o fato de ser baseada em respostas próprias a cenários hipotéticos, uma vez que pretendemos medir uma intenção de partilha. Isso significa que, embora a intenção de um indivíduo de se comprometer com um determinado comportamento seja o indicador mais adequado para o comportamento do próprio, isso ultrapassa o âmbito deste estudo. Aplicabilidade do trabalho - Esta pesquisa fornece informações relevantes sobre como criar conteúdo com grande probabilidade de ser partilhado online, ao contrário do conteúdo regular que a maioria das agências e profissionais de marketing utilizam para promover os seus produtos / Purpose – The purpose of this work is to examine the influence that gender and different emotional stimuli exert on people’s online sharing intentions. Precisely, we take a closer look at whether (1) people share more positive or negative content; (2) men or women react more strongly to these emotional stimuli; and (3) emotional valence has a heterogeneous effect across genders. Design/Methodology - This dissertation employs an experimental study: 2 (emotional valence: positive vs. negative) x 2 (gender: male vs. female) between-subjects design. Findings – Results show that emotional valence does indeed influence sharing intentions, and more importantly, that negative emotions lead to a higher willingness to share. Further, results demonstrated that women share more content online when compared to men but no heterogeneous effects of emotional valence were observed. Research limitations - The main limitation of this research is that it is based on self-reported answers to hypothetical scenarios, since we intend to measure potential behavior of sharing. Meaning that, although an individual’s intention to commit to a certain behavior is the most adequate predictor of one’s behavior, it is beyond the scope of this study to measure actual sharing behavior. Practical implications - This research produced valuable insights by providing relevant information on how to create content that will probably be highly shared, on the opposite to the regular content that most agencies and marketer use to promote their products.

At the intersection of geography and public health, the field of spatial epidemiology seeks to use the tools of geospatial analysis to answer questions about disease. In this work we explore two areas: the use of geostatistical modeling as an extension of niche modeling, and the use of mobility metrics to augment modeling for epidemic responses. Niche modeling refers to the practice of using statistical methods to relate the underlying spatially distributed environmental variables to an outcome, typically presence or absence of a species. Such work is common in disease ecology, and often focuses on exploring the range of a disease vector or pathogen. The technique also allows one to explore the importance of each underlying regressor, and the effect it has on the outcome. We demonstrate that this concept can be extended, through geostatistical modeling, to explore non-logistic phenomena such as incidence. When combined with weather forecasts, such efforts can even predict incidence of an upcoming season, allowing us to estimate the total number of expected cases, and where we would expect to find them. We demonstrate this in Chapter 2, by forecasting the incidence of melioidosis in Australia given weather forecasts a year prior. We also evaluate the efficacy of this technique and explore the impact of environmental variables such as elevation on melioidosis. But these techniques are not limited to free-living and vector-borne pathogens. We theorize that they can also be applied to diseases that spread exclusively by person-to-person contact. Exploring this allows us to find areas of underreporting, as well as areas with unusual local forcing which might merit further investigation by the health department. We also explore this in Chapter 4, by relating the incidence of hepatitis C in rural Virginia to demographic data. The West African Ebola Outbreak of 2014 demonstrated the need to include mobility in predictive disease modeling. One can no longer assume that neglected tropical diseases will remain contained and immobile, and the assumption of random mixing across large areas is unwise. Our efforts with modeling mobility are twofold. In Chapter 3, we demonstrate the creation of mobility metrics from open source road and river network data. We then demonstrate the usefulness of such data in a meta-population patch model meant to forecast the spread of Ebola in the Democratic Republic of Congo. In Chapter 4, we also demonstrate that mobility data can be used to strengthen outbreak detection via hotspot analysis, and to augment incidence models by factoring in the incidence rates of neighboring areas. These efforts will allow health departments to more accurately forecast incidence, and more readily identify disease hotspots of atypical size and shape. / Doctor of Philosophy / The focus of this work is called “spatial epidemiology”, which combines geography with public health, to answer the where, and why, of disease. This is a growing field, and you’ve likely seen it in the news and media. Have you ever seen a map of the United States turning red in some virus disaster movie? The real thing looks a lot like that. After the Ebola outbreak of 2014, public health agencies wanted to know where the next one might hit. Now that there is another outbreak, we need to ask where and how will it spread? What areas are hardest hit, and how bad is it going to get? We can answer all these questions with spatial epidemiology. Our work adds to two aspects of spatial epidemiology: niche modeling, and mobility. We use niche modeling to determine where we could find certain diseases, usually those that are spread by insects or animals. Consider Lyme disease, you get it from the bite of a tick, and the tick gets it from a white-footed mouse. But both the mice and ticks only live in certain parts of the country. With niche modeling we can determine where those are, and we can also guess at what makes those areas attractive to the mice and ticks. Is it winter harshness, summer temperatures, rainfall, and/or elevation? Is it something else? In Chapter 2, we show that you can extend this idea. Instead of just looking at where the disease is, what if we could guess how many people will get infected? What if we could do so, a year in advance? We show that this can be done, but we need a good idea of what the weather will be like next year. In Chapter 4, we show that you can do the same thing with hepatitis C. Instead of Lyme’s ticks and mice, hepatitis C depends on drug-use, unregulated tattooing, and unsafe sex. And like with Lyme, these things are only found in certain places. Instead of temperature or rainfall, we now need to find areas with drug-problems and poverty. But we can get an idea of this from the Census Bureau, and we can make a map of hepatitis C as easily as we did for Lyme. But hepatitis C spreads person-to-person. So, we need some idea of how people move around the area. This is where mobility comes in. Mobility is important for most public health work, from detecting outbreaks to estimating where the disease will spread next. In Chapter 3, we show how one could create a mobility model for a rural area where few maps exist. We also show how to use that model to guess where the next cases of Ebola will show up. In Chapter 4, we show how you could use mobility to improve outbreak and hotspot detection. We also show how it’s used to help estimate the number of cases in an area. Because that number depends on how many cases are imported from the surrounding areas. And the only way to estimate that is with mobility.