Francisco Mendes | Universidade de Brasília - UnB (original) (raw)

Papers by Francisco Mendes

Psicologia: Teoria E Pesquisa, 2016

American Journal Of Primatology, 2024

The availability of manmade foodstuffs in the environment may significantly alter the diets, beha... more The availability of manmade foodstuffs in the environment may significantly alter the diets, behavior and health of wild animals and the ecosystems ecology. One of the principal problems faced by urban populations of capuchin monkeys is their contact with household refuse, which may provoke a number of impacts on the health of these animals. The present study tested the use of feeding platforms as a strategy to reduce the consumption of unhealthy foodstuffs by these animals and analyzed the influence of this measure on the activity patterns and social interactions of the study groups. For this, we verified the patterns of use of a feeding platform by a capuchin group in an urban park in Goiânia, central Brazil, and compared this study population with those of other parks where alternative feeding protocols are implemented, ranging from continuous provisioning to no intervention whatsoever. Behavioral data were collected using scan sampling. The data analysis was divided into two steps: (i) comparison of the different conditions found in the populations with varying types of feeding platform usage and (ii) comparison of the time budget among sites in the context of seasonal variation. The presence of feeding platforms effectively reduced the consumption of refuse in the study groups, although it did also cause an increase in agonism in the animals and altered their activity patterns, leading to a greater dependence on provisioned resources. The results of this study highlight the complex interaction between human activities and the local wildlife in the urban setting, and the need for more detailed studies, to develop more effective management strategies.

Neotropical Primates, May 31, 1994

Primates

Studies of urban monkeys provide important insights into the behavioral flexibility of primate sp... more Studies of urban monkeys provide important insights into the behavioral flexibility of primate species. We studied two provisioned groups of capuchin monkeys that inhabit a small forest fragment in the city of Goiânia, Brazil. One of the groups was dominant and had priority of access to both native and provisioned resources. Anthropic resources were available in two relatively small areas within this forest, but varied in their quality. We hypothesized that intergroup dominance and the seasonality of native resources would have different impacts on the foraging strategies and use of space by the two study groups. Data on the location of the members of the two groups, their behavior, and consumption of different food items were collected during five dry season and five rainy season months. The members of the dominant group spent more time in the provisioned area where anthropic food was less costly to obtain and consumed more provisioned fruit and vegetables than the members of the subordinate group. The differences between groups were exacerbated during the dry season, when sources of native fruit were less abundant. The results of the present study illustrate how capuchins may respond to the variation in proximate factors, such as intergroup dominance and seasonality. These factors were determinants to the variation in the diet and the use of space observed between the two study groups.

American Journal of Primatology, 2024

The progressive growth of urban environments has increasingly forced populations of nonhuman prim... more The progressive growth of urban environments has increasingly forced populations of nonhuman primates to coexist with humans in many cities, which has resulted in problems such as behavioral alterations, conflicts with humans, and threats to the health of the monkeys, due to their consumption of anthropogenic foodstuffs. These

Primates

Socioecological models predict that disputes between primate groups will be more intense than tho... more Socioecological models predict that disputes between primate groups will be more intense than those within groups, given that the systematic loss of contests over a given resource will restrict the access of all of the members of that group to that resource. Higher levels of aggression are also expected for provisioned resources that have a more lucrative cost:benefit ratio. The levels of aggression in and between two free-ranging tufted capuchin monkey (Sapajus libidinosus) groups in the context of daily provisioning with bananas were evaluated. The aim of a complementary analysis was to identify possible predictors of the frequency of disputes at the site of the provisioned resource. The disputes were recorded using all-events sampling, while the social behaviour of the study groups was recorded by instantaneous scan sampling. The data were analysed using t-test, Mann-Whitney's U, and generalised linear modelling. Between-group disputes were no more intense than within-group events, and did not involve more individuals, or more adult females. The frequency of disputes increased as the number of individuals eating bananas increased. No evidence was found that disputes between groups were any more intense than those within groups. Dominance patterns may have affected these findings, by mediating intergroup disputes. An increase in the number of competitors affected the frequency of disputes at the site of the provisioned resource.

Zoologia (Curitiba)

Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically ... more Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically occur in contexts in which the energetic returns are relatively high. In anthropogenic environments, provisioned resources tend to be rich in energy and highly agglomerated. While females are expected to defend provisioned resources, the adult males, in turn, are expected to defend the females. Based on this premise, the present study focused on an urban forest in the city of Goiânia (Goiás, Brazil), which is inhabited by two groups of bearded capuchins. Behavioral data were collected using instantaneous scan sampling and all-events records to document intergroup conflicts and define their context. We used a backward logistic regression and stepwise linear regression to analyze the participation of the individuals in the conflicts. Conflicts were more frequent in the context of provisioning, although the number of neither females nor males involved in the conflict varied significantly between contexts. The females did avoid participating in conflicts involving adult males, however, to minimize the risk of being attacked by them. The adult males participated more in the presence of other adult males, which is partly consistent with the hypothesis of the defense of reproductive partners. The conflicts were not more intense in the context of provisioned resources, which contrasted with expectations. The hierarchical relationship between the two study groups, and the fact that the groups were derived from the same social unit, may have contributed to a reduction in the intensity of the conflicts.

Revista Brasileira de Zootecnia, 2013

The objective of the present study consisted of describing dam and calf suckling behaviour of Cur... more The objective of the present study consisted of describing dam and calf suckling behaviour of Curraleiro Pé Duro cattle. In this study, 38 mother-offspring pairs and one mother-offspring-orphan trio were observed for 10 hours daily during three consecutive days spaced every four months over a period of one year. After identification, the animals were observed under field conditions where calf posture and the number of suckling episodes (NS), mean suckling duration (MSD), total suckling duration per day (TSD) as well as natural weaning of these animals were recorded. The model assessed the effects of calf sex and age as well as feeding time. Suckling episodes (70.6%) had a duration of one to five minutes and the calf that suckled in the inverted parallel position had greater chances of success during suckling (99.5%); the younger animals had a shorter mean suckling duration (4.0±0.6 minutes) than the older ones (7.5±1.2 minutes) but they showed a higher number of suckling episodes (6.29±1.00 vs. 1.33±0.04 feeds in 10 hours for young and older calves). Only the factor age in the first three months was significant for NS, MSD, and TSD; males and females had similar suckling episode length and distribution. While these animals show some traits similar to other cattle breeds such as feeding their calves early in the morning and late in the afternoon, the dams spend large periods of the day away from their calves and suckling is more frequent but for shorter periods of time compared with other breeds. Other unique features such as allo-suckling and formation of day-long crèches are observed in this breed.

Zoologia (Curitiba), 2022

Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically ... more Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically occur in contexts in which the energetic returns are relatively high. In anthropogenic environments, provisioned resources tend to be rich in energy and highly agglomerated. While females are expected to defend provisioned resources, the adult males, in turn, are expected to defend the females. Based on this premise, the present study focused on an urban forest in the city of Goiânia (Goiás, Brazil), which is inhabited by two groups of bearded capuchins. Behavioral data were collected using instantaneous scan sampling and all-events records to document intergroup conflicts and define their context. We used a backward logistic regression and stepwise linear regression to analyze the participation of the individuals in the conflicts. Conflicts were more frequent in the context of provisioning, although the number of neither females nor males involved in the conflict varied significantly between contexts. The females did avoid participating in conflicts involving adult males, however, to minimize the risk of being attacked by them. The adult males participated more in the presence of other adult males, which is partly consistent with the hypothesis of the defense of reproductive partners. The conflicts were not more intense in the context of provisioned resources, which contrasted with expectations. The hierarchical relationship between the two study groups, and the fact that the groups were derived from the same social unit, may have contributed to a reduction in the intensity of the conflicts.

International Journal of Primatology, 2021

Some nonhuman primates use tools to modify the behavior of other animals in social contexts. For ... more Some nonhuman primates use tools to modify the behavior of other animals in social contexts. For example, during their proceptive periods, female bearded capuchins (Sapajus libidinosus) in two wild groups throw stones and push branches toward males, which may function to draw male attention to the females. To further clarify the social and communicative relevance of this behavior, we recorded all occurrences of object use in a captive group (one adult male and four females) at Brasília Zoo, during 963 h of observation. Additionally, we recorded the occurrence of typical proceptive behaviors and quantified behavioral changes of the male associated with throwing behavior. All females threw objects, such as stones and sticks, at the male (N = 205 events). One of the females also pounded objects near the male (N = 72). The two forms of object use were associated with female proceptivity. Male-directed throws increased the chances of the male changing his behavior, particularly by shifting his attention to the thrower, supporting the hypothesis that throwing at the male function as a communicative act. However, females also used aimed throwing in affiliative contexts (N = 2) and interactions with humans (N = 102) and other animals (N = 61). Thus, our results show that aimed throwing is a flexible behavior, elicited in multiple social contexts and for different purposes. Moreover, our study demonstrates that considering the effects of object use on the behavior of potential targets can help us to understand how primates use objects to mediate communication.

Frontiers in Psychology

Perceived vocal attractiveness and measured sex-dimorphic vocal parameters are both associated wi... more Perceived vocal attractiveness and measured sex-dimorphic vocal parameters are both associated with underlying individual qualities. Research tends to focus on speech but singing is another highly evolved communication system that has distinct and universal features with analogs in other species, and it is relevant in mating. Both speaking and singing voice provides relevant information about its producer. We tested whether speech and singing function as "backup signals" that indicate similar underlying qualities. Using a sample of 81 men and 86 women from Brazil and the Czech Republic, we investigated vocal attractiveness rated from speech and singing and its association with fundamental frequency (F0), apparent vocal tract length (VTL), body characteristics, and sociosexuality. F0, VTL, and rated attractiveness of singing and speaking voice strongly correlated within the same individual. Lower-pitched speech in men, higherpitched speech and singing in women, individuals who like to sing more, and singing of individuals with a higher pitch modulation were perceived as more attractive. In men, physical size positively predicted speech and singing attractiveness. Male speech but not singing attractiveness was associated with higher sociosexuality. Lower-pitched male speech was related to higher sociosexuality, while lower-pitched male singing was linked to lower sociosexuality. Similarly, shorter speech VTL and longer singing VTL predicted higher sociosexuality in women. Different vocal displays function as "backup signals" cueing to attractiveness and body size, but their relation to sexual strategies in men and women differs. Both singing and speech may indicate evolutionarily relevant individual qualities shaped by sexual selection.

Psicologia: Reflexão e Crítica, 2009

Resumo O fenômeno conhecido como school shooting vem chamando a atenção do mundo, principalmente ... more Resumo O fenômeno conhecido como school shooting vem chamando a atenção do mundo, principalmente após a tragédia na Columbine High School, na cidade de Littleton, Colorado, nos Estados Unidos, em 1999. Posteriormente, em abril de 2007, o estudante Cho Seung-Hui protagonizou um massacre de proporções ainda maiores ao atirar contra estudantes do Virginia Polytechnic Institute and State University, matando 32 pessoas e se suicidando ao final. O presente artigo reflete sobre o fenômeno chamando a atenção para a sua expansão pelo mundo e traz uma reflexão, baseada em dados empíricos, sobre o desenvolvimento dos protagonistas dos massacres em seus contextos sociais, incluindo o ambiente familiar, a mídia e interações entre colegas nas escolas e universidades.

International Journal of Primatology, 1993

Page 1. International Journal of Primatology, VoL 14, No. 4, 1993. Demography and Social Structur... more Page 1. International Journal of Primatology, VoL 14, No. 4, 1993. Demography and Social Structure of One Group of Muriquis (Brachyteles arachnoides) Karen B. Strier, 1,3 Francisco DC Mendes, 2 Jos6 Rimoli, 2 and Adriana ...

Folia Primatologica, 2000

The brown capuchin monkey, Cebus apella, occupies different biomes and habitats of South America.... more The brown capuchin monkey, Cebus apella, occupies different biomes and habitats of South America. Its large geographical range may be associated with its capacity to explore variable resources through the manipulation of food items and other objects [1–3]. Items such as palm hearts [4], insects [5], oysters [6] and nuts [7] are eaten by breaking stems, opening hard shells or

Anais da Academia Brasileira de Ciências, 2004

Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyt... more Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a larger proportion of tonal elements than those emitted by muriquis feeding in a cohesive manner. Sequential exchanges seem thus to be constituted by two inter-related subsystems of calls that aid muriquis to coordinate intragroup spacing, despite the poor visibility of the habitat.

Psicologia: Reflexão e Crítica, 2010

Resumo Investigamos a relação entre fatores de aprendizagem social, acessados via questionários, ... more Resumo Investigamos a relação entre fatores de aprendizagem social, acessados via questionários, e os comportamentos agressivos e lúdicos de meninos pré-escolares, através de observação direta durante o recreio. Os participantes foram 15 meninos com idades entre quatro e seis anos, da cidade de Goiânia, GO, Brasil. Uma análise multivariada de variância indicou efeitos significativos de modelos de agressividade em casa nas taxas de agressão durante o brincar. Crianças expostas a punições físicas abusivas, brigas entre adultos e programas violentos de TV apresentaram mais agressões reais. Meninos que relataram brincar com armas de brinquedo em casa não apresentaram mais agressões reais do que os que relataram o contrário, mas apresentaram maior proporção de agressões de faz-de-conta. Os resultados também indicaram que quanto mais modelos agressivos em casa, maior a incidência de comportamentos agressivos. Palavras-chave: Aprendizagem social; Comportamento agressivo; Comportamento lúdico.

Psicologia: Teoria E Pesquisa, 2016

American Journal Of Primatology, 2024

The availability of manmade foodstuffs in the environment may significantly alter the diets, beha... more The availability of manmade foodstuffs in the environment may significantly alter the diets, behavior and health of wild animals and the ecosystems ecology. One of the principal problems faced by urban populations of capuchin monkeys is their contact with household refuse, which may provoke a number of impacts on the health of these animals. The present study tested the use of feeding platforms as a strategy to reduce the consumption of unhealthy foodstuffs by these animals and analyzed the influence of this measure on the activity patterns and social interactions of the study groups. For this, we verified the patterns of use of a feeding platform by a capuchin group in an urban park in Goiânia, central Brazil, and compared this study population with those of other parks where alternative feeding protocols are implemented, ranging from continuous provisioning to no intervention whatsoever. Behavioral data were collected using scan sampling. The data analysis was divided into two steps: (i) comparison of the different conditions found in the populations with varying types of feeding platform usage and (ii) comparison of the time budget among sites in the context of seasonal variation. The presence of feeding platforms effectively reduced the consumption of refuse in the study groups, although it did also cause an increase in agonism in the animals and altered their activity patterns, leading to a greater dependence on provisioned resources. The results of this study highlight the complex interaction between human activities and the local wildlife in the urban setting, and the need for more detailed studies, to develop more effective management strategies.

Neotropical Primates, May 31, 1994

Primates

Studies of urban monkeys provide important insights into the behavioral flexibility of primate sp... more Studies of urban monkeys provide important insights into the behavioral flexibility of primate species. We studied two provisioned groups of capuchin monkeys that inhabit a small forest fragment in the city of Goiânia, Brazil. One of the groups was dominant and had priority of access to both native and provisioned resources. Anthropic resources were available in two relatively small areas within this forest, but varied in their quality. We hypothesized that intergroup dominance and the seasonality of native resources would have different impacts on the foraging strategies and use of space by the two study groups. Data on the location of the members of the two groups, their behavior, and consumption of different food items were collected during five dry season and five rainy season months. The members of the dominant group spent more time in the provisioned area where anthropic food was less costly to obtain and consumed more provisioned fruit and vegetables than the members of the subordinate group. The differences between groups were exacerbated during the dry season, when sources of native fruit were less abundant. The results of the present study illustrate how capuchins may respond to the variation in proximate factors, such as intergroup dominance and seasonality. These factors were determinants to the variation in the diet and the use of space observed between the two study groups.

American Journal of Primatology, 2024

The progressive growth of urban environments has increasingly forced populations of nonhuman prim... more The progressive growth of urban environments has increasingly forced populations of nonhuman primates to coexist with humans in many cities, which has resulted in problems such as behavioral alterations, conflicts with humans, and threats to the health of the monkeys, due to their consumption of anthropogenic foodstuffs. These

Primates

Socioecological models predict that disputes between primate groups will be more intense than tho... more Socioecological models predict that disputes between primate groups will be more intense than those within groups, given that the systematic loss of contests over a given resource will restrict the access of all of the members of that group to that resource. Higher levels of aggression are also expected for provisioned resources that have a more lucrative cost:benefit ratio. The levels of aggression in and between two free-ranging tufted capuchin monkey (Sapajus libidinosus) groups in the context of daily provisioning with bananas were evaluated. The aim of a complementary analysis was to identify possible predictors of the frequency of disputes at the site of the provisioned resource. The disputes were recorded using all-events sampling, while the social behaviour of the study groups was recorded by instantaneous scan sampling. The data were analysed using t-test, Mann-Whitney's U, and generalised linear modelling. Between-group disputes were no more intense than within-group events, and did not involve more individuals, or more adult females. The frequency of disputes increased as the number of individuals eating bananas increased. No evidence was found that disputes between groups were any more intense than those within groups. Dominance patterns may have affected these findings, by mediating intergroup disputes. An increase in the number of competitors affected the frequency of disputes at the site of the provisioned resource.

Zoologia (Curitiba)

Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically ... more Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically occur in contexts in which the energetic returns are relatively high. In anthropogenic environments, provisioned resources tend to be rich in energy and highly agglomerated. While females are expected to defend provisioned resources, the adult males, in turn, are expected to defend the females. Based on this premise, the present study focused on an urban forest in the city of Goiânia (Goiás, Brazil), which is inhabited by two groups of bearded capuchins. Behavioral data were collected using instantaneous scan sampling and all-events records to document intergroup conflicts and define their context. We used a backward logistic regression and stepwise linear regression to analyze the participation of the individuals in the conflicts. Conflicts were more frequent in the context of provisioning, although the number of neither females nor males involved in the conflict varied significantly between contexts. The females did avoid participating in conflicts involving adult males, however, to minimize the risk of being attacked by them. The adult males participated more in the presence of other adult males, which is partly consistent with the hypothesis of the defense of reproductive partners. The conflicts were not more intense in the context of provisioned resources, which contrasted with expectations. The hierarchical relationship between the two study groups, and the fact that the groups were derived from the same social unit, may have contributed to a reduction in the intensity of the conflicts.

Revista Brasileira de Zootecnia, 2013

The objective of the present study consisted of describing dam and calf suckling behaviour of Cur... more The objective of the present study consisted of describing dam and calf suckling behaviour of Curraleiro Pé Duro cattle. In this study, 38 mother-offspring pairs and one mother-offspring-orphan trio were observed for 10 hours daily during three consecutive days spaced every four months over a period of one year. After identification, the animals were observed under field conditions where calf posture and the number of suckling episodes (NS), mean suckling duration (MSD), total suckling duration per day (TSD) as well as natural weaning of these animals were recorded. The model assessed the effects of calf sex and age as well as feeding time. Suckling episodes (70.6%) had a duration of one to five minutes and the calf that suckled in the inverted parallel position had greater chances of success during suckling (99.5%); the younger animals had a shorter mean suckling duration (4.0±0.6 minutes) than the older ones (7.5±1.2 minutes) but they showed a higher number of suckling episodes (6.29±1.00 vs. 1.33±0.04 feeds in 10 hours for young and older calves). Only the factor age in the first three months was significant for NS, MSD, and TSD; males and females had similar suckling episode length and distribution. While these animals show some traits similar to other cattle breeds such as feeding their calves early in the morning and late in the afternoon, the dams spend large periods of the day away from their calves and suckling is more frequent but for shorter periods of time compared with other breeds. Other unique features such as allo-suckling and formation of day-long crèches are observed in this breed.

Zoologia (Curitiba), 2022

Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically ... more Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically occur in contexts in which the energetic returns are relatively high. In anthropogenic environments, provisioned resources tend to be rich in energy and highly agglomerated. While females are expected to defend provisioned resources, the adult males, in turn, are expected to defend the females. Based on this premise, the present study focused on an urban forest in the city of Goiânia (Goiás, Brazil), which is inhabited by two groups of bearded capuchins. Behavioral data were collected using instantaneous scan sampling and all-events records to document intergroup conflicts and define their context. We used a backward logistic regression and stepwise linear regression to analyze the participation of the individuals in the conflicts. Conflicts were more frequent in the context of provisioning, although the number of neither females nor males involved in the conflict varied significantly between contexts. The females did avoid participating in conflicts involving adult males, however, to minimize the risk of being attacked by them. The adult males participated more in the presence of other adult males, which is partly consistent with the hypothesis of the defense of reproductive partners. The conflicts were not more intense in the context of provisioned resources, which contrasted with expectations. The hierarchical relationship between the two study groups, and the fact that the groups were derived from the same social unit, may have contributed to a reduction in the intensity of the conflicts.

International Journal of Primatology, 2021

Some nonhuman primates use tools to modify the behavior of other animals in social contexts. For ... more Some nonhuman primates use tools to modify the behavior of other animals in social contexts. For example, during their proceptive periods, female bearded capuchins (Sapajus libidinosus) in two wild groups throw stones and push branches toward males, which may function to draw male attention to the females. To further clarify the social and communicative relevance of this behavior, we recorded all occurrences of object use in a captive group (one adult male and four females) at Brasília Zoo, during 963 h of observation. Additionally, we recorded the occurrence of typical proceptive behaviors and quantified behavioral changes of the male associated with throwing behavior. All females threw objects, such as stones and sticks, at the male (N = 205 events). One of the females also pounded objects near the male (N = 72). The two forms of object use were associated with female proceptivity. Male-directed throws increased the chances of the male changing his behavior, particularly by shifting his attention to the thrower, supporting the hypothesis that throwing at the male function as a communicative act. However, females also used aimed throwing in affiliative contexts (N = 2) and interactions with humans (N = 102) and other animals (N = 61). Thus, our results show that aimed throwing is a flexible behavior, elicited in multiple social contexts and for different purposes. Moreover, our study demonstrates that considering the effects of object use on the behavior of potential targets can help us to understand how primates use objects to mediate communication.

Frontiers in Psychology

Perceived vocal attractiveness and measured sex-dimorphic vocal parameters are both associated wi... more Perceived vocal attractiveness and measured sex-dimorphic vocal parameters are both associated with underlying individual qualities. Research tends to focus on speech but singing is another highly evolved communication system that has distinct and universal features with analogs in other species, and it is relevant in mating. Both speaking and singing voice provides relevant information about its producer. We tested whether speech and singing function as "backup signals" that indicate similar underlying qualities. Using a sample of 81 men and 86 women from Brazil and the Czech Republic, we investigated vocal attractiveness rated from speech and singing and its association with fundamental frequency (F0), apparent vocal tract length (VTL), body characteristics, and sociosexuality. F0, VTL, and rated attractiveness of singing and speaking voice strongly correlated within the same individual. Lower-pitched speech in men, higherpitched speech and singing in women, individuals who like to sing more, and singing of individuals with a higher pitch modulation were perceived as more attractive. In men, physical size positively predicted speech and singing attractiveness. Male speech but not singing attractiveness was associated with higher sociosexuality. Lower-pitched male speech was related to higher sociosexuality, while lower-pitched male singing was linked to lower sociosexuality. Similarly, shorter speech VTL and longer singing VTL predicted higher sociosexuality in women. Different vocal displays function as "backup signals" cueing to attractiveness and body size, but their relation to sexual strategies in men and women differs. Both singing and speech may indicate evolutionarily relevant individual qualities shaped by sexual selection.

Psicologia: Reflexão e Crítica, 2009

Resumo O fenômeno conhecido como school shooting vem chamando a atenção do mundo, principalmente ... more Resumo O fenômeno conhecido como school shooting vem chamando a atenção do mundo, principalmente após a tragédia na Columbine High School, na cidade de Littleton, Colorado, nos Estados Unidos, em 1999. Posteriormente, em abril de 2007, o estudante Cho Seung-Hui protagonizou um massacre de proporções ainda maiores ao atirar contra estudantes do Virginia Polytechnic Institute and State University, matando 32 pessoas e se suicidando ao final. O presente artigo reflete sobre o fenômeno chamando a atenção para a sua expansão pelo mundo e traz uma reflexão, baseada em dados empíricos, sobre o desenvolvimento dos protagonistas dos massacres em seus contextos sociais, incluindo o ambiente familiar, a mídia e interações entre colegas nas escolas e universidades.

International Journal of Primatology, 1993

Page 1. International Journal of Primatology, VoL 14, No. 4, 1993. Demography and Social Structur... more Page 1. International Journal of Primatology, VoL 14, No. 4, 1993. Demography and Social Structure of One Group of Muriquis (Brachyteles arachnoides) Karen B. Strier, 1,3 Francisco DC Mendes, 2 Jos6 Rimoli, 2 and Adriana ...

Folia Primatologica, 2000

The brown capuchin monkey, Cebus apella, occupies different biomes and habitats of South America.... more The brown capuchin monkey, Cebus apella, occupies different biomes and habitats of South America. Its large geographical range may be associated with its capacity to explore variable resources through the manipulation of food items and other objects [1–3]. Items such as palm hearts [4], insects [5], oysters [6] and nuts [7] are eaten by breaking stems, opening hard shells or

Anais da Academia Brasileira de Ciências, 2004

Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyt... more Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a larger proportion of tonal elements than those emitted by muriquis feeding in a cohesive manner. Sequential exchanges seem thus to be constituted by two inter-related subsystems of calls that aid muriquis to coordinate intragroup spacing, despite the poor visibility of the habitat.

Psicologia: Reflexão e Crítica, 2010

Resumo Investigamos a relação entre fatores de aprendizagem social, acessados via questionários, ... more Resumo Investigamos a relação entre fatores de aprendizagem social, acessados via questionários, e os comportamentos agressivos e lúdicos de meninos pré-escolares, através de observação direta durante o recreio. Os participantes foram 15 meninos com idades entre quatro e seis anos, da cidade de Goiânia, GO, Brasil. Uma análise multivariada de variância indicou efeitos significativos de modelos de agressividade em casa nas taxas de agressão durante o brincar. Crianças expostas a punições físicas abusivas, brigas entre adultos e programas violentos de TV apresentaram mais agressões reais. Meninos que relataram brincar com armas de brinquedo em casa não apresentaram mais agressões reais do que os que relataram o contrário, mas apresentaram maior proporção de agressões de faz-de-conta. Os resultados também indicaram que quanto mais modelos agressivos em casa, maior a incidência de comportamentos agressivos. Palavras-chave: Aprendizagem social; Comportamento agressivo; Comportamento lúdico.