Numerical abilities have been found to be adaptive in different contexts, including mating, foraging, fighting assessment and antipredator strategies. In species with parental care, another potential advantage is the possibility to adjust parental behavior in relation to the numerosity of the progeny. The finding that many fish vary their parental investment in relation to brood size advocates the existence of a mechanism for appraising offspring number, an aspect that has never been directly investigated. Here we tested the ability of parental female convict cichlid (Amatitlania nigrofasciata) to discriminate between two fry groups differing in number by measuring time spent attempting to recover groups of fry experimentally displaced from the next. Females spent more time trying to recover the fry from larger groups when tested with contrasts 6 versus 12 (1:2) and 6 versus 9 fry (2:3); however, they showed no preference in the 6 versus 8 (3:4) contrast, suggesting that this task exceeds their discrimination capacity. 相似文献
A number of neurobiological, psychological and social factors may account for cognitive impairment. In animal studies a relation between dental status and cognitive performance has been found. It is unclear whether such a relation exists for humans. In a first step we compared the performance of 1,351 participants (53% women, 47% men; age M = 54.0) with natural teeth to 487 edentulous participants (59% women, 41% men; age M = 71.3) on 12 cognitive tests. The natural teeth group had a lower mean age, fewer women, more years of education, higher mini-mental state (MMSE), and performed significantly higher on several cognitive tests. In a subsequent analysis, the cognitive performance of a subset of the participants (50-85 years) was examined. In this analysis, 211 had natural dentition and 188 were edentulous. The groups were matched for gender, age, social variables, diseases, stress and MMSE. The cognitive disadvantage of the edentulous group was still apparent. The results suggest that functional natural teeth relate to relatively preserved cognitive functioning in older age. 相似文献
This study investigated the potential for recreational gamblers to respond as if certain types of losing slot machine outcomes were actually closer to a win than others (termed the near‐miss effect). Exposure to conditional discrimination training and testing disrupted this effect for 10 of the 16 participants. These 10 participants demonstrated high percentages of conditional discrimination testing performance, and the remaining 6 participants failed the discrimination tests. The implications for a verbally based behavioral explanation of gambling are presented. 相似文献
This study evaluates the safe sex determinants in college students. In the qualitative section, premarital sex, sex with steady
girlfriend and religion’s impact were highlighted. In the quantitative part, the relations between the religiosity score and
past sexual activity, attitude, norms, and self-efficacy with regard to sexual abstinence were investigated. Students who
had a higher religious score were significantly more likely to have high self-efficacy in refusing sex, and their attitudes
supported their abstinence. Additionally, these students were more likely never to have had a sexual relationship. Findings
suggest that greater religious involvement is a protective factor in high-risk sexual behavior.
An erratum to this article can be found at 相似文献
This study was planned to evaluate the effect of an exposure to magnetic fields on consolidation and retrieval of hippocampus dependent spatial memory using a water maze. In Experiments 1 and 2, rats were trained in a hidden version (spatial) of water maze task with two blocks of four trials. The retention of spatial memory was evaluated 48 h later. Exposure to a 50 Hz 8 mT, but not 2 mT magnetic fields for 20 min immediately after training impaired retention performance. The same time exposure shortly before retention testing had no effect. In Experiment 3, rats were trained in a cued version of water maze with two blocks of four trials. Exposure to magnetic field at 8 mT for 20 min immediately after training did not impair retention performance. These findings indicate that acute exposure to a 50 Hz magnetic field at 8 mT for short time can impair consolidation of spatial memory. 相似文献
In an age in which vast progress has been made in organ transplant technology, it is imperative to determine the point at which a human being is considered dead, for transplantation cannot occur until after death. Traditional religious views imply that a human being is dead upon the departure of the soul from the body. Taking the biological death of the body as a conclusive sign of the soul's departure is not an option. Biological death refers to decomposition, and this cannot equate to the death of the person as such, for this would make the concept and practice of transplantation absurd, for transplantable parts of a biologically dead—i.e. decomposing—body could not be used. On the other hand, if parts of the human body are themselves still biologically alive, could it not be said that taking such parts would amount to murder?
Two conclusions follow from this predicament. First, death as a ‘normative’ concept stands in sharp distinction from a purely biological concept. Second, a normative concept of death is entangled with a normative concept of personhood. That is to say, from the moment that a human being is not considered a person as such, parts of the body could be removed for transplantation or, indeed, for any other justified medical purpose. In this regard, various theories of the person are put forward. Which of these theories is compatible with a workable concept of death? In this paper two principal theories of the person will be discussed and it will be argued that a brain-based theory of death is conducive to a normative concept of death, thus allowing for organ transplantation. 相似文献
This paper describes the main differences between behavioral and systems therapy with couples. To improve clinical decision making for a given case, the theoretical assumptions of the chosen treatment approach need to be clearly understood. Contrasting the two approaches will assist couple therapists in providing clinical services that better reflect the chosen theoretical framework. This paper reviews the common elements that can be found across models. A case example is presented to demonstrate the use of the therapy's theories and techniques. 相似文献
Drawing upon the theory of planned behaviour (TPB ), we developed and tested a conceptual model which integrates both internal personality factors and external contextual factors to determine their associations with motivational factors and entrepreneurial intentions (EIs ). We then investigated if the model of EI applies in a developing country, namely Iran. We also set out to identify the most relevant factors for EI within this developing country context. Do distal predictors of EI including personality factors (i.e. need for achievement, risk taking and locus of control) and contextual factors (i.e. perceived barriers and support) significantly relate to EI via proximal predictors including motivational factors (i.e. attitudes towards entrepreneurship and perceived behavioural control [PBC])? Data were collected on 331 students from 7 public universities. The findings support the TPB for EI in Iran. All three motivational factors related to EI , but PBC showed the strongest association, which is different than in developed country contexts. Possible explanations for these differences are discussed. All three personality characteristics indirectly related to EI via the proximal attitudes towards entrepreneurship and PBC . Perceived contextual support and barriers indirectly related to EI via proximal PBC while perceived barriers also directly related to EI . 相似文献