805 research outputs found

    Searching for the Critical p of Macphail's Null Hypothesis: The Contribution of Numerical Abilities of Fish.

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    In 1985, Macphail argued that there are no differences among the intellects of non-human vertebrates and that humans display unique cognitive skills because of language. Mathematical abilities represent one of the most sophisticated cognitive skills. While it is unquestionable that humans exhibit impressive mathematical skills associated with language, a large body of experimental evidence suggests that Macphail hypothesis must be refined in this field. In particular, the evidence that also small-brained organisms, such as fish, are capable of processing numerical information challenges the idea that humans display unique cognitive skills. Like humans, fish may take advantage of using continuous quantities (such as the area occupied by the objects) as proxy of number to select the larger/smaller group. Fish and humans also showed interesting similarities in the strategy adopted to learn a numerical rule. Collective intelligence in numerical estimation has been also observed in humans and guppies. However, numerical acuity in humans is considerably higher than that reported in any fish species investigated, suggesting that quantitative but not qualitative differences do exist between humans and fish. Lastly, while it is clear that contextual factors play an important role in the performance of numerical tasks, inter-species variability can be found also when different fish species were tested in comparable conditions, a fact that does not align with the null hypothesis of vertebrate intelligence. Taken together, we believe that the recent evidence of numerical abilities in fish call for a deeper reflection of Macphail's hypothesis

    Preliminary study to investigate the Delboeuf illusion in ring-tailed lemurs (Lemur catta): Methodological challenges

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    Visual illusions are commonly used in animal cognition studies to compare visual perception among vertebrates. To date, researchers have focused their attention mainly on birds and mammals, especially apes and monkeys, but no study has investigated sensitivity to visual illusions in prosimians. Here we investigated whether lemurs (Lemur catta) perceive the Delboeuf illusion, a well-known illusion that occurs when subjects misperceive the relative size of an item because of its surrounding context. In particular, we adopted the spontaneous preference paradigm used in chimpanzees and observed lemurs’ ability to select the larger amount of food. In control trials, we presented two different amounts of food on two identical plates. In test trials, we presented equal food portion sizes on two plates differing in size: If lemurs were sensitive to the illusion, they were expected to select the food portion presented on the smaller plate. In control trials, they exhibited poor performance compared to other mammals previously observed, being able to discriminate between the two quantities only in the presence of a 0.47 ratio. This result prevented us from drawing any conclusion regarding the subjects’ susceptibility to the Delboeuf illusion. In test trials with the illusory pattern, however, the subjects’ choices did not differ from chance. Our data suggest that the present paradigm is not optimal for testing the perception of the Delboeuf illusion in lemurs and highlight the importance of using different methodological approaches to assess the perceptual mechanisms underlying size discrimination among vertebrates

    Aesthetic restoration in maxillo-mandibular malformations: the role of genioplasty

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    Aim: The aim of this study was to determinate how orthognatic surgery aids to cure many skull and face abnormalities and to help re-establishing the correct occlusive relation thanks to the repositioning of the maxillo-mandibular skeleton basis. Methods: The study included 183 male patients and 338 female patients, with an average age of 23 years. The sample series was divided according to specific pathologies. All patients underwent surgical procedures and the therapeutic strategy was determined based on the anomalies presented. Results: 113 patients had a II class dental skeletal occlusion, 180 patients had a III class dental-skeletal occlusion and 222 patients had skull-facial abnormalities. 5 patients underwent only a genioplasty, 82 patients underwent a genioplasty associated with BSSO, 175 patients underwent a genioplasty associated with Le Fort I osteotomy and the remaining 253 patients underwent a genioplasty associated with BSSO and Le Fort I osteotomy. Conclusion: The experience shows that genioplasty has been successfully introduced in orthognathic surgical therapeutic procedures, for dental-skeleton abnormalities and mandibular asymmetries treatment. In recent years, the evolution of computer systems has allowed an accurate assessment and programming, by means of the three-dimensional display, which are of great help in the course of diagnosis and evaluation of the displacements to be carried out, in order to obtain optimal aesthetic results

    Management and treatment of sinonasal inverted papilloma

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    Aims: The aim of this paper is to describe the surgical experience of 35 patients with Inverted Papilloma (IP) of paranasal sinuses and its recurrence rate after a year of follow-up. Materials: A retrospective chart review was performed on patients presenting with IP of paranasal sinuses. Thirty-five patients comprised the focus of this study. For all patients was performed a pre-surgery TC, and for more 5 patients it was necessary to perform a Magnetic Resonance (MR) with gadolinium. Results: Among 35 patients selected, 18 patients underwent to open surgery, 4 patients had a combined approach with endoscopy and open surgery, while 13 patients were managed only with an endoscopic approach, with a minimum of 1 year of follow-up. Our results highlighted that the global percentage of success 12 months after the treatment was 93% and it not vary according to the tipology of the approach used if a radical excision of the lesion is achieved. More in depth, among 35 cases, only 2 patients were found to have recurrences and were treated with coronal and endoscopic approach. Conclusion: It is fundamental to underline that surgery must be carried on in a radical manner to treat these tend to recur. A complete removal of the lesion and bone peripheral border filing are essential to perform a correct and definitive treatment. Also, endoscopic approach can be taken into account when tumors are localized median to a sagittal plan crossing the orbit median wall and when they did not massively compromised paranasal sinus walls

    Large Number Discrimination by Mosquitofish

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    Background: Recent studies have demonstrated that fish display rudimentary numerical abilities similar to those observed in mammals and birds. The mechanisms underlying the discrimination of small quantities (,4) were recently investigated while, to date, no study has examined the discrimination of large numerosities in fish. Methodology/Principal Findings: Subjects were trained to discriminate between two sets of small geometric figures using social reinforcement. In the first experiment mosquitofish were required to discriminate 4 from 8 objects with or without experimental control of the continuous variables that co-vary with number (area, space, density, total luminance). Results showed that fish can use the sole numerical information to compare quantities but that they preferentially use cumulative surface area as a proxy of the number when this information is available. A second experiment investigated the influence of the total number of elements to discriminate large quantities. Fish proved to be able to discriminate up to 100 vs. 200 objects, without showing any significant decrease in accuracy compared with the 4 vs. 8 discrimination. The third experiment investigated the influence of the ratio between the numerosities. Performance was found to decrease when decreasing the numerical distance. Fish were able to discriminate numbers when ratios were 1:2 or 2:3 but not when the ratio was 3:4. The performance of a sample of undergraduate students, tested non-verbally using the same sets of stimuli, largely overlapped that of fish
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