Scio Ergo Sum: Knowledge of the Self in a Nonhuman Primate

The pressures of developing and maintaining intricate social relationships may have led to the evolution of enhanced cognitive abilities in many social nonhuman species, particularly primates. Knowledge of the dominance ranks and social relationships of other individuals, for example, is important in evaluating one’s position in the prevailing affiliative and dominance networks within a primate society and could be acquired through direct or perceived experience. Our analysis of allogrooming supplants among wild bonnet macaques had revealed that individual females successfully evaluate social relationships among other group females and possess egotistical knowledge of their own positions, relative to those of others, in the social hierarchy. These individuals, therefore, appeared to have abstracted and mentally represented their own personal attributes as well as those of other members of the group. Bonnet macaques also seem to recognise that other individuals have beliefs that may be different from their own, manipulate another individual’s actions and beliefs in a variety of social situations, and selectively reveal or withhold information from others—capabilities displayed by certain individuals that became evident in the course of our earlier studies on tactical deception in the species. In conclusion, the ability to develop belief systems and form mental representations, generated by direct personal experience, suggests a rather early evolutionary origin for fairly sophisticated cognitive capabilities, characterised by an objectified self with limited regulatory control over more subjective levels of self-awareness, in cercopithecine primates, pre-dating those of the great apes. We, therefore, argue, in this review, that bonnet macaques might represent an intermediate stage in the evolution of self-awareness, a process which began with the subjective awareness that characterises most, if not all, higher animal species and culminates in the most sophisticated form of symbolic self-awareness, apparently the hallmark of the human species alone

A test Of homogeneity against scale alternatives using subsample extrema

In this paper a new class of non-parametric tests for testing homogeneity of several populations against scale alternatives is proposed. For this, independent samples of fixed sizes are drawn from each population and from these samples, all possible sub-samples of the same size are drawn and their maxima and minima are computed. Using these extreme the class of tests is obtained. Tests of this type have been offered for the two-sample slippage problem by Kochar (1978). Under certain conditions, this class of tests is shown to be consistent against 'difference in scale' alternatives. The test has been compared with Bhapkar's V-test (1961), Deshpande's D-test (1965), Sugiura's Drs-test (1965) and with a classical test given by Lehmann (1959, pp. 273-275). It is shown that some members of this proposed class of tests are more efficient than the first three tests in the case of uniform, Laplace and normal distributions, when the number of populations compared is small

Non-parametric tests for several sample location problem based on subsample extrema

In this paper non-parametric tests for homogeneity of several populations against locationtype alternatives are proposed. For this all possible subsamples of fixed size are drawn from each sample and their maxima and minima are computed One class of tests is obtained using these subsample minima whereas other class of tests involves use of sub sample maxima. Tests belonging to these two classes have been compared with many of the presently available tests in terms of their Pitman asymptotic relative efficiency . Some of the members of these proposed classes of tests prove to robust in terms of efficiency

ON ESTIMATION FOLLOWING SUBSET SELECTION FROM TRUNCATED POISSON DISTRIBUTIONS UNDER STEIN LOSS FUNCTION Authors:

In this paper, we consider the problem of estimating the parameters of a subset selected from p(p ≥ 2) left-truncated Poisson distributions under Stein loss function. Two problems of estimations are considered; average worth and simultaneous estimation. For the average worth, the natural estimator is shown to be positively biased with respect to Stein loss function and the Unique Minimum Risk Unbiased Estimator UMRUE is obtained. For the simultaneous estimation problem, we have shown that the natural estimator is positively biased with respect to Stein loss function and the UMRUE is obtained. The inadmissibility of the natural estimator of the simultaneous estimation is also proved and a class of dominating estimators is obtained. Monte Carlo simulation is undertaken to compute the biases and risks of the two problems of estimation. Key-Words: simultaneous estimation after subset selection; average worth estimation; Stein loss function; difference inequalities; truncated Poisson distributions. AMS Subject Classification: • 62F10, 62F07. 2 A. Shanubhogue and Riyadh R. Al-MosawiOn Estimation following Subset Selection

Average worth estimation of the selected subset of Poisson populations

Let Pi(1), ... , Pi(p) be p(p >= 2) independent Poisson populations with unknown parameters theta(1), ... , theta(p), respectively. Let X-i denote an observation from the population Pi(i), 1 <= i <= p. Suppose a subset of random size, which includes the best population corresponding to the largest (smallest) theta(i), is selected using Gupta and Huang [On subset selection procedures for Poisson populations and some applications to the multinomial selection problems, in Applied Statistics, R. P. Gupta, ed., North-Holland, Amsterdam, 1975, pp. 97-109] and (Gupta et al. [On subset selection procedures for Poisson populations, Bull. Malaysian Math. Soc. 2 (1979), pp. 89-110]) selection rule. In this paper, the problem of estimating the average worth of the selected subset is considered under the squared error loss function. The natural estimator is shown to be biased and the UMVUE is obtained using Robbins [The UV method of estimation, in Statistical Decision Theory and Related Topics-IV, S. S. Gupta and J.O. Berger, eds., Springer, NewYork, vol. 1, 1988, pp. 265-270] UV method of estimation. The natural estimator is shown to be inadmissible, by constructing a class of dominating estimators. Using Monte Carlo simulations, the bias and risk of the natural, dominated and UMVU estimators are computed and compared

Statistical testing of equality of two break-points in experimental data

Two examples in quantitative biology are examined to emphasize the need for two-phase regression models: the osmotic behaviour of cells and the non-linear temperature kinetics of membrane-bound enzyme systems. Existing statistical techniques are inadequate to test the equality of break-points of two data sets for specific reasons. We suggest here a pragmatic solution by way of a computer programme useful in applying two-phase regression models to such data sets wherein a decision needs to be made whether the critical transition differs or not

Pre-imaginal biasing of caste in a primitively eusocial insect

Primitively eusocial insects often lack morphological caste differentiation, leading to considerable flexibility in the social and reproductive roles that the adult insects may adopt. Although this flexibility and its consequences for social organization have received much attention there has been relatively little effort to detect any pre-imaginal effects leading to a bias in the potential caste of eclosing females. Experiments reported here show that only about 50% of eclosing females of the tropical social wasp Ropalidia marginata build nests and lay eggs, in spite of being isolated from all conspecifics and being provided ad libitum food since eclosion. The number of empty cells in the parent nest, which we believe to be an indication of the queen's declining influence, and a wasp's own rate of feeding during adult life predict the probability of egg laying by eclosing females. These results call for an examination of the possibility that all females in primitively eusocial insect societies are not potentially capable of becoming egg layers and that reigning queens and possibly other adults exert an influence on the production of new queens