A suggestion for a new approach to the mathematical theory of imitative behavior

The theory of imitative behavior as developed hitherto by the author was based on the assumption that each individual has a natural preference for one of the two mutually exclusive behaviors. The endogenous fluctuations in the central nervous system then result in the individual’s exhibiting the two behaviors alternately with a relative frequency determined by the natural preference. Imitation shifts the natural preference towards one or the other of the two mutually exclusive behaviors. In the present approach it is suggested that the relative frequency of the two mutually exclusive behaviors exhibited alternately is determined by maximizing the “satisfaction function” of the individual, that is by hedonistic factors rather than by purely random fluctuations. Corresponding equations are developed. It is shown that in certain cases, even when the imitation effect is absent, a sort of “pseudoimitation” may occur. Another situation leads, in the case of two individuals only, to a complete “division of labor” between them, with respect to the two behaviors. Each one exhibits only one behavior. After that imitation is introduced explicitly by assuming that imitation by one individual or another increases the satisfaction function of the imitating individual. Results thus obtained show similarities to the results of the old theory.     

Contribution to the mathematical theory of contagion and spread of information: I. Spread through a thoroughly mixed population

An equation is derived from the spread of a “state” by contact through a thoroughly mixed population, in which the probability of transmission depends both on the over-all duration of the process and on the time an individual has been in the “state.” Cases in which this probability is a function of only one or the other of the two “times” are worked out. It is shown that in the case of dependence on “private time” alone the asymptotic value of the fraction of the population effected is the same as that derived by the random net approach.     

Structure of the bank vole (<Emphasis Type="Italic">Myodes glareolus</Emphasis>) population cycles in the core and periphery of its species area

The results of long-term studies of two bank vole (Myodes glareolus) populations in stationary sites in the central part and periphery of its species area are described. Four phases of a multiannual population cycle and two of its structural parts have been detected for both populations. The first part of the cycle is “determined,” with the “peak” phase passing into a “depression” (population collapse). This transition is mainly determined by intrapopulation processes and is weakly dependent on the external conditions of each individual year. The second part is “stochastic,” starting from a stable point in the cycle in the depression phase. The duration of the second part is determined by the state of the population and its ability to increase its size, as well as by the weather and food factors, predation pressure, and location of the population within the species area. The transition from the peak phase to the depression phase (the determined part) for both populations takes place during one fall-winter-spring season and has no effect on the cycle duration. The duration of the stochastic part in the core of the species area (the period from depression phase to peak phase) is 1–3 years and in the periphery, 2–4 years.     

Rhythmic signalling and entrainment inVespa orientalis larvae: Characterization of the underlying interactions

Rhythmic “circa-second” contrations of larvae of the hornetVespa orientalis, believed to serve as hunger signals, were studied. A considerable degree of coordination among individual larvae, both in frequency and phase of these contractions, has been observed. The oscillations of singly isolated larvae are of short duration, non-constant, with increasing intervals in between and there is a substantial variability in the patterns shown by different larvae. In contrast, the association of two or more larvae leads to enhancement of their periodic behaviour and to (partial) entrainment. Communication among larvae may perhaps be mediated by the sound pulses (“scratching” noises) which are generated by these contractions. We have subjected individual and grouped larvae to external sound pulses and were able to demonstrate: (a) enhancement of rhythmic activity; (b) phase resetting; (c) entrainment to an external oscillator within a range of frequencies; (d) the existence of a subharmonic mode of entrainment. We propose a simple phenomenologic model to account for these larvae responses. Our model assumes the existence of an “energy” variable which declines with time but is upgraded, in a phase-dependent way, by external stimuli. Based in part on work performed by V. Barenholz-Paniry in partial fulfillment of the requirements for the M.Sc. degree from the Sackler Faculty of Medicine, Tel Aviv University, 1986.     

Social influence in manipulations of a capuchin monkey raised in a human environment: A preliminary case study

This preliminary study reports manipulations in an 8-month infant capuchin monkey,Cebus apella, confronted with a variety of objects, during five 2-hour sessions. This subject is raised in a human environment as it participates to the “Aide Simienne aux Personnes Handicapées (Kerpape)” project. Objects have been chosen in order to expose the capuchin to manipulations it will be asked to perform when placed with a quadriplegic. This paper reports the analysis of five hours of video recording. During two sub-sessions within an experimental session, the “human mother” pointed the objects to the monkey, sequentially, either with a vocal designation or not. The results show that the monkey tends to contact more objects and manipulates them more when they have been previously designated by the “mother.” This suggests a form of social facilitation. There is no evidence for imitation.     

Biomechanical analysis of movement strategies in human forward trunk bending. II. Experimental study

 The large mass of the human upper trunk, its elevated position during erect stance, and the small area limited by the size of the feet, stress the importance of equilibrium control during trunk movements. The objective of the present study was to perform a biomechanical analysis of fast forward trunk movements in order to understand the coordination between movement and posture. The analysis is based on a comparison between experimentally observed bending and hypothetical “optimal bending” performed on an infinitely narrow support, as presented in a companion paper. The experimental data were obtained from 16 subjects who performed fast forward bending while standing on a wide platform or on a narrow beam. The analysis is performed by decomposition of the movement into three dynamically independent components, each representing a movement along one of the three eigenvectors of the motion equation. The eigenmovements are termed “hip”, “ankle”, and “knee” eigenmovements, according to the dominant joint. The experimentally observed movement is characterized mainly by the hip and ankle eigenmovements, whereas the knee eigenmovement is negligible. Similarly to the “optimal bending” the ankle eigenmovement starts earlier and lasts longer than the hip eigenmovement. An early forward acceleration of the center of gravity in the ankle eigenmovement is caused by anticipatory changes in the ankle joint torque. This clarifies the role of the early tibialis anterior burst and/or soleus inhibition usually observed in electromyographic recordings during forward bending. The results suggest that the hip and the ankle eigenmovements can be treated as independently controlled motion units aimed at functionally different behavioral goals: the bending per se and postural adjustment. It is proposed that the central nervous system has to control these motion units sequentially in order to perform the movement and maintain equilibrium. It is also suggested that the hip and ankle eigenmovements can be regarded as a biomechanical background for the hip and ankle strategies introduced by Horak and Nashner (1986) on the basis of electromyographic recordings and kinematic patterns in response to postural perturbations. Received: 1 July 1999 / Accepted in revised form: 23 October 2000     

Psychological Altruism Vs. Biological Altruism: Narrowing The Gap With The Baldwin Effect

This paper defends the position that the supposed gap between biological altruism and psychological altruism is not nearly as wide as some scholars (e.g., Elliott Sober) insist. Crucial to this defense is the use of James Mark Baldwin's concepts of “organic selection”and “social heredity” to assist in revealing that the gap between biological and psychological altruism is more of a small lacuna. Specifically, this paper argues that ontogenetic behavioral adjustments, which are crucial to individual survival and reproduction, are also crucial to species survival. In particular, it is argued that human psychological altruism is produced and maintained by various sorts of mimicry and self-reflection in the aid of both individual and species survival. The upshot of this analysis is that it is possible to offer an account of psychological altruism that is closelytethered to biological altruism without reducing entirely the former to thelatter.     

Correlations between the psychological peculiarities of an individual and the efficacy of a single neurofeedback session (by the EEG characteristics)

Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons). A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal. EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s (OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q₃ (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,” and “social temp” and with 16 PF factors M (“autia”), Q₄ (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q₃ (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the individual psychological pattern of the subject. Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006.     

QTL analysis of fruit components in the progeny of a Rennell Island Tall coconut (Cocos nucifera L.) individual

We investigated the genetic factors controlling fruit components in coconut by performing QTL analyses for fruit component weights and ratios in a segregating progeny of a Rennell Island Tall genotype. The underlying linkage map of this population was already established in a previous study, as well as QTL analyses for fruit production, which were used to complement our results. The addition of 53 new markers (mainly SSRs) led to minor amendments in the map. A total of 52 putative QTLs were identified for the 11 traits under study. Thirty-four of them were grouped in six small clusters, which probably correspond to single pleiotropic genes. Some additional QTLs located apart from these clusters also had relatively large effects on the individual traits. The QTLs for fruit component weight, endosperm humidity and fruit production were found at different locations in the genome, suggesting that efficient marker-assisted selection for yield can be achieved by selecting QTLs for the individual components. The detected QTLs descend from a genotype belonging to the “Pacific” coconut group. Based on the known molecular and phenotypic differences between “Pacific” and “Indo-Atlantic” coconuts, we suggest that a large fraction of coconut genetic diversity is still to be investigated by studying populations derived from crosses between these groups. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Effects of animal density,volume, and the use of 2D/3D recording on behavioral studies of copepods

Studies on the behavior of copepods require both an appropriate experimental design and the means to perform objectively verifiable numerical analysis. Despite the growing number of publications on copepod behavior, it has been difficult to compare these studies. In this study, we studied two species of copepods, Eurytemora affinis and Pseudodiaptomus annandalei, and employed recently developed scaling and non-scaling methodology to investigate the effects of density and volume on the swimming behavior of individual organisms in still water. We also compared the results of two- and three-dimensional projections of the swimming tracks. A combination of scale-dependent and scale-independent analysis was found to characterize a number of behavioral observations very effectively. We discovered that (i) density has no effect except to increase the time spent in the swimming state of “breaking”, (ii) smaller volumes resulted in more complex trajectories, and larger volumes, like density, increased the time spent in the swimming state “breaking”, and (iii) three-dimensional projections gave a more accurate estimation of speed and the time spent cruising. When only a vertical 2D projection was used, “cruising” could be confused with “sinking”. These results indicate that both experimental conditions and the selection of 2D or 3D projection have important implications regarding the study of copepod behavior. The development of standardized procedures with which to compare the observations made in different studies is an issue of particular urgency.     

Use of microsatellite DNA and otolith Sr:Ca ratios to infer genetic relationships and migration history of four morphotypes of <Emphasis Type="Italic">Rhinogobius</Emphasis> sp. OR

The genetic diversity and relationship among four morphotypes of Rhinogobius sp. OR, Gobiidae (“Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire”) were investigated with seven microsatellite DNA loci, and amphidromy of these morphotypes was verified by strontium (Sr) and calcium (Ca) deposition in the otolith. Samples of “Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire” were collected from, respectively, three, three, two, and four locations in Japan. Microsatellite analysis detected high genetic diversity (based on the number of alleles, allelic richness, and average observed heterozygosity) in the “Tōshoku” and “Shinjiko” morphotypes relative to the “Shimahire” morphotype; the “Gi-tōshoku” morphotype had an intermediate level of variation. Almost all pairwise F _ST values were significantly different from zero (P < 0.001), except between two populations of “Tōshoku.” Clear genetic independence was observed between the “Shinjiko” and “Shimahire” morphotypes in the Maruyama River. A principle component analysis based on microsatellite data indicated that the “Tōshoku,” “Shinjiko,” and “Gi-tōshoku” morphotypes were genetically similar. Furthermore, the three populations of “Tōshoku” were closely related each other, and two of those collected from the Lake Biwa system were a single population. There was, however, a high degree of genetic differentiation between “Shimahire” and the other morphotypes; moreover, there was high genetic divergence among four populations of the “Shimahire” morphotype. Amphidromous migratory histories were indicated by Sr:Ca ratios in two of three populations of the “Shinjiko” morphotype and in one of two “Gi-tōshoku” morphotypes, whereas all populations of the “Shimahire” morphotype were freshwater residents. The large genetic divergence and low genetic diversity in “Shimahire” are likely related to migration history.     

Can inverse density dependence at small spatial scales produce dynamic instability in animal populations?

All else being equal, inversely density-dependent (IDD) mortality destabilizes population dynamics. However, stability has not been investigated for cases in which multiple types of density dependence act simultaneously. To determine whether IDD mortality can destabilize populations that are otherwise regulated by directly density-dependent (DDD) mortality, I used scale transition approximations to model populations with IDD mortality at smaller “aggregation” scales and DDD mortality at larger “landscape” scales, a pattern observed in some reef fish and insect populations. I evaluated dynamic stability for a range of demographic parameter values, including the degree of compensation in DDD mortality and the degree of spatial aggregation, which together determine the relative importance of DDD and IDD processes. When aggregation-scale survival was a monotonically increasing function of density (a “dilution” effect), dynamics were stable except for extremely high levels of aggregation combined with either undercompensatory landscape-scale density dependence or certain values of adult fecundity. When aggregation-scale survival was a unimodal function of density (representing both “dilution” and predator “detection” effects), instability occurred with lower levels of aggregation and also depended on the values of fecundity, survivorship, detection effect, and DDD compensation parameters. These results suggest that only in extreme circumstances will IDD mortality destabilize dynamics when DDD mortality is also present, so IDD processes may not affect the stability of many populations in which they are observed. Model results were evaluated in the context of reef fish, but a similar framework may be appropriate for a diverse range of species that experience opposing patterns of density dependence across spatial scales.     

Spread of information through a population with socio-structural bias: III. Suggested experimental procedures

Experimental procedures are suggested to test the theory developed in previous papers which may have applications to predicting the spread of information by contact through a population. The experiment is designed to test the statistical properties of the “acquaintance net” of the population. Thus behavioral aspects are for the time being eliminated, and attention is focused exclusively in the properties of the potential communication net itself. Since the theory is not mathematically rigorous, it might be advisable to perform experiments with statistical materials only, such as playing cards, to test the validity of the assumptions and approximations of the theory in dealing with particular statistical processes. One such experiment has been performed. The results agree closely with those calculated from one of the derived equations.     

On the reversibility of environmentally induced alterations in abstract biological systems

The environmentally induced alterations in structure of (M, ℜ) which were described previously (R. Rosen,Bull. Math. Biophysics,23, 165–171, 1961) are examined from the standpoint of determining under what circumstances they can be reversed by further environmental interactions. For simplicity we consider only the case of (M, ℜ)-systems possessing one “metabolic” and one “genetic” component. In the case of environmentally induced alteration of the “metabolic” component alone, a necessary and sufficient condition is given for the reversibility of the alteration. In the case of alteration of the “genetic” component, the situation becomes more complex; several partial results are given, but a full analysis is not available at this time. Some possible biological implications of this analysis are discussed. This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command, under Contract no. AF-49(638)-917 and Grant no. AF-AFOSR-9-63.     

Cytotoxic and fluorescent assays for thymocyte subpopulations differing in surface thy-1 level

A number of analytical techniques for distinguishing and separating the “high θ” and “low θ” subpopulations of mouse thymocytes have been compared. A differential cytotoxic assay was compared to a quantitative immunofluorescent assay on individual cells using flow cytofluorometry and cell sorting. Conventional anti-Thy-1 antisera were compared with a monoclonal IgM anti-Thy-1. The monoclonal reagent greatly improved both types of assay, eliminated a number of artifacts and allowed either procedure to be used to give a clear distinction, based on Thy-1 level, between the two subpopulations. The distribution of Thy-1 on thymocytes is bimodal, rather than continuous. These separate “high θ” and “low θ” categories each includes a population of dividing cells.     

Pulses of movement across the sea ice: population connectivity and temporal genetic structure in the arctic fox

Lemmings are involved in several important functions in the Arctic ecosystem. The Arctic fox (Vulpes lagopus) can be divided into two discrete ecotypes: “lemming foxes” and “coastal foxes”. Crashes in lemming abundance can result in pulses of “lemming fox” movement across the Arctic sea ice and immigration into coastal habitats in search for food. These pulses can influence the genetic structure of the receiving population. We have tested the impact of immigration on the genetic structure of the “coastal fox” population in Svalbard by recording microsatellite variation in seven loci for 162 Arctic foxes sampled during the summer and winter over a 5-year period. Genetic heterogeneity and temporal genetic shifts, as inferred by STRUCTURE simulations and deviations from Hardy–Weinberg proportions, respectively, were recorded. Maximum likelihood estimates of movement as well as STRUCTURE simulations suggested that both immigration and genetic mixture are higher in Svalbard than in the neighbouring “lemming fox” populations. The STRUCTURE simulations and AMOVA revealed there are differences in genetic composition of the population between summer and winter seasons, indicating that immigrants are not present in the reproductive portion of the Svalbard population. Based on these results, we conclude that Arctic fox population structure varies with time and is influenced by immigration from neighbouring populations. The lemming cycle is likely an important factor shaping Arctic fox movement across sea ice and the subsequent population genetic structure, but is also likely to influence local adaptation to the coastal habitat and the prevalence of diseases.     

Genetic diversity of isolated populations of Nautilus pompilius (Mollusca, Cephalopoda) in the Great Barrier Reef and Coral Sea

Nautilus species are the only remaining cephalopods with an external shell. Targeted heavily by the shell trade across their distribution area, these species have a poorly known population structure and genetics. Molecular techniques have been used to assess levels of inter- and intra-population genetic diversity in isolated populations of Nautilus in the northern sections of the Great Barrier Reef (GBR), Australia and in the Coral Sea. Distinct populations, physically separated by depths in excess of 1,000 m were examined. RAPD analysis of genetic differences showed limited differentiation of the “Northern GBR” populations and the “Coral Sea” populations. Discrimination between the two geographic groups was observed from these data. In addition, partial sequencing of the CoxI gene region, yielded 575 bp of sequence, which was aligned for 43 samples and phylogenetic trees constructed to examine genetic relationships. Two distinct clades were resolved in the resulting trees, representing the “Northern GBR” and “Coral Sea” population groups. Inter- and intra-population relationships are presented and discussed. The differentiation of the Nautilus populations from the Northern section of the Great Barrier Reef and those from the Coral Sea were supported by two distinctly different methodologies and the significance of this separation and the potential evolutionary divergence of these two population groups is discussed.     

Exploring Scientific Misconduct: Isolated Individuals,Impure Institutions,or an Inevitable Idiom of Modern Science?

This paper identifies three distinct narratives concerning scientific misconduct: a narrative of “individual impurity” promoted by those wishing to see science self-regulated; a narrative of “institutional impropriety” promoted by those seeking greater external control of science; and a narrative of “structural crisis” among those critiquing the entire process of research itself. The paper begins by assessing contemporary definitions and estimates of scientific misconduct. It emphasizes disagreements over such definitions and estimates as a way to tease out tension and controversy over competing visions of scientific research. It concludes by noting that each narrative suggests a different approach for resolving misconduct, and that the difference inherent in these views may help explain much of the discord concerning unethical behavior in the scientific community.     

Synchrony and Asynchrony for Neuronal Dynamics Defined on Complex Networks

We describe and analyze a model for a stochastic pulse-coupled neuronal network with many sources of randomness: random external input, potential synaptic failure, and random connectivity topologies. We show that different classes of network topologies give rise to qualitatively different types of synchrony: uniform (Erdős–Rényi) and “small-world” networks give rise to synchronization phenomena similar to that in “all-to-all” networks (in which there is a sharp onset of synchrony as coupling is increased); in contrast, in “scale-free” networks the dependence of synchrony on coupling strength is smoother. Moreover, we show that in the uniform and small-world cases, the fine details of the network are not important in determining the synchronization properties; this depends only on the mean connectivity. In contrast, for scale-free networks, the dynamics are significantly affected by the fine details of the network; in particular, they are significantly affected by the local neighborhoods of the “hubs” in the network.