Individual-specific Information Research Articles

Dogs discriminate between barks: The effect of context and identity of the caller

In the present study we explored whether dogs (Canis familiaris) are able to discriminate between conspecific barks emitted in different contexts recorded either from the same or different individuals. Playback experiments were conducted with dogs using barks as stimuli in a habituation-dishabituation paradigm. Barks were recorded in two contexts (stranger at the fence and when the dog was left alone) from different individuals. We found that dogs distinguished between barks emitted in these two contexts and were also able to discriminate between different individuals which were barking in the same context. These findings suggest that dog bark may carry context- and individual-specific information for the conspecifics.

Social Norms, Information and Trust Among Strangers: Theory and Evidence

How do norms of trust and reciprocity arise? We investigate this question by examining behavior in an experiment where subjects play a series of indefinitely repeated trust games. Players are randomly and anonymously matched each period. The parameters of the game are chosen so as to support trust and reciprocity as a sequential equilibrium when no reputational information is available. The main questions addressed are whether a social norm of trust and reciprocity emerges under the most extreme information restriction (community-wide enforcement) or whether trust and reciprocity require additional, individual-specific information about a player’s past history of play and how long that history must be. In the absence of such reputational information, we find that a social norm of trust and reciprocity is difficult to sustain. The provision of reputational information on past individual decisions significantly increases trust and reciprocity, with longer histories yielding the best outcomes. Importantly, we find that making reputational information available at a small cost may also lead to a significant improvement in trust and reciprocity, despite the fact that most subjects do not choose to purchase this information.

The Voice of Bats: How Greater Mouse-eared Bats Recognize Individuals Based on Their Echolocation Calls

Echolocating bats use the echoes from their echolocation calls to perceive their surroundings. The ability to use these continuously emitted calls, whose main function is not communication, for recognition of individual conspecifics might facilitate many of the social behaviours observed in bats. Several studies of individual-specific information in echolocation calls found some evidence for its existence but did not quantify or explain it. We used a direct paradigm to show that greater mouse-eared bats (Myotis myotis) can easily discriminate between individuals based on their echolocation calls and that they can generalize their knowledge to discriminate new individuals that they were not trained to recognize. We conclude that, despite their high variability, broadband bat-echolocation calls contain individual-specific information that is sufficient for recognition. An analysis of the call spectra showed that formant-related features are suitable cues for individual recognition. As a model for the bat's decision strategy, we trained nonlinear statistical classifiers to reproduce the behaviour of the bats, namely to repeat correct and incorrect decisions of the bats. The comparison of the bats with the model strongly implies that the bats are using a prototype classification approach: they learn the average call characteristics of individuals and use them as a reference for classification.

Unraveling the Academic Productivity of Economists: The Opportunity Costs of Teaching and Service

This study investigates the relationships among research productivity, teaching, and service on the basis of individual-specific information involving approximately 715 academic economists. Responding to an online survey, these economists provided information regarding their teaching and service commitments as well as personal and institutional information. The publication record of each respondent was then obtained from EconLit. Together, these data constitute a rich field for the systematic study of research productivity. Results of a Tobit analysis reveal much about the nature of research productivity, underscoring, for instance, the importance of gender, coauthorship, presen tations at conferences, and peers who publish. Among the more important findings from this analysis is that both teaching and service commitments have a significantly negative impact on the research productivity of academic economists. These relations hold across types of academic employer, though to varying degrees. Taken together, the results provide interesting insights into the roles of academic scholars, teachers, and colleagues.

Explaining Gender Differentials In Scholarly Productivity: The Case Of Academic Economists

The purpose of this study is to examine the impact of personal characteristics, institutional factors, and time-competing workplace requirements on scholarly productivity in peer-reviewed economics journals. The study utilizes a unique data set of individual-specific information for 714 academic economists. The multivariate regression analysis shows that both teaching and service commitments reduce scholarly work in peer reviewed journals. The paper also presents an analysis of the data disaggregated by gender. While the impact of teaching and service on productivity appears roughly similar, the results indicate that collaborative efforts, whether formal or informal, benefit women’s publication efforts more than their male counterparts

The Social Function of Allo-marking in the European Badger (Meles meles)

The adaptive significance of sociality in European badgers (Meles meles) is often explained on the basis of ecological factors, but little is known about their social interactions. Here, we investigate how allo-marking of conspecifics with subcaudal gland secretions might serve as a behavioural mechanism to create a shared group-odour, thus functioning simultaneously to maintain group cohesion, and as an individual advertisement signal. The odour of subcaudal secretions, which encodes group-membership and individual-specific information, is partly generated by the bacterial flora in the subcaudal pouch. Studying the interactions of 40 different adults from two social groups, we analysed 3021 instances of allo-marking, which may be either mutual, i.e. two badgers pressing their subcaudal pouches against each other simultaneously (155 events) or sequential, i.e. one badger marking the body of another individual (2866 events). Sequential marking is significantly more frequent than mutual marking, although both occur significantly more often during the mating season and the cub-rearing season than at other times. Whereas mutual marking appears to be independent of individual-specific parameters, sequential allo-marking is strongly influenced by sex, age, and reproductive status. We propose that mutual marking generates a common group-smell by facilitating the exchange of pouch bacteria, thus aiding in group-cohesion, while sequential marking serves two purposes, to distribute the common group-smell, and to advertise individual-specific, fitness-related information. Strong correlation of the frequencies of sequential and mutual allo-marking as well as the allo-grooming behaviour between particular clusters of group members suggests the existence of sub-groups within badger groups.

Person Identification from the EEG using Nonlinear Signal Classification

This paper focusses on the person identification problem based on features extracted from the ElectroEncephaloGram (EEG). A bilinear rather than a purely linear model is fitted on the EEG signal, prompted by the existence of non-linear components in the EEG signal--a conjecture already investigated in previous research works. The novelty of the present work lies in the comparison between the linear and the bilinear results, obtained from real field EEG data, aiming towards identification of healthy subjects rather than classification of pathological cases for diagnosis. The EEG signal of a, in principle, healthy individual is processed via (non)linear (AR, bilinear) methods and classified by an artificial neural network classifier. Experiments performed on real field data show that utilization of the bilinear model parameters as features improves correct classification scores at the cost of increased complexity and computations. Results are seen to be statistically significant at the 99.5% level of significance, via the chi 2 test for contingency. The results obtained in the present study further corroborate existing research, which shows evidence that the EEG carries individual-specific information, and that it can be successfully exploited for purposes of person identification and authentication.

Caste- and colony-specific chemical signals on eggs of the bumble bee, Bombus terrestris L. (Hymenoptera: Apidae)

In the bumble bee, Bombus terrestris L., we investigated whether a chemical signal corresponding to the egg-marking in honey bees occurs, and whether the pattern of volatiles encodes caste-, colony- or even individual-specific information. Volatile compounds were obtained by surface extraction of individual eggs with pentane. The resulting complex mixtures were analysed by gas chromatography and mass spectrometry. Major classes of identified compounds were n-alkanes, n-alkenes and n-alkadienes comprising approximately 95% of the extracted volatile material. In addition, small amounts of methyl-branched alkanes, ethyl esters, methyl esters, wax type esters and acetates were present. Eggs produced by queens and individual workers showed significantly different compositions of volatiles. Furthermore, the volatile patterns were found to be colony-specific. Egg-odours contained all compounds identified in the Dufour’s glands and some additional components. Therefore, females very likely mark eggs with excretions of Dufour’s gland, however, other glands may also be involved.

Names and Identification: An Access Problem

Abstract information about individuals unless given their names, which, however, he could not produce. It is proposed that CB's previously unreported pattern of symptoms results from multiple functional disconnections isolating the collection of identity-specific semantic information from: (1) the corresponding phonological form, hence proper name anomia; (2) face recognition units, preventing faces being named and matched to semantic information; (3) general semantics, preventing the elements of a definition referring to an individual eliciting further individual specific information. The case is discussed together with similar cases and relevant theories that recently appeared in the literature. The peculiar role of persons' proper names in the semantic system is highlighted. Unlike common names, which denote categories, proper names are thought to just label unique sets of casually clustered attributes constituting a person's identity-specific semantics.

Names and identification: An access problem

information about individuals unless given their names, which, however, he could not produce. It is proposed that CB's previously unreported pattern of symptoms results from multiple functional disconnections isolating the collection of identity-specific semantic information from: (1) the corresponding phonological form, hence proper name anomia; (2) face recognition units, preventing faces being named and matched to semantic information; (3) general semantics, preventing the elements of a definition referring to an individual eliciting further individual specific information. The case is discussed together with similar cases and relevant theories that recently appeared in the literature. The peculiar role of persons' proper names in the semantic system is highlighted. Unlike common names, which denote categories, proper names are thought to just label unique sets of casually clustered attributes constituting a person's identity-specific semantics.

INDIVIDUAL AND SPECIES-SPECIFIC SONG PATTERNS OF ROCK AND MEADOW PIPITS: PHYSICAL CHARACTERISTICS AND EXPERIMENTS

ABSTRACT The songs of Anthus spinoletta littoralis and A. pratensis, in sympatric populations in SW Sweden were recorded, analysed in sound spectrographs and tested in the field. The purpose was to investigate: a) if the strophes are species specifically and individually distinct and, if so, whether pipits are able to make such distinctions; b) if the species-specific and individual-specific patterns are concentrated in different sections of the song and, if so, whether the species-specific section transmits individual-specific information and the individual-specific section transmits species-specific information as well. The basic structure of the syllables in the terminating section of the strophe was found to be intraspecifically stereotyped, but varied between the two species. Replay experiments showed that territorial males could discriminate between con- and heterospecific strophes and this ability persisted when the terminating section of the strophe was replayed alone. The terminating part of the strophe did not seem to transmit individual-specific information to conspecific males. On the other hand, the basic structure of the syllables in the first section of the strophe was intraindividually stereotyped but varied between most conspecific males. Playback experiments showed that a territorial male could discriminate his neighbours' song patterns and this ability remained intact when the introductory phrase of the strophe was replayed alone. Both song pattern and position were necessary properties of the identifying signal in these pipits. But the introductory phrase of a total stranger did not seem to transmit unambiguous species-specific information to conspecific males.

Imputing a Housewife's Earnings in a Wrongful Death and Injury Case

The accurate estimation of the present value of lifetime earnings is an ongoing source of concern to economists, lawyers, and insurance companies. The more reliable the estimates, the more efficient the judicial process and consequently, the less variability in compensation awards. An earlier article in this journal, by Lane and Glennon [ 1], proposed an alternative procedure for estimating the economic loss in wrongful death and injury cases that evolved around the use of an earnings function extensively used in the labor economic literature. This method avoids some of the pitfalls that plague the more standard methods, which key on earnings growth due to experience, inflation, and productivity [2], and focuses instead on the impact that education and human capital levels have on age/earning profiles. Specifically, the current earnings of individuals of different ages but similar socio-economic characteristics is used to estimate the growth in any one individual's future income. Since this method uses data on employed individuals only, however, it inhibits the estimations of earnings for non-participants in the labor force, for example, housewives [3]. The problem of imputing the value of a housewife's activity has been a persistent one. Though it is possible to 'cost out' the dollar value of a housewife's services calculated by multiplying the hours spent in each activity (as chauffeur, nurse, cleaning agent, cook, etc.) by the average market determined wage associated with each service, this approach is inefficient for two reasons. First, this method requires an extensive study of the proportion of time an individual spends in each activity. Second, this approach ignores the relevant information concerning the individual's work related qualifications and skills. It seems appropriate that we incorporate as much individual specific information as available in order to reduce the scope of a basically heterogenous group housewives to a more homogenous subgroup distinguished by group characteristics.

A Sampling Design for Mormon Utah, 1880

Mormon Culture Area for purposes of sampling the Utah Territory population in I880. With this sample as a baseline it will be possible to analyze structural change and population dynamics by successive linkage over time among different sources that encoded social identities and significant events in the life-cycle of individuals during the period from 1847 to I9oo.1 We distinguish between sources and records, as we would between aggregates and individuals. Sources are documents or collections of documents providing decipherable information. Records are decipherable lists identifying individuals (nominal records) together with individual-specific information.2 Initially, we shall be concerned with federal and Latter-day Saints church sources providing nominal records, where four types of record information are of particular concern: