Individual Preference Functions Research Articles

Regimes of collective logic

PurposeThe study aims to reveal regularities of collective decision in groups of varying cooperativity and to investigate the influence of individualism–collectivism cultural dimension on the emergence of collective behavioral entities.Design/methodology/approachAn agent-based model of group behavior is used to simulate the logic of collective binary decisions defined by reaching a consensus threshold. The key parameter of the model is the cooperativity of interaction between individuals which locates the group in individualism–collectivism cultural dimension. The probabilities of collective decisions are measured as a function of individual preferences and the strength of cooperation between agents.FindingsStrong, weak and middle point cooperativities of inter-individual interaction define three distinct regimes of collective decision logic, namely, individualism, conformism and criticality. The critical organization allows the group to generate coherent non-predetermined collective behavior in statistical agreement with individual preferences.Research limitations/implicationsEmergent collective behavior with coherent and nondeterministic decision-making can be modeled in an agent-based approach with local interaction between individuals tuned to a critical point. Variation of a single cooperativity parameter accounts for a continuous transition between organizations of the group inherent to inert matter and living systems.Social implicationsA new organization of social systems distinguished by internally relaxed relations and large-scale freedom is found beyond the traditional individualism–collectivism contraposition. This state is reached by tuning behavioral logic of individuals to a critical balance of individual and collective values.Originality/valueIndividualist, conformist and critical regimes of collective organization distinct in terms of integrity, complexity and determinism are recognized as universal organizational classes of nature spanning both inert and living systems. In particular, individualist and conformist regimes produce simple deterministic behavior typical for gases and solid bodies, whereas the critical organization generates complex nondeterministic behavior inherent to living organisms.

Individual preference functions exist without overall preference in a tropical jumping spider

Female mate choice is a widespread and well-recognized phenomenon. Nevertheless, individual variation in female preference has not yet received the same attention, although such preferences can have important effects on evolutionary dynamics. Here we assess and compare population- and individual-level female preferences for male ornaments and size in the tropical jumping spider Hasarius adansoni in two sets of laboratory experiments. First, we paired females with a single male and quantified receptive behaviours (e.g. receptive posture, number of copulations) and unreceptive behaviours (e.g. attacking the male, running away from a male). We assessed whether these male traits were related to offspring quality and quantity to determine whether there was selection on female preferences. Then, we paired different females with three different-sized males, one per day, and scored similar behaviours to measure preference functions (relationship between male traits and female receptivity). Generally, the population of females did not show a consistent average preference for male traits, despite our finding that females mated to larger males produced more offspring. However, at the individual level, females showed different preference functions for male size, such that some females preferred larger males, while others preferred smaller males. We discuss these data in terms of the causes and consequences of individual preference functions, highlighting the importance of including individual preference functions in future studies that focus on sexual selection and how individual preference can maintain phenotypic variation in wild populations.

MateSim: Monte Carlo simulation for the generation of mating tables

In species with sexual reproduction, the mating pattern is an important element for understanding evolutionary and speciation processes. Given a mating pool where individuals can encounter each other randomly, the individual mating preferences define the mating frequencies in the population. However, in every mating process we can distinguish two different steps. First, the encounter between partners, and second, the actual mating once the encounter has occurred. Yet, we cannot always assume that the observed population patterns accurately reflect the individuals’ preferences. In some scenarios, individuals may have difficulties to achieve their preferred matings, such as in monogamous species with low population size, where the mating process is similar to a sampling without replacement. In this case, the encounter process will introduce some noise that may disconnect the individual preferences from the obtained mating pattern. Such a difference between mating patterns and mating preferences has previously been shown by different modeling scenarios.Here I present a program that simulates the mating process for both discrete and continuous traits, under different encounter models and individual preference functions, and including effects such as time dependence and aging. The utility of the software is demonstrated by replicating and extending a recent study that showed how patterns of positive assortative mating, or marriage in human societies, may arise from non-assortative individual preferences. The previous result is confirmed and is shown to be caused by the marriage among the "ugliest" and oldest individuals, who after many attempts were finally able to mate among themselves. In fact, I show that the assortative pattern vanishes if an aging process prevents these individuals from mating altogether. The software MateSim is available jointly with the user's manual, athttp://acraaj.webs.uvigo.es/MateSim/matesim.htm

A statistical approach to understanding reproductive isolation in two sympatric species of tree crickets.

In acoustically communicating animals, reproductive isolation between sympatric species is usually maintained through species-specific calls. This requires that the receiver be tuned to the conspecific signal. Mapping the response space of the receiver onto the signal space of the conspecific investigates this tuning. A combinatorial approach to investigating the response space is more informative as the influence on the receiver of the interactions between the features is also elucidated. However, most studies have examined individual preference functions rather than the multivariate response space. We studied the maintenance of reproductive isolation between two sympatric tree cricket species (Oecanthus henryi and Oecanthus indicus) through the temporal features of the calls. Individual response functions were determined experimentally for O. henryi, the results from which were combined in a statistical framework to generate a multivariate quantitative receiver response space. The predicted response was higher for the signals of the conspecific than for signals of the sympatric heterospecific, indicating maintenance of reproductive isolation through songs. The model allows prediction of response to untested combinations of temporal features as well as delineation of the evolutionary constraints on the signal space. The model can also be used to predict the response of O. henryi to other heterospecific signals, making it a useful tool for the study of the evolution and maintenance of reproductive isolation via long-range acoustic signals.

Relaxing IIA and the effect on individual power

We allow departures from IIA in Arrow’s framework. Our measure of the extent of a departure is the amount of information needed to socially order a pair of alternatives. We also propose a measure of the scope of an individual’s power. The scope of at least one individual’s power increases in step with a reduction in the amount of information that has to be gathered to socially order two alternatives. This result is also established for correspondences, which select a subset of the feasible set as a function of individual preferences.

Group Recommendation Based on the PageRank

Social network greatly improve the social recommendation application, especially the study of group recommendation. The group recommendation, analyze the social factors of the group, such as social and trust relationship between users, as the factors for the prediction model established. In this paper, PageRank algorithm is introduced in the recommendation method to calculate the member’s importance in the group respectively, and to amend the aggregate function of individual preferences. The aggregate function consider the relationship between various users in the group, and optimize the aggregate function according to users different influence on the group, which can better reflect the social characteristics of group. In short, the study on group recommended model and algorithm can take the initiative to find the user's needs. Extensive experiments demonstrate the effectiveness and efficiency of the methods, which improve the prediction accuracy of the group recommended algorithms.

Work–family boundary management styles in organizations

We develop a cross-level model and typology of work–family (W–F) boundary management styles in organizations. A boundary management style is the general approach an individual uses to demarcate boundaries and attend to work and family roles. We argue that variation in W–F boundary management styles (integrator, separator, alternating) is a function of individual boundary-crossing preferences (flexibility, permeability, symmetry, direction); the centrality and configuration of work–family role identities; as well as the organizational work–family climate for customization. The model assumes that an individual’s perceived control to enact a boundary style that aligns with boundary-crossing preferences and identities has direct effects on individual perceptions of work–family conflict and also moderates the level of work–family conflict of boundary management styles experienced across organizational contexts. We offer propositions relevant to future research and practice.

A comment on « low levels of ethnic intolerance do not create large ghettos » by Michel Forsé and Maxime Parodi

Schelling’s model of segregation has long been considered a para-digmatic example of emergent behavior, as in the model seemingly tolerant individual choices produce complete racial segregation. The Forse and Parodi article takes issue with both the mathematical and substantive characterization of Schelling’s model. At a mathematical level, they argue that the model’s behavior is not emergent, paradoxical, non-linear or otherwise complex. Instead, they claim that the level of segregation is a linear function of individual preferences for segregation. Substantively, Forse and Parodi argue that tolerant individual choices do not produce segregation, and therefore that racial ghettos do not « result from innocent decisions. » While the authors identify important issues, their conclusions are potentially misleading and merit fuller discussion in light of contemporary research into segregation in particular and analytical sociology and complex social system dynamics more broadly.

Episodic Future Thinking Reduces Reward Delay Discounting through an Enhancement of Prefrontal-Mediotemporal Interactions

Humans discount the value of future rewards over time. Here we show using functional magnetic resonance imaging (fMRI) and neural coupling analyses that episodic future thinking reduces the rate of delay discounting through a modulation of neural decision-making and episodic future thinking networks. In addition to a standard control condition, real subject-specific episodic event cues were presented during a delay discounting task. Spontaneous episodic imagery during cue processing predicted how much subjects changed their preferences toward more future-minded choice behavior. Neural valuation signals in the anterior cingulate cortex and functional coupling of this region with hippocampus and amygdala predicted the degree to which future thinking modulated individual preference functions. A second experiment replicated the behavioral effects and ruled out alternative explanations such as date-based processing and temporal focus. The present data reveal a mechanism through which neural decision-making and prospection networks can interact to generate future-minded choice behavior.

Mate choice in field crickets: can females acoustically detect male body size?

Females can potentially choose high-quality males by evaluating male secondary sexual traits such as acoustic signals. In field crickets (Orthoptera: Gryllidae), body size is thought to indicate male quality. Song carrier frequency (FQ) has been suggested to indicate male body size because the areas of the wing that control FQ (harp) scale with body size. However, no direct evidence showing that males can advertise their size via FQ exists for grylline crickets. Firstly, we show the lack of evidence indicating a clear relationship between FQ and body size for grylline crickets by conducting a literature review. We then calculate the three-way relationship between body size, harp size and FQ and show no relationship between FQ and body size for Gryllus bimaculatus. Eight other commonly measured song parameters also failed to indicate body size. Individual female preference functions for FQ are calculated and we demonstrate that females cannot select large males on the basis of FQ. Furthermore, we demonstrate that variation in male FQ falls within the range of female preference at the population level. Females probably cannot evaluate male body size based on the temporal and spectral properties of male calling song and alternative avenues of study are suggested.

Does religion constrain the risky sex behaviour associated with HIV/AIDS?

This article examines the likely effectiveness of public health interventions designed to change the risky sexual behaviour associated with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS) by Faith-Based Organizations (FBOs). We utilize data from the General Social Survey (GSS) to estimate an economic model of sexual behaviour. Our theoretical approach proceeds by rationalizing, on evolutionary grounds, the existence of sexual activity in individual preference functions, with unobservable costs imposed by religious beliefs and participation. Given the objective of utility maximization, we justify the existence of demand functions for sexual activity that generate empirically testable hypotheses about the effects of religion and religious participation on risky sexual activity. Our results suggest that, at least in the case of heterosexuals, FBOs can indeed influence the risky sexual behaviour that is associated with the transmission of HIV/AIDS.

Statistical analysis of tourism destination competitiveness

The growing relevance of tourism industry for modern advanced economies has increased the interest among researchers and policy makers in the statistical analysis of destination competitiveness. In this paper we outline a new model of destination competitiveness based on sound theoretical grounds and we develop a statistical test of the model on sample data based on Italian tourist destination decisions and choices. Our model focuses on the tourism decision process which starts from the demand schedule for holidays and ends with the choice of a specific holiday destination. The demand schedule is a function of individual preferences and of destination positioning, while the final decision is a function of the initial demand schedule and the information concerning services for accommodation and recreation in the selected destinations. Moreover, we extend previous studies that focused on image or attributes (such as climate and scenery) by paying more attention to the services for accommodation and recreation in the holiday destinations. We test the proposed model using empirical data collected from a sample of 1.200 Italian tourists interviewed in 2007 (October - December). Data analysis shows that the selection probability for the destination included in the consideration set is not proportional to the share of inclusion because the share of inclusion is determined by the brand image, while the selection of the effective holiday destination is influenced by the real supply conditions. The analysis of Italian tourists preferences underline the existence of a latent demand for foreign holidays which points out a risk of market share reduction for Italian tourism system in the global market. We also find a snow ball effect which helps the most popular destinations, mainly in the northern Italian regions.

Love will tear you apart: different components of female choice exert contrasting selection pressures on male field crickets

Female mate choice is a driving force in the evolution of male secondary sexual characters. It can be dissected into several components: discrimination describes the degree to which females distinguish male trait variation, responsiveness indicates the speed or likelihood of females’ reactions to a mate, and preference functions illustrate how the probability of mating relates to male trait variation. Relatively little is known about how these components interact to produce final mating decisions and influence the strength and direction of sexual selection, so I used female field crickets (Teleogryllus oceanicus) to measure interactions between individual preference functions, discrimination, and 2 measures of responsiveness (number of responses and response effort). Preference function shape varied considerably between individual females. Highly discriminating females showed greater numbers of responses to playbacks and were more likely to have stabilizing preference functions. When I constructed 2 population-level preference functions using either response number or response effort, the first yielded a linear, directional function, whereas the second implied a stabilizing function. The clear differences between the 2 imply that different components of female choice can exert contrasting selection pressure on a single male trait. Overall, both response number and discrimination were mutually reinforcing and likely govern the strength of sexual selection in this population. The direction of selection in a wild setting ultimately depends on the relative importance of response number versus response effort, where exogenous factors such as predation risk or density will determine which component of female choice predominates mating decisions. Key words: choosiness, discrimination, mate choice, preference function, sexual selection, Teleogryllus oceanicus. [Behav Ecol]

Multi-Agent Negotiation Using Linguistically Expressed Mediation Rules

The problem of multi-agent negotiation is considered. We provide an framework for the multi-agent negotiation process in which each of the participating agents provides a preference function over the set of alternatives. This framework involves a mediation step in which the individual agent preference functions are aggregated to obtain a group preference function. The determination of the satisfaction of a stopping rule which decides whether a suitable final group preference function has been obtained or whether the agents must participate in another round of mediation. It also involves a selection procedure for choosing a alternative based on the final group preference function. We describe various implementations for these different steps. Considerable interest is focused on the implementation of the mediation rule where we allow for a linguistic description of the rule using fuzzy logic. A particularly notable feature of our approach is the inclusion in the mediation step of a mechanism rewarding the agents for being open to alternatives other then simply their most preferred.

Repeatability of mate choice in the zebra finch: consistency within and between females

Numerous studies have measured the mating preferences of female zebra finches, Taeniopygia guttata, using choice-chamber experiments, but no study has focused on how consistent individual females are in their choices and the extent to which females agree on their preferences, although these questions are of great conceptual importance. We conducted a large number of mate choice trials involving unmanipulated stimulus males, and found low but significant consistency (repeatability of time allocation by a female tested twice with the same set of males R = 0.29), and very low but significant between-female agreement (different females tested with the same set of males: R = 0.11). Although low individual consistency indicates that preferences were relatively weak or hard to measure, we found significant repeatability of individual preference functions with regard to beak colour, song rate and male aggressiveness when individual females were tested twice with different sets of males. This means that some females consistently preferred red-beaked males whereas others preferred orange-beaked males, some preferred high and others low song rates, and some preferred aggressive and others less aggressive males. Of these male traits, only song rate was positively related to average male attractiveness. Low between-female agreement did not seem to result from assortative mating for quality, because there was no repeatability of an individual female's preference for attractive or unattractive males. It is possible that disagreement follows from choice for genetic compatibility, but much of it could also result from weak preferences and little variation in male quality.

Natal dispersal and personalities in great tits (Parus major).

Dispersal is a major determinant of the dynamics and genetic structure of populations, and its consequences depend not only on average dispersal rates and distances, but also on the characteristics of dispersing and philopatric individuals. We investigated whether natal dispersal correlated with a predisposed behavioural trait: exploratory behaviour in novel environments. Wild great tits were caught in their natural habitat, tested the following morning in the laboratory using an open field test and released at the capture site. Natal dispersal correlated positively with parental and individual exploratory behaviour, using three independent datasets. First, fast-exploring parents had offspring that dispersed furthest. Second, immigrants were faster explorers than locally born birds. Third, post-fledging movements, comprising a major proportion of the variation in natal dispersal distances, were greater for fast females than for slow females. These findings suggest that parental behaviour influenced offspring natal dispersal either via parental behaviour per se (e.g. via post-fledging care) or by affecting the phenotype of their offspring (e.g. via their genes). Because this personality trait has a genetic basis, our results imply that genotypes differ in their dispersal distances. Therefore, the described patterns have profound consequences for the genetic composition of populations.

Penalizing strategic preference manipulation in multi-agent decision making

We consider the problem of group decision making where the selection process is based upon a group preference function, obtained by an aggregation of the participating agents individual preference functions. We describe some methods for formulating the group preference from the individual preference functions. We note the possibility of the individual agents strategically manipulating the information they provide, so as to further their own goal of getting their most preferred alternative selected by the group. With this in mind, we suggest ways of modifying the formulation of the group decision functions to discourage strategic manipulation by the participating agents.

Symposium on Amartya Sen's philosophy: 2 Unstrapping the straitjacket of ‘preference’: a comment on Amartya Sen's contributions to philosophy and economics

The concept of preference dominates economic theory today. It performs a triple duty for economists, grounding their theories of individual behavior, welfare, and rationality. Microeconomic theory assumes that individuals act so as to maximize their utility – that is, to maximize the degree to which their preferences are satisfied. Welfare economics defines individual welfare in terms of preference satisfaction or utility, and social welfare as a function of individual preferences. Finally, economists assume that the rational act is the act that maximally satisfies an individual's preferences. The habit of framing problems in terms of the concept of preference is now so entrenched that economists rarely entertain alternatives.

Mating preference functions of individual female barking treefrogs, Hyla gratiosa, for two properties of male advertisement calls.

A mating preference function describes the relationship between variation in a trait in potential mates and the strength of the preference for that trait. Few studies have measured mating preference functions either at a population level or for individuals. We used two-choice playback experiments to determine the mating preference functions of individual female barking treefrogs for two call characteristics: call-repetition rate and fundamental frequency. We tested each female four times with each pair of stimuli and with three to six pairs of stimuli. Individual females exhibited directional preferences for higher call rates and stabilizing preferences for intermediate fundamental frequency. These individual preference functions were similar to population-level preferences documented in previous studies. Within a stimulus type (call rate or fundamental frequency), nearly all females exhibited the same general preference function. However, females varied in the minimum difference between stimuli necessary to elicit a unanimous choice for the higher call rate, and they differed in both the intermediate fundamental frequency they preferred most and the minimum difference in fundamental frequency that elicited a unanimous choice for one of the two alternatives. The variation we observed among females was not repeatable; repeatabilities were in general low and statistically nonsignificant. The observed variation in the preferences of females, even if unrepeatable, should weaken selection on male traits relative to selection in the absence of such variation.

Measuring female mating preferences

Interest in the evolution of female mating preferences has increased greatly in recent years, and numerous hypotheses have been proposed to explain how mating preferences evolve. Despite this interest, little is known about how selection acts on mating preferences in natural populations. One reason for this lack of information may be that experimental designs commonly used for testing female preferences make it difficult to quantify the preferences of individual females. Most commonly used designs share three features: they examine the preferences of populations of females, they test female responses when they are presented simultaneously with two stimuli, and they infer information on female preferences by observing female choices between alternative stimuli. Population-level choice tests, in which each female is tested only once with a set of stimuli, do not evaluate within-female variation in preference, which is necessary to document between-female variation in preference. Two-stimulus designs test only for directional preferences if female responses are tested with only a single pair of stimuli. In addition, dichotomous scoring of female responses makes detection of between-female variation in preference difficult. Simultaneous stimulus presentations can confound female preference and female sampling behaviour. An alternative method to assess female preferences is to measure repeatedly the preference functions of individual females using a single-stimulus design. The shape of a female's preference function indicates how a female's mating response varies with male trait value, and repeated measures of individual preference functions allow measurement of within- and between-female variation in preferences.