Individual Behavioral Type Research Articles

Fencing amplifies individual differences in movement with implications on survival for two migratory ungulates.

Fences have recently been recognized as one of the most prominent linear infrastructures on earth. As animals traverse fenced landscapes, they adjust movement behaviours to optimize resource access while minimizing energetic costs of coping with fences. Examining individual responses is key for connecting localized fence effects with population dynamics. We investigated the multi-scale effects of fencing on animal movements, space use and survival of 61 pronghorn and 96 mule deer on a gradient of fence density in Wyoming, USA. Taking advantage of the recently developed Barrier Behaviour Analysis, we classified individual movement responses upon encountering fences (i.e. barrier behaviours). We adopted the reaction norm framework to jointly quantify individual plasticity and behavioural types of barrier behaviours, as well as behaviour syndromes between barrier behaviours and animal space use. We also assessed whether barrier behaviours affect individual survival. Our results highlighted a high-level individual plasticity encompassing differences in the degree and direction of barrier behaviours for both pronghorn and mule deer. Additionally, these individual differences were greater at higher fence densities. For mule deer, fence density determined the correlation between barrier behaviours and space use and was negatively associated with individual survival. However, these relationships were not statistically significant for pronghorn. By integrating approaches from movement ecology and behavioural ecology with the emerging field of fence ecology, this study provides new evidence that an extraordinarily widespread linear infrastructure uniquely impacts animals at the individual level. Managing landscape for lower fence densities may help prevent irreversible behavioural shifts for wide-ranging animals in fenced landscapes.

Social context mediates the expression of a personality trait in a gregarious lizard

The social environment is a key factor that influences behavioural traits across a wide array of species. Yet, when investigating individual differences in behaviour, studies tend to measure animals in isolation from other conspecifics—even in social species. Surprisingly, whether behavioural traits measured in isolation are predictive of individual-level behaviour when in social groups is still poorly understood. Here, we repeatedly measured risk-taking behaviour (i.e. boldness; 741 total trials) in both the presence and absence of conspecifics in a social lizard, the delicate skink (Lampropholis delicata). Further, we manipulated food availability during group trials to test whether the effect of the social environment on risk-taking behaviour was mediated by competition over resources. Using 105 lizards collected from three independent populations, we found that individual risk-taking behaviour was repeatable when measured in either social isolation or within groups both with and without food resources available. However, lizards that were bolder during individual trials were not also bolder when in groups, regardless of resource availability. This was largely driven by individual differences in social behavioural plasticity, whereby individual skinks responded differently to the presence of conspecifics. Together, this resulted in a rank order change of individual behavioural types across the social conditions. Our results highlight the importance of the social environment in mediating animal personality traits across varying levels of resource availability. Further, these findings suggest that behavioural traits when measured in isolation, may not reflect individual variation in behaviour when measured in more ecologically realistic social groups.

Predator Group Composition Indirectly Influences Food Web Dynamics through Predator Growth Rates.

AbstractConsiderable theoretical work predicts that intraspecific trait variation can have profound ecological consequences by altering species interactions. Because of their high flexibility, behavioral traits may be especially relevant in mediating how species respond to one another, thus affecting food web dynamics and ecosystem functioning. However, empirical evidence supporting this idea is limited. Here, we generated predator groups where we manipulated the composition of behavioral types within the groups to assess effects on predator growth rates, prey communities, basal resources, and ecosystem functioning in replicated outdoor ponds. Using European perch (Perca fluviatilis), we created three types of predator populations: two where all individuals expressed either bold or shy phenotypes and one that contained a mix of individuals of the two behavioral types. Bold perch grew faster in mixed populations, indicating that predator growth depends on each individual's behavioral type and that of its group members. However, there was no evidence that the behavioral composition of the perch population directly altered the dynamics of lower trophic levels. Instead, final perch biomass, not behavioral composition, had the strongest influence on lower trophic levels. Thus, the central question may not be whether predator behavior matters at all for trophic dynamics but rather when behavioral effects will predominate over effects of other influences, such as predator biomass variation.

Individual behavioral type captured by a Bayesian model comparison of cap making by sponge crabs.

‘Animal personality’ is considered to be developed through complex interactions of an individual with its surrounding environment. How can we quantify the ‘personality’ of an individual? Quantifying intra- and inter-individual variability of behavior, or individual behavioral type, appears to be a prerequisite in the study of animal personality. We propose a statistical method from a predictive point of view to measure the appropriateness of our assumption of ‘individual’ behavior in repeatedly measured behavioral data from several individuals. For a model case, we studied the sponge crab Lauridromia dehaani known to make and carry a ‘cap’ from a natural sponge for camouflage. Because a cap is most likely to be rebuilt and replaced repeatedly, we hypothesized that each individual crab would grow a unique behavioral type and it would be observed under an experimentally controlled environmental condition. To test the hypothesis, we conducted behavioral experiments and employed a new Bayesian model-based comparison method to examine whether crabs have individual behavioral types in the cap making behavior. Crabs were given behavioral choices by using artificial sponges of three different sizes. We modeled the choice of sponges, size of the trimmed part of a cap, size of the cavity of a cap, and the latency to produce a cap, as random variables in 26 models, including hierarchical models specifying the behavioral types. In addition, we calculated the marginal-level widely applicable information criterion (mWAIC) values for hierarchical models to evaluate and compared them with the non-hierarchical models from the predictive point of view. As a result, the crabs of less than about 9 cm in size were found to make caps from the sponges. The body size explained the behavioral variables namely, choice, trimmed cap characteristics, and cavity size, but not latency. Furthermore, we captured the behavioral type as a probabilistic distribution structure of the behavioral data by comparing WAIC. Our statistical approach is not limited to behavioral data but is also applicable to physiological or morphological data when examining whether some group structure exists behind fluctuating empirical data.

Personality is associated with dominance in a social feeding context in the great tit

Abstract Despite the growing interest in consistent individual differences in behaviour (animal personality), the influence of social context on different behavioural types remains poorly understood. The suite of correlated behaviours within and across contexts is called behavioural syndromes. Most personality studies have investigated consistent individual behavioural types and their consequences in a asocial context, however few studies have considered the influence of social context on individual behaviour. In addition, the evolutionary and ecological consequences of personality differences in social context remain unknown. In the present study, we confirm individual personality in Great tits (Parus major) using room exploration and neophobia tests. As a result of these two tests, repeatability and correlational structure of two personality traits were investigated. Additionally we assessed the extent to which personality influences dominance in a social feeding context. Great tits remained consistent in their personality traits (exploration and neophobia). Individuals who explored a novel environment faster also approached a novel object faster, while those who spent more time exploring a novel environment were also slower to approach a novel object. In a social feeding context personality was linked to dominance: with proactive individuals being more likely to be dominant. Our result provides evidence of the importance of social context in a wild population of birds and may have fitness consequence, both for focal individuals and their conspecifics.

Top-down control by an aquatic invertebrate predator increases with temperature but does not depend on individual behavioral type.

Variation in behavioral traits among individuals within a population can have implications for food webs and ecosystems. Temperature change also alters food web structure and function, but potential interactions between warming and intraspecific behavioral variation are largely unexplored. We aimed to test how increased temperature, individual activity level of a predatory backswimmer (Anisops assimilis), and their interaction influenced the strength of top‐down control of zooplankton and phytoplankton. We used stable isotopes to support our assumption that the study population of A. assimilis is zooplanktivorous, and behavioral trials to confirm that activity level is a repeatable trait. We established freshwater microcosms to test for effects of warming, backswimmer presence, and backswimmer behavioral type on zooplankton density, zooplankton composition, and phytoplankton chlorophyll a. Top‐down control was present and was generally stronger at increased temperature. There was no indication that predator behavioral type influenced the strength of top‐down control either on its own or interactively with temperature. Predator behavioral type may not be associated with ecologically important function in this species at the temporal and spatial scales addressed in this study, but the links between behavior, temperature, and food web processes are worthy of broader exploration.

Top predator’s aggressiveness and mesopredator’s risk-aversion additively determine probability of predation

Predator–prey interactions strongly affect ecological dynamics. Consistent inter-individual differences in behaviour (individual behavioural types, BTs) of predator and prey (or both) may fundamentally shape their mutual interactions. Several recent studies have shown that it is important to consider the interaction of BTs on both sides of predator–prey interactions. Otherwise, there is a high risk of erroneous inference about the outcome of predation. Until now, however, no study has investigated how BT vs BT interaction affects the predation of mesopredators by top predators, especially when the mesopredator is a low-ranked prey for the top predator. Such knowledge is extremely important if we want to predict the effect of individual BTs on food web dynamics. We have investigated in our laboratory experiments how foraging aggressiveness of the top predator (spider, Philodromus cespitum, Philodromidae) and risk-aversion as a form of shyness of the mesopredator (spider, Philodromus albidus, Philodromidae) determine the probability of predation. The highest explanatory power had the model with additive effects of mesopredator’s risk-aversion and top predator’s foraging aggressiveness. Other models, including those with BT vs BT interaction, had poor explanatory power. It was probably due to the fact that timid top predators are often choosy and do not catch low-ranked prey, while aggressive top predators are opportunists. The risk-averse mesopredators are also more cautious than risk-prone mesopredators regarding their surroundings and can defend themselves faster. Our results therefore fit with the classical hypothesis about trade-off between foraging and safety. Behavioural types of predator and prey jointly determine the mortality of prey. In our laboratory experiments, we investigated how foraging aggressiveness of a top predator spider and the risk-aversion of a mesopredator spider (potential prey) determine the probability of predation. We demonstrated that top predator’s foraging aggressiveness and mesopredator’s risk-aversion determine the probability of mesopredator’s mortality only additively. The mesopredator’s probability of being killed decreased with its risk-aversion and increased with top predator’s foraging aggressiveness. The effect was additive instead of interactive because the mesopredator represents a dangerous prey for the top predator. The timid top predators are also choosy and do not attack dangerous prey, while the aggressive/non-choosy top predators are opportunistic. Further, the risk-averse mesopredators are more cautious regarding their surroundings and can react faster to the presence of a top predator, compared to risk-prone and slowly reacting mesopredators.

ВПЛИВ СЕНСОРНОЇ ДЕПРИВАЦІЇ НА СЕНСОМОТОРНЕ РЕАГУВАННЯ У ДІТЕЙ

Introduction. The study devoted to the characteristics of human sensorimotor functions. It is essential to understanding the physiological mechanisms of the integrative activity of the brain, which has complex dynamic organisation of its various structures, developing the types of individual behavior. The sensorimotor reactions reflect the integration between neurophysiological and mental processes. They show interaction between the sensory and motor components of human mental activity. The initiation, regulation, control and correction of all psychomotor system types are based on sensory and kinesthetic information coming from analyzers. It also establishes the cognitive functions in the process of children’s individual development. Limited access to the information, connecting with one or more analyzers impairment, creates unusual conditions for the development of human psyche. Purpose. The aim is obtain and analyze new scientific data about specificity of the influence of auditory and visual sensory deprivation on the sensorimotor response. Methods. The study was conducted among 87 children aged 9 years. All the students were divided into three groups: I – a control group (healthy children), II – a group of children with hearing impairments, ІІІ – a group of children with visual impairments. The experimental study for each person surveyed lasted no more than 30 minutesfor research. At the beginning of the study each person was individually acquainted with the methods of sensorimotor re action .The methods were implemented with using the computer system Diagnost-1M that was developed by professors M. Makarenko and V.Lyzohub. Results. The research of the sensorimotor reactionto acoustic and visual stimuli revealed: there is much lower index of latency rates of different complexity of responds to sounds in the group of children with auditory sensory deprivation; children with hearing impairments have better index of sensory-motor response to sound stimuli of low tonality than high tonality; the index of sounds in the group of children with visual sensory deprivation indicate that they have better oral memory, they are more likely to understand and determine the source of sound.There is also better index of sensorimotor response on figures in the control group than in experimental ones.This is because of the visual analyzer problems in children with visual impairment and the problems of hearing aids in children with hearing impairments. Conclusion . The experiment showed better index of sensorimotor functions to sounds in children of the control group in contrast to the experimental one.It connects with the problems of hearing aids in children with hearing impairments.There are significant differences between the index of latent period of the reaction of of choosing one from three stimuli (LP Rc 1-3) and LP Rc 2-3 in children with sensory deprivations, in contrast to healthy ones.It means that hearing-impaired person are more likely to perceive sounds of low tone level than medium or high. The best values of sensorimotor functions were observed when us ed sounds as stimuli in children of the experimental group (with visual impairment), in contrast to the group of children with hearing impairments .This is due to the fact that the weak-sighted have better developed auditory memory, they are more likely to understand and determine the source of sound.

A predation cost to bold fish in the wild

Studies of predator-mediated selection on behaviour are critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations. Consistent individual differences in prey behaviour, especially in the propensity to take risks (“boldness”), are widespread in the animal kingdom. Theory predicts that individual behavioural types differ in a cost-benefit trade-off where bolder individuals benefit from greater access to resources while paying higher predation-risk costs. However, explicitly linking predation events to individual behaviour under natural conditions is challenging and there is currently little data from the wild. We assayed individual behaviour and electronically tagged hundreds of fish (roach, Rutilus rutilus) before releasing them into their lake of origin, thereby exposing them to predation risk from avian apex predators (cormorants, Phalacrocorax carbo). Scanning for regurgitated tags at the cormorant roosting site provided data on individual predation events. We found that fish with higher boldness have a greater susceptibility to cormorant predation compared to relatively shy, risk-averse individuals. Our findings hereby provide unique and direct evidence of behavioural type-dependent predation vulnerability in the wild, i.e. that there is a predation cost to boldness, which is critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations.

The Effect of Challenge-Hindrance Stressor on Engineering Design Innovation Behavior — The Mediating Role of Intrinsic Motivation

This paper explores the differential effects of work stressors on employee innovation behavior, the mediating role of intrinsic motivation by data collected from 282 engineering design staff under the situations of high strength construction project tasks and heavy stress through questionnaires. Empirical study results show that the challenge stressor has significant positive prediction function on individual innovation behavior, hindrance stressor has significant negative influence on individual innovation behavior; intrinsic motivation has partial mediating role between two types of stressors and individual innovation behavior.

Trait-mediated functional responses: predator behavioural type mediates prey consumption.

The predator functional response (i.e. per capita consumption rate as a function of prey density) is central to our understanding of predator-prey population dynamics. This response is behavioural, depending on the rate of attack and time it takes to handle prey. Consistent behavioural differences among conspecific individuals, termed behavioural types, are a widespread feature of predator and prey populations but the effects of behavioural types on the functional response remain unexplored. We tested the effects of crab (Panopeus herbstii) behavioural type, specifically individual activity level, on the crab functional response to mussel (Brachidontes exustus) prey. We further tested whether the effects of activity level on the response are mediated by the presence of toadfish (Opsanus tau) predation threat in the form of waterborne chemical cues known to reduce crab activity level. The effects of crab activity level on the functional response were dependent on crab body size. Individual activity level increased the magnitude (i.e. slope and asymptote) of the type II functional response of small crabs, potentially through an increase in time spent foraging, but had no effect on the functional response of large crabs. Predation threat did not interact with activity level to influence mussel consumption, but independently reduced the slope of the type II functional response. Overall, this study demonstrates size-specific effects of a behavioural type on a predator-prey interaction, as well as a general pathway (modification of the functional response) by which the effects of individual behavioural types can scale up to influence predator-prey population dynamics.

Does male behavioral type correlate with species recognition and stress?

The persistence of gynogenetic organisms is an evolutionary paradox. An ideal system for examining the persistence of gynogens is the unisexual–bisexual mating complex of the unisexual Amazon molly (Poecilia formosa), and the bisexual, parent species, the sailfin molly (Poecilia latipinna) and the Atlantic molly (Poecilia mexicana). Insight into the maintenance of this mating complex might be enhanced by taking a more holistic view of male and female behavior through a behavioral syndrome framework. In this study, we examined whether male mate choice is part of a behavioral syndrome. We quantified behaviors related to activity, boldness, exploration, and sociability in male sailfin mollies, as well as their mate preference for conspecific females or the all-female species of Amazon mollies. In addition, we explored the relationship between behavioral type and cortisol (a fish stress hormone) production in male sailfin mollies. We found evidence for behavioral correlations in male sailfin mollies, but individual behavioral type was not correlated with their mate preference or stress hormone production. However, we did find differences in preexperience cortisol production related to male boldness behaviors. The lack of correlation between behavioral types, mate preference, and stress hormone production emphasizes that the nature of behavioral–hormonal interactions is complex. In summary, neither individual traits nor the behavioral types found here are adequate to explain the maintenance of this unisexual–bisexual mating system.

RETRACTED: Linking levels of personality: personalities of the ‘average’ and ‘most extreme’ group members predict colony-level personality

Understanding how colony-level behaviour is determined is of evolutionary significance because colony-level traits can influence individual fitness and group success. Here we explore how the composition of individual behavioural types within colonies influences colony-level behaviour in the social spider Stegodyphus sarasinorum. First, we tested whether S. sarasinorum show stable individual differences in behaviour (i.e. individual personalities) and whether aspects of individuals' behaviour are correlated across contexts, in the form of a behavioural syndrome. As documented in many other animals, S. sarasinorum showed stable individual differences in behaviour that were repeatable across time, and correlated across contexts (i.e. aggressiveness, boldness). Second, we tested for and confirmed the presence of consistent intercolony variation (i.e. colony-level personalities) in collective foraging behaviour. Third, we generated artificially reconstituted colonies of known group size and personality composition to test for associations between colonies' personality composition and their collective foraging behaviour. In experimental colonies, we found that the average phenotypes of colony constituents were associated with colony-level behaviour, where colonies composed of smaller and bolder spiders were more responsive during foraging. However, the single best predictor of colony-level behaviour was the behavioural type of the single most extreme individual, where the boldness score of boldest individuals explained 66–69% of the variation in colony-level behaviour. Together, our results suggest that variation in the personality composition of social groups may be an important driver of variation in colony-level personality.

Larval behavioral syndrome does not affect emergence behavior in a damselfly (Lestes congener)

Activity is a key behavioral trait that often mediates a trade-off between finding food for growth and evading predation. We investigated how activity of the damselfly Lestes congener is affected by larval state and predator presence and if larval behavioral type (BT) can be used to predict larval emergence behavior. Activity level of individual larvae was studied without predators at two different physiological states (hungry, fed) and in two predator treatments (familiar or unfamiliar predator cues). Larvae did not adjust their activity depending on state or when subjected to unfamiliar predator cues but a general reduction in activity was seen in the familiar predator treatment. Hence, active individuals remained active compared to their conspecifics, independent of state or predator treatment illustrating the presence of a behavioral syndrome. However, we found no correlation between larval BT and emergence behavior. Active individuals did not differ from less active individuals in any emergence characteristics. The results illustrate that the larval BT occurs in many situations keeping active larvae active even in maladaptive situations. Furthermore, we show that damselfly emergence behavior can be completely decoupled from larval BT, indicating a loss of stability in individual BT during critical stages in ontogeny.

A COMPUTER VISION METHOD FOR ON-LINE BEHAVIORAL QUANTIFICATION OF INDIVIDUALLY CAGED POULTRY

In addition to production, physiology, and health, behavior is an important issue with respect to animal welfarewhen evaluating novel housing systems. Behavioral characteristics are usually evaluated by audio-visual observation doneby a human observer present on the scene. This method is time consuming, expensive, subjective, and prone to human error.Automated objective surveillance, by means of inexpensive cameras and image-processing techniques, has the ability togenerate data that provide an objective measure of behavior, without disturbing the animals. The specific purpose of this studywas to develop a fully automatic on-line image-processing technique to quantify the behavior of a single laying hen as opposedto the current human visual observation. The image-processing system is based on the principle that the classification ofbehavior can be translated into classification of time series of different postures of the hen. The hens postures can berecognized in the camera image. The classification of the hens behavior is performed by dynamic analysis of a set ofmeasurable parameters, which are calculated from the images using image-processing techniques. The parameters werechosen based on their computational demands and analysis of their discriminative power regarding the different types of aspecific behavior. A first implementation of the system allowed us to identify three different types of individual behavior(standing, walking, and scratching). The objective of further investigation will be the classification of up to 15 different typesof behavior, such as pecking, eating, drinking, wing stretching, etc.

User-Centered Awareness in Computer-Supported Cooperative Work-Systems: Structured Embedding of Findings from Social Sciences

An increasing number of computer-supported cooperative work (CSCW) software systems try to provide users with awareness information-information about the presence, activities, and availability of members of a community. However, most of these software systems are designed from a feature-oriented, rather than a human-oriented, point of view. In this article, a structured embedding of findings in social sciences is proposed. It reveals the variety of approaches in technology-driven CSCW developments featuring awareness, as well as the variety of empirical evidence in small-group research with respect to awareness. The authors have been looking at different aspects of awareness: the terminology used in both disciplines, the concepts that have been developed, and the different constructs that have evolved from empirical research. Finally, operational instances of awareness have been revisited. From these findings it can be concluded that awareness addresses different constellations of group settings, different types of individual behavior, and different contexts of use. These findings can be used by CSCW software system developers for postevaluation-that is, to identify empirical evidence for awareness features already implemented and to identify those already implemented features still lacking empirical evidence. The findings should also encourage social scientists to empirically investigate the usage of existing and envisioned software features in CSCW settings. Overall, the results should help to achieve a shift from technology-driven development toward human-centered design of collaborative communities, due to the envisioned integration of understandings and concepts.

Peer relations across contexts: individual-network homophily and network inclusion in and after school.

Peer relations across 2 contexts (in school and after school) were examined for 577 participants, approximately 12 years old, from 3 middle schools in Milan, Italy. The primary research questions were: Do peer networks from different contexts uniquely contribute to explaining variance in individual behavior? Do measures of peer preference and peer network inclusion across contexts uniquely contribute to explaining individual depressive symptoms? Structural equation models showed that both the in-school and the after-school peer networks uniquely contributed to explaining variance in 2 types of individual problem behavior (in-school problem behavior, after-school delinquency), and that similarity with the 2 peer networks varied according to behaviors specific to each context and across gender. Finally, both in-school and after-school peer network inclusion contributed to explaining variance in depressive symptoms, after controlling for classroom peer preference.

Characteristics of heart rate fluctuations and respiratory movements during orienting, passive avoidance and flight-fight behavior in rabbits

In the present study different heart rate patterns were demonstrated to accompany flight-fight behaviour, orienting behaviour and passive avoidance in rabbits. Flight-fight behaviour was characterized by markedly increased heart rate and diminished overall heart rate variability. The effect was mediated by vagal inhibition and β-adrenergic activation in a type-specific relation. Orienting behaviour was accompanied by a smaller heart rate increase and the exaggeration of slow heart rate fluctuations. The latter effect was absent during β-adrenergic blockade suggesting a behaviourally provoked β-adrenergic activation. Single β-adrenergic blockade did not change the characteristics of the heart rate fluctuations at rest. During passive avoidance a vagally mediated heart rate deceleration was followed by a slow heart rate return toward the initial heart rate level. This level was not reached during β-adrenergic blockade. The enhanced overall heart rate variability during passive avoidance was mainly caused by strengthened respiratory-induced heart rate fluctuations and, furthermore, by exaggerated slow rhythmical heart rate fluctuations. The latter effect was not observed during β-adrenergic blockade and is referred to as an orienting component within passive avoidance. Three individual behavioural types may be differentiated in rabbits ‘Weisses Gross-Silber’ by stable behavioural characteristics i.e. spontaneous motor activities, preferred postures at rest and coping behaviour. The results of the present study suggest that different neurovegetative reaction types, i.e. dominating β-adrenergic or vagal activation are correlated with stable behavioural characteristics, especially in terms of preferring active or passive coping behaviour, respectively.

Proception: An important fertility behavior

Social and behavioral scientists have constructed a number of distinct models of fertility and its antecedents. Davis and Blake (1956) originally identified a set of 11 variables that they described as intermediate between a society's culture and social structure, on the one hand, and its fertility, on the other. They included three union variables, three sexual intercourse variables, three conception variables, and two gestation variables. Although these intermediate variables subsequently underwent some modification and redefinition (Bongaarts 1978, 1982), they continue to provide an important basis for theorizing and model building on the part of sociologists and demographers. Economists have also developed models of the antecedents of fertility. For example, the formulation of Easterlin (1978) postulates that fertility depends on both the relative demand for children and fertility regulation. The former is a balance between the household's demand for children, called desired family size, and the potential supply of children, the number of surviving children the household would have if it did not regulate fertility. Fertility regulation is the limitation of fertility through the practice of abstinence, contraception, and abortion. Psychologists have contributed a variety of formulations, many being variations on the notion of subjective expected utility (Adler 1979). For example, Jaccard and Davidson (1976), building on the theoretical work of Fishbein (1972), proposed that fertility was a function of fertility intentions, which were a function of an attitudinal factor and a normative factor. Beckman et al. (1983) elaborated a psychological-level model that specifically includes both husband and wife variables. They postulated that fertility is determined by contraceptive use, which is determined by husband's intentions, wife's intentions, and their joint decision. Recently an interdisciplinary panel of the National Academy of Sciences proposed an analytic framework for studying the determinants of fertility in developing countries (Bulatao and Lee 1983). It incorporates biological, psychological, economic, and social factors in an effort to promote understanding at the individual, household, community, societal, and cultural levels. It draws heavily on each of the types of models already mentioned, fitting them into a single, comprehensive, yet flexible framework. What is missing in all of these formulations is a full analysis of the different types of individual behavior that lead directly to conception. In particular, none of these formulations discusses or considers what in many post-fertility-transition nations may be the most important determinant of conception, namely the attempt to achieve conception, what I have called proception (Miller 1973, 1980; Miller and Godwin 1977). This article is devoted to a discussion of the concept of proception and the presentation of some empirical findings regarding patterns of proceptive behavior among married women, the relative importance of proception for marital conceptions, and the psychological antecedents of marital proception.