Is self-deception an effective non-cooperative strategy?

Robert Trivers has proposed perhaps the only serious adaptationist account of self-deception—that the primary function of self-deception is to better deceive others. But this account covers only a subset of cases and needs further refinement. A better evolutionary account of self-deception and cognitive biases more generally will more rigorously recognize the various ways in which false beliefs affect both the self and others. This article offers formulas for determining the optimal doxastic orientation, giving special consideration to conflicted self-deception as an alternative to outright self-delusion. A novel taxonomy of self-deception, as it relates to the beliefs held by others, is also presented. While Trivers makes a plausible case for the adaptive value of certain cognitive biases, a more fragmented and nuanced account of the social forces impacting the evolution of self-deception is needed.     

Self-deception in an evolutionary game

From the perspective of philosophy, the idea of humans lying to themselves seems irrational and maladaptive, if even possible. However, the paradigm of cognitive modularity admits the possibility of self-deception. Trivers argues that self-deception can increase fitness by improving the effectiveness of inter-personal deception. Ramachandran criticizes Trivers' conjecture, arguing that the costs of self-deception outweigh its benefits. We first modify a well-known cognitive modularity model of Minsky to formalize a cognitive model of self-deception. We then use Byrne's multi-dimensional dynamic character meta-model to integrate the cognitive model into an evolutionary hawk-dove game in order to investigate Trivers' and Ramachandran's conjectures. By mapping the influence of game circumstances into cognitive states, and mapping the influence of multiple cognitive modules into player decisions, our cognitive definition of self-deception is extended to a behavioral definition of self-deception. Our cognitive modules, referred to as the hunger and fear daemons, assess the benefits and the cost of competition and generate player beliefs. Daemon-assessment of encounter benefits and costs may lead to inter-daemonic conflict, that is, ambivalence, about whether or not to fight. Player-types vary in the manner by which such inter-daemonic conflict is resolved, and varieties of self-deception are modeled as type-specific conflict-resolution mechanisms. In the display phase of the game, players signal to one another and update their beliefs before finally committing to a decision (hawk or dove). Self-deception can affect player beliefs, and hence player actions, before or after signaling. In support of Trivers' conjecture, the self-deceiving types do outperform the non-self-deceiving type. We analyse the sensitivity of this result to parameters of the cognitive model, specifically the cognitive resolution of the players and the influence of player signals on co-player beliefs.     

Evolution of spite through indirect reciprocity

How can cooperation persist in the face of a temptation to ''cheat''? Several recent papers have suggested that the answer may lie in indirect reciprocity. Altruistic individuals may benefit by eliciting altruism from observers, rather than (as in direct reciprocity) from the recipient of the aid they provide. Here, we point out that indirect reciprocity need not always favour cooperation; by contrast, it may support spiteful behaviour, which is costly for the both actor and recipient. Existing theory suggests spite is unlikely to persist, but we demonstrate that it may do so when spiteful individuals are less likely to incur aggression from observers (a negative form of indirect reciprocity).     

Self-deception as self-signalling: a model and experimental evidence

Self-deception has long been the subject of speculation and controversy in psychology, evolutionary biology and philosophy. According to an influential ‘deflationary’ view, the concept is an over-interpretation of what is in reality an instance of motivationally biased judgement. The opposite view takes the interpersonal deception analogy seriously, and holds that some part of the self actively manipulates information so as to mislead the other part. Building on an earlier self-signalling model of Bodner and Prelec, we present a game-theoretic model of self-deception. We propose that two distinct mechanisms collaborate to produce overt expressions of belief: a mechanism responsible for action selection (including verbal statements) and an interpretive mechanism that draws inferences from actions and generates emotional responses consistent with the inferences. The model distinguishes between two modes of self-deception, depending on whether the self-deceived individual regards his own statements as fully credible. The paper concludes with a new experimental study showing that self-deceptive judgements can be reliably and repeatedly elicited with financial incentives in a categorization task, and that the degree of self-deception varies with incentives. The study also finds evidence of the two forms of self-deception. The psychological benefits of self-deception, as measured by confidence, peak at moderate levels.     

OBSERVER VARIABILITY IN PINNIPED COUNTS: GROUND-BASED ENUMERATION OF WALRUSES AT HAUL-OUT SITES

Pinnipeds are often monitored by counting individuals at haul-out sites, but the often large numbers of densely packed individuals at these sites are difficult to enumerate accurately. Errors in enumeration can induce bias and reduce precision in estimates of population size and trend. We used data from paired observers monitoring walrus haul-outs in Bristol Bay, Alaska, to quantify observer variability and assess its relative importance. The probability of a pair of observers making identical counts was < 0.1 for walrus groups with >50 individuals. Mean count differences ranged up to 25% for the largest counts, depending on beach and observers. In at least some cases, there was a clear tendency for counts of one observer to be consistently greater than counts of the other observer in a pair, indicating that counts of at least one of the observers were biased. These results suggest that efforts to improve accuracy of counts will be worthwhile. However, we also found that variation among observers was relatively small compared to variation among visits to a beach so that efforts to account for other sources of variation will be more important.     

Self-deception as a mediator of cooperation and defection in varying social contexts described in the iterated prisoner''s dilemma

Deception and self-deception may be two related psychological capacities serving to enhance an individual's inclusive fitness. Self-deception has been defined as any psychological act in which one thought or belief is held at the expense of another. This study was designed to test the notion that we may deceive ourselves about our own intentions or the intentions of others in order to facilitate cooperation, if the cooperative behavior has the potential to improve fitness. We may also deceive ourselves in situations where we may need to compete with others, if not competing might represent a loss of fitness. The Self-Deceptio Questionnaire was administered to 80 women and 70 men to determine their levels of self-deception. A series of vignettes, conforming to the Prisoner's Dilemma game format, were administered in questionnaire material to measure participant's predispositions to cooperate or defect in three different contexts (family, mating, and neutral). Men predicted they would be less cooperative than women over all conditions, and participants anticipated cooperating more with kin than with non-kin. Moreover, participants who were high self-deceivers chose more cooperative responses in both family and mating contexts than those with low self-deception scores. Finally, the three-way interaction among sex, context, and level of self-deception suggested that the role of selfdeception in cooperation may vary according to the sex of the individual and the context.     

Self-deception does not explain high-risk sexual behavior in the face of HIV/AIDS: A test from northern Kenya

Throughout sub-Saharan Africa, there is resistance to changing sexual behavior despite survey data indicating high levels of knowledge about HIV transmission patterns and high-risk behavior. Previous explanations for this paradox emphasize indigenous cultural models. An alternative explanation is that, due to a strong natural selection for sexual gratification, individuals evoke the evolved trait of self-deception to continue practicing high-risk sexual behavior. This alternative is tested using survey data from an Ariaal community in Marsabit District, northern Kenya. Results indicate that respondents make highly accurate self-assessments of HIV risk, negating the concept of self-deception in this study. These results are discussed within the larger context of the applicability of evolutionary theory to the AIDS pandemic.     

Investigating detection success: lessons from trials using decoy rare plants

Imperfect detection leads to underestimates of species presence and decreases the reliability of survey data. Imperfect detection has not been examined in detail for boreal forest understory plants, despite widespread use of surveys for rare plants prior to development. We addressed this issue using detectability trials conducted in Alberta, Canada with decoy vascular plants. Volunteer observers searched in survey plots for species while unaware of their true presence or abundance. Our findings indicate that the detection of cryptic species is very low when abundance is low (0–35%) and plot size is large (<?50% in?≥?100 m²). Plant density (individuals per unit area) was the most important determinant of detection probability, where more abundant species were detected more often and with less survey effort. When abundance was held constant, diffusely arranged species were twice as likely to be detected compared to those in clumps. Detection of cryptic species can be low even when individuals are flowering, and even morphologically distinct species can go unnoticed in small plots. We suggest that future decoy trials investigate search strategies that could improve detection and that field surveys for vascular plants address imperfect detection through careful consideration of plot size, characteristics of the target species, and survey effort, both in terms of time expenditure within an area and the number of observers employed.     

Cortical processing and perceived timing

As of yet, it is unclear how we determine relative perceived timing. One controversial suggestion is that timing perception might be related to when analyses are completed in the cortex of the brain. An alternate proposal suggests that perceived timing is instead related to the point in time at which cortical analyses commence. Accordingly, timing illusions should not occur owing to cortical analyses, but they could occur if there were differential delays between signals reaching cortex. Resolution of this controversy therefore requires that the contributions of cortical processing be isolated from the influence of subcortical activity. Here, we have done this by using binocular disparity changes, which are known to be detected via analyses that originate in cortex. We find that observers require longer stimulus exposures to detect small, relative to larger, disparity changes; observers are slower to react to smaller disparity changes and observers misperceive smaller disparity changes as being perceptually delayed. Interestingly, disparity magnitude influenced perceived timing more dramatically than it did stimulus change detection. Our data therefore suggest that perceived timing is both influenced by cortical processing and is shaped by sensory analyses subsequent to those that are minimally necessary for stimulus change perception.     

Paranoia,self-deception and overconfidence

Self-deception, paranoia, and overconfidence involve misbeliefs about the self, others, and world. They are often considered mistaken. Here we explore whether they might be adaptive, and further, whether they might be explicable in Bayesian terms. We administered a difficult perceptual judgment task with and without social influence (suggestions from a cooperating or competing partner). Crucially, the social influence was uninformative. We found that participants heeded the suggestions most under the most uncertain conditions and that they did so with high confidence, particularly if they were more paranoid. Model fitting to participant behavior revealed that their prior beliefs changed depending on whether the partner was a collaborator or competitor, however, those beliefs did not differ as a function of paranoia. Instead, paranoia, self-deception, and overconfidence were associated with participants’ perceived instability of their own performance. These data are consistent with the idea that self-deception, paranoia, and overconfidence flourish under uncertainty, and have their roots in low self-esteem, rather than excessive social concern. The model suggests that spurious beliefs can have value–self-deception is irrational yet can facilitate optimal behavior. This occurs even at the expense of monetary rewards, perhaps explaining why self-deception and paranoia contribute to costly decisions which can spark financial crashes and devastating wars.     

Zoos through the Lens of the IUCN Red List: A Global Metapopulation Approach to Support Conservation Breeding Programs

Given current extinction trends, the number of species requiring conservation breeding programs (CBPs) is likely to increase dramatically. To inform CBP policies for threatened terrestrial vertebrates, we evaluated the number and representation of threatened vertebrate species on the IUCN Red List held in the ISIS zoo network and estimated the complexity of their management as metapopulations. Our results show that 695 of the 3,955 (23%) terrestrial vertebrate species in ISIS zoos are threatened. Only two of the 59 taxonomic orders show a higher proportion of threatened species in ISIS zoos than would be expected if species were selected at random. In addition, for most taxa, the management of a zoo metapopulation of more than 250 individuals will require the coordination of a cluster of 11 to 24 ISIS zoos within a radius of 2,000 km. Thus, in the zoo network, the representation of species that may require CBPs is currently low and the spatial distribution of these zoo populations makes management difficult. Although the zoo community may have the will and the logistical potential to contribute to conservation actions, including CBPs, to do so will require greater collaboration between zoos and other institutions, alongside the development of international agreements that facilitate cross-border movement of zoo animals. To maximize the effectiveness of integrated conservation actions that include CBPs, it is fundamental that the non-zoo conservation community acknowledges and integrates the expertise and facilities of zoos where it can be helpful.     

Testing the importance of auditory detections in avian point counts

ABSTRACT.   Recent advances in the methods used to estimate detection probability during point counts suggest that the detection process is shaped by the types of cues available to observers. For example, models of the detection process based on distance-sampling or time-of-detection methods may yield different results for auditory versus visual cues because of differences in the factors that affect the transmission of these cues from a bird to an observer or differences in an observer's ability to localize cues. Previous studies suggest that auditory detections predominate in forested habitats, but it is not clear how often observers hear birds prior to detecting them visually. We hypothesized that auditory cues might be even more important than previously reported, so we conducted an experiment in a forested habitat in North Carolina that allowed us to better separate auditory and visual detections. Three teams of three observers each performed simultaneous 3-min unlimited-radius point counts at 30 points in a mixed-hardwood forest. One team member could see, but not hear birds, one could hear, but not see, and the third was nonhandicapped. Of the total number of birds detected, 2.9% were detected by deafened observers, 75.1% by blinded observers, and 78.2% by nonhandicapped observers. Detections by blinded and nonhandicapped observers were the same only 54% of the time. Our results suggest that the detection of birds in forest habitats is almost entirely by auditory cues. Because many factors affect the probability that observers will detect auditory cues, the accuracy and precision of avian point count estimates are likely lower than assumed by most field ornithologists.     

Morphological differences between extranidal and intranidal workers in the ant Temnothorax rugatulus,but no effect of body size on foraging distance

Most ant genera are thought to have monomorphic workers, indicating perhaps a high degree of flexibility in task allocation, and the well-studied genus Temnothorax is an example of this. However, considerable size variation may exist between individuals. In addition, though workers can show flexible behavior, it has been shown that individuals may consistently differ in their task profiles. Here we test whether body size variation among workers affects foraging behavior. Two main hypotheses were tested: first, whether larger ants forage at greater distance from the nest, and second, whether larger individuals show a higher propensity to work outside of the nest. Our results showed that ant body size does not significantly affect foraging distance. However, larger ants were more likely to be found outside the nest. Though Temnothorax ants are a common model system, this is the first study demonstrating task allocation based on body size, which is fixed in adults. Our study suggests that particularly small species may have to be examined carefully for body size variation before concluding that body size is uniform and therefore irrelevant for task allocation.     

Reconstructing pedigrees: a stochastic perspective

A pedigree is a directed graph that describes how individuals are related through ancestry in a sexually-reproducing population. In this paper we explore the question of whether one can reconstruct a pedigree by just observing sequence data for present day individuals. This is motivated by the increasing availability of genomic sequences, but in this paper we take a more theoretical approach and consider what models of sequence evolution might allow pedigree reconstruction (given sufficiently long sequences). Our results complement recent work that showed that pedigree reconstruction may be fundamentally impossible if one uses just the degrees of relatedness between different extant individuals. We find that for certain stochastic processes, pedigrees can be recovered up to isomorphism from sufficiently long sequences.     

Individual‐ and population‐level personalities in a floriphilic katydid

Behaviour, including personality, informs us about the response of animals towards their changing environment. Despite the widespread occurrence of florivorous insects and the important but often underrated ecological roles that they play, the study of florivore behaviour is neglected relative to that of pollinators and other herbivores. Specifically, we do not know how different personality types can develop among florivores and enable them to persist in habitats with an ephemeral and dynamic availability of food resources. To address this knowledge gap, we investigated the following questions: whether the (a) inter‐individual differences of exploration and boldness are consistent; (b) inter‐population differences of exploration and boldness are consistent; (c) exploration and boldness are correlated. We collected individuals of the polyphagous floriphilic katydid, Phaneroptera brevis from four populations from wasteland sites in Singapore and performed a personality assay conducted in an insectary to investigate the exploratory and boldness levels of the individuals and populations. The major novel finding was that the floriphilic P. brevis katydids exhibit population‐level personality types for boldness, but not for exploration. Some katydid individuals were consistently more exploratory and bolder than other individuals. However, contrary to our predictions, we did not find any evidence of behavioural syndromes in the katydid individuals, as the boldness level for individuals was not significantly correlated with exploration for individuals. This suggests that an individual which is more exploratory may not be equally keen to take risks and consume novel food that it encounters. Our findings also suggest that boldness and exploration are linked to ecologically important behaviours, but more studies are needed to better understand population‐level personality and how and why natural selection may favour the evolution of personality in certain populations.     

Effect of observer experience on the monitoring of a mouflon population

Analysis of changes in population size can be severely biased when factors related to the acquisition of data, such as differences between observer experience and changes through time in the ability of individual observers to detect animals, are not controlled for. We analysed the effect of observer qualification on the number of groups and individuals observed during two census days of a mouflonOvis gmelini musimon xOvis sp. population. The difference between professional wildlife biologists and volunteers was strong during the census day one (87 groups and 410 mouflons vs 55 and 249 by experienced observers and volunteers, respectively) but decreased significantly on the second day for the number of animals detected (390 vs 292 mouflons by experienced observers and volunteers, respectively). Our result indicates that additional training will enhance reliability of data obtained from volunteers. Given the effect of observer qualification on performance during the census, we recommend to use observers of similar and adequate qualification in population counts.     

A test for linkage and association in general pedigrees: the pedigree disequilibrium test

Family-based tests of linkage disequilibrium typically are based on nuclear-family data including affected individuals and their parents or their unaffected siblings. A limitation of such tests is that they generally are not valid tests of association when data from related nuclear families from larger pedigrees are used. Standard methods require selection of a single nuclear family from any extended pedigrees when testing for linkage disequilibrium. Often data are available for larger pedigrees, and it would be desirable to have a valid test of linkage disequilibrium that can use all potentially informative data. In this study, we present the pedigree disequilibrium test (PDT) for analysis of linkage disequilibrium in general pedigrees. The PDT can use data from related nuclear families from extended pedigrees and is valid even when there is population substructure. Using computer simulations, we demonstrated validity of the test when the asymptotic distribution is used to assess the significance, and examined statistical power. Power simulations demonstrate that, when extended pedigree data are available, substantial gains in power can be attained by use of the PDT rather than existing methods that use only a subset of the data. Furthermore, the PDT remains more powerful even when there is misclassification of unaffected individuals. Our simulations suggest that there may be advantages to using the PDT even if the data consist of independent families without extended family information. Thus, the PDT provides a general test of linkage disequilibrium that can be widely applied to different data structures.     

Sampling bias in the determination of first and last occurrences

Background: Past studies of first and last occurrence dates of phenological events have revealed close associations with climatic parameters. Consequently, it is widely acknowledged that recent shifts in the beginning, duration or ending of such events are a response to present climate change. In addition, in recent times, there have tended to be many more observers than in earlier times, especially in urban areas. Furthermore, the number of individuals (plants or animals) observed has often changed markedly. In many situations it is not possible to obtain the average first or last occurrence date of a group of individuals, and only the most extreme occurrence is recorded. This common observational difficulty leads to sampling bias that needs to be taken into account.

Aim: Our aim is to use statistical models to quantify the sampling bias and its dependence on sample size and the variability and correlation amongst the individuals under consideration.

Methods: n-dimensional multivariate normal distribution and two-way fixed-effects analysis of variance models were developed to examine the dependence of the sampling bias on the above factors. Our results are compared with real data.

Results: For first and last occurrence observations, which are the most common index in many phenological studies, we found that changes in observational practice and sample size can, in certain circumstances, easily produce changes in bias that can swamp (or indeed reverse) any climatic change effects.

Conclusions: Our new, realistic statistical models allow the sampling bias to be quantified and calculated in terms of the number of individuals under observation, their variability and the degree of correlation between individuals.     

Observations on the Behavior of Rain Forest Peccaries in Perú: Why do White-lipped Peccaries Form Herds?

The ecology and behavior of Tayassu tajacu and T. pecari were studied for a total period of 16 months in the years 1975–1978 in the Manú National Park in southeastern Perú. It appears from 132 sightings of T. tajacu at the study site, and from reports from other regions, that groups of this species in rain forest usually contain fewer than 12 individuals. The more observers were at the study site, the more frequently this species was encountered. T. tajacu also repeatedly used wallows in the forest. These observations suggested that individuals of this species were relatively sedentary. Herds of T. pecari were encountered on 60 occasions. Five counts indicated that there were over 100 individuals in the herds. This species was encountered at practically random intervals, independent of number of observers at the site, but more frequently in the dry season than in the rainy season. Adults of both species are prey primarily of large cats and humans. Both species feed on green plant parts, fruits, nuts and seeds, but T. pecari feeds on more resistant seeds and nuts than T. tajacu. The hardest palm nuts that only T. pecari can consume are distributed in a patchy manner. Cracking these nuts between the teeth causes the animals to be heard more than 50 m away. The patchy distribution of the hard nuts and seeds prevents T. pecari from being sedentary, and group formation likely has several individual benefits for foraging efficiency and defense against predators. These may include (1) avoidance of searching for food in places recently visited by others, (2) benefitting from the knowledge of experienced foragers, (3) reducing the per capita probability of detection by predators, (4) reducing the probability of being captured after group detection by predators, (5) increasing the ability to counterattack as a group, (6) increasing the probability of detecting the predator before it can attack, and (7) “confusing” the predator through escape behavior. T. tajacu seems to live in small groups because its typical foods are distributed more evenly and because consumption of these foods does not cause individuals to be so noticeable to predators.