Evidence from pyrosequencing indicates that natural variation in animal personality is associated with DRD4 DNA methylation
Verhulst, Eveline C. ; Mateman, A.C. ; Zwier, Mathijs V. ; Caro, Samuel P. ; Verhoeven, Koen J.F. ; Oers, Kees Van - \ 2016
Molecular Ecology 25 (2016)8. - ISSN 0962-1083 - p. 1801 - 1811.
behaviour - birds - DNA methylation - epigenetics - personality
Personality traits are heritable and respond to natural selection, but are at the same time influenced by the ontogenetic environment. Epigenetic effects, such as DNA methylation, have been proposed as a key mechanism to control personality variation. However, to date little is known about the contribution of epigenetic effects to natural variation in behaviour. Here, we show that great tit (Parus major) lines artificially selected for divergent exploratory behaviour for four generations differ in their DNA methylation levels at the dopamine receptor D4 (DRD4) gene. This D4 receptor is statistically associated with personality traits in both humans and nonhuman animals, including the great tit. Previous work in this songbird failed to detect functional genetic polymorphisms within DRD4 that could account for the gene-trait association. However, our observation supports the idea that DRD4 is functionally involved in exploratory behaviour but that its effects are mediated by DNA methylation. While the exact mechanism underlying the transgenerational consistency of DRD4 methylation remains to be elucidated, this study shows that epigenetic mechanisms are involved in shaping natural variation in personality traits. We outline how this first finding provides a basis for investigating the epigenetic contribution to personality traits in natural systems and its subsequent role for understanding the ecology and evolution of behavioural consistency.
To tweet or not to tweet : the role of personality in the social networks of great tits : the role of personality in the social networks of great tits
Snijders, L. - \ 2016
Wageningen University. Promotor(en): Marc Naguib, co-promotor(en): Kees van Oers. - Wageningen : Wageningen University - ISBN 9789462576940 - 237
cum laude - parus major - personality - communication between animals - social structure - vocalization - bird song - social behaviour - animal behaviour - behavioural biology - parus major - persoonlijkheid - communicatie tussen dieren - sociale structuur - vocalisatie - vogelzang - sociaal gedrag - diergedrag - gedragsbiologie
To tweet or not to tweet: The role of personality in the social networks of great tits
Project video: https://www.youtube.com/watch?v=zy0HysxhQz0
When mentioning social networks it is easy to think of online networks for people, such as Facebook and Twitter. But many animals also have social networks. In proximity networks they encounter each other physically and in communication networks they connect to each other by using signals. Their position in such social networks is important. It can influence the likelihood of finding new food, acquiring novel foraging techniques, rising in social status and acquiring a mate. However, having many contacts can also be risky as it increases the likelihood of encountering infectious diseases, social stress or ending up in a fight.
An ideal model to study this hypothesis is the great tit. A common garden bird. There are well established methods to quantify personality differences in great tits and with the newest tracking technologies we can now also monitor their face-tot-face contacts. What makes the great tit even more interesting is that they like to breed in nest boxes and so we can also study potential fitness effects of specific network positions. Additionally, great tits are songbirds, which makes them also ideal to answer a second question: Do individuals that are shy to approach others, use communication instead? Since communication is often a less risky connection strategy than face-to-face contact.
In this PhD thesis I reveal how and when personality explains why some birds are better connected than others. In wild territorial populations pro-active males were better connected to other males and were most likely to approach a rival. In contrast, when removing the risk of fights during male-to-male spatial associations, via a video-playback experiment in captivity, the re-active males appeared to be most social. When confronted with the life-size video image of a novel conspecific, they spent the most time associating with it. When lowering the risks associated with spatial associations the social preferences of re-active individuals might thus increase. No relationship was found between social network position in the wild and reproductive success, an important fitness component.
Data from: Evidence from pyrosequencing indicates that natural variation in animal personality is associated with DRD4 DNA methylation
Verhulst, E.C. ; Mateman, A.C. ; Zwier, Mathijs V. ; Caro, Samuel P. ; Verhoeven, K.J.F. ; Oers, Kees van - \ 2015
Wageningen University & Research
epigenetics - behaviour - personality - DNA methylation - birds
Contain all the individual methylation levels per CpG position for assays A-D. Each tab ($data_$assay_$tissuetype) contains the results from one pyrosequence run and one type of tissue (blood or brain). The columns indicate: SampleID: bird sample Note: EEB score, F is Fast exploring, S is Slow exploring Pos. 1 Meth%: Methylation percentage for CpG position 1 in assayB Pos. 2 Meth%: Methylation percentage for CpG position 2 in assayB Etc. Cell colours indicate quality scores In green: highly reliable methylation scores In yellow: reliable methylation scores In pink: unreliable methylation scores (not used in downstream analyses) SampleID with *_replicate indicates that the DNA sample with this number was used in duplo on this plate for within assay analysis.
Effects of co-creation claim on consumer brand perceptions and behavioural intentions
Dijk, J. van; Antonides, G. ; Schillewaert, N. - \ 2014
International Journal of Consumer Studies 38 (2014)1. - ISSN 1470-6423 - p. 110 - 118.
product development - users - personality - performance - familiarity - innovation - agents - model
Increasingly often, companies co-create' with consumers in open innovation practices to develop new products more effectively. Little is known about how co-creation affects consumer brand perceptions in the mass market. We hypothesize that co-creative brands - as opposed to non-co-creative brands - are perceived as more authentic and sincere, and are associated with relatively positive behavioural intentions. A between-subjects experiment was conducted to test these hypotheses in an online panel of consumers who did not take part in co-creation. The experiment had a 3 (control vs. co-creation vs. co-creation supported with some visual proof)x2 (well-known existing brand vs. fictitious brand) design. Quantitative data analyses (n=530) confirmed that for both brands, co-creation affects brand personality perceptions directly and behavioural intentions indirectly. This study shows that co-creating with consumers can be a strategic method to positively influence product perceptions and behavioural intentions.
Determinants of maternal fetal attachment in women from a community-based sample
Maas, A.J.B.M. ; Vreeswijk, C.M.J.M. ; Braeken, J. ; Vingerhoets, A.J.J.M. ; Bakel, H.J.A. van - \ 2014
Journal of Reproductive and Infant Psychology 32 (2014)1. - ISSN 0264-6838 - p. 5 - 24.
prenatal attachment - antenatal attachment - child characteristics - personality - pregnancy - representations - temperament - variables - validity - behavior
BackgroundMaternal fetal attachment (MFA) has been found to be an important predictor for the developing relationship between mother and child. During the last decades, research on determinants of MFA has yielded inconclusive and even contradictory results. Until now, a process model in which multiple determinants of MFA are studied concurrently has been lacking. The present study evaluates a process model (based on Belsky's model of parenting) in which the specific contributions of parental, contextual, and expected child characteristics to MFA were examined.MethodsParticipants, 351 pregnant women from a community-based sample, completed questionnaires concerning their personality, attachment security, partner support, perceived stress, expected child temperament, and MFA at 26 weeks gestational age. Based on Belsky's model, a set of competing structural equation models were formulated and evaluated with path analysis.ResultsMFA was found to be multiply determined by parental, contextual, and expected child characteristics. These factors explained 19% of the variance in MFA. Pregnant women who were more extrovert, conscientious and agreeable reported having higher levels of MFA. In contrast, those women who perceived more stress and expected having an infant with a dull temperament reported lower levels of MFA.ConclusionThis study demonstrated that the theoretical framework of Belsky's model is applicable for explaining variations in the quality of the mother-fetus relationship in the pregnancy period. More knowledge of the determinants of MFA could help to identify mothers at risk for developing suboptimal feelings of attachment.
Social Information use by Barnacle Geese Branta leucopsis, an Experiment Revisited
Kurvers, R.H.J.M. ; Straates, K. ; Ydenberg, R.C. ; Wieren, S.E. van; Swierstra, P.S. ; Prins, H.H.T. - \ 2014
Ardea 102 (2014)2. - ISSN 0373-2266 - p. 173 - 180.
public information - brent geese - goose flocks - group-size - food quality - bernicla - personality - vigilance - selection - patch
Reproducing research results is one of the cornerstones of science. However, few biological findings are actually replicated. Here, we repeat a study done more than 35 years ago on social information use in Barnacle Geese. In the original study, models of Barnacle Geese were used to measure how they attracted wild Barnacle Geese (Drent & Swierstra 1977). Models were placed in different locations in a pasture and these models attracted many wild Barnacle Geese, providing strong evidence for the use of social information. 37 years later we repeated this experiment, using the same models, the same area and a similar research protocol. Despite an abundance of wild Barnacle Geese in the area frequently flying over the models, the models did not elicit a landing response. In line with the original study, we scored vigilance rates and abundance of geese. Comparing these data to previous records we found that total abundance increased but that vigilance rates were lower than previously recorded. The decreased vigilance suggests that the landscape has become safer or that competition between geese has intensified; both could explain a reduced use of social information. More generally, our study shows the importance of repeating experiments in ecology, especially in a rapidly changing world.
Kippen zijn soms haantjes
Lokhorst, Kees ; Rodenburg, Bas - \ 2014
personality - animal behaviour - poultry - dairy cattle - animal welfare - sensors - precision agriculture - animal production
Fear responses to novelty in testing environments are related to day-to-day activity in the home environment in dairy cattle
MacKay, J.R.D. ; Haskell, M.J. ; Deag, J.M. ; Reenen, C.G. van - \ 2014
Applied Animal Behaviour Science 152 (2014). - ISSN 0168-1591 - p. 7 - 16.
individual-differences - beef-cattle - behavior - cows - humans - personality - animals - consistency - situations - boldness
Behavioural tests for cattle take time to perform and can be stressful for the animals but are currently the only way of assessing behavioural reactions to fear-causing stimuli in a standardised manner. It may be possible to use behavioural data collected remotely in the home pen environment through the use of activity monitors and robotic milkers to identify fearful cattle without testing. In this study eighty five dairy cows were given a novel arena novel object (NANO) test and 79 of these were also human approach (HAP) tested, both thought to reflect fear. All animals had their activity recorded for 40 days prior to the testing period using a tri-axial accelerometer activity monitor. High numbers of novel object contacts in the test was associated with younger animals with fewer lying bouts per day and were less variable in their lying bout duration (Radj2=0.13, F 3,75 = 4.65, P = 0.005). Cows with a higher tolerance for human approach had fewer lying bouts per day, a shorter average standing bout duration and presented themselves to the robot milker more often (Radj2=0.08, F 3,69 = 3.12, P = 0.032). Personality traits constructed from a principle components analysis of the observed NANO behaviours were also associated with home pen activity. Cows which scored highly on the first component termed ‘neophobia’ were older, had more lying bouts and a greater variation in the duration of their average lying bout (Radj2=0.15, F 3,75 = 5.32, P = 0.002) while cows which scored highly on the second component termed ‘boldness’ were older cows with less variation in their average lying bout duration (Radj2=0.11, F2,75 = 5.63, P = 0.005). To conclude, significant relationships exist between behaviours in short-term personality tests and home pen activity recorded over several weeks. As fearfulness is reflected in spontaneous home pen behaviours, activity databases could be incorporated into models predicting fearfulness and welfare assessment protocols.
Analysing and promoting entrepreneurship in Iranian higher education : entrepreneurial attitudes, intentions and opportunity identification
Karimi, S. - \ 2014
Wageningen University. Promotor(en): Martin Mulder, co-promotor(en): Harm Biemans; Thomas Lans. - Wageningen : Wageningen University - ISBN 9789461738455 - 272
ondernemerschap - onderwijs - hoger onderwijs - studenten - attitudes - psychologie - menselijk gedrag - besluitvorming - culturele waarden - geslacht (gender) - persoonlijkheid - individuele kenmerken - iran - entrepreneurship - education - higher education - students - attitudes - psychology - human behaviour - decision making - cultural values - gender - personality - individual characteristics - iran
Given the positive influences of entrepreneurship in tems of increasing economic growth and creating jobs, considerable efforts have been made to promote entrepreneurship in both developed and developing countries. Scholars and policymakers are also increasingly interested in the factors which influence the decision to become an entrepreneur and thus understanding why some people decide to start a business while others do not. The research reported in this dissertation therefore explored the factors which influence the entrepreneurial intentions of students in higher education in the developing country of Iran.
A weak sense of coherence is associated with a higher mortality risk
Super, S. ; Verschuren, W.M.M. ; Zantinge, E.M. ; Wagemakers, M.A.E. ; Picavet, H.S.J. - \ 2014
Journal of Epidemiology and Community Health 68 (2014). - ISSN 0143-005X - p. 411 - 417.
all-cause mortality - antonovskys sense - depressive symptoms - prospective cohort - oral-health - scale - disease - time - personality - population
Background Sense of coherence (SOC) is a health-promoting resource within the salutogenic theory that reflects an individual's coping ability. The association between SOC and mental health has been confirmed, but its association with mortality is less clear. We examined the association between SOC and all-cause mortality in an adult Dutch population.
Naar coaching op maat : project ‘Persoonlijkheidskenmerken en competentieontwikkeling van leerlingen’
Biemans, H.J.A. ; Gulikers, J.T.M. ; Oonk, C. ; Wel, M. van der; Leereveld, G. ; Frijters, S. ; Born, T. van den - \ 2013
In: Op weg naar leerwinst : WURKS- 1 onderzoeksprogramma 2011-2013 : competenties voor het groene kennissysteem – deel I / Biemans, H., Wageningen : Wageningen Universiteit en Researchcentrum, Leerstoelgroep Educatie- en competentiestudies - ISBN 9789461737090 - p. 6 - 7.
agrarisch onderwijs - vaardigheidsonderwijs - vaardigheden - persoonlijkheid - leerlingen - coachen - persoonlijke ontwikkeling - docenten - agricultural education - competency based education - skills - personality - pupils - coaching - personal development - teachers
Welke relaties bestaan er tussen persoonlijkheidskenmerken van leerlingen en de mate van ontwikkeling van bepaalde competenties die relevant zijn voor hun opleiding? En hoe kunnen docenten hier bij de coaching van leerlingen rekening mee houden? Dit project wil een stap zetten naar coaching op maat.
Antecedents of self identity and consequences for action control: An application of the theory of planned behaviour in the exercise domain
Bruijn, G.J. de; Verkooijen, K.T. ; Putte, B. van den; Vries, N.K. de - \ 2012
Psychology of Sports and Exercise 13 (2012)6. - ISSN 1469-0292 - p. 771 - 778.
vigorous physical-activity - continuation intentions - metaanalysis - salience - efficacy - identification - maintenance - personality - integration - validation
Objectives: To study whether exercise action control profiles should be usefully extended to include exercise identity. Further, this study investigated theory of planned behaviour antecedents of exercise identity. Design: Prospective data from 413 undergraduate students (M age ¼ 21.4; 73.5% females). Method: Validated questionnaires were used at baseline and follow-up two weeks later to assess exercise behaviour, intention, self-identity, and theory of planned behaviour concepts. Research questions were analysed using chi-square analysis, discriminant function analysis and structural equation modelling. Results were interpreted using p-values and effect sizes. Results: There was a higher proportion of exercise intenders in the strong exercise identity group than in the weak exercise identity group (81.9% vs. 14.5%) and a higher proportion of successful intenders in the high exercise identity group than in the low exercise identity group (45.5% vs. 18.2%). Affective attitude and perceived behavioural control (PBC) were the most important predictors of exercise action control. Regarding the antecedents of identity, results showed significant and small-sized associations for baseline affective attitude and perceived behavioural control and large-sized association for baseline self-identity. Conclusion: Exercise identity should be usefully employed to understand exercise motivation and action control. Affective attitude and perceived behavioural control facilitate action control and exercise identity development and are suggested to be taken into account when developing exercise interventions.
Boldness affects foraging decisions in barnacle geese: an experimental approach
Kurvers, R.H.J.M. ; Nolet, B.A. ; Prins, H.H.T. ; Ydenberg, R.C. ; Oers, K. van - \ 2012
Behavioral Ecology 23 (2012)6. - ISSN 1045-2249 - p. 1155 - 1161.
social-context - body-size - herbivorous anatidae - branta-leucopsis - anser-indicus - zebra finches - goose flocks - personality - leadership - behavior
Individuals foraging in groups constantly need to make decisions, such as when to leave a group, when to join a group, and when to move collectively to another feeding site. In recent years, it has become evident that personality may affect these foraging decisions, but studies where individuals are experimentally forced into different roles are still absent. Here, we forced individual barnacle geese, Branta leucopsis, differing in boldness scores, either in a joining or in a leaving role in a feeding context. We placed a food patch at the far end of a test arena and measured the arrival latency and number of visits of individuals to the patch either in the presence of a companion that was confined near the food patch (“joining context”) or in the presence of a companion that was confined away from the food patch (“leaving context”). We also ran trials without a companion (“nonsocial context”). Bolder individuals arrived more quickly than shyer individuals in the “leaving” context, but there was no effect of boldness in the “joining” context, suggesting that boldness differences are important in explaining variation in leaving behavior but not in joining behavior. The difference in arrival latency between the “joining” and non-social context increased with decreasing boldness score, suggesting that shyer individuals are more responsive to the presence of other individuals (i.e., social facilitation). These results indicate that individual differences in boldness play a role in patch choice decisions of group-living animals, such as when to leave a flock and when to join others at a patch.
Diereigen : typologische indeling van landbouwhuisdieren voor de diagnostiek van dierenwelzijn en diergezondheid, houderij en productie
Verwer, C.M. - \ 2011
Driebergen : Louis Bolk Instituut - 36 p.
dierhouderij - biologische landbouw - diergezondheid - dierenwelzijn - persoonlijkheid - filosofie - geiten - veehouderij - dierlijke productie - animal husbandry - organic farming - animal health - animal welfare - personality - philosophy - goats - livestock farming - animal production
Welzijn en gezondheid zijn belangrijke praktische begrippen waarvan het van groot belang is dat de veehouder zelf in staat is de mate van welzijn en gezondheid van zijn veestapel te beoordelen en waar nodig bij te sturen. Dit rapport beschrijft een concept voor een nieuwe werkwijze waarin wordt nagestreefd de bedrijfsvoering meer vanuit het dier zelf te benaderen en in te vullen. Kenmerken van het dier zoals constitutie en gedrag, maar ook fysiologische parameters en de geestelijke gesteldheid van het dier worden in dit concept meegenomen. Het project ‘weerstand geiten’ wordt als voorbeeld gebruikt om de toepassing van de nieuwe werkwijze te illustreren.
Personality in a group living species : social information, collective movements and social decision-making
Kurvers, R.H.J.M. - \ 2011
Wageningen University. Promotor(en): Herbert Prins; Ron Ydenberg, co-promotor(en): Sip van Wieren. - [S.l.] : S.n. - ISBN 9789085859840 - 132
ganzen - branta - persoonlijkheid - besluitvorming - diergedrag - foerageren - geese - branta - personality - decision making - animal behaviour - foraging
Animals need to make constant decisions throughout their lives and to make optimal decisions individuals rely on information. Information can be obtained in two distinct ways: personal or social information. The current paradigm in the information theory use in animal ecology assumes that the decision between using either personal or social information is entirely flexible and context dependent. However, the potential link between variation in personality and information use has received little attention. In this thesis I studied the effect of personality on the use of personal and social information in barnacle geese. I show that individual barnacle geese differ consistently in boldness and that boldness affects the type of information individuals use in various different contexts: In a maze solving task, a producer scrounger game and a public information experiment I found that bold individuals use less social information compared to shy individuals, providing strong evidence that the type of information individuals prefer to use depends on their boldness level. To study the ultimate causes of variation in boldness and the relationship between boldness and social information use I used an experimental and theoretical approach. In a producer scrounger experiment I tested whether the rare personality type outperformed the common personality type which could lead by means of negative frequency dependent selection to the maintenance of variation in boldness. Parallel to that I used a genetic algorithms approach to study the co-evolution of boldness and foraging tactic use in a producer scrounger game. The experimental results as well as the genetic algorithms provided no evidence for a role of negative frequency dependent selection for the maintenance of variation in boldness. Rather, our simulations suggest that differences in selection pressures in space or time (i.e., fluctuating environments) in a social foraging game may cause variation in boldness levels between populations. In our simulations bold individuals evolved to play both producer and scrounger, whereas shy individuals remained confined to scrounging, suggesting that shy individuals have difficulties when they have to collect personal information and that this might be the explanation for the increased tendency of shy individuals to use social information. I experimentally confirmed these model predictions in an experiment in which I forced individuals in either a producer or a scrounger role. Therefore, I argue that the value of social information is higher for shy individuals as compared to bold individuals since it is more costly for shy individuals to collect personal information. This thesis challenges the current paradigm that the decision between using either personal or social information is entirely context dependent. Rather, I provide evidence that personality affects the trade off between using personal and social information.
The effect of boldness on decision-making in barnacle geese is group-size-dependent
Kurvers, R.H.J.M. ; Adamczyk, M.A.P. ; Wieren, S.E. van; Prins, H.H.T. - \ 2011
Proceedings of the Royal Society. B: Biological Sciences 278 (2011)1714. - ISSN 0962-8452 - p. 2018 - 2024.
social information - 3-spined sticklebacks - influence leadership - zebra finches - personality - behavior - exploration - context - fish - organization
In group-living species, decisions made by individuals may result in collective behaviours. A central question in understanding collective behaviours is how individual variation in phenotype affects collective behaviours. However, how the personality of individuals affects collective decisions in groups remains poorly understood. Here, we investigated the role of boldness on the decision-making process in different-sized groups of barnacle geese. Naive barnacle geese, differing in boldness score, were introduced in a labyrinth in groups with either one or three informed demonstrators. The demonstrators possessed information about the route through the labyrinth. In pairs, the probability of choosing a route prior to the informed demonstrator increased with increasing boldness score: bolder individuals decided more often for themselves where to go compared with shyer individuals, whereas shyer individuals waited more often for the demonstrators to decide and followed this information. In groups of four individuals, however, there was no effect of boldness on decision-making, suggesting that individual differences were less important with increasing group size. Our experimental results show that personality is important in collective decisions in pairs of barnacle geese, and suggest that bolder individuals have a greater influence over the outcome of decisions in groups.
Self-awareness of mastery and improvability of entrepreneurial competence in small businesses in the agrifood sector
Lans, T. ; Biemans, H.J.A. ; Mulder, M. ; Verstegen, J.A.A.M. - \ 2010
Human Resource Development Quarterly 21 (2010)2. - ISSN 1044-8004 - p. 147 - 168.
opportunity identification - other agreement - management - performance - congruence - recognition - personality - efficacy - feedback - owners
An important assumption of entrepreneurial competence is that (at least part of) it can be learned and developed. However, human resources development (HRD) practices aimed at further strengthening and developing small-business owner–managers' entrepreneurial competence are complex and underdeveloped. A multisource assessment of owner–managers' entrepreneurial competence in a well-defined sector was conducted to provide an answer to the research question: How do self-assessments about mastery and improvability of entrepreneurial competence made by owner–managers relate to the same assessments made by significant others in the small-business work environment? The data show that owner–managers rate their own mastery of entrepreneurial competence significantly lower than internal assessors in their work environment do. Furthermore, the assessors indicate many possible areas for improvement of owner–managers' entrepreneurial competence. Nonetheless, mastery and improvability patterns differ considerably between the assessors. Multisource assessments as adopted in this study can help owner–managers raise their self-awareness, and consequently help them bypass some of their often costly trial-and-error learning.
Evaluation of behaviour testing for human directed aggression in dogs
Borg, J.A.M. van der; Beerda, B. ; Ooms, M. ; Silveira de Souza, A. ; Hagen, M. ; Kemp, B. - \ 2010
Applied Animal Behaviour Science 128 (2010)1-4. - ISSN 0168-1591 - p. 78 - 90.
temperament - personality - traits
Behaviour test batteries are used to identify aggressive dogs. The Dutch Socially Acceptable Behaviour (SAB)-test has been used since 2001 to select against unwanted aggression and fear in specific dog breeds, though much is unknown yet regarding its reliability, validity and feasibility. In this paper the SAB-test is evaluated and the results describe its usefulness for identifying aggression towards humans in dogs. Behaviour test outcomes on 345 dogs (479 records on tests performed indoor and outdoor) scored by the judges of the Dutch Kennel Club were compared to owner reported assessments of their dogs’ behaviour prior to testing. Dogs were labelled aggressive when having bitten a human at least once according to the owner and were diagnosed by the judges as such when attacking at least once during the SAB-test. Aggressive dogs showed significantly more attacks than non-aggressive controls and a Principal Components Analysis of detailed observations on 76 dogs grouped aggressive behaviours like growl, bare teeth, snap, lunge and bite in one dimension, confirming the test's validity. Analysis of 479 test records revealed a sensitivity, specificity and accuracy of 0.33, 0.81 and 0.64, respectively. The specificity could be increased to 0.93 by raising the threshold for positive test results to at least 2 attacks during the test. The low sensitivity is explained by the decision to classify dogs as aggressive on the basis of one bite incident only and by a relative weak capacity of the test to detect specific forms of aggression. The reliability of the test was investigated by comparing test outcomes on 133 dogs when tested indoor and outdoor. The accuracy decreased from 0.67 to 0.62, but overall the indoor test outcomes were similar to those found outdoors. Scores for aggression and anxiety were significantly higher when dogs were tested for the first time in the morning than the second time in the afternoon, suggesting desensitization. Salivary cortisol concentrations in 20 dogs were not different in samples taken before and after the test, which oppose severe levels of stress. The SAB-test allows one to evaluate aggression in dogs, but present findings indicate that probably those that behave aggressively in the absence of fear remain undetected. It is recommended to increase the test's usefulness by refining or including new test components that target different forms of aggression. Formulating a risk assessment based on detailed information on a dog's behaviour during testing instead of simply producing a pass–fail judgement will facilitate a purpose specific use of the SAB-test.
Weiden of opstallen: een keuze op basis van persoonlijke waarden
Well, E. van; Aarts, M.N.C. - \ 2008
V-focus 5 (2008)april (2). - ISSN 1574-1575 - p. 16 - 17.
melkveehouderij - bedrijfsontwikkeling in de landbouw - melkkoeien - weiden - begrazing - agrarische bedrijfsvoering - waarden - persoonlijkheid - bedrijfssystemen - beweidingssystemen - keuzegedrag - dairy farming - farm development - dairy cows - pastures - grazing - farm management - values - personality - farming systems - grazing systems - choice behaviour
In het project Koe & Wij heeft CLM individuele gesprekken gevoerd met 25 melkveehouders om een beeld te krijgen van de rol die persoonlijke waarden spelen in de bedrijfsvoering en meer specifiek waar het gaat om weidegang. Er blijken 4 typen melkveehouders uit het onderzoek naar persoonlijke waarden naar voren te komen
Divortium 1967 : Sociologische faktoren van invloed op echtscheiding [Sociological factors influencing divorce 1967]
Douma, W.H. ; Suy, L. - \ 2007
sociology - family life - women - sexual behaviour - personality - marriage - sociology of the family
Detailed background data on own husband, parents and ex-husband / religious attitude / experiences during courtship / premarital sexual relations / what happened after divorce ( house, children ) / relationships with both families / friends / problems in financial matters / different hobbies / children / drinking problems of self and husband / personality descriptions of former husband and self / reasons for divorce ( also for husband's wife ). Background variables: basic characteristics/ household characteristics/ occupation/employment/ education/ religion