Jan van Hooff | Universiteit Utrecht (original) (raw)
Papers by Jan van Hooff
Journal of Child Psychology and Psychiatry, 1991
Social and task-oriented behaviours of autistic children were compared to those of individually a... more Social and task-oriented behaviours of autistic children were compared to those of individually age- and IQ-matched non-autistic retarded controls. Autistic children showed deficits in visual reciprocity, in indicating joint attention and referential head gestures, and in the integration of gaze and gestures when reacting to tasks. The findings confirmed the notion of social and pragmatic communicative deficits in autism. The implications of these findings for theories of social behaviour in autism (avoidance, facial perception, theory of mind) are discussed.
Child Psychiatry and Human Development, 1995
This study investigated the behavior of children with conduct disorder or oppositional defiant di... more This study investigated the behavior of children with conduct disorder or oppositional defiant disorder (CD/ODD) in interaction with each other and with normal control (NC) children in a semi-standardized setting over a period of 25 minutes. This short time turned out to be sufficient to demonstrate the behavioral manifestations of CD/ODD in children's interactions with peers. In addition, the role of the interactional partner on antisocial behaviour of CD/ODD children became apparent.
Experientia, 1992
When charting the structure of the social behavior of autistic children by means of an ethologica... more When charting the structure of the social behavior of autistic children by means of an ethologically analyzed playroom session, deficits appeared in the reciprocity of eye-contact and in the location of verbal initiatives. These deficits in social behavior were beneficially influenced by treatment with the adrenocorticotrophic hormone (4-9) analog ORG 2766.
Animal Behaviour, 1991
Behavioural and endocrine parameters were studied in a large colony of stumptail macaques. This p... more Behavioural and endocrine parameters were studied in a large colony of stumptail macaques. This paper deals with harassment behaviour during copulation, and its possible underlying motivation. The study corroborates some findings of other studies such as that harassment is triggered by ejaculation and is directed at the mating male. Both males and females harassed most frequently around puberty, but only females continued to harass when adult, although at a lower rate, especially when pregnant. Harassment was seldom retaliated, even when severe aggression to dominant mating males was involved. Social factors that correlated with harassment included family ties, affiliative ties and reciprocity between harasser and female copulant, dominance status and aggression between harasser and male copulant. Motivational factors appeared not to be exclusively associated with the harassers' attitude towards the female copulant, as other studies suggested, but also involved the harassers' attitude towards the male copulant since the behaviour was invariably directed at him. In addition to possessiveness, it is suggested that revanchism may be a motive. Because of aggression received earlier, monkeys take 'revenge' when they have an opportunity, i.e. when the opponent is mating and at the moment of orgasm. It is suggested that, as an evolutionary mechanism, harassment reinforces power structures in the group. Harassers may unwittingly serve as sentinels for top-ranking males who thus become better able to monopolize fathership. As an additional effect, high-ranking matrilines can grow at the cost of low-ranking ones because of the preference of top-ranking males for high-ranking females.
Animal Welfare 2000, 9: 49-62 Four groups of dogs, which had been subjected to housing conditions... more Animal Welfare 2000, 9: 49-62 Four groups of dogs, which had been subjected to housing conditions of varying quality for years, were assumed to experience different levels of stress. The groups were compared for behavioural and hormonal parameters in order to identifY measures that indicate chronic stress in the dog and which may help to identifY poor welfare in this species. As a standard for comparison, one of the four groups was composed of privately owned dogs; we assumed that chronic stress levels were relatively low in this group (GI). The three remaining groups of dogs (GIl, GIIl and GIV) were kept under conditions of low to relatively high austerity, and had basal urinary ratios of cortisol to creatinine, adrenaline to creatinine and, to a lesser extent, noradrenaline to creatinine, that varied from low to high, respectively. Significant differences (P < 0.05) were found in cortisol to creatinine ratios when comparing GI to GIl, GIll and GIV and when GIl was compared to GIV. Statistical analyses indicated that the mean adrenaline to creatinine ratio in GI differed from that in the remaining groups and that the ratio in GIl differedfrom that in GIll Noradrenaline to creatinine ratios differed significantly only between GI and GIll Dopamine to creatinine ratios and noradrenaline to adrenaline ratios did not differ significantly between groups. When dogs were not disturbed, those that were kept under the most austere conditions typically had high levels of locomotor activity, nosing, urinating and paw lifting. After mild disturbance by a slamming door or in the presence of a researcher these animals reacted actively, with increased locomotor activity, circling and nosing, and they showed high levels of behaviours that have previously been associated with acute stress: body shaking, yawning, ambivalent postures and displacement behaviours. Chronic stress in dogs may be identified by increased paw lifting when animals are not disturbed and by ample behavioural expressions of arousal when they are mildly stimulated. Since some behaviours may occur in contexts not related to stress, behavioural data are easily misinterpreted with regard to chronic stress. Interpretation will only be meaningful when physiological measures such as urinary adrenaline to creatinine ratios and, especially, urinary cortisol to creatinine ratios are also determined.
International Zoo Yearbook, 1962
The question whether animals experience pain has found different answers. The question cannot be ... more The question whether animals experience pain has found different answers. The question cannot be answered in as far as it deals with the aspect of subjective experience; this is unaccessible to empirical investigation, for fundamental reasons. Most scientists, however, will accept a ‘postulate of homology’: because sensory and neural processes and structures are organised in essentially similar ways, at least in mammals, they feel bound to assume that these animals know experiences that are homologous to ours, also with respect to the sensation of pain (20). A more modest approach is to investigate the behavioural responses to damaging influences.
Sociobiology and Conflict, 1990
The use of frequently destructive and bloody violence in group encounters, which we know in its m... more The use of frequently destructive and bloody violence in group encounters, which we know in its most extensive and organized form as war, seems to be as old as mankind itself, if not older. In any case, early hominid fossil finds indicate that death as a result of armed violence must not have been uncommon (Birdsell, 1972). In nearly all the cases the conduct of war and related heroics form an important subject for the arts of literature and design. It is almost a paradox for us, we who live under the apocalyptic threat of nuclear weapons, to ascertain that the tone of these expressions of artistry is seldom negative, on the contrary! Cultures in which violent confrontations between groups appear not to occur form startling but nevertheless marginal exceptions. Instead of disproving it, they confirm the rule that man is a belligerent being. They do, however, contradict any explanation saying that war is an inevitable result of a deep-rooted, insurmountable bellicosity in human nature. One idea which finds popular acceptance is that there exists in our species a kind of innate need for war, a trait in our make-up which manifests itself under particular circumstances with a certain necessity and inevitability. This idea has also found its advocates in scientific circles, where it rests on a ‘drive model’ of aggressive behaviour (Lorenz, 1963). There is, however, no evidence to support such a view (Hinde, 1960, 1973, 1974).
Tijdschrift voor diergeneeskunde, Jan 15, 1985
To better understand the pain phenomenon, its occurrence and its functional significance, pain sh... more To better understand the pain phenomenon, its occurrence and its functional significance, pain should be considered as a part of a behaviour system which activates two functions: defensive and aversive behaviour on the one hand, and recuperative behaviour on the other. In the former especially the more short-lasting primary pain plays a role, in recuperative behaviour more chronic secondary pain is of importance. Pain should not be seen primarily as the unconditioned stimulus in the fear system, but as one of the independent behaviour systems. Within the framework of this ethological model both the facilitative and inhibitive influences which 'pain' and 'fear' exert on each other can be more satisfactorily explained. We assume that animals feel pain on the grounds of the so-called 'analogy decision'. The only objective measure, of course, is the behaviour which is observable as a consequence of harmful influences. This behaviour varies greatly with the nature...
The Neglected Ape, 1995
At first sight, the orangutan may well be the least spectacular of the great apes. In comparison ... more At first sight, the orangutan may well be the least spectacular of the great apes. In comparison with its African cousins, this solitary creature seems to lead a far less exciting life. Superficially, its social organization is exceptional in comparison with that of other diurnal primates. It is precisely this exceptional characteristic which makes the red ape an interesting test case for socio-ecological theorizing.
International Zoo Yearbook, 1973
International Zoo Yearbook, 1965
Applied Animal Behaviour Science, 1997
Veterinary Quarterly, 1998
PsycEXTRA Dataset, 1967
This technical report has been reviewed and is approved for publication.
Experientia, 1970
Mittels Komponentenanalyse wurde die Struktur des sozialen Verhaltens einer in Halb-Gefangenschaf... more Mittels Komponentenanalyse wurde die Struktur des sozialen Verhaltens einer in Halb-Gefangenschaft lebenden Gruppe von Schimpansen untersucht. Das Repertoire der 53 allgemeinsten sozialen Verhaltensmuster konnte als Funktion von 5 unabhängigen motivationellen Komponenten beschrieben werden.
Zoo …, 1984
The cotton-topped, tamarin, Saguinus oedipus oedipus, is a species that is severely threatened in... more The cotton-topped, tamarin, Saguinus oedipus oedipus, is a species that is severely threatened in the wild. Thus, if its survival is to be ensured, a self-sustaining captive population needs to be established. However, the breeding results of cotton-topped tamarins in zoos are far from optimal; infant mortality is high and the fertility of captive-born specimens is critically low. The roots of both these problems may be sought in the social behavior of this species in zoos. In order to evaluate the influence of the zoo environment on behavior, a comparison is made between the behavior of a group of tamarins housed in a typical zoo environment and groups of successfully breeding cotton-topped tamarins housed off public display in the zoo. Significant differences were found between the behavior of the animals in the two different situations. Behavioral differences were correlated with the number of visitors in the zoo environment and with the design of the cage.
Journal of Child Psychology and Psychiatry, 1991
Social and task-oriented behaviours of autistic children were compared to those of individually a... more Social and task-oriented behaviours of autistic children were compared to those of individually age- and IQ-matched non-autistic retarded controls. Autistic children showed deficits in visual reciprocity, in indicating joint attention and referential head gestures, and in the integration of gaze and gestures when reacting to tasks. The findings confirmed the notion of social and pragmatic communicative deficits in autism. The implications of these findings for theories of social behaviour in autism (avoidance, facial perception, theory of mind) are discussed.
Child Psychiatry and Human Development, 1995
This study investigated the behavior of children with conduct disorder or oppositional defiant di... more This study investigated the behavior of children with conduct disorder or oppositional defiant disorder (CD/ODD) in interaction with each other and with normal control (NC) children in a semi-standardized setting over a period of 25 minutes. This short time turned out to be sufficient to demonstrate the behavioral manifestations of CD/ODD in children&amp;amp;amp;#39;s interactions with peers. In addition, the role of the interactional partner on antisocial behaviour of CD/ODD children became apparent.
Experientia, 1992
When charting the structure of the social behavior of autistic children by means of an ethologica... more When charting the structure of the social behavior of autistic children by means of an ethologically analyzed playroom session, deficits appeared in the reciprocity of eye-contact and in the location of verbal initiatives. These deficits in social behavior were beneficially influenced by treatment with the adrenocorticotrophic hormone (4-9) analog ORG 2766.
Animal Behaviour, 1991
Behavioural and endocrine parameters were studied in a large colony of stumptail macaques. This p... more Behavioural and endocrine parameters were studied in a large colony of stumptail macaques. This paper deals with harassment behaviour during copulation, and its possible underlying motivation. The study corroborates some findings of other studies such as that harassment is triggered by ejaculation and is directed at the mating male. Both males and females harassed most frequently around puberty, but only females continued to harass when adult, although at a lower rate, especially when pregnant. Harassment was seldom retaliated, even when severe aggression to dominant mating males was involved. Social factors that correlated with harassment included family ties, affiliative ties and reciprocity between harasser and female copulant, dominance status and aggression between harasser and male copulant. Motivational factors appeared not to be exclusively associated with the harassers' attitude towards the female copulant, as other studies suggested, but also involved the harassers' attitude towards the male copulant since the behaviour was invariably directed at him. In addition to possessiveness, it is suggested that revanchism may be a motive. Because of aggression received earlier, monkeys take 'revenge' when they have an opportunity, i.e. when the opponent is mating and at the moment of orgasm. It is suggested that, as an evolutionary mechanism, harassment reinforces power structures in the group. Harassers may unwittingly serve as sentinels for top-ranking males who thus become better able to monopolize fathership. As an additional effect, high-ranking matrilines can grow at the cost of low-ranking ones because of the preference of top-ranking males for high-ranking females.
Animal Welfare 2000, 9: 49-62 Four groups of dogs, which had been subjected to housing conditions... more Animal Welfare 2000, 9: 49-62 Four groups of dogs, which had been subjected to housing conditions of varying quality for years, were assumed to experience different levels of stress. The groups were compared for behavioural and hormonal parameters in order to identifY measures that indicate chronic stress in the dog and which may help to identifY poor welfare in this species. As a standard for comparison, one of the four groups was composed of privately owned dogs; we assumed that chronic stress levels were relatively low in this group (GI). The three remaining groups of dogs (GIl, GIIl and GIV) were kept under conditions of low to relatively high austerity, and had basal urinary ratios of cortisol to creatinine, adrenaline to creatinine and, to a lesser extent, noradrenaline to creatinine, that varied from low to high, respectively. Significant differences (P < 0.05) were found in cortisol to creatinine ratios when comparing GI to GIl, GIll and GIV and when GIl was compared to GIV. Statistical analyses indicated that the mean adrenaline to creatinine ratio in GI differed from that in the remaining groups and that the ratio in GIl differedfrom that in GIll Noradrenaline to creatinine ratios differed significantly only between GI and GIll Dopamine to creatinine ratios and noradrenaline to adrenaline ratios did not differ significantly between groups. When dogs were not disturbed, those that were kept under the most austere conditions typically had high levels of locomotor activity, nosing, urinating and paw lifting. After mild disturbance by a slamming door or in the presence of a researcher these animals reacted actively, with increased locomotor activity, circling and nosing, and they showed high levels of behaviours that have previously been associated with acute stress: body shaking, yawning, ambivalent postures and displacement behaviours. Chronic stress in dogs may be identified by increased paw lifting when animals are not disturbed and by ample behavioural expressions of arousal when they are mildly stimulated. Since some behaviours may occur in contexts not related to stress, behavioural data are easily misinterpreted with regard to chronic stress. Interpretation will only be meaningful when physiological measures such as urinary adrenaline to creatinine ratios and, especially, urinary cortisol to creatinine ratios are also determined.
International Zoo Yearbook, 1962
The question whether animals experience pain has found different answers. The question cannot be ... more The question whether animals experience pain has found different answers. The question cannot be answered in as far as it deals with the aspect of subjective experience; this is unaccessible to empirical investigation, for fundamental reasons. Most scientists, however, will accept a ‘postulate of homology’: because sensory and neural processes and structures are organised in essentially similar ways, at least in mammals, they feel bound to assume that these animals know experiences that are homologous to ours, also with respect to the sensation of pain (20). A more modest approach is to investigate the behavioural responses to damaging influences.
Sociobiology and Conflict, 1990
The use of frequently destructive and bloody violence in group encounters, which we know in its m... more The use of frequently destructive and bloody violence in group encounters, which we know in its most extensive and organized form as war, seems to be as old as mankind itself, if not older. In any case, early hominid fossil finds indicate that death as a result of armed violence must not have been uncommon (Birdsell, 1972). In nearly all the cases the conduct of war and related heroics form an important subject for the arts of literature and design. It is almost a paradox for us, we who live under the apocalyptic threat of nuclear weapons, to ascertain that the tone of these expressions of artistry is seldom negative, on the contrary! Cultures in which violent confrontations between groups appear not to occur form startling but nevertheless marginal exceptions. Instead of disproving it, they confirm the rule that man is a belligerent being. They do, however, contradict any explanation saying that war is an inevitable result of a deep-rooted, insurmountable bellicosity in human nature. One idea which finds popular acceptance is that there exists in our species a kind of innate need for war, a trait in our make-up which manifests itself under particular circumstances with a certain necessity and inevitability. This idea has also found its advocates in scientific circles, where it rests on a ‘drive model’ of aggressive behaviour (Lorenz, 1963). There is, however, no evidence to support such a view (Hinde, 1960, 1973, 1974).
Tijdschrift voor diergeneeskunde, Jan 15, 1985
To better understand the pain phenomenon, its occurrence and its functional significance, pain sh... more To better understand the pain phenomenon, its occurrence and its functional significance, pain should be considered as a part of a behaviour system which activates two functions: defensive and aversive behaviour on the one hand, and recuperative behaviour on the other. In the former especially the more short-lasting primary pain plays a role, in recuperative behaviour more chronic secondary pain is of importance. Pain should not be seen primarily as the unconditioned stimulus in the fear system, but as one of the independent behaviour systems. Within the framework of this ethological model both the facilitative and inhibitive influences which 'pain' and 'fear' exert on each other can be more satisfactorily explained. We assume that animals feel pain on the grounds of the so-called 'analogy decision'. The only objective measure, of course, is the behaviour which is observable as a consequence of harmful influences. This behaviour varies greatly with the nature...
The Neglected Ape, 1995
At first sight, the orangutan may well be the least spectacular of the great apes. In comparison ... more At first sight, the orangutan may well be the least spectacular of the great apes. In comparison with its African cousins, this solitary creature seems to lead a far less exciting life. Superficially, its social organization is exceptional in comparison with that of other diurnal primates. It is precisely this exceptional characteristic which makes the red ape an interesting test case for socio-ecological theorizing.
International Zoo Yearbook, 1973
International Zoo Yearbook, 1965
Applied Animal Behaviour Science, 1997
Veterinary Quarterly, 1998
PsycEXTRA Dataset, 1967
This technical report has been reviewed and is approved for publication.
Experientia, 1970
Mittels Komponentenanalyse wurde die Struktur des sozialen Verhaltens einer in Halb-Gefangenschaf... more Mittels Komponentenanalyse wurde die Struktur des sozialen Verhaltens einer in Halb-Gefangenschaft lebenden Gruppe von Schimpansen untersucht. Das Repertoire der 53 allgemeinsten sozialen Verhaltensmuster konnte als Funktion von 5 unabhängigen motivationellen Komponenten beschrieben werden.
Zoo …, 1984
The cotton-topped, tamarin, Saguinus oedipus oedipus, is a species that is severely threatened in... more The cotton-topped, tamarin, Saguinus oedipus oedipus, is a species that is severely threatened in the wild. Thus, if its survival is to be ensured, a self-sustaining captive population needs to be established. However, the breeding results of cotton-topped tamarins in zoos are far from optimal; infant mortality is high and the fertility of captive-born specimens is critically low. The roots of both these problems may be sought in the social behavior of this species in zoos. In order to evaluate the influence of the zoo environment on behavior, a comparison is made between the behavior of a group of tamarins housed in a typical zoo environment and groups of successfully breeding cotton-topped tamarins housed off public display in the zoo. Significant differences were found between the behavior of the animals in the two different situations. Behavioral differences were correlated with the number of visitors in the zoo environment and with the design of the cage.