General Aims and questions

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AIM: To explore the designating function of directional gestures in humans. More precisely we aim to investigate the modulatory effects of offline social cues on the allocation of attention in a change detection task.

MAIN QUESTION: Whether intensive social stimulation induces the forming of referential expectations by exerting an effect on information processing that is similar to priming effects.

Study 2: The effects of positive and negative social stimulation on dogs’ behaviour in an instrumental helping situation

AIM: To investigate whether pretreatment with positive and negative social stimulation would affect subsequent behaviour of dogs in an instrumental helping situation.

MAIN QUESTION: How does perceived affective quality of a social interaction with an unfamiliar experimenter affects subsequent behaviour of dogs in an instrumental helping situation?

Thesis 2. Social categorization

Social preference for ingroup members is one of the central aspects of human behaviour.

Research evidence indicates that category-based social preferences emerge early in development (e.g. Buttelmann, Zmyj, Daum & Carpenter, 2013). Although there are some salient category distinctions that are based on innate/biological features (such as age, race and sex - Fiske, 2000), the functional significance of social categorization is to understand the details of inter-individual and inter-group relations (Sperber & Hirschfeld, 2004). This presents a paradox for social categorization: while categorization in general is most effective if it can capture something stable about the given kind, one of the most important features of the social environment is that social groupings may change dynamically and thus the relevance of distinction may also change rapidly.

It is still unclear, however, whether such flexibility is indeed an inherent feature of the social categorization processes in children. One further question that remains to be answered is how the social impairments seen in autism affect social categorization. In general, research suggests that autism results in reduced abilities to extract abstract categorization rules from environmental stimuli, while categorization based on simple features may be intact (see e.g.

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Klinger & Dawson, 2001). In line with these, we investigated preschool aged children’s (both autistic and neurotypical participants) ability to spontaneously form social categories (Study 3).

Moreover, the study of canine behaviour, from a comparative perspective, offers intriguing possibilities to study the nonhuman analogues of social categorization in general, and the phenomenon of ingroup favouritism in more particular. Thus in an additional study (Study 4) we investigated whether dogs, after having familiarized with two unfamiliar humans displaying different degrees of similarity to their owners, would show a tendency to interact differently with these prospective partners in an unsolvable problem (inaccessible toy) situation. More specifically, we tested the effects of an arbitrary group marker conveying transient similarity to their owners (clothing) and the effects of persistent behavioural characteristics (language and motion pattern).

Study 3: Social categorization based on permanent vs transient visual traits in neurotypical children and children with autism spectrum disorder.

AIM: To investigate the importance of different category markers (transient vs. permanent features) during social categorization processes from a developmental perspective and to understand how social categorisation is affected in ASD.

MAIN QUESTIONS: Whether typically developing children are sensitive to the fact that social categories are first and foremost social constructs that are characterized with flexible category boundaries. Whether children with autism have different category learning performance or use different criteria when forming categories compared to (mental-) age matched neurotypical controls.

Study 4: Social categorization in dogs: the effects of similarity between an unfamiliar human and the owner on dogs’ tendency to interact with human partners.

AIM: To investigate domestic dogs’ ability to form social categories based on the degree of similarity between their owners and unfamiliar people.

MAIN QUESTION: How does similarity between an unfamiliar human and the owner affects dogs’ visual preference for human partner (as potential helper) when responding to an unsolvable problem.

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Thesis 3. Audience effect

Being watched by others has a strong effect on both human and non-human behaviour:

children for example, tend to perform better with easy tasks, if an audience is present. Furthermore, the audience effect has been shown to play an important role in the differential diagnosis of autism, as children diagnosed with autism react differently to the observation than typically developing children (Chevallier, Parish-Morris, Tonge, Le, Miller, & Schultz, 2014; Izuma et al., 2011).

Increasing evidence indicate that domestic dogs (Canis familiaris) attend to a human’s attentional state, and thus fulfil one of the core requirements for audience effect.

Two studies were conducted to explore adult pet dogs’ sensitivity to audience effect (i.e.

whether dogs, like human children, show a tendency to change their behaviour according to the visual attention of humans). In the first experiment (Study 5) dogs participated in two types of observational conditions in the presence of a familiar and an unfamiliar human partner (Attentive Owner & Attentive Experimenter) and a control condition in which both human participants turned their back and engaged in distracting activity (No Audience condition). The human partners disallowed the dog from eating a piece of food. This paradigm offers a possibility for uncovering the context-dependent nature of audience effect in dogs (through analysis of dogs’ different visual monitoring strategies in the presence of their caregiver and an unfamiliar observer). In a second study (Study 6) we aimed to investigate the impact of the owner’s visual attention on dogs’

willingness to perform a repetitive, fairly monotonous object-retrieval task (while being commanded to do so by an unfamiliar human). Behavioural observations were complemented by additional trait-like parameters such as the owner-dog attachment style and the dogs’ brain activity during sleep. Analysing the relationship between dogs’ sleep EEG spectrum and fetching task behaviour is a novel approach to investigate the neuro-cognitive link between dogs’ personality traits and their susceptibility to audience effect.

Study 5. How do dogs monitor the human’s attentional state after challenged by the presence of forbidden food?

AIM:To assess dog’s sensitivity to the audience effect and the importance of familiarity in a

“forbidden food” situation.

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MAIN QUESTION: Whether dogs are particularly sensitive to being observed by their caregiver relative to being observed by an unfamiliar human.

Study 6. Behavioural and neurophysiological correlates of dogs’ individual sensitivity to being observed by their owners while performing a repetitive fetching task.

AIM: To examine the impact of the owner’s visual attention on dogs’ tendency to bring back an object to an unfamiliar experimenter and to investigate the potential associations among owner-dog relationship, owner-dogs’ task performance and spectral EEG sleep profile.

MAIN QUESTIONS: Whether the nature of the dog-owner relationship facilitates the dog’s behaviour, and, whether dog’s spectral EEG sleep profile and their susceptibility to the audience effect are related.

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5. E