Department of Physics, Chemistry and Biology (IFM)

From the 100 video recorded dogs only breeds with more than five individuals tested were included in the analysis resulting in the behavioural coding of 64 dogs belonging to nine different breeds (Table 1).

For the subtests 'approaching person', 'surprise' and 'rattle' most striking differences between the two clusters were found for behaviours of the behaviour groups 'vocalization' (Figure 3) and 'interaction with the stimulus' (Figure 4). 

A total of seven factors were extracted from the two PCAs performed on the behaviours included in the behavioural coding. According to the most salient variables these factors were labelled 'reactivity', 'stranger-directed fear', 'arousal', 'non-social fear', 'non-social aggression', 'curiosity' and 'nervousness'.

Significant differences between cluster 1 and cluster 2 were found for the scores on the factors 'reactivity', 'stranger-directed fear' and 'non-social aggression' (Figure 5).