In empirical projects conducted in interdisciplinary and international collaborations, I apply these foundations to investigate humans of different ages and sociocultural backgrounds as well as individuals of various species of nonhuman primates, especially great apes, capuchin monkeys and macaques. Nonhuman primates are particularly interesting for comparative research given the variability in their social systems and behavioural ecologies and in their degree of phylogenetic relationship to humans. 

The broad perspective taken in my research offers unique opportunities for studying social, societal, biological and ecological processes that are associated with the emergence of individual-specificity ('personality') and their promotion by the development of semiotic representations (everyday psychology of 'personality'). This perspective may also be illuminative with regard to evolutionary research questions, in particular to the age-old question of what actually makes humans unique amongst all the species that exist today.
 

A central approach to comparative psychology are behavioural studies because behaviours can be studied in humans and other species alike, whereas judgements can be obtained only from humans. To identify individual-specific behaviours, I employ a broad portfolio of behavioural research methods, including live observations in real-life settings, behavioural experiments, and audiovisual and computerised methods for the detailed recording of behaviours. 

My empirical studies have shown that individual-specificity ('personality') occur in a broad range of behaviours across the behavioural repertoires of great apes (Uher, Asendorpf, & Call, 2008) and various monkey species, such as capuchin monkeys (Uher, Addessi, & Visalberghi, 2013a), crab-eating macaques (Uher, Werner, & Gosselt, 2013b).

Interestingly, sex differences were less pronounced in crab-eating macaques (Uher et al., 2013b) and largely absent in capuchin monkeys (Uher et al., 2013a), mandrills, toque macaques and rhesus macaques (Uher, 2015e). This contrasts with the pronounced gender differences that young children displayed in their behaviours in kindergarten settings, indicating cultural but not necessarily evolutionary influences (Uher & Collard, in prep.).

Further information: primate-personality.net
 

Exploring humans' impression formation and their assessments of individuals from other species that are phylogenetically related yet have different social and behavioural systems can make attribution biases derived from sociocultural beliefs about human individuals particularly apparent. My multi-method studies have shown substantial coherence between personality ratings on different types of items and individual-specific behaviours measured in behavioural tests and observations (Uher, 2011b; Uher & Asendorpf, 2008). But they have also revealed complex attribution biases related to the raters' stereotypical beliefs about age, sex, social position and early life history (Uher & Visalberghi, 2016; Uher, Werner, & Gosselt, 2013b). 

Further information: primate-personality.net
 

A further aim is to investigate the psychical processes involved in standardised 'personality' assessments. The aim is to systematically deconstruct the requirements that standardised assessment tasks impose on respondents and to reconstruct the social knowledge and the psychical processes involved therein. These processes are still largely unknown despite the fact that standardised questionnaires have become the primary tool of investigation in many fields of psychology and the social sciences.

Further information: id-research.org