Human's "personality glasses" - Why we form
impressions of individuals. New insights into a uniquely human
release in PDF-Version
The ability to quickly form impressions of other individuals'
"personality" seems to be a uniquely human ability. A 3-year
cross-species study of 104 crab-eating macaques and 99 human
observers of these monkeys further explored this fascinating human
ability. The study illuminated the ways in which judgements of
individuals are influenced by beliefs about age, status and sex
differences that are rooted in our everyday knowledge and that tend
to be stereotypical. These intuitive beliefs are like glasses
through which we form impressions of the "personality" of
individuals. These beliefs even affect how we judge individuals of
other species! The study unravels common mistakes that we make when
forming impressions of individuals. But despite widespread
inaccuracies and mistakes, the ability to quickly form impressions
of strangers could have been of enormous importance in human
evolution: It enabled our ancestors to trade with unknown
individuals of foreign cultures, and it was also an essential
prerequisite for the domestication of animals. An exciting study
about humans and monkeys from different continents.
(© Photo: Karlijn Gielen, Utrecht University)
Information about who is doing what with whom plays an essential
role in our everyday lives. By communicating such information, we
exchange experiences that we have had with particular individuals as
well as our ideas and opinions about these individuals. Within our
sociocultural communities, we develop shared beliefs and values
about individuals and their peculiarities as well as a shared
language for communicating this information.
Our everyday language therefore contains numerous words that we
can use to efficiently and quickly communicate complex information
about individuals. We use the small piece of information that
somebody is "friendly" to draw conclusions about an individual whom
we have not yet met and we align our actions accordingly. This is
possible because our everyday knowledge contains a differentiated
system of social categories. This system is partially based on our
own experiences, but in particular on our everyday language, i.e.,
on the experiences and beliefs of previous generations.
Therefore, all individuals of our cultural and language community
share this knowledge system in similar ways. We intuitively use this
knowledge system when we encounter foreign individuals to mentally
categorise these individuals with regard to their "personality" and
to form impressions about how they may behave towards us. But even
if first impressions do not always prove to be fully accurate, they
provide a sense of security in dealing with unknown individuals and
offer clues by which we adjust our behaviours also proactively.
The ability to deal peacefully with foreign or even anonymous
individuals is so common in our daily lives that, at first glance,
it does not seem to be any special. But it may be uniquely human, at
least when only mammalian species are considered. Even our closest
living relatives, the nonhuman primates, show tremendous
difficulties in dealing peacefully with unknown conspecifics. We are
able to sit tight and calmly next to strangers, such as in public
But for many other species, encounters with strangers are
extraordinarily stressful and often involve aggressive conflicts,
some even with fatal outcomes. "Especially in the great apes who are
often so amazingly similar to us with regard to many social and
cognitive abilities, is is often disturbing to see how stressful
encounters with strangers are for these individuals and how these
encounters sometimes escalate into violence", says Jana Uher, the
director of the study. Why is that so?
Jana Uher suggests that this is not only a consequence of other
species' greater territoriality and their general lack of abstract
language ability in and of itself. Instead, stressful encounters may
result from a lack of the ability to develop mental categories of
individuals that can be used to assess unknown individuals with
regard to their "personality".
The researcher explains: "Without a basic knowledge of the ways
in which individuals differ from one another in their behaviours,
that is, without "personality" categories that are useful for
differentiating between individuals, one cannot mentally categorise
an unknown individual and therefore cannot deduce assumptions about
how it may behave next. Thus, every encounter with strangers is
characterised by high uncertainty and one can learn only stepwise
from interactions with a stranger how he or she may tend to
In view of the stressful encounters with unknown conspecifics,
Jana Uher assumes that not even the great apes are able to develop
mental categories of individuals and to use these categories to form
impressions of others. "This may explain why, for the individuals of
many nonhuman species, such encounters are often difficult, and why,
in zoological institutions, introductions of new individuals are
often so stressful", Jana Uher says.
The researcher emphasises, however, that individuals of many
nonhuman species are able to learn over some time how particular
individuals in their social environment tend to behave; otherwise,
individualised relationships could not be found in other species as
well, in particular in primates. But the ability to develop general
categories about individual differences from peculiarities of single
individuals and to use using these categories in social interactions
seems to be a uniquely human ability.
In our everyday lives, we use this ability so intuitively that,
at a first glance, it does not seem to be any special. Rather, its
uniqueness could be revealed only through comparisons with other
species. To further explore this ability, Jana Uher and her research
colleagues from the ethology station of the Dutch
Utrecht University investigated how humans form "personality"
impressions of individuals of other species.
Our ability to recognise individual differences in the behaviour
of nonhuman species was an essential prerequisite for the
domestication of animals. For a long time, it was assumed that our
ancestors had domesticated animals based on selective breeding for
bodily features. But groundbreaking breeding experiments with farm
foxes in Russia have impressively shown that selective breeding for
specific individual behaviours-less fear of and aggression towards
humans - results within only 30 generations in a host of physical
changes through which today's domesticated animals differ markedly
from their wild relatives.
Stone-age fossils that resemble today's dogs more than wolves
suggest that, as early as some 30,000 years ago, humans had to have
already been able to mentally develop "personality" categories that
are useful for differentiating individuals of other species as
Domesticated animals have been bred for those particular behavioural
properties that we as humans can easily perceive and for which we
have developed "personality" categories in our everyday language.
Therefore, Jana Uher and her research team explored how humans
develop "personality" impressions of individuals of a nonhuman
species with which the observers were previously inexperienced -
crab-eating macaques from Southeast-Asia.
In the ethology station's colony that is has been studied for
their social behaviours for decades already, 91 students of
behavioural biology first learned about this particular monkey
species and about scientific methods of behavioural observation.
Then, the students worked in pairs; each pair intensely observed 5
monkeys over 5 days and systematically recorded their behaviours.
Thereafter, they assessed their 5 monkey individuals with two
"personality" questionnaires. In addition, 8 researchers from the
ethology station assessed the monkey individuals many of which they
had known for several years.
The results were intriguing. "I had assumed that observations of
just 5 individuals of a species with which one was previously not
familiar would not be sufficient to form impressions of their
individual peculiarities that would be comparable to the impressions
that other observers formed of the monkeys several weeks later and,
importantly, that would be comparable to the experts' impressions.
But astonishingly, we found hardly any differences.", says Jana
Moreover, to get to know individuals, 5 days is only a very
brief amount of time, despite the use of systematic scientific
observations. "Without the robust findings that we obtained from 6
study waves over 3 years, I would have had doubts about whether this
could be possible at all", she says. This shows how quickly we form
impressions of individuals of other species and how similar the
impressions are that we form of them. But how accurate are they?
To find this out, the researchers used a novel paradigm to
categorise individual differences. In contrast to previous studies,
these new approaches are not based on human's everyday language, but
instead on the behavioural repertoire of those individuals whose
"personality" is under study; in this case crab-eating macaques.
"These new approaches enable us to clearly differentiate and
compare how individuals behave with what observers think about how
individuals behave. This is not possible with the previous methods
used in "personality" psychology that are rooted in everyday
language", explains Jana Uher. She has developed the new paradigm
and has already applied it successfully in studies on individual
behaviours of capuchin monkeys and great apes and on human
observers' impressions of these individuals' "personality".
The results were amazing. The observers judged younger
crab-eating macaques as more curious and impulsive than older ones,
high-ranking monkeys as more impulsive than low-ranking ones, and
females as more clean than males. But none of these age, status and
sex differences were found in the monkeys' behaviours. Moreover,
younger monkeys behaved more anxiously than older ones and males
more anxiously than females, but this was not reflected in the
observers' "personality" judgements. The results are consistent with
stereotypical beliefs about human individuals. This shows that such
beliefs can also bias judgements about monkey individuals in
As human "personality" differences have been studied almost
exclusively with questionnaires so far, it is still unknown in what
ways "personality" judgements of human individuals are biased by
stereotypical beliefs, such as about persons of different age,
sex/gender or social and ethnic background.
Judgements reflect what people think about and how they describe
themselves and other humans or even individuals of other species -
but judgements cannot reflect how the judged individuals actually
behave. Only comparisons with the individuals' behaviours can show
to what extent we form accurate impressions of individuals through
our "personality glasses" and in what ways we jump too quickly to
using our everyday knowledge and potential stereotypical or
Contact person: Dr. Jana
Uher, J., Werner, C. S., & Gosselt, K. (2013). From observations
of individual behaviour to social representations of personality:
Developmental pathways, attribution biases, and limitations of
questionnaire methods. Journal of Research in Personality, 47,
Uher, J. (2013). Personality psychology: Lexical approaches,
assessment methods, and trait concepts reveal only half of the
story. Why it is time for a paradigm shift. Integrative
Psychological and Behavioral Science, 47, 1-55.
Last update: 21.02.2014
Keywords: Macaca fascicularis, sex differences, gender
differences, age differences, social status differences,
personality, judgement, rating, assessments, personality
questionnaire, individual differences, individual behavior,
individual-specific behavior, assessment bias, judgment bias, sex
stereotypes, gender stereotypes, age stereotypes, behavioral test,
behavioural observation, primates.