10 research outputs found
How Humans Differ from Other Animals in Their Levels of Morphological Variation
Animal species come in many shapes and sizes, as do the individuals and populations that make up each species. To us, humans might seem to show particularly high levels of morphological variation, but perhaps this perception is simply based on enhanced recognition of individual conspecifics relative to individual heterospecifics. We here more objectively ask how humans compare to other animals in terms of body size variation. We quantitatively compare levels of variation in body length (height) and mass within and among 99 human populations and 848 animal populations (210 species). We find that humans show low levels of within-population body height variation in comparison to body length variation in other animals. Humans do not, however, show distinctive levels of within-population body mass variation, nor of among-population body height or mass variation. These results are consistent with the idea that natural and sexual selection have reduced human height variation within populations, while maintaining it among populations. We therefore hypothesize that humans have evolved on a rugged adaptive landscape with strong selection for body height optima that differ among locations
As cold as a fish? Relationships between the Dark Triad personality traits and affective experience during the day: A day reconstruction study
The Dark Triad of personality is a cluster of three socially aversive personality traits: Machiavellianism,
narcissism and psychopathy. These traits are associated with a selfish, aggressive
and exploitative interpersonal strategy. The objective of the current study was to
establish relationships between the Dark Triad traits (and their dimensions) and momentary
affect. Machiavellianism, grandiose narcissism, vulnerable narcissism and the dimensions
of the Triarchic model of psychopathy (namely, boldness, meanness and disinhibition) were
examined. We used the Day Reconstruction Method, which is based on reconstructing
affective states experienced during the previous day. The final sample consisted of 270 university
students providing affective ratings of 3047 diary episodes. Analyses using multilevel
modelling showed that only boldness had a positive association with positive affective states
and affect balance, and a negative association with negative affective states. Grandiose
narcissism and its sub-dimensions had no relationship with momentary affect. The other
dark traits were related to negative momentary affect and/or inversely related to positive
momentary affect and affect balance. As a whole, our results empirically demonstrated distinctiveness
of the Dark Triad traits in their relationship to everyday affective states. These
findings are not congruent with the notion that people with the Dark Triad traits, who have a
dispositional tendency to manipulate and exploit others, are generally cold and invulnerable
to negative feelings. The associations between the Dark Triad and momentary affect were
discussed in the contexts of evolutionary and positive psychology, in relation to the role and
adaptive value of positive and negative emotions experienced by individuals higher in
Machiavellianism, narcissism and psychopathy
Tracking historical changes in trustworthiness using machine learning analyses of facial cues in paintings
International audienc