Birds of a feather flock together

The Pekingese owner with the turned-in nose, the rider with the horse's bit, the messy one whose street mutt is a guarantee for chaos in the apartment – the often surprising similarity between animal and owner, whether purely external or as 'character affinity', is a well-known, often ridiculed phenomenon.

Science has also pondered the similarity between humans and animals and offers several explanations for the astonishing parallels between the species: Genetic similarities determine kinship – for example, only 1.5 percent of genes decide between humans and apes; the similarity is 98.5 percent with chimpanzees. The dog shares 90 percent of its genes with humans and also ranks just behind apes and rabbits regarding the identity of its amino acids. Similar reactions to situations are therefore not purely coincidental, but already genetically predisposed.

Similar sociability or attractive opposites

Sometimes the external or even character similarity is so strong that the harmony immediately catches the eye. The similarity, which often seems coincidental, is usually based on the selection of the animal. Owners often unconsciously choose an animal that corresponds to them externally or character-wise. This is referred to as 'sympathy or resonance animal', freely based on the motto: 'Like attracts like'. Psychologists give people with a resonance animal good grades: The sympathy for the similar and kindred spirit means that the owner is also satisfied with themselves. One buys their animal just as one looks or is – type-wise, so to speak. And one wouldn't wear a suit that they don't like. When selecting the animal, if the similarity is often only latent, upbringing and mutual habituation fully express it. If one finds traits in older couples as if the man and woman were siblings, similarities can also be observed between the owner and dog over the years.

In partner selection, the same applies to many personality traits: 'Like attracts like'. For example, partners in a relationship should have a similar need for closeness or wish for a somewhat structured daily life. Furthermore, scientists have found that the cycles of women living together align and that spouses become seemingly or actually more similar over the years. The weight, which is most easily influenced by body measurements, is a good example of the 'approach' problem.

A study in England in 1982 found, among other things, that in cases where one partner is overweight, the other is at risk of doing the same. Conversely, this means that slimmer individuals also tend to live together more often. Similar observations can be made regarding other physical characteristics. There is homogamy (similarity choice) concerning the characteristics of eyebrows (height, density, shape) and eyelashes (length, curvature, density, color) as well as a clear homogamy in the mouth. This is particularly interesting since the first sexual contact usually occurs through the mouth. You kiss!

Among psychological traits, intelligence has been particularly studied for compatibility in couples. Here, a particularly strong homogamy has been found. This aligns with common experiences and can perhaps be explained as follows: A reasonably matching general intelligence is required for balanced communication between partners. Similar talents and interests also promote this. Additionally, shared interests facilitate contact. A comparatively strong homogamy has also been found for libido.

Regarding social traits, there is consistent homogamy. This is well documented in many studies, especially for social status or socioeconomic status, and remains unchanged. Other traits do not behave as clearly. Here, the individual combinations are decisive, so no blanket answer can be given about what fits and what does not. Whether two people harmonize in these traits depends on whether they are strongly, moderately, or weakly pronounced in them. Opposites are recommended, for example, when one partner shows an extremely strong assertiveness. Moreover, the interplay of several traits, the way they are combined and complemented in the individual, plays an important role.