Skip to main content

Negative emotional contagion and cognitive bias in common ravens (Corvus corax)

A team of researchers affiliated with institutions in Austria, the U.S. and Switzerland has found evidence of negative emotional contagion in lab ravens. In their paper published in Proceedings of the National Academy of Sciences, the group describes their experiments with lab ravens and what they learned.

Emotional contagion describes the emotional state of one person impacting that of another, followed by a cascade of subsequent impacts in other people. In such a scenario, one crabby person could conceivably push an entire crowd into crabbiness. In this new effort, the researchers report that ravens apparently have some form of negative emotional contagion, as well.

Dlium Negative emotional contagion and cognitive bias in common ravens (Corvus corax)

To find out if ravens are impacted by the moods of another in close proximity, they paired eight of the birds and put each pair through an experiment. Both birds were given a choice between a box containing nothing and one with cheese, which the birds like to eat. After several trials, the birds learned which box held the cheese and which one was empty.

The researchers presented them with a third box and then noted how they both behaved. This part of the experiment was known as a cognitive bias test, intended to measure the degree of optimism or pessimism. Next, the birds were separated, and one was given a choice between eating carrots, which ravens do not really care for, or dried dog food, which they like.

The other raven (the observer) could see how its comrade was behaving, but was not allowed to see which choices it was given. Afterward, both of the birds were given the cognitive bias test again.

The researchers report that the observer ravens that had watched their paired comrade behave badly took much longer to investigate the third box presented to them, suggesting they had been negatively emotionally impacted by watching their fellow raven behave negatively.

Those observer ravens who had witnessed normal behavior, on the other hand, also exhibited normal behavior when tested. The researchers suggest their experiments indicate that ravens can experience negative emotional contagion.

Journal : Jessie E. C. Adriaense et al. Negative emotional contagion and cognitive bias in common ravens (Corvus corax), PNAS, May 20, 2019, DOI:10.1073/pnas.1817066116

Comments

Popular

Guinea grass (Panicum maximum)

Guinea grass or buffalo grass or green panic ( Panicum maximum ) is a plant species in Poaceae, annual grasses, growing upright to form clumps, strong, cultivated in all tropical and subtropical regions for very high value as fodder. P. maximum reproduces in very large pols, fibrous roots penetrate into the soil, upright stems, green, 1-1.5 m tall and have smooth cavities for diameters up to 2.5 mm. Propagation is done vegetatively and generatively. Ribbon-shaped leaves with a pointed tip, very many, built in lines, green, 40-105 cm long, 10-30 mm wide, erect, branched, a white linear bone, often covered with a layer of white wax, rough surface by hair short, dense and spread. The flower grows at the end of a long and upright stalk, open with the main axis length to more than 25 cm and the length of the bunches down to 20 cm. Grains have a size of 3x4 mm and oval. Seeds have a length of 2.25-2.50 mm and each 1 kg contains 1.2 - 1.5 million seeds. Guinea grass has two varieties. P

Temulawak (Curcuma zanthorrhiza)

Temulawak or Java ginger or Javanese ginger or Javanese turmeric or Curcuma xanthorrhiza ( Curcuma zanthorrhiza ) is a plant species in Zingiberaceae, grows well in loose soil in tropical forests in the lowlands to an altitude of 1500 meters above sea level and tubers are used for medicinal herbs and drinks. C. zanthorrhiza has pseudo stems up to 2 m tall. The stem is a midrib of upright, overlapping leaves, green or dark brown in color. Rhizomes are perfectly formed, large, branched and reddish brown, dark yellow or dark green. Each bud forms 2-9 leaves with a circular shape extending to lancet, green or light purple to dark brown, leaves 31-84 cm long and 10-18 cm wide, stems 43-80 cm long and each strand is connected with a midrib. Flowers are dark yellow, uniquely shaped and clustered with lateral inflorescences. The stems and scales are in the form of lines, 9-23cm long and 4-6cm wide, having protectors with comparable crowns. Petals are white, hairy and 8-13mm long. The

Giant green leech (Raksasa hijau)

Lintah raksasa or giant green leech ( Raksasa hijau ) is a species of animal in Salifidae, large green leeches, carnivores, not hematophagic, can grow to lengths of more than 50 cm, the front is perfectly tubular, but it is getting bigger, wider and flat backward. R. hijau has a front end that ends with a white mouth and has a width equal to the diameter of the front end of the body. The rear end ends with the anus and has a width equal to the diameter of the rear end of the body. The upper surface is whole dark green or leafy green, looks shiny and has no other additional color features. The bottom surface is lighter or brownish green. The skin is wrinkled like tight, elastic joints that make it possible to lengthen the body. Giant green leech moves forward by extending the tip of the front of the body to keep the new location farther away and this movement is then followed by the middle body and gradually the rear where the body moves completely. R. hijau does not suck blo