Mirror test hints at surprising cognitive abilities in fish

A fish called a cleaner wrasse interacts with its reflection in a mirror placed on the outside of the aquarium glass at a laboratory in Konstanz, Germany in this image released February 6, 2019. (REUTERS)
Updated 10 February 2019

Mirror test hints at surprising cognitive abilities in fish

  • The test has been passed by great apes including chimpanzees, bonobos, gorillas and orangutans as well as dolphins, killer whales, an elephant and a magpie species, but failed by some other animals

WASHINGTON: A small tropical reef fish was able to recognize itself in a mirror, scientists said on Thursday in a finding that raises provocative questions about assessing self-awareness and cognitive abilities in animals.
The study involved experiments in which the fish species Labroides dimidiatus, called the bluestreak cleaner wrasse, was given a mirror self-recognition test, a technique developed in 1970 for gauging animal self-awareness.
In aquarium experiments at Osaka City University in Japan, the researchers applied a brown-colored mark on the fish’s body in a place that could be seen only in a mirror reflection.
The fish tried to remove the marks by scraping their bodies on hard surfaces after watching themselves in a mirror, but never tried to remove them without a mirror present, indicating they understood the reflection was of them, the researchers said. When a transparent, rather than brown, mark was applied, the fish never tried to remove it.
The four-inch-long (10-cm) species consumes parasites and dead tissue off skin of other reef fish in a relationship benefiting both. The brown mark’s color resembled the color of these parasites.
The fish “shows behaviors during the mirror test that are accepted as evidence for self-awareness in many other species,” said evolutionary biologist Alex Jordan of the Max Planck Institute for Ornithology in Germany, who led the study published in the journal PLOS Biology.
Jordan, however, questioned whether the test represents a reliable measure of animal cognitive abilities.
“I don’t claim that fish lack self-awareness, but rather that the minimal required explanation for the behaviors we observe in the mirror test does not require invocation of self-awareness, self-consciousness, or theory of mind,” Jordan said.
The test has been passed by great apes including chimpanzees, bonobos, gorillas and orangutans as well as dolphins, killer whales, an elephant and a magpie species, but failed by some other animals. Humans pass it at around 18 months old.
“I consider that there is a spectrum of animal consciousness, with some animals, likely primates, showing abilities closer to human consciousness,” Jordan said. “My point with this paper is not that fish are as smart as chimpanzees, but that the way we ask that very question across taxa (animal groups) needs to be re-evaluated.”
University at Albany evolutionary psychologist Gordon Gallup, who pioneered the mirror test, called the new study “not methodologically sound” and faulted the researchers for a “zeal to undermine the integrity” of the technique to appraise animal self-awareness.
Emory University primatologist Frans de Waal, who has studied mirror self-recognition in mammals, called the findings “interesting and provocative.”
“The hope is that this study will throw open the discussion about self-awareness in animals. Instead of the black-and-white distinction we have had thus far, that some animals have it and most of them don’t, we need to develop a more gradualist perspective,” de Waal said.


“Punch in the gut” as scientists find micro plastic in Arctic ice

Chief Scientist for the Northwest Passage Project Dr. Brice Loose drills an ice core in the Arctic as part of an 18-day icebreaker expedition that took place in July and August 2019 in the Northwest Passage, in a still image taken from a handout video obtained by REUTERS on August 14, 2019. (REUTERS)
Updated 15 August 2019

“Punch in the gut” as scientists find micro plastic in Arctic ice

  • The researchers said the ice they sampled appeared to be at least a year old and had probably drifted into Lancaster Sound from more central regions of the Arctic

LONDON: Tiny pieces of plastic have been found in ice cores drilled in the Arctic by a US-led team of scientists, underscoring the threat the growing form of pollution now poses to marine life in even the remotest waters on the planet.
The researchers used a helicopter to land on ice floes and retrieve the samples during an 18-day icebreaker expedition through the Northwest Passage, the hazardous route linking the Pacific and Atlantic Oceans.
“We had spent weeks looking out at what looks so much like pristine white sea ice floating out on the ocean,” said Jacob Strock, a graduate student researcher at the University of Rhode Island, who conducted an initial onboard analysis of the cores.
“When we look at it up close and we see that it’s all very, very visibly contaminated when you look at it with the right tools — it felt a little bit like a punch in the gut,” Strock told Reuters by telephone.
Strock and his colleagues found the material trapped in ice taken from Lancaster Sound, an isolated stretch of water in the Canadian Arctic, which they had assumed might be relatively sheltered from drifting plastic pollution
The team drew 18 ice cores of up to two meters in length from four locations, and saw visible plastic beads and filaments of various shapes and sizes. The scientists said the findings reinforce the observation that micro plastic pollution appears to concentrate in ice relative to seawater.
“The plastic just jumped out in both its abundance and its scale,” said Brice Loose, an oceanographer at the University of Rhode Island and chief scientist of the expedition, known as the Northwest Passage Project.
The scientists’ dismay is reminiscent of the consternation felt by explorers who found plastic waste in the Pacific Ocean’s Marianas Trench, the deepest place on Earth, during submarine dives earlier this year.
The Northwest Passage Project is primarily focused on investigating the impact of manmade climate change on the Arctic, whose role as the planet’s cooling system is being compromised by the rapid vanishing of summer sea ice.
But the plastic fragments — known as micro plastic — also served to highlight how the waste problem has reached epidemic proportions. The United Nations estimates that 100 million tons of plastic have been dumped in the oceans to date.
The researchers said the ice they sampled appeared to be at least a year old and had probably drifted into Lancaster Sound from more central regions of the Arctic.
The team plans to subject the plastic they retrieved to further analysis to support a broader research effort to understand the damage plastic is doing to fish, seabirds and large ocean mammals such as whales.
Funded by the National Science Foundation and the Heising-Simons Foundation in the United States, the expedition in the Swedish icebreaker The Oden ran from July 18 to Aug. 4 and covered some 2,000 nautical miles.