Tag: high school

Animals can lie to themselves too

Like Humans, Crayfish Talk a Tough Game

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Self-deception like this seems very human. Now, thanks to a recent study led by an Arizona State University biologist, for the first time we know that it happens in the animal kingdom, too.

Crayfish are some of the most aggressive creatures on earth. They fight with big claws capable of doing real damage. But sometimes there’s not much muscle under the bravado.

“What males are doing is making as little crappy muscle as possible, which is energetically saving,” said Michael Angilletta, a biology professor in the School of Life Sciences.

It’s like buying designer knockoffs. You save a lot of money, and most people can’t tell the difference. In the case of crayfish, you make a big claw without much muscle, and you put crappy muscle on it to boot. Everyone sees you wave your big claw and they presume that you’re a powerful crayfish.

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“Since they signal to each other before fighting, this is a way they can convince someone to back down without fighting,” Angilletta said. “Importantly, this only works if there’s enough crayfish out there that have big claws that are actually strong. If you accidentally fight one of those and call a bluff, you’re going to lose a claw.”

In the crayfish world, losing a claw is a disaster: It takes up to two years for a claw to regenerate. In the meantime, no one is mating with anyone who has a puny claw. 

Angilletta and his co-authors have been studying self-deception in crayfish for about 10 years. In 2006 they accidentally discovered that many crayfish with big claws were quite weak. There was about a tenfold variation.

“You would go, ‘Oh, this (pinch) is going to hurt,’ but it doesn’t hurt at all,” Angilletta said. “The question is are they not trying, or are they really not strong? And it’s repeatable from day after day with the same individuals.”

They combined mathematical modeling with an experiment to show that crayfish meet the criteria for self-deception. This approach opens up the possibility of studying self-deception in nonhuman animals, without being able to talk to them. They used 97 adult males, staging fights between 20 select crayfish and 77 opponents.

“How do we know what a crayfish would do if it knows whether it’s weak or it’s strong?” Angilletta asked. “If it knows that (it has a weak claw), it should actually be less aggressive.”

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It might escalate up to the point of a fight, and then run away. The probability that a crayfish engaged in a fight depended on two factors: the relative size of its claws and the expected difference in force. How do they know how strong (or not) they are? Crayfish use claws to deter predators, defend territory and capture prey. They have a pretty good idea of how strong their own claws are. They’re also skilled at assessing their size versus an opponent’s. They can even recognize previous opponents.

So natural selection has given them an ability to detect size and identity. Given that they have those abilities, it naturally follows that they have an ability to gauge strength when knowing it will improve decisions.

“In our population of crayfish, deceptive signalers largely ignored their own strength when escalating or evading aggression,” Angilletta said. “If this benefit of heightened aggression outweighs any long-term cost, natural selection should favor individuals who escalate aggression through self-deception.”

In other words, they buy into their own bluff. Angilletta teaches a biology course on human behavior called “Why people steal, cheat, and lie,” which explores the ecological and evolutionary causes of selfishness and cooperation in human societies.

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“What’s new about this study is that if you’re ever in a situation where I’m lying to you, there’s also a possibility I’m selling my lie exceptionally well because I’ve convinced myself that it’s true,” he said. “That’s because of self-deception. It’s very common in psychology but it’s not really that much in biology because we’re usually thinking about nonhuman animals and we don’t know what they’re thinking. We have a hard time understanding what they know and don’t know.”

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The paper was published last summer in Behavioral Ecology.

Video Credits:  Ken Fagan, ASU

Photo Credit: Charlie Leight, ASU

About ASU

Arizona State University has developed a new model for the American Research University, creating an institution that is committed to access, excellence and impact. ASU measures itself by those it includes, not by those it excludes. As the prototype for a New American University, ASU pursues research that contributes to the public good, and ASU assumes major responsibility for the economic, social and cultural vitality of the communities that surround it.

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Autism Study Stresses Importance of Communicating with All Infants

Photo by Zoltan Tasi

Language Skills Can Benefit from Parents’ Early Support, Interactions.

University of Texas at Dallas

Dr. Meghan Swanson, assistant professor at The University of Texas at Dallas, is the corresponding author of the study, published online June 28 in Autism Research. It is the first to extend research about the relationship between caregiver speech and infant language development from typically developing children to those with autism. The findings could inform guidelines for earlier action in cases of developmental difficulties.

A new language-skills study that included infants later diagnosed with autism suggests that all children can benefit from exposure to more speech from their caregivers.

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“You can diagnose autism at 24 months at the earliest; most people are diagnosed much later. Early intervention, from birth to age 3, has shown to be effective at supporting development in various cohorts of children,” said Swanson, who joined the School of Behavioral and Brain Sciences in January as the director of the Infant Neurodevelopment & Language Research Lab, known as the Baby Brain Lab.

She said there has been a push to identify autism earlier or demonstrate that the same techniques that help most children develop language skills also benefit those eventually diagnosed with autism.

The study involved 96 babies, 60 of whom had an older sibling with autism. Swanson said that this “baby-sibling” research design was necessary.

“How do you study autism in infancy when you can’t diagnose it until the kids are age 2 at least?” she asked. “The answer relies on the fact that autism tends to run in families. These younger siblings have about a 20% chance of being diagnosed eventually with autism.”

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Indeed, 14 children from the high-risk subset of 60 were diagnosed with autism at 24 months.

The study results directly tied the number of words an infant hears, as well as the conversational turns he or she takes, to the performance on the 24-month language evaluation — both for typical children and those with autism.

“One conclusion we’ve come to is that parents should be persistent in talking with their babies even if they aren’t getting responses,” Swanson said.

Swanson emphasized how important large, longitudinal studies — tracking the same individuals across an extended period — like this one are in her field.

“You have to follow the same children for years to learn anything conclusive about development,” she said. “You can’t simply shift from a group of 2-year-olds to a different group of 3-year-olds and so on.”

Correcting the misunderstanding of parents’ influence in autism has been a gradual fight against outdated conceptions, Swanson said.

“When parents receive an autism diagnosis for a child, some might wonder, ‘What could I have done differently?’” she said. “There is no scientific backing for them to think in these terms. But there is a dark history in autism where parents were wrongly blamed, which reinforced these thoughts. To do research involving mothers as we have, you must approach that topic with sensitivity but also firmly reinforce that the logic that parenting style can cause autism is flawed.”

The children’s interactions with caregivers were recorded over two days — once at nine months and again at 15 months — via a LENA (Language Environment Analysis) audio recorder. The children’s language skills were then assessed at 24 months.

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“The LENA software counts conversational turns anytime an adult vocalizes and the infant responds, or vice versa,” Swanson said. “The definition is not related to the content of the speech, just that the conversation partner responds. We believe that responding to infants when they talk supports infant development, regardless of eventual autism diagnosis.”

The project was undertaken by the Infant Brain Imaging Study (IBIS) network, a consortium of eight universities in the United States and Canada funded by the National Institutes of Health as an Autism Center of Excellence. Before joining UT Dallas, Swanson was a postdoctoral fellow at the University of North Carolina at Chapel Hill, one of IBIS’ study sites. The other study sites are Children’s Hospital of Philadelphia, Washington University in St. Louis, the University of Washington in Seattle and the University of Minnesota Twin Cities campus.

Dr. Joseph Piven, the IBIS network’s principal investigator, is the director of the Carolina Institute for Developmental Disabilities at UNC-Chapel Hill. For parents, the results should highlight the long-term effect of initiating conversations from an early age, he said.

“Talking to your kids makes a big difference,” Piven said. “Any impact on early language skills will almost certainly have an impact on a wide range of later abilities in school-age children and significantly enhance their probability of success.”

Swanson said the most important takeaway from this work is that parents can make a significant difference in language development, even in children who are eventually diagnosed with autism.

“Parents can be amazing agents of change in their infants’ lives from as early as 9 months old,” she said. “If we teach parents how to provide their children with a rich communication environment, it helps support their children’s development. I find that incredibly hopeful — the power that parents have to be these positive role models.”

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In addition to UT Dallas and the IBIS study sites, researchers from Temple University, Perelman School of Medicine at the University of Pennsylvania, McGill University and the University of Alberta contributed to this study. The Simons Foundation also supported the research.