Rapid Genetic Evolution Linked to Lighter Skin Pigmentation in a Southern African Population

By Karen Nikos-Rose

Populations of indigenous people in southern Africa carry a gene that causes lighter skin, and scientists have now identified the rapid evolution of this gene in recent human history.

The gene that causes lighter skin pigmentation, SLC24A5, was introduced from eastern African to southern African populations just 2,000 years ago. Strong positive selection caused this gene to rise in frequency among some KhoeSan populations.

Brenna Henn

UC Davis anthropologist Brenna Henn and colleagues have shown that a gene for lighter skin spread rapidly among people in southern Africa in the last 2000 years.

Do You Have a Healthy Personality? Researchers Think They Can Tell You

By Karen Nikos-Rose

What are the most psychologically healthy personality traits? Scholars have been interested in characterizing the healthy personality as long as they have been trying to understand how people differ from one another. Researchers from the University of California, Davis have identified a healthy personality prototype in a recent study using a contemporary trait perspective.

Associate Professor of psychology Wiebke Bleidorn studies personality change.

Measuring Wear in Bone Tools

A UC Davis anthropologist has been building a catalog of high-resolution 3D models of bone tools worn by working various materials, all in the name of archaeology.

UC Davis graduate student Naomi Martisius with a rib bone she has shaped as a leather-working tool. Bone tools like these are often found in archaeological sites with the tips broken off.

Humans have been using bone tools for about two million years, and by about 100 thousand years ago were processing bones to make tools for specific purposes, such as working animal skins into leather. Both the way tools are made, and the way they are used, leave tiny marks on the bones that could give information about how these tools were prepared and used.

The Whole Tooth: New Method to Find Biological Sex From a Single Tooth

A team led by UC Davis researchers have come up with a new way to estimate the biological sex of human skeletal remains based on protein traces from teeth.

Tooth of a European-American buried in San Francisco in the 1850s. A new technique developed at UC Davis allows archaeologists
to find a person’s biological sex based on a single tooth. (Jelmer Eerkens)

Estimating the sex of human remains is important for archaeologists who want to understand ancient societies and peoples. Researchers can measure features of bones that differ between males and females, usually the pelvis. But skeletons of children and adolescents don’t show these structural changes, and often sites may only yield a few pieces of bone.

Diagnosing and Treating Personality Disorders Needs a Dynamic Approach

By Karen Nikos-Rose

Someone who is “neurotic” does not necessarily show anger or anxiety in a given situation, even though those are generally accepted traits of a person with that personality style.

New UC Davis research suggests that lumping those with personality disorders into a package of traits should be left behind for more dynamic analysis instead. Those who study and treat people with personality disorders need to more deeply look at personality dynamics and variation over time, not just box people into specific categories or traits.

UC Davis psychologist Chris Hopwood wants to take a more dynamic view of personality traits and disorders.

How Rants on Social Media Can Come Back to Haunt You

UC Davis study finds that negative chat has a much longer tail and stronger snowball effect than positive chat

By Karen Nikos-Rose

We all know that those angry rants on social media can come back to hurt you—and sooner than you think. “Good,” positive chat resonates for a few seconds, generally, but negative chat, even in a chat room where exchanges happen more immediately than on Facebook or Twitter, persists for many minutes, new UC Davis research suggests.

Seth Frey

Cognitive scientist Seth Frey used millions of chat room messages to study how positive and negative messages reflected back to their senders.

If Pigeons Were Brilliant, Would They Flock?

UC Davis Study Finds People Flock, or Behave Similarly to Others, Despite Reasoning Abilities

By Karen Nikos-Rose

Crowd panics, market bubbles, and other unpredictable collective behaviors would not happen if people were smart about these things and just thought through their behavior before they acted. Right? That’s the perspective in economics, and even psychology and sociology.

Pigeons

“Let’s be smart about this, guys” (Via PBS.org)

But a UC Davis researcher looked at how people behave in simple reasoning games and found that people are usually driven to “flock,” or behave similarly to others in a given situation. Seth Frey, an assistant professor of communication at UC Davis, said this happens “even when people use the fancy reasoning processes that are supposed to make humans so special.”

Agricultural Index Insurance Pairs Economics, Natural Sciences For Climate Resilience in East Africa

By Alex Russell

For poor and subsistence farmers in developing countries, a severe drought, flood or other catastrophe can cost them everything. In response to these kinds of climate-related risks, farmers often choose to minimize their exposure to loss. They might avoid higher-cost improved seeds that promise bigger harvests or riskier but profitable cash crops. Both of these strategies can keep them poor.

Maize farmers in Tanzania. Agricultural index insurance could help small farmers like these invest in higher-value crops and increase their income.

Podcast: Intensive Training for Parents Referred to CPS Improves Child Physiology

Traumatic experiences, such as maltreatment as children, can influence how our mind and body react to stressful situations. UC Davis psychologist Paul Hastings and colleagues at the University of Washington have shown that intensive training for parents referred to Child Protective Services can improve physiological reactions to stress in their young children.

Listen: Three Minute Egghead: Parenting and Child Physiology (Soundcloud)

More information

Training for Parents Referred to CPS Improves Toddler’s Physiological Regulation (UC Davis News)

Listen to more episodes of Three Minute Egghead on Soundcloud or subscribe to the podcast on iTunes.

Study Challenges Evolution of How Humans Acquired Language

By Karen Nikos-Rose

A gene implicated in affecting speech and language, FOXP2, is held up as a “textbook” example of positive selection on a human-specific trait. But in a paper in the journal Cell on Aug. 2, researchers challenge this finding. Their analysis of genetic data from a diverse sample of modern people and Neanderthals saw no evidence for recent, human-specific selection of FOXP2 and revises the history of how we think humans acquired language.

Brain graphic

What makes us human? The FOXP2 gene has been associated with uniquely human language abilities. But a new study with a wider variety of people shows no evidence of selection for FOXP2 in modern humans. (Image by Brenna Henn, UC Davis)