Sarah and Jennifer Hart and their six adopted children were believed to be in the SUV at the time.
While socio-economic and cultural background are often considered the most influential factors in a child's ability to succeed at school, Hancock said the research demonstrates that children's family history - particularly in relation to their grandparents - is of upmost importance.
Photo The Harts' vehicle was recovered off Highway 1, near Westport, Calif., on March 26.
A Kansas mother is upset after her 4-year-old child came home from daycare with several missing teeth.
Washington state authorities began investigating the Harts for possible child neglect a few days before the five bodies were recovered.
A boat team recovered the deceased juvenile about 7 miles (11 kilometers) south of where the family's SUV fell into the rain-swollen Eel River last week, Mendocino County Sheriff Thomas Allman told a news conference in the community of Leggett. Officials found no skid marks to indicate sudden acceleration or braking, according to a search-warrant affidavit.
"Everything they did that night was wrong", she said.
Wife Sarah Hart and two of the dead children had "an ingredient that's commonly found in [the over-the-counter allergy medication] Benadryl", in their systems when they perished, but it's not clear what authorities are making of that finding, the captain added. The office was still waiting on toxicology results from a third child. The authorities were still searching for the other three children: Hannah, 16; Devonte, 15; and Sierra, 15.
Child Protective Services also monitored the home on March 27, unaware the family had been in a crash in Mendocino County, California.
KGW obtained a 911 call that provided further clues to what was happening when the Harts left their Washington home and drove to California.
Devonte Hart gained fame when this picture of him hugging officer Johnny Nguyen at a Portland rally went viral.
Baarts said items were retrieved from the home during the search, including computers, credit cards and bank statements. "That was the first room I hit when we were able to go inside with the Fire Department and it was really hard to see", said Lori, a retired special educator at Noble High School.
The Hart home in Woodland, Wash. "It's not right and they don't care".
Toxicology tests found that Jennifer Hart had an alcohol level of.102, according to California Highway Patrol Captain Bruce Carpenter.
The Oregonian obtained court records from Texas that shows the paternal aunt of Devonte, Sierra and Jeremiah Hart repeatedly tried to gain custody of the kids but was denied in 2010.