Death Row Inmate Uses Young Adult Brain Science to Argue Death Sentence is Cruel and Unusual

Recent Cases in Law and Neuroscience, Curated by the Center for Law, Brain & Behavior and the Shen Neurolaw Lab with support from the Dana Foundation

Center for Law, Brain & Behavior
3 min readMar 23, 2021
Above: Defendant La Twon Weaver — Image Source: San Diego Tribune

On December 15, 2020, a United States District Court in California granted a motion filed by La Twon Weaver, who was sentenced to death in 1993 for crimes he committed at age 23, to hold federal habeas proceedings in abeyance in light of Weaver’s arguments premised on new scientific consensus on brain development in younger adults.

In 1992, Weaver killed a store owner during a robbery. He was convicted of robbery, burglary, and first-degree murder in a San Diego Superior Court, and was sentenced to death.

Weaver appealed, and his sentence was affirmed. He filed several habeas petitions in the California Supreme Court. In 2019, Weaver filed a motion to hold federal habeas proceedings in abeyance while his state petitions are pending.

Relying on “newly-available advances in brain science and scientific research regarding physical brain maturity and its psychological consequences” and recent developments in the law in response to this brain science, Weaver alleged that trial counsel was ineffective because they did not investigate his mental health and cognitive condition before advising him to waive the jury during his trial. Weaver also contended that his death sentence and a sentence of mandatory life without parole (LWOP) constitutes cruel and unusual punishment because “he was 23 at the time of the offense and his brain development was incomplete and his culpability thus reduced.”

The state argued that the brain science cited by Weaver was available during his earlier petitions, contending that he could have used the science at that point. Weaver countered by asserting that the relevant science “had not reached the mainstream” at the time of his earlier petition, and that “[w]hile the theory that ‘emerging adulthood’ continued until age 25 was the subject of scientific investigation, the body of research did not produce a scientific consensus until after the petition was filed.” The U.S. District Court noted that “experts appear to each agree that a scientific consensus on the matter of brain development in younger adults has only been reached in recent years.” Because of this, the court found that “it is unclear how Petitioner could reasonably have brought such claims earlier” and was persuaded by Weaver’s claims.

The court therefore granted Weaver’s motion to hold the federal proceedings in abeyance and ordered Weaver to file a brief concerning the status of the state habeas petitions.

Key words: death penalty, LWOP, adolescent brain, emerging adult, California

Citation: Weaver v. Davis, 2020 WL 7353758

This post is the 37th post as part of an ongoing Center for Law, Brain & Behavior (CLBB) series tracking the latest developments in law and neuroscience cases. To see previous posts about recent cases, see the full case archive on the CLBB website. To see updates on legal scholarship, see the Neurolaw News, hosted by the MacArthur Foundation Research Network on Law and Neuroscience. This project is made possible through support of the Dana Foundation.