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Defense questions memory expert in Castro murder

• Lighting conditions also arise as issue.

Posted: April 11, 2008 1:18 a.m.
Updated: June 12, 2008 5:02 a.m.
SAN FERNANDO - The second day of defense testimony in the Castro trial turned technical, as defense attorney Peter Korn questioned an expert in the field of eyewitness memory and visual perception.

Esperanza Castro, 45, is accused of killing her husband, Ramon, in the bedroom of their Canyon Country home on March 22, 2006, then leaving his body on Sierra Highway in the bed of his pickup ttruck. It was found the next morning.

Earlier testimony in the trial revealed that Julie Piercy and Tony Garcia, neighbors who live across the street from the Castro home, saw Esperanza and Ramon Castro arguing in the garage of their Evron Street home on the night of the murder. Shortly thereafter Garcia saw an unknown man help Mrs. Castro place a large object into Ramon's truck.

Garcia said he saw a man with a cowboy hat and a mustache in a vehicle parked outside the house that same evening.

During Thursday's questioning, Korn seemed to be trying to create reasonable doubt amongst the jurors about the testimony of those witnesses. Without specifically referring to the conditions on Evron Street on the night of March 22, Dr. Scott Fraser talked of how low light conditions and natural neurological processes can sometimes lead witnesses to incorrectly identify people.

Fraser, a Stanford and New York University-trained neurophysiologist, said that a person can only discern enough detail in a human face to make a correct identification if there is enough light present and if the person is close enough to be seen well. He presented a graph which visually represented a mathematical formula of the exact light and distance combinations required to see someone clearly, within the limitations of the human eye.

The graph indicated that visual acuity drops dramatically after 60 to 80 feet in low light conditions.

Fraser added that in the event that a clear view of facial features is not available, the human brain often fills in missing details in a process called "conscious transference." In this process, the brain creates a memory of the details from prior experience or logical inference based on factors such as the familiarity of the place or the similarity of known individuals to the unknown person. Fraser said that despite the name, this is actually not a conscious process, but rather is an involuntary function of the brain, which cannot tolerate a void.

"If it is important to identify a person where we are unclear who it is, we are far more likely to select a person who is previously associated with a context or place than someone who is not," he said.

Fraser also testified as to the light conditions on Evron Street between 10 p.m. and midnight on March 14, 2007, the night he went to the street to make an analysis of the area. He said that light levels were low, due to the fact that only two streetlights and two porch lights were illuminating the street.

He estimated that the distance between the porch of the Garcia house and the driveway of the Castro residence was about 100 to 110 feet.

Judge Burt Pines did not permit Fraser to speculate if the light conditions on the night of his analysis were the same as those that existed on the night of March 22, 2006, or whether the conditions would allow for a positive identification of a suspect by a witness.

He did, however, allow Fraser to use astronomical reference materials to describe the phase and position of the moon on the night in question. He said that it did not rise until shortly after 2 a.m. on March 23, and set around 11:30 a.m. that same day. Since the moon was not present between 10 p.m. and midnight on the night of March 22, he said it would not have provided any ambient light on the neighborhood.


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