Defence invokes 'invisible' gorilla

Joanne Wang. Photo / Supplied

Lawyers for a man accused of murdering a woman in a hit-and-run yesterday showed someone dressed as a gorilla walking through a group of ball-throwing people to show how a person under stress could miss something.

Christopher Wilkinson-Smith called psychologist Joseph Sakdalan to give evidence during the murder trial of Christopher Shadrock in the High Court at Auckland.

Shadrock, 23, denies murdering Joanne Wang but admits manslaughter.

Mrs Wang received fatal head wounds after she was struck by a car driven by Shadrock. She was trying to retrieve her handbag containing a large sum of money which Shadrock had snatched from her in the Manukau shopping centre carpark on June 16, 2008.

The Crown alleges Shadrock chose to drive forward into her to escape because cars had blocked him in behind.

Shadrock says Mrs Wang was on the passenger's side of the car, not directly in front, when she fell after being hit.

Dr Sakdalan said people in stressful situations did not always see things they normally would, especially if there was a lot of movement.

To illustrate, he used film from an American university of six people throwing balls at one another in a test where observers had to count the number of times the ball was thrown.

During the test, someone in a gorilla suit walked through the scene. The observers were then asked if they noticed anything unusual.

Just over half - 54 per cent - saw the gorilla.

Dr Sakdalan said people could miss something during a dynamic event depending on where their attention was focused.

Prosecutor Christine Gordon, SC, said the study showed that blindness could occur, not that it always would. The doctor agreed.

Earlier, Mr Wilkinson-Smith told the jury the Crown had to convince them that in the few seconds before Shadrock accelerated forward he knew his action would be lethal.

He said the jurors had to put aside any feelings they had about the bag-snatching.