NEW WESTMINSTER, B.C. - Accused serial murderer Robert Pickton has an average IQ, though it's at the very low end of average, an expert who tested Pickton testified Monday.

Pickton scored an 86, Larry Krywaniuk told Pickton's trial Monday. Scores between 85 and 115 are considered average.

Krywaniuk, an expert in administering and interpreting intelligence quotient tests, told jurors Pickton seems slow and inaccurate when it comes to processing information.

Krywaniuk conducted an IQ test on Pickton last year to gauge his verbal and performance skills and another test aimed solely at his verbal skills. The second test was given to him again earlier this year.

As Krywaniuk testified, Pickton sat in the witness box appearing disinterested.

Krywaniuk said Pickton scored an 80 for verbal tests, which put him in the lowest 10 per cent of the population. His performance score was 95, which put him in the 37th percentile or 37 out of 100, Krywaniuk told defence lawyer Adrian Brooks.

Krywaniuk told Crown lawyer Mike Petrie under cross-examination that Pickton's overall IQ score was 86.

Krywaniuk also hesitantly agreed under cross-examination that 68.2 per cent of the population falls within that 85-115 range.

He suggested the 86 score was "not a fair representation."

"Your job was to determine his IQ and it was 86," said Petrie.

"There are other ways to look at it. . .The number is accurate," Krywaniuk conceded, "but the interpretation has to be qualified. What it means is a little bit indeterminate."

Pickton's IQ test took place at the jail in Port Coquitlam where he has been in custody since his arrest in February 2002.

Krywaniuk said he only conducted the tests and did not interview Pickton, nor did he read any police reports or Pickton's statements to police after his arrest.

Petrie suggested that conducting other observations and making inquiries might have helped in his conclusions about Pickton's IQ.

Pickton is standing trial for six counts of first-degree murder in the deaths of Sereena Abotsway, Mona Wilson, Georgina Papin, Marnie Frey, Brenda Wolfe and Andrea Joesbury.

The trial began in late January and a second trial on an additional 20 counts of murder is expected to follow at a later date.

Krywaniuk testified Pickton was given two tests known as Peabody tests, which try to measure verbal skills.

In the first test, conducted last year, the witness said Pickton had a score that put him on a level of a person of a little more than 11 years old.

The second test, said the expert, resulted in a higher score that he testified put Pickton at a level of 27 out of 100.

Not all of Pickton's tests, however, yielded low scores, said the witness.

A subtest of the IQ exam, known as the "matrix reasoning score" resulted in a score that put him in the top 10 per cent of the population.

The defence has earlier maintained Pickton didn't understand what police were saying to him when he made statements during an 11-hour interrogration and also with an undercover policeman who was placed in his cell.

Brooks asked Krywaniuk what problems someone with Pickton's verbal test scores might encounter in an interview situation.

Krywaniuk said there might be concerns about Pickton's ability to understand "ideas and words he encounters" as well as potential problems with keeping "a lot of things in him mind at any given time."

"His short-term recall is not good," said Krywaniuk.