EVIDENCE - CREDIBILITY OF OPINION WITNESSES
Testimony has been introduced of certain witnesses who purport to be skilled in their line of endeavor or who possess peculiar knowledge acquired by study, observation, and practice.
You may consider the testimony of these witnesses, and give it such weight and value as you think it should have, but the weight and value to be given their testimony is for you to determine. You are not required to surrender your own judgment to that of any person testifying, based on that person's education, training or experience. You need not give controlling effect to the opinion of such witnesses for their testimony, like that of any other witness, is to be received by you and given such weight and value as you deem it is entitled to receive.
This instruction is similar to an instruction approved by the Court of Criminal Appeals in Sharp v. State, 1965 OK CR 133, 407 P.2d 593. In order to reduce the likelihood that the jury will give undue deference to opinion testimony, references to expert witnesses have been removed from the instruction and replaced by the term "opinion witness testimony." The admissibility of opinion testimony, both from lay witnesses and experts, is governed by 12 O.S. 1991, §§ 2701-2705.
In Toms v. State, 95 Okl. Cr. 60, 239 P.2d 812 (1952), the Court of Criminal Appeals stated:
[Expert testimony is permissible any time] when the conclusions to be drawn by the jury depend on the existence of facts which are not common knowledge and which are particularly within the knowledge of men whose experience or study enables them to speak with authority on those facts, and in those cases in which the conclusions to be drawn from the facts stated, as well as knowledge of the facts themselves, depend upon professional or scientific knowledge or skill not within the range of ordinary training or intelligence.
Id. at 66, 239 P.2d, at 818. An expert is not allowed to testify as to matters which are generally within the knowledge or understanding of most persons. Gossett v. State, 1962 OK CR 75, 373 P.2d 285; Plumlee v. State, 1961 OK CR 42, 361 P.2d 223.
When an expert witness is permitted to testify, he may testify not only as to the facts, but also as to opinions and conclusions drawn from the facts. Toms v. State, supra. However, the jury is not bound by the testimony or conclusions of the expert. Barnhart v. State, 1956 OK CR 105, 302 P.2d 793; Toms v. State, supra.
The Court of Criminal Appeals has determined that the jury should be instructed that evidence in the form of expert testimony is not conclusive upon their factual findings, but should be afforded whatever weight the jury deems it is entitled to receive. Rouse v. State, 1979 OK CR 31, 594 P.2d 787; Peterson v. State, 1970 OK CR 93, 473 P.2d 293; Daggs v. State, 1957 OK CR 95, 317 P.2d 279; Barnhart v. State, supra; Toms v. State, supra. Although the failure so to instruct the jury has been found to be a basis for modification of sentence, rather than reversal of conviction, it was stated in Daggs, supra.
In some cases, the failure to so instruct might constitute grounds for reversal, and in others grounds for modification because of the great weight the jury might attach to such expert testimony in the absence of an instruction covering the same, especially if the results of the case hinged on the expert testimony. Failure to so instruct, in such event, might constitute a material failure.
1957 OK CR 95, ¶ 7, 317 P.2d at 282.