Terry Johnson appeals from a Supplemental Judgment of the district court denying his motion to change custody of the parties’ minor children, Jeremiah and Jacob, from their mother, Joli Johnson, to Terry. Because the district court’s finding that there has not been a significant change of circumstances since the original *435custody decree warranting a change of custody is not clearly erroneous, we affirm.
After a six-year marriage, Terry and Joli were divorced in December 1988. The parties stipulated that other matters such as property division, child custody, and spousal support would be determined at a later date. On May 16, 1990, the district court entered a decree, awarding Joli custody and settling the other unresolved divorce-related issues, based upon a stipulated agreement between Terry and Joli.
Between the entry of the divorce decree in December 1988 and the original custody decree in May 1990, there was a thorough and on-going investigation of allegations made by Jeremiah that his father, Terry, had sexually abused him. Jeremiah had graphically described instances of abuse which implicated Satanic cult practices by his father and unrelated persons while the family was living in the mountains of Northern Idaho. Although the experts involved in the investigation, including psychologists and social workers, were perplexed about the origin of these allegations by Jeremiah, who was only four years old when he first made them, they were unable to substantiate that Jeremiah had ever been abused by Terry or others.
On August 7, 1990, Joli filed a motion requesting permission to move to Minnesota with the boys. Terry resisted the motion, and on August 21,1990, filed a motion for a change of custody. The district court held a hearing on December 19, 1990, to consider both motions. During the proceedings, Joli withdrew her motion for permission to leave North Dakota. At the conclusion of the hearing, the district court denied Terry’s motion for a change of custody, and Terry then filed this appeal.
An original custody award revolves solely around a determination of what is in the best interests of the child. Miller v. Miller, 305 N.W.2d 666 (N.D.1981). However, a request to modify an original custody award requires a determination by the court of two issues in chronological order: (1) whether there has been a significant change of circumstances since the original custody award; and, if so, (2) whether the significant change of circumstances requires, in the best interests of the child, that the court change custody. Wright v. Wright, 431 N.W.2d 301 (N.D.1988). The burden is on the party seeking modification to demonstrate that there has been a significant change of circumstances which requires a change in custody. Lapp v. Lapp, 336 N.W.2d 350 (N.D.1983). The trial court’s determination on a motion to modify an original custody award is subject on appeal to the clearly erroneous standard of review under Rule 52(a), N.D.R.Civ.P. Therefore, the trial court’s findings will not be set aside unless they are clearly erroneous. Ebertz v. Ebertz, 338 N.W.2d 651 (N.D.1983).
In denying the motion for a change of custody, the trial court found that there had been no significant change of circumstances since the May 1990 custody award that “indicate[s] that the best interests of the children would be served by a change in custody.” The trial court also made specific findings that since the original custody award Joli and the boys have moved into a home apart from her parents with whom they had been living at the time the original decree was entered, that the structured visitations with Terry “have been working smoothly” and that the school-aged boy, Jeremiah, “is doing very well in school.”
On appeal, Terry asserts that the trial court erred in finding that there was not a significant change of circumstances to warrant a custody change. More specifically, Terry asserts that Joli continues to believe Jeremiah’s allegations that, while living in Idaho, Terry abused him in satanic rituals and that because of Job’s anger and distrust of Terry she attempts to sabotage Terry’s relationship with the boys.
Prior to the December 19, 1990, hearing, Terry, Joli, and the two boys were reevaluated by three psychologists: Dr. Barney Greenspan, Dr. Jim Wahlberg, and Dr. James Brandt. Dr. Brandt and Dr. Wahl-berg concluded from their evaluations that Jeremiah and Jacob should remain in Job’s custody. Terry primarily relies upon Dr. *436Greenspan’s report and testimony to support his request for a change of custody.
Dr. Greenspan is the Chief of Psychological Services at the North Central Human Service Center in Minot. Dr. Greenspan evaluated this family prior to the original custody award. At that time he concluded that Jeremiah has “an enormous loyalty conflict” toward his parents. He concluded that the relationship between Terry and Jeremiah has been “deliberately and systematically sabotaged” by Joli. Nevertheless, Dr. Greenspan made a reserved recommendation that it was in the best interests of Jeremiah to continue to live with Joli, contingent, however, upon her supporting Terry and Jeremiah’s relationship.
In his subsequent evaluation of the parties, after Terry had moved the court for a change of custody, Dr. Greenspan observed that “the central issue in this ongoing struggle is Jeremiah’s conflicts regarding parental loyalty.” He stated that while Jeremiah is living with Joli “he feels compelled to degrade and blame” Terry. Dr. Greenspan stated that he did not suspect Joli was consciously directing Jeremiah in that direction, but that “the damage has already been done.” After concluding that it would be appropriate to change custody of the boys to Terry, Dr. Greenspan offered some of these final thoughts:
“Jeremiah is a youngster at risk, psychologically speaking. I believe his mother has truly interfered with his healthy development of a working conscience. I worry about his future ability to distinguish reality from fantasy, the ways in which his anger could manifest itself, and how his guilt feelings will interfere with his emotional growth and development. ...
“Jeremiah will do fine living with his father, although he will undoubtedly tell mother the opposite to please her. If Mr. Terry Johnson is denied custody at this juncture, Jeremiah will learn that deceit, deception, and neurosis rule the day. As long as Ms. Joli Johnson is convinced of her previous allegations about Mr. Johnson, she will attempt to do whatever she can to interfere with the father/sons relationship....”
While testifying at the motion hearing, Dr. Greenspan was asked what his recommendation would be now about Jeremiah and Jacob’s custody. He responded,
“Well, considering there has to be a recommendation one way or the other, I recommend that custody go with the father and the reason that I say that is that I don’t feel Mrs. Johnson has given enough due credence to the father-child relationship to be able to support that and defend that and protect that....”
He was also asked what he had observed as to the relationship between Jeremiah and Joli. He responded that they had a “caring, loving, kind, meaningful relationship.” Later in his testimony, Dr. Greenspan stated that he had no doubt that Joli gives the boys good care and is a good mother. Dr. Greenspan testified that he was bothered by Job’s “delusional” belief that Terry had been involved in some type of satanic cult activity in Idaho and had, at that time, abused Jeremiah. However, Dr. Greenspan testified that Job’s unfounded belief in this specific matter does not extend to other areas and “doesn’t interfere ostensibly with other aspects of her functioning.”
Dr. Wahlberg holds a doctorate degree in social work as well as a bachelor’s degree in psychology and sociology. He is a professor at Minot State University and also does consultant work in his field. Dr. Wahlberg also reevaluated the family. He concluded that custody should remain with Job. He recommended that both Terry and Job be encouraged to refrain from using the children to get at their own unresolved personal problems. Dr. Wahlberg described Jeremiah as a delightful and energetic boy who is well-mannered, well-behaved, and very likeable. He concluded that Jeremiah’s allegations of past happenings could neither be substantiated nor denied. However, he believed that the counseling Terry, Job, and Jeremiah were receiving would help them deal with unresolved issues from the divorce.
Dr. James Brandt is a professor of psychology and Director of the Student Coun*437seling Center at Minot State University. He is a staff psychologist at St. Joseph’s Hospital and the Medical Arts Clinic, and he is also a consultant with Trinity Hospital in Minot. He also reevaluated Terry, Joli, and the boys. Dr. Brandt concluded that “all parties want what is best for the children,” and that both parents would provide a good home for them. Dr. Brandt testified that Joli is well capable of caring for the children and has very strong bonding with them. He stated that although Joli continues to believe that Terry abused Jeremiah in the past, there is “nothing wrong with her thinking in all other areas.” Dr. Brandt testified that it is possible that some abuse of Jeremiah did occur but that “[i]t’s just very hard for me to believe that much has happened to him.” Dr. Brandt indicated that Job’s persistent belief that Terry had abused Jeremiah was perpetuated by professionals who had examined Jeremiah in Minneapolis and Seattle and “threw up red flags.” Dr. Brandt stated that a parent faced with this situation would certainly investigate every possibility surrounding the child’s allegations out of concern for the child. Dr. Brandt concluded that it would be in the boys’ best interests to remain with Joli.
In addition to the psychologists’ reports and testimony, the trial court had other evidence to consider, including a letter, to the court from the boys’ guardian ad litem and the testimony of both parents.
In a letter, Gerald Rustad, the boys’ guardian ad litem, told the court that both parents have love and affection for the children and that both of them could provide a completely adequate home for the boys. He noted that Jeremiah is doing very well in school and that both boys’ clear preference is to live with Joli. Rus-tad told the court that he did not spend considerable time worrying about the “change of circumstances” standard that the court must utilize, but that he would recommend, in the best interests of the children, that they reside with Terry, subject to very liberal visitation with Joli.
Terry testified at the hearing that he has obtained a job as a soil conservationist at Forsyth, Montana, where he and his present wife, Sissy, reside with her two teenage boys. Terry agreed that Jeremiah is “progressing well in school,” and getting A’s on his report card. Terry concedes that since the original custody award visitations have “gone good” and that although picking the boys up was at first a problem “lately, it has been getting better.” Terry testified that during the early visitations Jeremiah was real bad about telling lies, but that now “he doesn’t do that too much anymore.” He also testified that he has been able to reestablish a very good relationship with the boys. Terry also testified that the boys are excited about moving into a new trailer house with their mother. When asked during cross-examination if the urgency of his motion for a change of custody had changed when Joli withdrew her motion to leave North Dakota, he responded, “[y]eah, the urgency has — of it has definitely changed; yes.”
Joli also testified at the hearing. Regarding Jeremiah’s allegations of abuse Joli testified, “I really want it to be over.” She testified that she does not encourage Jeremiah to talk about the past, and that she especially refrains from discussing with him the subject of abuse. She also testified that she has no objection to Terry seeing the children, and that she does the best she can to see that the boys’ visitations with Terry proceed smoothly, without trauma.
The trial court concluded that in the few months between the time when Joli was awarded custody of the boys and when the court was asked to change custody there had not been a significant change of circumstances. Although there was conflicting testimony by the experts on factors relevant to this issue, there was substantial evidence upon which the trial court could reach the conclusion that it did.
This court limits its scope of review, recognizing the trial judge’s ability to ascertain the demeanor and credibility of witnesses. Ebertz v. Ebertz, 338 N.W.2d 651 (N.D.1983). Although the trial court cannot arbitrarily disregard expert testimony, the court, as the trier of fact, can *438assign the weight to be given to an expert’s testimony, and the court is not required to accept an expert’s opinion as being conclusive. Gardebring v. Rizzo, 269 N.W.2d 104 (N.D.1978); see also Cross v. Cross, 374 N.W.2d 346 (N.D.1985). The court obviously gave greater weight to the expert conclusions of Dr. Wahlberg and Dr. Brandt than it gave to the opinion of Dr. Greenspan. However, it is not apparent that the trial court arbitrarily disregarded any of the relevant evidence.
Every expert was in agreement that Joli is a fit mother who has provided good care for the boys and has bonded very well with them. There was no evidence to the contrary.
Dr. Greenspan concluded that Joli should no longer have custody of either boy because she continues to harbor beliefs that Jeremiah was probably abused by Terry in the past. Dr. Brandt and Dr. Wahlberg disagreed. They recognized that Joli is not without reasons for persisting in her belief. Ultimately, Dr. Brandt concluded that there had been very little, if any, actual abuse of Jeremiah in the past. However, Dr. Wahlberg was less certain of what occurred, and he indicated that perhaps no one will ever really know.
One could reasonably conclude from Terry and Job’s testimony that Joli has not sabotaged Terry’s relationship with the boys, but instead, has allowed that relationship to grow and to improve. Terry even testified that, during the period following the original custody award, he has been able to establish a good relationship with the boys and that visitations have continued to improve and are now going smoothly.
In addition, the court undoubtedly took into consideration that both boys have lived their entire lives with Joli, that they have strong bonds with her, and that they have developed quite well in most aspects of their lives. With regard to Jeremiah’s apparent tendency to lie and to confuse reality with fantasy, the court obviously gave consideration to Job’s continued efforts to get counseling for herself and for Jeremiah, and to the fact that Jeremiah is improving.
The trial court should order a change of custody only for a compelling reason, not upon a finding that some marginal improvement in a child’s life may occur. Orke v. Olson, 411 N.W.2d 97 (N.D. 1987). Furthermore, a trial court should be more reluctant to modify a decree that is based upon a stipulation of the parties rather than upon findings made by the court. See Wheeler v. Wheeler, 419 N.W.2d 923 (N.D.1988). With these principles in mind, and having reviewed the entire record, we are not convinced that the trial court made a mistake. There is substantial evidence to support the trial court’s finding that there has not been a significant change of circumstances since the original custody award that warrants a change of custody at this time.
In accordance with this opinion, the Supplemental Judgment of the district court, denying Terry’s motion for a change of custody, is affirmed.
LEVINE, J., concurs. Justice H.F. GIERKE III, a member of the Court when this case was heard, resigned effective November 20, 1991, to accept appointment to the United States Court of Military Appeals and did not participate in this decision.