State v. Rac, 124 N.E.3d 878

Davor Rac was indicted for felony domestic violence (third-degree) based on an alleged assault of his live-in girlfriend; a jury later acquitted him.
After empaneling but before openings, the trial court gave extended preliminary jury instructions emphasizing the fallibility and malleability of human memory (drawing on cognitive-memory concepts). The State objected.
The court omitted the detailed memory material from its final instructions; the jury returned a not-guilty verdict.
The State sought and received leave to appeal the trial court’s preliminary-memory instructions under R.C. 2945.67(A); several amici filed briefs.
The appellate court reviewed whether the court abused its discretion or misstated the law by (on its own initiative) giving detailed memory-science instructions without evidentiary foundation or adversarial vetting.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the trial court erred by giving preliminary jury instructions on the fallibility of memory that amounted to opinion rather than law	Trial: instructions adopted untested expert opinion, unsupported by controlling law, and thus improperly presented as legal guidance	Rac: court’s instructions were permissible discretionary preliminary guidance and reflected admissible, relevant concepts about witness credibility	The court sustained the State’s assignment: the trial court abused its discretion by giving those detailed memory instructions without evidentiary foundation or established Ohio authority; not a demonstrated error of law, but improper under the facts here
Whether detailed memory/identification instructions were appropriate on these facts (defendant known to witness; no contested identification)	Trial: instructions were unnecessary and not specifically applicable; they risked overemphasizing memory issues and were not tailored to the case	Rac: memory issues are always relevant to credibility and the court may acquaint jurors with weighing testimony	Held: instructions were not specifically applicable and thus were an abuse of discretion in this case; limited, neutral instructions might be appropriate but required foundation or expert testimony first

State v. White, 142 Ohio St.3d 277 (Ohio 2015) (jury instructions must be correct, pertinent, and appropriate to the facts)
Bistricky v. State, 51 Ohio St.3d 157 (Ohio 1990) (State may seek discretionary appeal of substantive law rulings resulting in acquittal)
Daubert v. Merrell Dow Pharm., 509 U.S. 579 (U.S. 1993) (court must ensure scientific expert opinion rests on reliable foundation and is relevant)
State v. Henderson, 208 N.J. 208 (N.J. 2011) (surveyed memory/identification science and endorsed enhanced jury guidance on eyewitness reliability)
Commonwealth v. Gomes, 470 Mass. 353 (Mass. 2015) (proposed model instructions reflecting generally accepted memory principles; cautioned that instructions require evidentiary support)
State v. Mahmoud, 147 A.3d 833 (Me. 2016) (permitted juror instruction on eyewitness reliability where relevant; cautioned when witness already knew the identified person)