The opinion of the court was delivered by: Pigott, J.:
This opinion is uncorrected and subject to revision before publication in the New York Reports.
In this case, turning on the accuracy of eyewitnesses' recognition of an assailant's partially concealed face, we consider whether two additional eyewitness identifications sufficiently corroborated the victim's identification of the defendant, so as to render expert testimony on eyewitness recognition memory unnecessary. We conclude that they did not, and that it was error to exclude much of the proposed testimony.
In the early morning of January 10, 2003, a woman waiting for a train at a Manhattan subway station was attacked by a stranger. She had noticed the man when, after they made eye contact on the platform, he stepped behind a pillar before approaching her. When he was an arm's length away from her, the man asked whether she was "working." When she inquired what he meant, he asked if she was an escort. After she looked away and said "No," the man began assaulting her. She closed her eyes while raising her hands to protect herself. She could not tell whether her assailant had a weapon. After about ten seconds, the attack stopped, and the assailant fled.
The victim was assisted by workers at the station, who, along with the police, searched fruitlessly for the assailant.
An ambulance transported her to a hospital where she was treated. At the hospital, the victim gave detectives a description of her attacker, a Hispanic male, late 20s or early 30s, five feet, eight inches to five feet, nine inches tall, with a mustache and a goatee. To one detective, the victim described her assailant's "brown/yellow mustache."
The man was wearing a winter jacket, a hooded sweatshirt or "hoodie," jeans, and a "winter hat." The jacket, hoodie and hat together covered the assailant's head in such a way that his face was concealed "from the middle of his top lip, down, and from the top of his eyebrows up." The victim could not see her assailant's hair, except for his eyebrows and mustache. On the day after the attack, the victim was interviewed by a police artist who created a sketch of the perpetrator.
Police detectives visited the subway station in search of eyewitnesses. Edwin Rios, who had seen the assault, described the assailant as a Hispanic male in his mid- to late 20s, with a goatee, wearing a hood. The assailant had passed Rios after the attack, carrying a knife. Later, police located another witness, Pablo Alarcon, who had noticed the assailant beforehand because the man's facial expression made Alarcon nervous. After the attack, Alarcon saw the assailant put a knife away as he fled. Alarcon also described the perpetrator as a Hispanic male with a goatee. Police officers showed Rios a copy of the artist's sketch of the perpetrator; Rios thought it was "more or less" accurate.
On January 19, 2003, a plain-clothes police officer patrolling a subway station in Brooklyn noticed a man in a winter jacket, jeans and winter cap selling Metrocard "swipes." Later, the officer saw the same man engaged in the same activity at the next stop. The officer arrested the man, defendant Edwin Santiago, and his photograph made its way to the detective squad investigating the January 10 attack.
An array comprising photographs of six men and including defendant's arrest photograph was shown to Alarcon on January 22. He claimed not to recognize defendant or any of the other men in the array. The victim viewed the photographic array on January 24. She testified that, when she saw the photograph of Santiago, it felt as if her "heart stopped and [she] got really scared and  said that that was him."
Santiago, who had been released, was rearrested the following day, at a shelter for the homeless. A photograph taken after the second arrest shows Santiago with a dark mustache and goatee. He was 30 years old and five feet, five inches in height.
On January 26, the victim identified Santiago in a six-person line-up. According to the victim, when she saw defendant, she felt "really scared" -- it was, once again, as if her "heart stopped" and she "knew it was him." On the same day, Alarcon viewed the line-up. As he later explained at defendant's suppression hearing and trial, he recognized defendant as the perpetrator of the attack with an "eighty percent" feeling of confidence in his identification, but, because he was concerned about his immigration status, he told the police that he did not recognize anyone. The following day, Alarcon saw a photograph of Santiago in handcuffs, accompanied by police officers, in a Spanish-language newspaper; the article made it clear that Santiago had been identified by the victim of the subway attack and arrested.
Santiago was indicted by a grand jury on a first-degree assault charge ...