Domain: Healthcare — Human Physiology
Target concept: Pupillary Light Reflex (Bright Light)

Video generation prompt: A person is seated facing forward. First, one of the eyes is observed under normal lighting conditions. A handheld flashlight is briefly directed toward this eye from the side. The observer watches the eye for a moment and then removes the light source.

Evaluation guide:
(i) Target concept: Neural reflex arc mediating rapid, involuntary pupil constriction in response to increased retinal light intensity.
Minimum mechanism: Intact afferent limb (optic nerve), central relay (pretectal nucleus), efferent limb (oculomotor nerve + ciliary ganglion), and effector (iris sphincter muscle); bilateral midbrain connectivity enabling consensual response.
(ii)Storyline: Frame 1–2: Baseline, seated person, forward gaze, ambient-lit visible eye showing dilated/medium pupil. Frame 3–4: Stimulus onset, flashlight enters from side, beam aligns with eye, light contacts cornea/iris. Frame 5–7: Response phase, ipsilateral pupil begins narrowing; within same frames, contralateral pupil narrows identically (no delay). Frame 8–10: Recovery, flashlight withdrawn, beam ceases, both pupils gradually relax toward baseline size. Perspective: Fixed frontal/slightly oblique viewpoint capturing full face and side-approaching flashlight; no camera movement; eye region always in focus and unoccluded.

Manual:
Experimental Procedure
1. Person seated, facing forward, one eye fully visible.
2. Handheld flashlight held adjacent to head, aimed at visible eye from side.
3. Flashlight briefly activated toward eye, then deactivated and removed.
Observation of Experimental Phenomena
Pupil of illuminated eye constricts during light exposure; contralateral pupil also constricts simultaneously (consensual reflex); both pupils return toward original size after light removal.
Summary of Experimental Principles
Pupillary Light Reflex (Bright Light): Retinal photoreceptors detect light → signal via optic nerve → pretectal nucleus → Edinger-Westphal nucleus → parasympathetic fibers → ciliary ganglion → sphincter pupillae muscle contraction → pupil constriction (ipsilateral and consensual).

Prompt Grounding rubric:
level_1: No seated person is shown; or the person's eye is never visible; or no flashlight appears anywhere in the shot; or there is no moment where a light source is aimed at the eye.
level_2: A seated, forward-facing person is shown, but the eye of interest is fully occluded for the whole clip, or a flashlight never appears alongside it; no side-directed lighting action toward the eye ever takes place.
level_3: A seated, forward-facing person is shown with one eye clearly visible and unoccluded; a handheld flashlight appears in frame positioned to the side of the head, oriented so it could illuminate that same eye; this side-approach framing is present even if the beam's on and off moments are not both clearly shown.
level_4: All score 3 elements are present, AND the flashlight is visibly switched on with a beam directed at the eye from the side, AND the same eye stays visible and unoccluded before, during, and after the light is shone on it.
level_5: All score 4 elements are present, AND all four stages appear in a single continuous, fixed-viewpoint shot in this order: the eye at rest under normal room lighting, the flashlight brought in from the side and switched on, the beam held on the eye for a clearly visible stretch of time, and finally the flashlight switched off and withdrawn.

Scientific and Causal Correctness rubric:
level_1: The eye being illuminated by the flashlight shows no narrowing at all while the light is on it: it either stays the same size, gets larger, or only the other (non-illuminated) eye appears to narrow while the lit one does not change.
level_2: The illuminated pupil does narrow at some point, but only after the flashlight has already been switched off or withdrawn, so the narrowing's timing is disconnected from the light exposure shown.
level_3: The illuminated eye's pupil visibly narrows while the flashlight beam is on it, with the narrowing starting only after the light reaches the eye (not before) and lasting for as long as the beam remains on; when only one eye is shown, no claim is made about the other eye.
level_4: All score 3 criteria hold, AND, whenever the other eye is also shown, that non-illuminated pupil is seen to narrow over a similar timeframe as the illuminated one (the consensual response), rather than staying the same size or widening; both pupils loosen back toward their starting size only after the flashlight is removed, not before.
level_5: All score 4 criteria hold, AND when both eyes are visible together, the two pupils narrow within a similar short window of each other, with neither eye lagging the other by a noticeably longer stretch than its own narrowing takes, AND neither pupil widens unexpectedly partway through the light exposure or right after the light is removed.

Spatiotemporal Consistency rubric:
level_1: The seated person's position or the flashlight's position jumps discontinuously between frames with no visible movement carrying it there; the visible eye briefly goes off-screen and reappears with nothing (hand, object, blink) explaining the gap; the room's ambient lighting cuts out completely and returns within a single frame; the eye region is replaced by a visibly different shot (a hard cut) partway through.
level_2: The person's head or shoulders rotate away from forward-facing by more than about 30 degrees at some point; the flashlight enters the shot from the front or above rather than from the side; the eye is blocked from view for more than a brief moment and then reappears; the flashlight's beam appears on the eye with no visible transition (present in one frame with none in the frame before it, and no beam seen approaching).
level_3: The person stays seated and facing forward for the whole clip; the flashlight stays near the side of the head, aimed at the same eye, without swinging to another angle; the eye stays visible and unobstructed in every frame; once the beam appears, it stays aimed at the same spot on the eye rather than sweeping around.
level_4: All score 3 criteria hold, AND the flashlight's distance from the head stays roughly constant rather than drifting closer or farther in a way that looks unintentional, AND the eye stays in roughly the same place in the frame with no unexplained camera pan, zoom, or jump, AND the ambient room lighting stays at a steady overall brightness throughout, aside from the flashlight's own beam.
level_5: All score 4 criteria hold, AND the flashlight's approach into position looks like smooth, natural hand movement rather than snapping into place, AND the pupil's narrowing (and widening, if shown) proceeds as one smooth continuous motion rather than jumping partway through or briefly reversing, AND the eye and surrounding face keep a consistent look, with no warping, doubling, or mismatched framing, from the first frame to the last.