Domain: Healthcare — Human Physiology
Target concept: Moro Reflex (Human Infant)

Video generation prompt: The caregiver supports the infant's head and upper body with both hands while the infant lies in a supine position. The caregiver then suddenly releases the head support downward by a few centimeters in one quick motion before immediately restoring full support with both hands.

Evaluation guide:
(i) Target concept: Vestibular-triggered startle reflex mediated by brainstem circuitry in response to perceived postural instability.
Minimum mechanism: Mechanical unloading of infant head must generate detectable linear acceleration signal via otolith organs → brainstem reticular formation → bilateral spinal motor neuron activation → synchronous upper/lower limb motor output.
(ii)Storyline: Frame 1–2: Stable supine infant with full bimanual head/upper body support. Frame 3–4: Onset of vertical lowering, head support reduces, triggering vestibular signal. Frame 5–7: Limb response initiates, arms abduct/extend, legs extend/abduct, all bilaterally symmetric. Frame 8–10: Support fully restored; limbs begin adduction/flexion. Perspective: Fixed frontal view, centered on infant torso/head; full visibility of both hands, infant face, and all four limbs throughout; no occlusion of reflex zone (shoulders, elbows, hips, knees).

Manual:
Experimental Procedure
1. Infant placed supine on flat surface.
2. Caregiver positions both hands to fully support infant head and upper back/shoulders.
3. Caregiver suddenly releases head support downward by a few centimeters — a brief, vertical, controlled motion (rapid, not gradual).
4. Caregiver immediately restores full head and upper body support.
Observation of Experimental Phenomena
Bilateral symmetric abduction and extension of arms, followed by adduction; simultaneous extension and slight abduction of legs — occurring *in response to the lowering phase*.
Summary of Experimental Principles
Moro Reflex is an involuntary primitive reflex in healthy newborns, elicited by sudden loss of head support; indicates intact brainstem function and vestibular-proprioceptive integration.

Prompt Grounding rubric:
level_1: No infant appears in the video, or no caregiver hands are shown; the infant is not shown lying face-up (supine); there is no visible hand contact supporting the infant's head/upper body, and no lowering-then-restoring motion of that support ever occurs; the scene shows an unrelated setting with no connection to infant care or physiology.
level_2: The infant is present and lying supine, but no caregiver hand actually rests on the infant's head or upper body at any point (hands hover nearby or touch elsewhere, such as the arms or feet); no clear lowering-and-restoring motion of head support is shown; a supporting surface or nursery object (crib, mat, blanket) appears, but the caregiver's support action itself is never performed.
level_3: The infant lies supine while the caregiver's hands visibly rest on both the head and upper body at the same time; a downward lowering of the head support happens, followed by a restoring motion; however, the transition between lowering and restoring is not fully continuous (there is a visible pause or reset), or the support is incomplete at some point (e.g., only one hand touches the head during part of the support phase).
level_4: The infant lies supine while the caregiver uses both hands together to fully support the head and upper body; the lowering motion is a clearly separate, brief dip, and the restoring motion follows it right away; contact between the hands and the infant's head/upper body never breaks during either motion; no unrelated action interrupts the sequence (no repositioning the infant, no turning the head), and the support-lower-restore sequence proceeds in the order given.
level_5: The infant lies supine with the head in a neutral, straight alignment; the caregiver's palms fully cradle the head while the other hand supports the upper back and shoulders; the lowering motion moves straight down, is brief, and shows no side-to-side tilt or twist; the restoring motion begins as a direct continuation of the same movement and re-establishes the identical two-handed support configuration; contact with the head and upper body is never lost, no hand slips or repositions mid-motion, and the support region stays visible in every frame.

Scientific and Causal Correctness rubric:
level_1: No Moro-reflex-like limb response occurs: the infant's arms and legs stay still throughout, or the infant only shows an unrelated reflex (such as rooting or sucking); there is no visible connection between the change in head support and any limb movement.
level_2: The infant moves its limbs, but not as a mirrored, two-sided response, for example only one arm extends outward while the other stays still or moves differently, or the legs stay still or flex unevenly; the limb movement happens well before the support change starts or long after it ends, and it looks more like a slow, drifting movement than a sudden startle.
level_3: Both arms swing outward and extend together, then draw back in; both legs extend and spread slightly at the same time as each other; the movement matches the Moro reflex pattern, but it only begins after the caregiver has already restored full support, rather than during the drop itself, leaving a noticeable delay between the support change and the limb response.
level_4: Both arms swing outward and extend together, matched by both legs extending and spreading slightly, starting during the lowering motion itself or right as it finishes, then drawing back inward as support is restored; the response is bilateral and symmetric with no one-sided lag, no delayed onset (the response must begin within roughly one visible beat of motion after the lowering completes, not well after the drop), and no voluntary-looking movement (such as reaching or kicking at an object) mixed in.
level_5: The arms begin swinging outward within the very first moment the head support starts to drop, continue smoothly through the full lowering, and swing back inward exactly as support is restored; the legs extend and spread slightly in the same instant as the arms, all four limbs moving together in matching range and timing; there is no hesitation, no one-sided or partial response, and no voluntary movement layered on top; the full, symmetric Moro reflex plays out precisely in step with the caregiver's motion.

Spatiotemporal Consistency rubric:
level_1: Basic physical continuity fails: the infant's head, torso, or a limb jumps to a different position or angle between adjacent frames with no connecting motion, one of the caregiver's hands vanishes from the frame without a visible release, the mat or crib surface beneath the infant changes pattern or shape mid-sequence, or an arm or leg appears detached from its shoulder or hip joint.
level_2: The camera view drifts away from centering on the infant's torso and head, or the fixed frontal framing shifts enough that one of the reflex zones (a shoulder, elbow, hip, or knee) moves in and out of frame; a caregiver hand overlaps the infant's head at an anatomically implausible angle before correcting itself; the infant's head rotates more than roughly a quarter turn with no corresponding neck motion; the lowering-to-restoring hand motion shows a visible skip rather than one continuous path.
level_3: The caregiver's hands stay in contact with the infant's head and upper back throughout, the infant remains centered under the fixed frontal camera framing, and both shoulders, both elbows, both hips, and both knees stay visible without being cut off or blocked at any point. The mat/crib background keeps the same pattern and position from first frame to last, with only minor unsteadiness in the hand-lowering path or slight camera wobble that never breaks the visible connection between infant and caregiver hands.
level_4: The infant's head, torso, and all four limbs stay in anatomically correct alignment relative to the caregiver's hands across every frame, with the hands never overlapping each other or the infant's face in an impossible way. All four reflex-zone joints (shoulders, elbows, hips, knees) remain continuously visible and unoccluded, and the mat/crib surface and camera framing stay fixed and unchanging throughout. The vertical lowering-and-restoring hand motion reads as one smooth, uninterrupted path.
level_5: Every frame preserves exact anatomical continuity: the infant's supine posture holds steady except for the limb motion of the reflex itself, and the caregiver's hands travel only in a straight vertical path during the lowering and restoring, with no sideways drift, no independent finger movement, and no wrist rotation. Each limb's motion visibly originates from its correct joint (shoulder, elbow, hip, or knee), all four joints stay fully visible in the fixed frontal frame at all times, and the mat/crib background and camera framing never shift even slightly at any point in the sequence.