Domain: Healthcare — Human Physiology
Target concept: Righting Reflex (Cat)

Video generation prompt: Lift the cat gently to a certain height while it is in a supine position, then release the support. Allow the cat to naturally adjust its body posture during the fall. Record the entire process and briefly use slow motion to highlight the changes in posture.

Evaluation guide:
(i) Target concept: Vestibular-proprioceptive integration enabling gravity-referenced self-orientation in absence of external torque.
Minimum mechanism: Intact vestibular system (semicircular canals + otolith organs), functional cervical proprioceptors, intact descending brainstem-spinal pathways, and unconstrained freedom of movement (no air resistance dominance, no tethering, no surface contact during maneuver).
(ii)Storyline: [Phase 1: Baseline] Cat stationary, supine, eyes open, limbs symmetrically extended; visible full ventral surface. [Phase 2: Perturbation] Hands lift vertically → hands withdraw completely → cat separates from support → first frame of unsupported flight. [Phase 3: Response Initiation] Head rotates ≥45° horizontally while torso remains aligned; visible chin movement relative to sternum. [Phase 4: Propagation] Forelimbs draw in toward the chest while hindlimbs extend outward as the front half of the body (head, shoulders, spine) rotates toward upright; the hindquarters then follow with the reverse limb posture (hindlimbs draw in, forelimbs extend) as the rear half completes its turn; the front-half and rear-half rotations overlap in time rather than one finishing before the other starts, consistent with the cat redistributing its rotational inertia through limb posture instead of using any external torque. [Phase 5: Completion] All four paws point downward, spine horizontal, head forward, tail neutral, sustained for ≥1 frame before contact. Perspective constraint: Fixed frontal or 30° oblique view showing full body silhouette; no occlusion of head, spine, or paws during Phases 3–5.

Manual:
Experimental Procedure
1. Place cat gently on flat surface in supine position (belly up, limbs extended).
2. Lift cat vertically upward to ~30 cm height, maintaining supine orientation.
3. Release all support abruptly — allow cat to fall freely without rotation assistance.
4. Record full fall until cat achieves upright posture mid-air or contacts surface.
Observation of Experimental Phenomena
Cat initiates rapid head rotation first, then twists torso, tucks forelimbs, extends hindlimbs, and aligns all four paws downward before landing — all while airborne and unsupported.
Summary of Experimental Principles
Righting Reflex (Cat): Vestibular and proprioceptive input triggers brainstem-mediated spinal motor output, enabling cats to reorient mid-air via asymmetric limb positioning and spinal bending — independent of visual input and requiring no external torque.

Prompt Grounding rubric:
level_1: No cat is present; or the cat is not in a supine (belly-up) position at the start; or no lifting of the cat is shown; or the support is never released; or no falling/airborne motion is shown at all.
level_2: The cat is present and starts supine, but the lift is missing or incomplete (e.g., cat is lifted but never released); or the support is released but the cat never becomes airborne (e.g., it slides off a surface instead of falling freely); or the cat lands, or the shot cuts away, before any posture change begins.
level_3: The cat starts supine, is lifted to a height, the support is fully withdrawn from view, and the cat becomes airborne with its body still extended for at least one clearly visible moment before it begins to turn; all of these setup steps are shown unambiguously and in order.
level_4: All 3-point conditions are met, AND the cat's full body silhouette (head, spine, and all four paws) stays visible and unoccluded for the entire mid-air sequence, AND no supporting hand, strap, sling, or other visible aid touches or appears near the cat after release, AND the camera holds the fixed frontal or ~30°-oblique framing specified without cutting away during the turn.
level_5: All 4-point conditions are met, AND the entire fall, from the moment of release to the cat reaching its final airborne posture, is shown as one continuous, unedited shot (no cuts, no reframing, no zoom changes) with the cat fully inside the frame at all times; if slow motion is briefly used to highlight the posture change, as called for in the prompt, it plays within that same continuous take with a smooth speed transition and no skipped or dropped frames, rather than needing to cover the entire fall in slow motion.

Scientific and Causal Correctness rubric:
level_1: No coordinated righting response is shown: the cat lands on its back or side, or shows no rotational reorientation at all, or its head, torso, and limbs appear to rotate together as one rigid, locked unit with no independent motion between body segments.
level_2: A rotation begins, but the head does not visibly lead it (e.g., the torso and head turn together, or the hindquarters begin rotating before the head does); or the forelimbs and hindlimbs move identically throughout (neither pair tucks while the other extends), giving no visible means for the body to twist without an external push; or the cat appears to rotate through more than a full 360° turn without ever settling into an upright orientation, which is not anatomically plausible for a single righting maneuver.
level_3: The head visibly turns toward an upright orientation before the trunk has fully followed, and at some point during the fall the front half of the body (head, shoulders, tucked forelimbs) and the back half (hips, extended hindlimbs) show visibly different rotation timing or limb posture from each other, consistent with the two halves twisting somewhat independently rather than as a single rigid rod; the cat reaches at least a partially upright orientation (e.g., two or more paws angled toward the ground) before any surface contact.
level_4: All 3-point conditions are met, AND the differential limb posture is visible in both parts of the maneuver: forelimbs drawn in close to the body while hindlimbs extend outward as the front half turns, then the reverse (hindlimbs drawing in while forelimbs extend) as the rear half completes its turn, AND the cat ends the visible sequence without any leftover twist about its long axis relative to the direction of fall.
level_5: All 4-point conditions are met, AND by the end of the visible fall the cat reaches a fully upright posture (head level, spine roughly parallel to the ground, all four paws oriented toward the landing surface), with the front-half and back-half rotations visibly overlapping in time rather than one finishing before the other begins, matching the compact, near-simultaneous character of the real righting reflex rather than a slow, segment-by-segment crawl through the turn.

Spatiotemporal Consistency rubric:
level_1: The cat vanishes and reappears mid-fall, or the video cuts abruptly between two non-continuous moments of the fall; or the background changes abruptly; or the light in the scene switches from bright to dark (or the reverse) between one moment and the next; or the cat's body visibly stretches, tears, or merges with another object unnaturally.
level_2: A noticeable but less severe break: the cat's apparent size changes noticeably during the fall without any change in camera distance to explain it; or the cat's shadow separates from its body and stays disconnected for more than two consecutive frames; or the camera jerks or rotates without the cat or the camera moving in a way that would explain it; or the supporting hand vanishes from view before the release is complete.
level_3: The cat stays visible for the whole fall, without vanishing or reappearing; the room background and light level stay the same throughout; the cat's body never snaps to a new position or distorts into an impossible shape; its motion looks continuous, without freezing, stuttering, or repeated frames; the camera stays at roughly the frontal or slightly-angled position described in the prompt rather than jumping to an overhead or extreme low angle.
level_4: All 3-point conditions are met, AND the cat's joints bend within realistic limits (no inverted paws, no elbow or knee bending the wrong way), AND the cat's overall path through the air follows a smooth, gravity-consistent arc rather than a jagged or wandering path, AND the head, spine, and paws stay visible and unobstructed during the turning motion.
level_5: All 4-point conditions are met, AND the whole motion looks smooth from start to finish: the turning motion neither snaps on instantly nor pauses partway through, and the fall does not slow down before any landing unless a landing is actually shown; every part of the cat's body (limbs, spine, head) moves in a way that looks physically coupled to the rest of the body, with no limb appearing to move independently of the torso.