[Experiment] Surprise / Bug-Eyes Expression Prompts | 10 Conditions, 30 Images

Conclusions First

• surprised, shocked, exaggerated shock, and jaw drop all stably produce surprise expressions in 3 out of 3 images. Widely opened eyes, open mouth, and both hands on cheeks are consistently generated
• wide eyes, bulging eyes, bug eyes, and eyes popping are weak as surprise expressions — eyes widen only slightly. Mouth stays closed and pose doesn’t change in most cases
• Cartoonish exaggeration of “eyes popping out” was not generated in any condition. This appears to be a limitation of photorealistic models
• comedic surprise caused an anime-style visual change in 1 out of 3 images
• surprised is the simplest and most effective keyword for stable surprise expressions

Experiment Design

Base Prompt

upper body + frontal composition used to observe expression changes.

A00: control

seed 1	seed 2	seed 3

Observation: All 3 show a calm closed-mouth expression. Eyes are natural size with no widening. Gaze is toward camera or slightly sideways. Hands naturally at the sides. This serves as the expression baseline.

A01: surprised

seed 1	seed 2	seed 3

Observation: Clear surprise expression in all 3 images. Eyes clearly more widened than control with increased white sclera area. Mouth open in 2 out of 3 (s2, s3); both hands on cheeks in all 3. s1 has hands covering the mouth with widened eyes. Very large difference from control.

A02: shocked

seed 1	seed 2	seed 3

Observation: Surprise expression in all 3 images — very similar to surprised. Widely open eyes, open mouth, and hands on cheeks consistently generated. s1 has hands covering the mouth. Visual difference from surprised is small — similar level of surprise expression.

A03: wide eyes

seed 1	seed 2	seed 3

Observation: Mouth closed in all 3. Eyes slightly more open than control but difference is small. s1 has a sideways composition making the change hard to confirm. s2 near-profile with slightly wider eyes. s3 is calm. No hands-on-cheeks pose generated. Being interpreted as a physical instruction “open eyes wide” rather than “surprise.”

A04: bulging eyes

seed 1	seed 2	seed 3

Observation: Mouth closed in all 3, no surprise pose generated. s1 is a bust shot from the side with slight eye change but neutral expression. s2 changes to a split-panel composition with two faces, eyes slightly open but expression is calm. s3 is a frontal close-up with slightly larger eyes but no surprise expression reached. Side effect of composition shifting to close-up was observed.

A05: eyes popping

seed 1	seed 2	seed 3

Observation: 1 out of 3 (s1) shows widened eyes with a tense expression but mouth is closed. s2 is sideways with calm expression — no surprise elements. s3 faces forward with calm expression. No cartoonish eye-popping effect generated at all — effect is unstable.

A06: bug eyes

seed 1	seed 2	seed 3

Observation: Mouth closed in all 3, no surprise pose generated. s1 is a close-up where iris color changes to light (blue-to-gray) with larger-appearing pupils. s2 similarly has lighter-colored, larger-appearing pupils. s3 faces forward with small eye change. The tendency is to affect pupil color and size rather than physical eye size. Composition tends to shift to close-up.

A07: exaggerated shock

seed 1	seed 2	seed 3

Observation: Surprise expression in all 3 images. Widely open eyes, open mouth, and hands on cheeks consistently generated — similar output to surprised and shocked. No additional exaggeration from “exaggerated” was confirmed. Cartoonish eye-popping was not generated. Remains within realistic surprise expression range.

A08: jaw drop

seed 1	seed 2	seed 3

Observation: Surprise expression in all 3 images. Eyes widely open and mouth open. Hands on or near the cheeks/chin in all 3. Mouth opening tends to be slightly larger compared to surprised. s1 shows a particularly wide-open mouth with the jaw visibly dropped. True to its name — close to a “dropping jaw” expression.

Note: jaw drop is notable for how wide the mouth opens. Surprise-related keywords tend to come with the “hands on cheeks” pose attached as a package — a template-like pattern, but consistent and easy to work with.

A09: comedic surprise

seed 1	seed 2	seed 3

Observation: 2 out of 3 (s1, s3) produce realistic surprise expressions with wide eyes, open mouth, and hands on cheeks. However, 1 out of 3 (s2) shows a side effect of the art style shifting to anime/illustration style. “Comedic” appears to have triggered a departure from photorealism. A keyword to avoid when consistently targeting photorealistic images.

Summary

Results for all 10 conditions:

Surprise expression prompts fell into two clear groups:

Strong and stable group: surprised, shocked, exaggerated shock, and jaw drop all stably generate eye widening, mouth opening, and hands-on-cheeks pose as a package. jaw drop in particular produces the widest mouth opening — effective for emphasizing the degree of surprise. However, differences between the 4 conditions are small — surprised alone is sufficient for most needs.

Weak and unstable group: wide eyes, bulging eyes, eyes popping, and bug eyes all specify physical eye changes but are hard to use as surprise expressions. Mouth stays closed and pose doesn’t change. Side effects like composition shifting to close-up or pupil color changes may occur.

Cartoonish “eyes popping out” exaggeration was not generated in any condition with this photorealistic model. Realistic models only express faces within the range of what could actually exist — if cartoonish effects are desired, using an anime-focused model should be considered.

Note: surprised alone is sufficient for surprise expressions. It’s notable that physical eye specifications like wide eyes and bulging eyes don’t work well, while specifying an emotion triggers everything — eyes, mouth, and pose — together as a package.

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