Smiles responsively at caregiver's face and voice

social.attachment.social_smile

socialrelational2mo–2.5y

Measured by 2 instruments· Cross-instrument confidence:

What this is

Infant produces a true social smile in response to a familiar caregiver's face, voice, or gaze — distinct from reflexive neonatal smiling.

Instrument	Approach	Age range	Mapping confidence	Ref
M-CHAT-R/F Modified Checklist for Autism in Toddlers, Revised, with Follow-Up	Parent screening report Subscale: Autism risk indicators	16mo–2.5y		q11
Bayley-4 Bayley Scales of Infant and Toddler Development, Fourth Edition	Clinician observation (developmental) Subscale: Social-Emotional	1mo–3.5y		social_emotional.social_smile

“Approach” describes how the instrument assesses this construct, not the specific items. We never reproduce proprietary test items.

Consensus window: 16mo–2.5y (all 2 instruments overlap).

Baseline: developmental_24mo_en_gbAge: 2yLocale: en-GBTone: mixed

“If you catch {child_name}'s eye and give {him_her} a big smile, do you usually get a smile back?”

Follow-up: “Is smiling-back something {he_she} does easily with you, or does it take warming up?”

Not yet

Rarely smiles back, even when looking at you

Emerging

Occasionally returns a smile

Developing

Usually smiles back when you smile first

Secure

Freely exchanges smiles throughout the day

The same canonical item shows up on the developmental page with prerequisites, activities, and full developmental context.

M-CHAT-R/F
Robins, D.L., Casagrande, K., Barton, M., Chen, C.M., Dumont-Mathieu, T., Fein, D. (2014). Validation of the Modified Checklist for Autism in Toddlers, Revised With Follow-Up (M-CHAT-R/F)
doi:10.1542/peds.2013-1813
Bayley-4
Aylward, G.P. (2020). New Bayley-4 Normative Data: Implications for Clinical Practice
doi:10.1097/DBP.0000000000000739