Infants and Adults Are Sensitive to the Costs of Upright Versus Non‐Upright Locomotion
Bibliographic record
Abstract
Variety in locomotor forms-upright (e.g., walking) versus non-upright (e.g., crawling)-reflects a "decision" about how to move. A decision about whether to move upright or non-upright reflects the costs incurred from getting into and moving in a particular posture-energy, stability, time, comfort, and so on. Are infants and caregivers sensitive to the immediate costs of upright and non-upright locomotion? We tested bout-level sensitivity to the costs of locomotor form in groups with different locomotor skills and body size (24 crawling and 24 walking infants and their caregivers). To encourage both short and long bouts, dyads played with toys clustered in a pile and toys dispersed around the room. Most critically, all groups showed bout-level sensitivity to the costs of upright and non-upright locomotion-they factored in their starting posture, typical mode of locomotion, and travel distance when deciding how to move. Walkers and caregivers only moved non-upright if they were already seated and traveled short distances; otherwise, they walked. Conversely, crawlers only moved upright if they were already standing and traveled short distances; if they were seated or moved long distances, they crawled. Moreover, across toy conditions, crawlers moved less than walkers and caregivers moved less than infants. Both crawlers and walkers displayed longer bouts when toys were dispersed, and caregivers mirrored their infants' activity. Thus, despite infants' propensity to move, babies-like adults-are indeed sensitive to the costs of upright versus non-upright locomotion. SUMMARY: Infants and caregivers showed bout-level sensitivity to locomotor costs by accounting for starting posture and travel distance when deciding whether to move upright or non-upright. Walkers and caregivers crawled when starting non-upright and traveling short distances; otherwise, they walked. Crawlers walked when starting upright and traveling nearby; otherwise, they crawled. Infants and caregivers moved more when toys were dispersed than when toys were clustered. Walkers moved more than crawlers, and infants moved more than caregivers. Despite infants' willingness to accumulate large amounts of seemingly gratuitous locomotion, infants, like adults, are sensitive to the varying, dynamic costs of different locomotor forms.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".