How do young children learn to use everyday artifacts-doorknobs, zippers, and so on-in the ways they were designed to be used? Although the designed actions of such objects seem obvious to adults, little is known about how young children learn the "hidden affordances" of everyday objects. We encouraged 115 11- to 37-month-old children to open 2 types of containers: circular jars with twist-off lids (Experiment 1) and rectangular Tupperware-style containers with pull-off lids (Experiment 2). We varied container size to examine effects of the body-environment fit on display of the designed action and successful implementation of the designed action. Results showed a developmental progression from nondesigned actions to performance of the designed twisting or pulling actions to successful implementation of the designed action. Nondesigned actions decreased with age as performance of the designed action increased. Successful implementation lagged behind performance of the designed action. That is, even after children appeared to know what to do, they were still unsuccessful in opening the container. Why? For twist-offs, very large lids were difficult to manipulate, and younger children often twisted to the right, or in both directions, and did not persist in consecutive turns to the left. Larger pull-off containers required new strategies to stabilize the base, such as holding the container against the tabletop or the chest. Findings provide insights into the body-environment factors that facilitate children's learning and implementation of the hidden affordances inherent in everyday artifacts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Aim: Children with moderate-severe cerebral palsy (CP) show postural control deficits that affect their daily activities, like reaching. The Seated Postural and Reaching Control test (SP&R-co) was developed to address the need for clinical measures that objectively identify dimensions of postural imbalance and corresponding reaching limitations in children with CP. Methods: SP&R-co documentation was designed for test validity and rater training. Rater and internal consistency were examined using Cronbach’s α. Reference SP&R-co score sheets of children and rater’s scores were used for absolute item-by-item, average inter-rater, and intra-rater reliability. Motor classification systems and performance tests were used for construct and concurrent validity. Results: The SP&R-co scoring showed acceptable-good consistency (α = 0.76–0.84). Interrelatedness of SP&R-co items was good-excellent (α = 0.82–0.97). The raters demonstrated fair, good, and excellent item-by-item reliability (ICC = 0.41–0.92). Inter-rater and intra-rater reliability of SP&R-co dimensions were good-excellent (ICC = 0.68–0.86 and ICC = 0.64–0.95, respectively). Construct and concurrent validity showed moderate-excellent correlations (r = 0.49–0.88). Conclusions: Results provide evidence that the SP&R-co is a reliable and valid test for therapists to objectively examine and quantify seated postural and reaching control in children with CP.

Previous studies provided evidence that persons with Multiple Sclerosis (pwMS) who walk intermittently experience less fatigue and walk longer distances than when walking continuously. However, tot...