From exploration to play: A cross-sectional study of infant free play behavior.

40 infants, divided into 10 evenly spaced age groups between the ages of 7.5 and 21 mo, were observed playing with 2 sets of toys in their own homes for up to 30 min. Narrative records of Ss' behavior were coded in terms of a 12-step sequence of play development. Analysis of individual performance indicated that this level-of-play scale satisfied the requirements of a valid Guttman scale. Analyses of means revealed that frequency of mouthing and simple manipulation decreased linearly across the age period studied, whereas several types of pretense play increased linearly. Behavior that involved relating 2 or more materials and approximation of pretense behavior displayed curvilinear functions, which suggests that they are transitional forms of activity that link early exploration with more developmentally advanced pretense play. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)