The orthogenetic principle in the perception of "forests" and "trees"?

This study explores possible links between ontogenetic and microgenetic cha nge (Werner, 1948, 1957) in the perception of stimuli with multiple levels of structure, Visual search for targets defined by local versus global stru cture was examined in observers aged 6, 8, 10, and 22 years. Perceptual acc ess to each level of structure was varied by using pattern elements of same (easy) or opposite contrast polarity (hard); attentional processes were is olated from sensory processes by varying the number of display items. The r esults showed large improvements with age in search rates for global target s, with search rates for local targets being more constant over age. This p attern held regardless of whether perceptual access to a target was easy or hard. These results support the view that the perception of local and glob al structure involves different underlying processes.