Method
Twenty-four children aged 37.53–54.53 months (M = 45.71 months, SD = 5.52) and 21 children aged 55.77–71 months (M = 63.56 months, SD = 4.54) were recruited from five local kindergartens in Hong Kong. Three participants of the younger age group responded incorrectly to the memory control question in either one of the two cooperative and competitive trials, so they were excluded in the analyses. The mean age of the remaining sample (N = 42) was 54.81 months (SD = 10.16). All participants were native Chinese Cantonese-speakers and were reported to have no history of receiving speech therapy by the parents. The populations of the kindergartens were generally of middle-to-low socio-economic status. Ethical approval was obtained from the ethics committee in the University of Hong Kong and parental informed consent was obtained before testing.