Background: It is well established that processing speed and IQ test scores are correlated, although the strength of this relationship is a matter of debate (Neisser et al., 1996). It was proposed that processing speed is a component of intelligence (Deary, Penke, & Johnson, 2010; Hunt, 2011). In our previous research we have not revealed the relationship between IQ and processing speed in children (Kiselev et al., 2000). However, it is possible that processing speed can predict intelligence test scores in the developmental perspective. This study investigated whether processing speed in 5 year-old children predicts intelligence test scores in 8 year-old children using the longitudinal approach.

Methods: The participants were 35 children (17 males and 18 females) at the age of 5 years (5,34±0,45). We used computerized sensorimotor technique (Kiselev et al., 2009) to investigate processing speed in children. Children completed simple, discrimination and choice reaction time tasks. The IQ of 8-year children was assessed by the Wechsler Intelligence Scale for Children.

Results: The regression analysis has revealed the significant (p≤0,05) relationships between discrimination and choice reaction time tasks in 5 years-old children and non-verbal IQ performance in these children at 8 years of age. However, we did not find this relationship for simple reaction time task.

Conclusion: In view of obtained results it can be assumed that processing speed in preschool children can predict non-verbal intelligence test scores in the developmental perspective. However, it is true only for processing speed in discrimination and choice reaction time tasks. The received data can give new perspective in the understanding the interrelation between processing speed and IQ in children.