Abstract: New findings in the Seattle Longitudinal Study showed that vocabulary comprehension could predict some cognitively impaired, including spatial ability, memory, and speed, and so on. It may be concerned that if vocabulary comprehension can predict the age related change of other primary mental abilities. The findings from research of the aging of Primary Mental Abilities showed that spatial orientation and inductive reasoning declined with age growth and verbal abilities retained stable until 70 years old. Salthouse distinguished these two aspects of cognition as process and product. Process refers to the efficiency or effectiveness of processing at the time of assessment. Product refers to the accumulated products of processing carried out in the past. The interaction between process (such as spatial) and product (such as vocabulary) in aging is one of the issues needing to be clarified in the study of cognitive aging. As an index of knowledge, the role of vocabulary comprehension in cognitive process as spatial orientation is also concerned in this study.
Verbal explanation and mental rotation task were chosen to measure vocabulary comprehension and spatial orientation, respectively. 240 people 60 years old or above in Beijing were assessed at Time 1 and 171 at Time 2. The data of 144 elders were final accepted to analysis according to the reaction accuracy. There was no education level difference among different age groups.
Repeatedly measure ANOVA showed that vocabulary decreased and spatial increased after 20 months even controlled standard error of measurement of pretest performance. Cross-lagged regression analysis based on vocabulary and spatial showed that vocabulary at Time 1 can predict spatial at Time 2, β＝-0.17; on the contrary, spatial can not predict vocabulary. There was no difference among the gain of practice effects in spatial of participants with different vocabulary levels (high, middle, and low).
These findings suggest that the maintaining or increasing vocabulary comprehension can protect against spatial aging. There is interaction between process and product in the change with time, and product as well as knowledge may be a migrator in age-related change of process.

Key words: vocabulary comprehension, spatial orientation, aging, cross-lagged analysis