Abstract: Previous studies of global and local perception usually require subjects to respond to targets at the global or local level of compound stimuli, which are task relevant and attended. The current study investigated how global and local processes differ from each other when compound stimuli are unattended by examining the priming effect produced by global or local information of compound letters on responses to the following targets. In Experiment 1, we found a negative priming effect produced by compound stimuli on responses to probe letters. However, the priming effects produced by global and local primes did not differ. In Experiment 2, when the stimulus onset asynchrony between primes and probes was reduced relative to that used in Experiment 1, the priming effect arising from both global and local primes was eliminated. Interestingly, subjects made more errors to local than global letters when responding to the primes in both experiments. The results are discussed in terms of the advantage of global over local processing under the attended and unattended conditions.

Key words: attention, global, local, compound stimulus, negative priming