A central-peripheral asymmetry in masked priming

Masked primes presented prior to a target result in behavioral benefits on incompatible trials tin which the prime and the target are mapped onto oppo site responses) when they appear at fixation, but in behavioral benefits on compatible trials (in which the prime and the target are mapped onto the s ame response) when appearing peripherally. In Experiment 1, the time course of this central-peripheral asymmetry (CPA) was investigated. For central p rimes, compatible-trial benefits at short stimulus onset asynchronies (SOAs ) turned into incompatible-trial benefits at longer SOAs. For peripheral pr imes, compatible-trial benefits at short SOAs increased in size with longer SOAs. Experiment 2 showed that these effects also occur when primes and ta rgets are physically dissimilar, ruling out an interpretation in terms of t he perceptual properties of the stimulus material. In Experiments 3 and 4, the question was investigated as to whether the CPA is related to visual-sp atial attention and/or retinal eccentricity per se. The results indicate th at the CPA is independent of attentional factors but strongly related to th e physiological inhomogeneity of the retina It is argued that central and p eripheral primes trigger an initial motor activation, which is inhibited on ly if primes are presented at retinal locations of sufficiently high percep tual sensitivity. The results are discussed in terms of an activation thres hold model.