Abstract: Two experiments of semantic Negative Priming (NP) using a Lexical Decision Task (LDT) are reported. This effect (Tipper, 1985) is considered in some theories as a result of an attentional inhibitory mechanism, and it has been shown with different tasks and stimuli. In these experiments, two words were presented in prime display, one on the left and another on the right of fixation point. In experiment 1 one word was cued by a mark and subjects had to attend to it and ignore the other word. In experiment 2 a central arrow was used as selection cue. In probe display only a letter string (word or nonword) was presented, which was related to the attended prime, to the ignored prime or unrelated to both. Subjects had to respond with LDT. In both experiments Negative Priming from ignored primes, and Positive Priming from attended primes were obtained. Nevertheless, these effects were obtained only from words displayed at the Right Visual Field (RVF). Positive Priming was obtained from ignored words displayed at the LVF, but not from attended ones. Some experiments have shown that availability to consciousness of ignored information is necessary to obtain the effect of NP (Marcel, 1980). That could explain the change of the nature of the priming effect obtained from ignored primes in the experiments reported here (negative on the right, positive on the left). Results are discussed in the context of inhibitory attentional mechanisms: "Center-Surround Attentional Mechanism" (Dagenbach & Carr, 1994) and "Inhibitory Mechanism in Selective Attention" (Houghton & Tipper, 1994).

VIII Congress of the European Society for Cognitive Psychology (ESCOP).
Roma, 1995.