Negative Compatibility Effect Suppression Mechanism

The negative compatibility effect is that response time is faster and error rate is lower when prime and target are congruent than incongruent. Studies about the negative compatibility effect always use masked prime paradigm, the negative compatibility effect is closely related to mask target SOA:when mask target SOA is100to200ms, negative compatibility effect occurs; when mask target SOA is0to60ms, positive compatibility effect occurs. Eimer&Schlaghecken et al. pointed the occurrence of negative compatibility effect is because initial activation of a motor response elicited by a prime is inhibited. And this inhibition occurs need some time, so negative compatibility effect occurs only when mask target SOA is long enough. Although researchers have proposed the activation hypothesis later, and suggested that negative compatibility effect occurs because perceptual interaction between the prime and mask stimuli activate opposite response. But this hypothesis suggested only relevant mask stimuli can activate opposite response, while the late-stage studies found negative compatibility effect also when irrelevant mask stimuli was used. This suggested that the negative compatibility effect occurs dose involve inhibition mechanism, activate opposite response only part of reason, not all reason. But now the generating process of inhibition mechanism remains controversial. Eimer&Schlaghecken assumed self-inhibition hypothesis that the motor system detect unexpected activation, inhibition stage comes automatically after initial activation elicited by prime. There are two conditions for self-inhibition can come into effect. First, primes with low visibility, because only if the sensory evidence of the prime is immediately removed by mask, self-inhibition can occur. Second, prime's sensory strength must sufficiently large, because there is a threshold for Self-inhibition to occur.Jas'kowski pointed mask triggered inhibition theory that mask will stop the processing of a prime and lead to the inhibition of the primed response if it does not support the perceptual hypothesis concerning the prime's identity, and the occurrence of negative compatibility effect depend on the balance of power between motor activation triggered by the prime and motor inhibition triggered by the mask. Substance of the debate about two theories is whether self induce inhibition or mask stimuli trigger inhibition. This study was designed to start from the issues involved in this debate and explore the mechanism of inhibition lead to negative compatibility effect.There are three experiments in this study, to exclude negative compatibility effect produced by perceptual interaction activate opposite response, we used irrelevant masks in all three experiments. In experiment1, ensure motor inhibition triggered by the mask constant, change motor activation triggered by the prime by manipulating visibility of primes, we found that although the activation in high visibility condition was significantly greater than in low visibility condition, negative compatibility effect in high visibility condition was still significantly greater than in low visibility condition. In experiment2and3, we ensured motor activation triggered by peripheral primes constant, enhanced motor inhibition triggered by the mask by reducing difficulty of mask features identify, The results showed that when mask feature indentified easier, negative compatibility effect still not occur.With the results and discussion in the three experiments, we draw the following conclusions:Experiment1:There are two different forms of inhibition mechanism produce negative compatibility effect. When the visibility of primes is low, the main cause of inhibition is self induced, when the visibility of primes is high, the main cause of inhibition is mask stimulus induced inhibition. The reason for visibility of prime stimulus influence negative compatibility effect is that self-inhibition occurs depend on the low visibility of primes, and when the visibility of primes is high, the main cause of inhibition is mask stimulus induced inhibition, change the visibility of primes will change balance of power between motor activation triggered by the prime and motor inhibition triggered by the mask, thus influence negative compatibility effect. Experiment2and3:When the visibility of primes is low, the main cause of inhibition is self induced, when the visibility of primes is high, the main cause of inhibition is mask stimulus induced inhibition. The reason for procession of activation-followed-by-inhibition asymmetry in central and peripheral is that there is a threshold for self-inhibition to occur, only when prime's sensory strength large sufficiently, motor activation triggered by the prime can achieve and exceed the threshold for self-inhibition to occur, produce negative compatibility effect.The experimental results show that there are two different forms of inhibition mechanism produce negative compatibility effect. When the visibility of primes is low, the main cause of inhibition is self induced, when the visibility of primes is high, the main cause of inhibition is mask stimulus induced inhibition.