The Mechanism Of The Effect Of Task Demands On Negative Compatibility Effect

Negative Compatibility Effect (NCE) is the surprising result that masked prime arrowsinhibit the responses to compatibe arrow targets and facilitate the responses to oppositedirection arrow targets at the prime-target Interstimulus Interval of around100ms in themasked prime paradigm. Traditionally, it is considered that subliminal information processingwas automatic and can not be regulated by top-down cognition control process like taskdemand; however, recent studies began to challenge the viewpoint. As a kind of subliminalperception effect, whether NCE can be affected by top-down cognition control is stillunknown. At the same time, some researches pointed out the subliminal information can beobtained by semantic semantic prime, but there are few studies examine whether the NCEaccess to semantic level, so the existence of semantic NCE still need to explore. Therefore,this study control task demand to examine the effect of top-down cognitive control processeson NCE and explore its mechanism, and investigate whether exist the semantic NCE.The first research employed the masked prime paradigm, studied the effects of taskdemand on NCE. In Experiment1task demand is not related to the prime; in Experiment2task demand is related to the prime. There are NCE only in Experiment2. It means that therearise NCE only when the task demand is related to the prime. These results suggest that,cognitive control processes regulate the subliminal information processing may be affected bya top-down, rather than the traditional point of the automation process.The second research investigated the effect of prime-target relationship on NCE, and thenproved the top-down cognition control had an effect on the subliminal information process.Moreover, we investigated subliminal semantic prime in the time courses of NCE at the sametime. Experiment3and4employed masked-prime paradigm to investigate the effect of theprime-target relationship on subliminal information processing. In experiment3, primes weredouble arrows point to left or right, with double arrow (identical condition), long arrow (samecognitive process condition) or character (different cognitive process condition) as targets. Inexperiment4, primes were Chinese character “左”or“右”, and targets were character(identicalcondition), English word(same cognitive process condition) or double arrow(differentcognitive process condition). In each trial, target was either compatibile or incompatibile toprime. Participants were instructed to judge the direction of the arrow or the character bypressing the left arrow or right arrow keys. Results showed that, NCE was significant in bothidentical and same cognitive process level condition, which was larger in identical condition.There was no significant effect when prime and target belong to different cognitive processlevel. The research proved that there are subliminal semantic prime in masked prime paradigm, and the direction of priming was negative. The perception repeation of prime andtarget influence the size of NCE but not determine the NCE. When prime and target called forthe same cognitive process, the more similar they were, the bigger NCE was. The relationshipbetween cognitive process level of prime and target has significant effect on NCE, there weresignificant effect when prime and target called for the same level of cognitive process; therewas no effect when they called for different kind of cognitive process. It means theprime-target relationship has an effect on subliminal information processing. The effect mightoccur in the stage of subliminal prime processing or the stage of response processing.The third research combined masked-prime paradigm and Go-Nogo paradigm toinvestigate the effects and mechanism of task demands on Negative Compatibility Effect, andalso proved the existence of semantic NCE. In experiment6, primes were Chinese character“左”(Left) or“右”(Right), targets were character or double arrows in Go condition, eithercompatibile or incompatibile to the prime. Participants were instructed to judge the directionof the arrow or the character by pressing the left arrow or right arrow keys. There s no targetcalls for no response in Nogo condition. Behavior datas showed that, the main effect ofcompatibility and task demand were both significant; the interaction between compatibilityand task demand was significant. Further analysis examined the interaction, showed that NCEwas significant only in the condition when prime is related to task demands; there was nosignificant effect when prime is not related to task demands. The behavior result proved theexist of semantic NCE, which can be observed only when prime is related to task demands.ERP waveform analysis revealed that in Go trials, P3latency is longer only when prime isrelated to the task demand. In Nogo trials, N2mean amplitude has significant differencebetween two character prime only in the related condition; P3mean amplitude has significantdifference between related and unrelated conditions. The result suggests that P3latency is aneffective component to measure NCE, especially in the Go condition. The findings proved theexistence of semantic NCE, and indicated that task demands have an effect on semantic NCEthrough top-down cognition control process.In this paper investigated the effect of the task demand on the NCE and explored themechanism, and also investigated the existence of semantic NCE. Find NCE when the taskdemand is related to the prime no matter the prime is graphic or semantic information. Thissuggested that task demand has an important influence on the NCE; cognitive control systemadjusts the top-down cognitive process according to the task requirements, impact on theprocessing information of the prime. Experiment4and Experiment6also obtained the similarresult with subliminal semantic prime, illustrate the subliminal semantic information can alsobe obtained, there existe the semantic NCE. Finally, the discussion part analysisd the resultswith the theory of subliminal information processing and the theory of NCE. The comprehensive discuss conclude that negative compatibility effect may be the cooperativecognitive process of multi-levels, which includes perception and reaction components, and acentral semantic component.