Visibility, type of masking, prime duration and task as determinants of effects of masked stimuli

最近的理论指出，意识与信息的整合和可及性有关。由此可见，当意识受损时，存在着根本不起作用或至少以受损的方式起作用的心理功能。更具体地说，简单的（非集成）刺激功能的处理应该是独立的意识，而复杂的（集成）功能的语义处理应增加与刺激的意识增加。一系列实证报告支持这一观点。因此，早期知觉或运动启动效应不依赖于启动可见性，而语义启动效应似乎依赖于启动可见性。然而，在许多研究中，操纵的启动可见性已混淆与启动的持续时间，因为审判与短期和长期的启动持续时间已被比较为无意识和有意识的条件下，分别。此外，语义研究最常使用的模式掩蔽，这可能会产生一个人为的相关性之间的启动效应和启动的可见性。独立的运动启动效应和可见性已报告经常使用元对比掩蔽的研究。事实上，我们的初步研究表明，语义和运动启动效应取决于启动可见性时，模式掩蔽，但不与元对比掩蔽。除此之外，启动效应和启动可见性之间的关系也可能取决于产生启动效应所需的启动处理。计划的项目包括13个实验，系统地比较了三种不同的掩蔽程序（模式掩蔽，元对比，拥挤）时，在不同的任务中使用相同的刺激的效果。在每个实验中，启动可见性是不同的面具的特定类型，但具有不同的掩蔽强度和启动效果和可见性之间的关系被记录。如果启动词的加工依赖于启动词的意识，那么启动效应也依赖于启动词的可见性。为了掌握不连续的关系，给素数产生其效果的时间是不同的。功能性磁共振成像被用来检查是否在视觉层次的处理后期水平的启动诱导的皮层激活是系统地确定所使用的掩蔽程序的类型。通过这种方式，可以直接研究掩蔽刺激在大脑中的效应的扩展以及掩蔽的位点。本项目的研究有助于我们进一步探索意识的功能，并加深我们对启动效应产生机制和不同类型掩蔽效应的理解。

Recent theories state that consciousness is related to the integration and accessibility of information. From this it follows that mental functions exist which do not operate at all or at least operate in an impaired way when consciousness is impaired. More specifically, processing of simple (non-integrated) stimulus features should be independent from consciousness whereas semantic processing of complex (integrated) features should increase with an increasing consciousness of the stimuli. A series of empirical reports support this view. Thus, early perceptual or motor priming effects do not depend on the prime visibility whereas semantic priming effects seem to depend on prime visibility. However, in many studies the manipulation of prime visibility has been confounded with the duration of the primes because trials with short and long prime durations have been compared as unconscious and conscious conditions, respectively. Additionally, semantic studies most often used pattern masking which might produce an artificial correlation between priming effects and prime visibility. Independence of motor priming effects and visibility has been reported frequently from studies that used metacontrast masking. And indeed, our pilot studies show that semantic and motor priming effects depend on prime visibility when pattern masking is used, but not with metacontrast masking. Beyond this, the relation between priming effects and prime visibility could also depend on the processing of the primes which is needed to generate priming effects. The planned project comprises 13 experiments which systematically compare the effects of three different masking procedures (pattern masking, metacontrast, and crowding) when the same stimuli are used in different tasks. Within each experiment, prime visibility is varied by masks of a specific type but with different masking strength and the relationship between priming effects and visibility is recorded. If the processing of the primes in a certain task depends on consciousness of the primes the priming effect should also depend on prime visibility. To grasp also discontinuous relationships, the time that is given to the prime to generate its effects is varied. Functional magnetic resonance imaging is used to examine whether the prime induced cortical activation at later levels of processing in the visual hierarchy is systematically determined by the type of masking procedure used. In this way the expansion of the effects of masked stimuli in the brain and the loci of masking can be directly investigated. The studies of this project contribute to confine the search for the function of consciousness and to improve our understanding of the mechanisms that produce priming effects and the different types of masking effects.