How Fear Relevance Intensity Affect The Fear Generalization And Fear Extinction Process

Fear is a kind of basic human emotion,it helps us remember dangers deeply, it is critical for adaptive function, but at times fear learning can be maladaptive, resulting in excessive fear and anxiety.so it is important to learn how to control and diminish fear effectively.In lab study we often use Pavlovian conditioning as research paradigm, a neutral conditioned stimulus (CS) is paired with an aversive unconditioned stimulus (US). After several trials, the CS induces conditioned fear responses (CRs), such as freezing and skin conductance responses (SCRs) repeatedly presenting the CS without the US extinguishes the CR. In early study we often use specific physical quality such as color geometric figure and then tested with several different values along the same stimulus dimension as the CS, these stimulus can not match the reality very well. In real life we are unlikely to be fear conditioned for a meaningless stimulus, the one which contained threat information is easier to be paried with fear. And maybe generalization is based along dimensions of fear relevance. For example, an individual may acquire fear of all dogs after an aversive experience with a single vicious dog. In this case, recognizing that a novel animal is related to a feared (or fear conditioned) animal may not be based on shared physical features to the fear exemplar, such as four legs and a tail. But, based on those features that are associated with natural categories of threat such as sharp teeth and claws. Previous studies had found that stimulus such as threatening faces or spiders, are biologically prepared to be fear relevant. Compared with fear-irrelevent CSs, biologyically prepared stimuli capture attention and are contioned without awareness, increase brain activity in visual and emotional processing region, and become more resistant extinction when paired with an aversive uncondition stimulus. We define this kind of feature as fear relevance intensity. Present study investigated how fear relevance intensity affect fear conditioning, fear generalization and fear extinction.The first experiment:if fear condition is based on fear relevance intensity, then stimulus contained higher fear intensity will elicit stronger fear reaction. To address this issue, the present study examined generalization to fearful faces along an gradient of fear intensity. The result suggests that fear generalize along fear relevance intensity.The second experiment:based on the result of the first experiment. We surmise that if use the higher intensity of fear relevance stimulus to extinction a conditioned fear, it will be more efficient. In the second experiment we still use fearful faces as stimulus. Firs we make two groups to get the same conditioned fear, then the first group accepts an more fearful face as the extinction stimuli, the second group accept the previous fearful face as extinction stimuli. The result show that the first group exhibit less fear responses than the second group.