真实物体搜索中的视角依赖效应:来自眼动的证据

已有研究发现物体识别存在视角依赖效应,那么在真实物体搜索中是否也存在视角依赖效应呢?本研究采用物体阵列搜索任务,通过眼动技术探讨真实物体搜索中的视角依赖效应及其来源。结果发现:(1)图片提示的搜索绩效优于名称提示;(2)以名称提示时,常规视角的搜索绩效高于新异视角,与新异视角相比,以常规视角呈现的目标物体在扫描和确认阶段的注视点数较少且持续时间较短,表现出视角依赖效应;(3)以图片为提示时,搜索绩效与视角无关。由此可见,在以名称提示的物体搜索中,常规视角比新异视角条件下的注意引导更高效,对目标物体的确认也更快,扫描和确认阶段均存在视角依赖效应,支持目标模板的双功能理论。

Viewpoint Dependent Effects in Real Object Search

Previous studies have found viewpoint-dependent effect in object recognition.Hence one important question is whether view-dependent effect is held in object search.The present study explores the viewpoint dependent effect and its roles in real object search.The pilot study was used to select 25 objects from 60 objects.Each type of object had two pictures-one canonical view and one accidental view,and totally 50 pictures were used as formal experimental material.Real object search paradigm and a two(cue type:picture cue vs.name cue)by two(target object view:canonical view vs.accidental view)within-subject design was employed.The events of one trial were as follows:the fixation cross was firstly presented for 500-800 ms at the center of screen.Then a picture or a name cue of target object was remained on screen for 1000 ms and was followed by an 800 ms blank screen.Then the search display composed of six items(one target object and five distractive objects)was presented and participants were asked to search target object within 5000 ms.When participants found the target object,they fixated it and pressed the response key.The picture cue and name cue were counterbalanced in blocks between participants.The whole experiment composed of two blocks of 50 trials(totally 100 trials).The experimental stimuli were presented using a PsychoPy-programmed PC and LCD monitor(21"TFT;resolution:1920×1280 pixels;refresh rate:60 Hz;view distance:70 cm).The SMI RED eye tracking system(SensoMotoric Instruments,Teltow,Germany)was employed to record the participants’eye movements during the whole search processes.As shown in Figure 1,the findings of this study are as follows:a similar data pattern appears on accuracy and response time,showing a significant interaction between cue type and view type of target object.Specifically speaking,when the search cue is the name of target object,the search performance for canonical view target object is superior to that for accidental view of target object(accuracy:p<.05;reaction times:p<.001);When the search cue is the picture of target object,there is no difference in search performance between canonical view and accidental view conditions(ps>.210).A similar interactive data pattern also appears on eye movements during scanning epoch and verification epoch of the whole search processes.Specifically speaking,when the search cue is the name of target object,the durations of scanning epoch and verification epoch for canonical view target object are shorter than those for accidental view(ps<.001),and the fixation numbers of scanning epoch and verification epoch for canonical view target object are less than those for accidental view(ps<.001);When the search cue is the picture of target object,there is no difference in durations and fixation numbers of scanning epoch and verification epoch between canonical view and accidental view conditions(ps>.05).It can draw the following conclusions:in the search for object with the name as cue,the canonical view enhances the efficiency of attentional guidance by selecting the potential locations of the target object and speeds up the target object verification process by reducing the fixation number.Therefore,the viewpoint dependent effects are held in both scanning epoch and verification epoch,supporting the dual-function theory of target template.