Conflict Control In Visual Images Scanning

Visuospatial ability is the part and parcel of intelligence structure.It plays a major role in various technical operations,such as flight in aviation and space,machine work,architectural design, and survey-cartography.It also takes an important part in everyday life.As the core of visuospatial cognition,mental imagery is closely related with various high-level visuospatial processes. Moreover,it plays an important role in creative thinking and restricts the development of spatial intelligence.In this dissertation,guided by Kosslyn's Visual Imagery Subsystem Model as well as the theory of conflict control,we conducted 5 studies by using behavioral experimentation and event-related brain potentials(ERPs).We aimed at exploring the mechanisms of multiple conflict-induced control as well as the relationships between them.Based on these studies,we constructed the Conflict Control Model for Visual Images Processing in order to improve our understanding of mental imagery as well as human's visuospatial ability.In the first study,the effect of conflicting reference frames(RF) on mental scanning process was explored.When cued by directional Chinese characters,conceptual framework effect was found, which suggested that a conceptual RF was projected onto the Chinese character.When this conceptual RF was dissociated from the environmental RF,a conflict between them was induced. The conflict caused slow reaction and more errors.Further,when the orientation of Chinese character's intrinsic RF was rotated so as to make it aligned with the conceptual RF,the cost of solving these RF conflicts decreased accordinglyIn the second study,conflicts occurred during encoding and response selection.The cost of solving these conflicts also varied.In order to reveal how the resolution of these conflicts was regulated by level of cognitive control,we increased incongruent trials in one block,so as to improve the level of cognitive control.It was found that conflict during encoding was immune to the level of cognitive control,whereas the effect of conflict in response selection was modulated by cognitive control.The results suggested that cognitive control system can regulate the resolution of conflicts in various information processing stages in a real time manner.In the third study,we investigated how resolution of conflicts was modulated by level of cognitive control.We used a reversed scanning task,in which subjects had to inhibit mental set of scanning along direction of arrow cues.The inhibition process enhanced level of cognitive control.It was found that the enhanced cognitive control was mainly used to inhibit mental set of automatic scanning,but not to improve efficiency of mental scanning.However,when level of cognitive control was further improved through task cuing,both the inhibition process and the efficiency of mental scanning were promoted.The results indicated that conflict resolution was realized through blocking automatic processing as well as enhancing attention to relevant task.The aim of the fourth study was to examine relationships between various conflicts in order to deduce whether mechanisms of conflict resolution were independent to each other.It was found that effect of conflicting cues was independent to effect of conflict between distinct stimulus-response mappings.On the contrary,effect of conflicting cues was dependent to effect of conflicting tasks. It suggested that mechanisms of conflict control were both domain-general and domain-specific.In the fifth study,ERPs were used to reveal the neural correlate of conflict control.The results indicated that the amplitude of P1 and P2 was modulated by scanning distance,whereas the amplitude of N2 and the average amplitude of late sustained positivity were modulated by level of conflict.These results suggested that N2 and the late sustained positivity acted as the neural basis for conflict control.The results of the studies mensioned above supported the following conclusions:First,resolution of conflicts among distinct reference frames was realized through interaction between top-down and bottom-up processing.Second,conflicts can occur at various stages of mental scanning process.The level of cognitive control did not influence conflicts at the encoding stage,but it did regulate conflicts during response selection.Third,conflict between distinct tasks during mental scanning was resolved through enhancing executive attention to relevant attributes of task.It was also realized through blocking automatic processing.Fourth,multiple conflict control mechanisms existed in the brain.At the same time,these mechanisms were monitored by a domain-general control system.Fifth,N2 and the sustained positivity were the neural substrates of conflict control during mental scanning.