Spatial Updating Based On Allocentric Reference Frame

Accurate representation and real-time updates of the space are the basic conditions for the accurate execution of the movement.What kind of spatial reference system is the basis of the spatial representation of the real-time change? According to the traditional view,spatial reference system can be divided into egocentric reference frame and allocentric reference frame.The two theoretical views are supported by experimental evidence respectively,but it is difficult to reach a unity due to different factors such as environment,conditions and specific tasks.In the past,most studies focused on orientation perception,one of the elements of spatial cognition,however,there are few researches on distance,especially dynamic distance judgment.In this study,the scientific problem of which reference frame is used to establish and update the spatial representation of the condition of self-motion is studied.In study 1,we took blind walking as the experimental task to investigate the influence of the observer’s own orientation change in the representation and memory of the target’s spatial position,providing experimental evidence for the hypothesis that the spatial representation and spatial update are based on the environmental reference system.In the second study,we further discuss the spatial representation of the environmental reference system,where the observer’s "starting point of the reference system" is located,and its characteristics and influencing factors.In study 1,we separated and investigated the observe phase and response phase of blind walking task.In experiment 1 and experiment 2,we manipulated the participants’ walking expression direction in the response phase to be consistent or opposite to the target(observation)direction,and investigated the effect of their own orientation(head orientation and body orientation)on spatial updating,the experimental design was 2(orientation of the response phase: same as the target,opposite to the target)*5(target distance: 1.5m,4.0m,7.0m,10.0m,15.0m).In experiment 3,we increased a delay phase between observation and response phase stage,controlled the head orientation at this stage,in the same or opposite to the target,and to investigate the influence of delay time,to 2(the head orientation of the delay phase: same as the target,opposite to the target)* 2(delay time: 10 s,40s)* 3(the target distance: 4.0m,7.0m,10.0m).The results showed that :(1)when the direction of the observer’s behavior was inconsistent with the direction of the target(observation),the accuracy of distance judgment was significantly reduced,and the stability of multiple repetitions was significantly reduced.(2)When the observer’s head orientation in the delay stage was inconsistent with the target(observation)direction,the accuracy of distance judgment for a specific target was significantly reduced,and the stability of multiple repetitions was significantly reduced.In the absence of continuous visual input at the end of observation,the change of self orientation has a significant impact on the memory and expression of spatial representation,which may occur immediately in the response stage or in the delayed stage,and has a significant impact on the accuracy and stability of spatial scene representation.Accordingly,we think,the experimental data show that the observer in the absence of visual input,along with its movement toward change,it is difficult to characterize the space overall shift to a new direction with the rotation of the head,shows its building space represent the coordinates of the starting point is not in the observer,but somewhere in the environment,or based on their own starting point coordinate rotation,Should not bring about significant differences in distance judgment accuracy and stability.In study 2,we further explored where the coordinate starting point in the environment might be located.We guessed that it was the observation starting point,which is similar to the home base and has important significance of us.Therefore,we examine the effect of representation and memory on the starting point of observation during the observer’s journey to the target.In experiment 4,2(observation-walking mode: direct to the target from the front and then back to the starting point,turn your head to look back to the target behind and walk back to the starting point)*3(target distance: 6.4m,10.9m,15.2m),the participants observed at any starting point,walked/retreated blindly to the target position,and then retreated/retreated blindly to the observation starting point in memory.The results show that even without continuous visual input,the observer can still return to the starting point of observation accurately without turning around,which is consistent with the previous findings that the starting point of spatial update coordinates is located at the starting point of observation in dark environment.In addition,we also found that the judgment accuracy and stability of the starting point were significantly higher in the condition of blinding backward to the target and then blinding back to the starting point,which was consistent with the findings of Study 1.In the response phase,orientation has a significant effect on the updating of spatial representation.In conclusion,the accuracy and stability of distance judgment were investigated under the condition of observer’s own motion,and the results supported the environmental reference frame hypothesis of spatial representation and spatial renewal.Our further study found that the starting point of the environmental reference frame may be located at the starting point of observation,and the individual’s orientation has significant significance for maintaining and updating its spatial representation.