The Spatial Representations Of Time

Lots of studies on SNARC(Spatial Numerical Association Response Code)effect shows that,in cultures in which people read and write from left to right,people's mental representation of numbers is a mental number line on which the cognitive representations of numbers are mapped from left-to-right in accordance with their increasing magnitude.Small numbers are spontaneously associated with left space and larger ones with right space. Likewise,researches on the relation of quantity and space show that orderly information like numerals(small vs.large),auditory pitches(low vs.high)months and letters of the alphabet possess spatial character,in other words there is a mental magnitude line,all sorts of quantitative information displays according to their positions in spatial coordinates.Walsh (2003a)argued that the inferior parietal lobule caters to the common need for space,time and quantity information.The aim of the current study is to assess whether temporal information is cognitively represented through left-to-right spatial coordinates in analogy to other types of ordered Material.In Experiment 1,the task-relevant information was the temporal duration of a cross(1s or 3s).A trial started with the central fixation cross,lasting for a foreperiod(FP)of 1 or 3 s.The task consisted of pressing left key for a short cross duration(i.e.,1 s)and right key for a long cross duration(i.e.,3 s).The stimulus duration/response key assignment was inverted after 160.The order of presentation of the two possible S-R mappings was counterbalanced across participants.The results showed that,RTs were shorter for the long FP than for the short one.RTs were shorter when short and long durations had to be responded to with left and right hands,respectively,than with the opposite stimulus-response mapping.In Experiment 2,the cross appeared either to the left or right of the screen,the index and middle fingers of the dominant hand were used to give the responses.The results showed that,RTs were shorter for the long FP than for the short one.Judgments were facilitated when the short FP appeared to the left or the long one appeared to the right,This pattern suggests that elapsing time may be represented progressively from left to right.The aim of Experiment 3 was to further investigate the nature of the compatibility found in the previous experiments by parametrically varying the FP length.The temporal duration was parametrically varied using different values for each response category(500ms, 1000ms,1500ms,2000ms,2500ms,3000ms,3500ms).We used the temporal bisection task The results showed that,RTs were shorter when short and long durations had to be responded to with left and right hands,To examine the STEARC effect for each participant,RT differences(dRT)between left response and right response for every timings were calculated at the individual level and then linear regression was applied.The results showed that,the dRT was positive when response to the long FP,whereas negative values represent when response to the long FP.in other words,RTs were shorter when short and long durations had to be responded to with left and right hands.These results suggest that time is represented from left to right along the horizontal axis in space,The existence of a'mental time line'in space and the spatial-temporal association of response codes(STEARC)effect are discussed.