The Position Of Numerical Mental Representation Affect The Association Between Number And Time Perception

There is a tight association between number and time, which exist in daily language expression and psychological cognitive research. In the psychological study, this association mainly focus on the effect of number on time perception, which reports the observation that numbers with small magnitude are easily associated with short duration and number with large magnitude are easily associated with long duration. This observation is mainly explained by the same magnitude system behind the number and time, namely a theory of magnitude(ATOM), but there is another hypothesis(metaphor theory, MT) can also explain it. According to MT, numbers are usually represented along a spatial line, namely mental number line(MNL). MNL shows that smaller numbers are represented on the left side of MNL and bigger ones on the right side. And the temporal durations are also represented along a spatial line, namely mental time line(MTL), which shows that brief duration are represented on the left side of MTL and long ones on the right side. According to MT,it implies that the mental position of numerical representation may affect its time perception.Throughout the past researches, they never systematically explore the effect of the mental position of numerical representation on the association between number and time. And van Dijck et al(2011) found that spatial coding of numbers can be in short-and long-term memory. In long-term memory, spatial coding of numbers is that smaller numbers are on left and longer ones on right, this pattern is automatic activated without voluntary effort and it is mainly interpreted culturally as a side effect of directional reading /writing long-term habits. In shortterm memory, spatial coding of numbers can be represented in a free-form, but it is activated with voluntary effort. No matter what the form the numbers represented, it can be reflected that the number represented on left side of psychological space easily associated with short duration and the number represented on right side of psychological space easily associated with long duration.In order to resolve this hypothesis, this study reorganized the paradigm designed by van Dijck and Fias(2011) and include two experiments. In experiment 1, we manipulated the position of number in working memory(WM) to explore the role of the position of numerical mental representation in the association between number and time perception. It included 3 phases: an encoding phase, a classification phase, and a control phase. During the encoding phase, four digitals(randomly chosen in “123789”) and digital “5”(always at the center of screen) were presented in a spatial sequence, Subjects were instructed to memorize all digits in correct order. During the classification phase, participants continued to keep the memorized numerical sequence in mind while performing a time bisection task only when the digital belong to the sequence previously memorized(go-nogo paradigm). During the last phase, namely the control phase, subjects had to judge a new sequence of five digitals whether or not the same as the one kept in the memory. The results reflect that numbers from the beginning of a verbal WM sequence(left side of psychological space) are easily associated with short duration during the maintenance interval and the opposite is true for numbers towards the end of sequence(right side of psychological space), it imply that numerical temporary spatial representation indeed influence the association between time and number and reflect that the position of numerical mental representation affect the association between number and time perception in a form of short-term representation.In experiment 2, as to explore whether the retrieve of the number position in WM is essential to the generation of the experiment 1 or not, we dismiss the go-nogo procedure and ask subjects to judge the duration of every target number. We found that it involved the mental process(the retrieve of the number position in WM) when doing time bisection task in experiment 1. As a result, we get a different result which reports the observation that the numerical sequence position do not affect its time perception, it imply that the retrieval of the item from working memory is essential to make the temporary mental position of numerical representation affect the association between number and time perception. The results just show that smaller numbers are easily associated with short duration and bigger ones associated with long duration, it implies an automatic activation of numerical long-term memory.Through the two experiment, we deserve the results as follows: the mental position of numerical representation indeed influence its time perception, behave as that the number represented on left side of psychological space easily associated with short duration and the number represented on right side of psychological space easily associated with long duration. And this pattern of influence can be accounted by two type of numerical spatial coding, namely short-term memory and long-term memory.