The Negative Space In The Auditory Channel Characterization And Processing Mechanisms

The mechanism of the mental representation of number is a hot research topic in the domain of numerical cognition. Most of previous studies which investigated the representation of number focus on positive numbers, but works on the representation of negative numbers are scarce. In the recent years, the question of whether negative num-bers are mentally represented in terms of their holistic values or the values of their components has been raised by the researchers. To answer this question, most research-ers have looked at three different effects:the distance effect, the semantic congruity ef-fect and the spatial-numerical association of response codes (SNARC) effect. However, there are conflicting findings obtained in numerous studies. An important influence fac-tor is the use of visual modality. The presentation of negative numbers might be the fact that magnitude and polarity are marked separately by two spatially distinct sym-bols—the number and the polarity sign. The minus polarity sign is perceived as indicat-ing "small" while the number itself is perceived as indicating "large"(e.g.,-9), so they probably cancel each other out. Moreover, due to the different tasks, these two symbols are activated in varying degrees, leading to the conflicting findings. Addressing itself to these problems, the present study was conducted using the stimuli detection and number classification task to further investigate the mechanism of the representation of negative number in the auditory modality.The present study concludes four experiments. In Experiment1, we employed an auditory stimuli detection task which had proven effective to investigate the representa-tion of numbers, and only negative numbers were presented as cues. In Experiment2, the same task was employed, but both positive and negative numbers were mixed as cues. The goal of the mixed presentation of negative and positive ones was to ensure that participants were processing polarity sign. In Experiment3, we employed a number classification task where participants need discriminate whether the number presented binaurally referred to the smaller or to the larger than-5. The goal was to ensure that participants process negative numbers, especially numerical magnitude at a higher level. In Experiment4, the same task was used, but both positive and negative numbers were mixed as cues, which ensured that participants were processing polarity sign at a deeper level.The main conclusions of the present study are as follows:(1) In the low processing level, we found that a reverse attentional SNARC effect for negative numbers. These results suggest participants did not use the polarity sign but only the absolute magnitude, thus supporting the phylogenetic hypothesis. In the deep processing level, a reverse SNARC effect for negative numbers was found, further supporting the phylogenetic hypothesis.(2) The sign and the digit of negative numbers can be processed separately, which supported the idea of a components representation.(3) The results of the present study also suggest that the representation of negative numbers is relatively stable in the auditory modality, and they are generated from the set of positive numbers, thus sup-porting the notion that the mental representation of negative numbers is independent of modality.