摘要:
近几年来，SNARC (空间–数字反应联合编码)效应受到广泛关注，其内在机制也得到深入探讨。本文总结数字认知引起空间注意转移和空间注意线索激活不同数字表征两个方面的文献，试从注意的自上而下(top-down)和自下而上(bottom-up)加工理论来分析SNARC效应中的注意机制，最后从认知控制的角度来讨论自下而上的加工和自上而下的加工之间的交互作用——即主动性和被动性两种认知控制的动态平衡。
Abstract:
The SNARC (Spatial Numerical Association of Response Codes) effect, in that people respond faster with the left-hand side to small numbers and with the right-hand side to large numbers, had in-spired intensive studies on spatial-numerical representation and its underlying mechanisms in recent years. Deheane et al. (1993) indicated that there is a mental number line in brain, in which the smaller number located in the left side and the larger number located in the right side. The spatial position of a number is activated automatically when a number was displayed. Attention plays the non-neglectable role in SNARC effect. Top-down and bottom-up driven processing are two important thinking ways. Bottom-up driven theory holds that the spacial characteristics of number are stable. Numerical and spacial information are activated simultaneously, yet top-down driven theory holds that number have no stable spacial characteristics and SNARC effect is output of subjective strategy control according to tasks. Concerning the role of attention in SNARC, majority studies have been focusing on the spatial characteristics of numbers, e.g. whether numbers can elicit attentional shifts automatically. Several studies have found that small numbers shift spacial attention to the left, while large numbers shift spacial attention to the right (Calabria & Rossetti, 2005; Fias et al., 2001; Fischer et al., 2003). In bottom-up driven processing, posterior parietal cortex (PPC) play a key role. But when participants were told to image a right-to-left ruler before response, the SNARC effect would disappeared or even reversed (Ristic et al., 2006). The prevailing view is that number can elicit attentional shifts, but under the mediation of top-down driven processing. However, new emerging evidence contributed to this topic from a completely new angle, e.g. how attentional cues, such as encoding of spatial locations, might activate numerical re-presentations differently. Recently the studies from endogenous and exogenous paradigms in spa- cial attention cues, visuospacial priming cues, the special information in interoreceptor show that special attentional cues could activate numerical representations automatically: Firstly, comparing with endogenous, exogenous cue has more stable influence than endogenous cue on SNARC effect. In early processing, exogenous cue play a main role, then along with the SOAs (cue-target stimulus onset asynchrony) increased, endogenous cue take the advantage (Pan et al., 2009, 2010, 2011); Secondly, visuospacial and numerical have an interaction before selection stage, that is to say, right visuospacial priming cues activated faster response with large number, while left visuospacial priming cue activated fast response with small number in bottom-up driven way (Herrera & Macizo, 2011); In addition, body movement could be taken as special cue too. Head, eye or whole body move to left direction facilitated the generation of small number, while move to right direction facilitated the generation of large number (Hartmann et al., 2012; Loetscher et al., 2010; Loetscher et al., 2008). In terms of attentional cues activate numerical representations, a bottom-up driven processing deed exist in SNARC effect. By presenting literatures from abovementioned two perspectives of number elicit attention shift and attentional cues activate numerical representations, we try to perform a thorough review and analysis on the potential role of attention involved in SNARC via either a top-down- or a bottom-up-driven processing. Moreover, in cognitive control perspective, the interaction of top-down driven and bottom-up driven process- ing is discussed. The mechanism of SNARC effect may be the balance of proactive control and inactive control. Finally, some potential researches for this topic are also presented and discussed.