Cappelletti Marinella, Didino Daniele, Stoianov Ivilin, Zorzi Marco
UCL Institute of Cognitive Neuroscience, 17 Queen Square, London WC1N 3AR, UK; Goldsmiths College, University of London, New Cross London, SE14 6NW, UK.
Department of Cognitive and Education Science, University of Trento, via Tartarotti 7, Rovereto, Trento, Italy.
Cogn Psychol. 2014 Mar;69:25-45. doi: 10.1016/j.cogpsych.2013.11.004. Epub 2014 Jan 11.
Numerical skills have been extensively studied in terms of their development and pathological decline, but whether they change in healthy ageing is not well known. Longer exposure to numbers and quantity-related problems may progressively refine numerical skills, similar to what happens to other cognitive abilities like verbal memory. Alternatively, number skills may be sensitive to ageing, reflecting either a decline of number processing itself or of more auxiliary cognitive abilities that are involved in number tasks. To distinguish between these possibilities we tested 30 older and 30 younger participants on an established numerosity discrimination task requiring to judge which of two sets of items is more numerous, and on arithmetical tasks. Older participants were remarkably accurate in performing arithmetical tasks although their numerosity discrimination (also known as 'number acuity') was impaired. Further analyses indicate that this impairment was limited to numerosity trials requiring inhibiting information incongruent to numerosity (e.g., fewer but larger items), and that this also correlated with poor inhibitory processes measured by standard tests. Therefore, rather than a numerical impairment, poor numerosity discrimination is likely to reflect elderly's impoverished inhibitory processes. This conclusion is supported by simulations with a recent neuro-computational model of numerosity perception, where only the specific degradation of inhibitory processes produced a pattern that closely resembled older participants' performance. Numeracy seems therefore resilient to ageing but it is influenced by the decline of inhibitory processes supporting number performance, consistent with the 'Inhibitory Deficit' Theory.
关于数字技能的发展和病理性衰退已经进行了广泛研究，但在健康老龄化过程中它们是否会发生变化却鲜为人知。与数字和数量相关问题的更长时间接触可能会逐渐提升数字技能，这与言语记忆等其他认知能力的情况类似。或者，数字技能可能对衰老敏感，这反映了数字处理本身的衰退，或者是参与数字任务的更多辅助认知能力的衰退。为了区分这些可能性，我们让30名老年参与者和30名年轻参与者完成一项既定的数量辨别任务，该任务要求判断两组物品中哪一组数量更多，同时还进行了算术任务。尽管老年参与者的数量辨别能力（也称为“数字敏锐度”）受损，但他们在算术任务中的表现非常准确。进一步分析表明，这种损伤仅限于需要抑制与数量不一致信息的数量试验（例如，数量少但体积大的物品），并且这也与标准测试所测量的较差抑制过程相关。因此，数量辨别能力差可能反映的是老年人抑制过程的不足，而不是数字损伤。这一结论得到了最近一个关于数量感知的神经计算模型模拟的支持，在该模型中，只有抑制过程的特定退化产生了一种与老年参与者表现非常相似的模式。因此，算术能力似乎对衰老具有弹性，但它受到支持数字表现的抑制过程衰退的影响，这与“抑制缺陷”理论一致。
