Conlon Elizabeth G, Power Garry F, Hine Trevor J, Rahaley Nicole
a School of Applied Psychology and Menzies Health Institute Queensland , Griffith University , Gold Coast , Queensland , Australia.
Exp Aging Res. 2017 Jan-Feb;43(1):55-79. doi: 10.1080/0361073X.2017.1258226.
Background/Study Context: Reports of age-related differences on motion discrimination tasks have produced inconsistent findings concerning the influence of sex. Some studies have reported that older women have higher thresholds than older men, with others finding that women have higher motion thresholds regardless of age group. Reports of the age at which declines in motion discrimination first occur also differ, with some studies reporting declines only in groups aged over 70 years, with others reporting that age-related decline occurs at a younger age. The current study aimed to determine whether the sex differences found occur because relative to men, women have greater difficulty extracting motion signals from noise (Experiment 1) or have greater difficulty making use of the available motion cues (Experiment 2) in these complex moving stimuli. In addition, the influence of these manipulations on groups aged under and over 70 years was explored.
Motion discrimination measures were obtained using 39 older adults aged between 60 and 85 years (21 women) and 40 younger adults aged between 20 and 45 years (20 women). In Experiment 1, coherent motion and relative motion displacement thresholds were obtained. In Experiment 2, coherent motion thresholds were obtained for stimuli containing either 150 or 600 dots.
In Experiment 1, the older group had significantly higher thresholds on the relative motion displacement and coherent motion tasks than a younger group. No differences in motion sensitivity were found in the older groups aged under or over 70 years. Women regardless of age group had significantly higher thresholds than men on both tasks. In Experiment 2, the older group had higher coherence thresholds than the younger group, and the number of dots presented had no influence on thresholds, for the older group or older women specifically. In the younger group, women had higher coherence thresholds than men with presentation of 150 but not 600 dots. There were 51% of the older group who showed evidence of age-related decline on all the motion coherence tasks conducted, with half of these in each the group aged under and over 70 years.
Difficulties with noise exclusion failed to explain the sex differences found. The increased number of motion cues present when a larger number of dots were included was sufficient to reduce coherence thresholds in younger women but not older men or women. In addition to age, developmental history and sex may provide further predictors in older individuals of decline on measures of motion discrimination.
背景/研究背景：关于运动辨别任务中年龄相关差异的报告，在性别影响方面得出了不一致的结果。一些研究报告称，老年女性的阈值高于老年男性，而另一些研究发现，无论年龄组如何，女性的运动阈值都更高。关于运动辨别能力首次下降的年龄报告也有所不同，一些研究报告称仅在70岁以上的人群中出现下降，而另一些研究报告称年龄相关的下降在更年轻的年龄就会出现。本研究旨在确定所发现的性别差异是否是因为相对于男性，女性在从噪声中提取运动信号方面有更大困难（实验1），或者在这些复杂的运动刺激中利用可用运动线索方面有更大困难（实验2）。此外，还探讨了这些操作对70岁以下和70岁以上人群的影响。
使用39名年龄在60至85岁之间的老年人（21名女性）和40名年龄在20至45岁之间的年轻人（20名女性）获得运动辨别测量值。在实验1中，获得了连贯运动和相对运动位移阈值。在实验2中，针对包含150个或600个点的刺激获得了连贯运动阈值。
在实验1中，老年组在相对运动位移和连贯运动任务上的阈值显著高于年轻组。在70岁以下或70岁以上的老年组中未发现运动敏感性差异。无论年龄组如何，女性在两项任务上的阈值均显著高于男性。在实验2中，老年组的连贯阈值高于年轻组，并且呈现的点数对老年组或特定老年女性的阈值没有影响。在年轻组中，当呈现150个点而非600个点时，女性的连贯阈值高于男性。在所有进行的运动连贯任务中，51%的老年组表现出与年龄相关的下降迹象，其中各有一半在70岁以下和70岁以上的组中。
噪声排除困难无法解释所发现的性别差异。当包含更多点数时出现的运动线索数量增加足以降低年轻女性而非老年男性或女性的连贯阈值。除年龄外，发育史和性别可能为老年人运动辨别测量值下降提供进一步的预测因素。
