Montaser-Kouhsari Leila, Carrasco Marisa
Department of Psychology, New York University, 6 Washington Place, Room 957, New York, NY 10003, USA.
Atten Percept Psychophys. 2009 Nov;71(8):1782-92. doi: 10.3758/APP.71.8.1782.
Visual performance is heterogeneous at isoeccentric locations; it is better on the horizontal than on the vertical meridian and worse at the upper than at the lower region of the vertical meridian (Carrasco, Talgar, & Cameron, 2001; Talgar & Carrasco, 2002). It is unknown whether these performance inhomogeneities are also present in spatial frequency tasks and whether asymmetries present during encoding of visual information also emerge in visual short-term memory (VSTM) tasks. Here, we investigated the similarity of the perceptual and VSTM tasks in spatial frequency discrimination (Experiments 1 and 2) and perceived spatial frequency (Experiments 3 and 4). We found that (1) performance in both simultaneous (perceptual) and delayed (VSTM) spatial frequency discrimination tasks varies as a function of location; it is better along the horizontal than along the vertical meridian; and (2) perceived spatial frequency in both tasks is higher along the horizontal than along the vertical meridian. These results suggest that perceived spatial frequency may mediate performance differences in VSTM tasks across the visual field, implying that the quality with which we encode information affects VSTM.
在等偏心率位置，视觉表现存在异质性；在水平子午线上的表现优于垂直子午线，且在垂直子午线的上部区域比下部区域差（卡拉斯科、塔尔加和卡梅隆，2001年；塔尔加和卡拉斯科，2002年）。目前尚不清楚这些表现的不均匀性是否也存在于空间频率任务中，以及视觉信息编码过程中出现的不对称性是否也会在视觉短期记忆（VSTM）任务中出现。在这里，我们研究了空间频率辨别（实验1和2）以及感知空间频率（实验3和4）中感知任务和VSTM任务的相似性。我们发现：（1）同时性（感知）和延迟性（VSTM）空间频率辨别任务中的表现均随位置而变化；在水平子午线上的表现优于垂直子午线；（2）两项任务中感知到的空间频率在水平子午线上均高于垂直子午线。这些结果表明，感知到的空间频率可能介导了整个视野中VSTM任务的表现差异，这意味着我们编码信息的质量会影响VSTM。
