Age-related directional asymmetry in the rod-and-frame test

In the classic Rod-and-Frame Test (RFT), participants align a pivoted rod with the vertical while viewing a tilted, coaxially mounted frame. In doing so, they can use the edge of the frame or its imaginary diagonal as visual cues. The error in this simple perceptual task has long been used to distinguish field-dependent from field-independent cognitive styles. Recent findings indicate that aging increases field dependence. Here, we test whether the shape of the RFT error curve as a function of frame tilt changes with age.

Thirty-nine young adults (range: 19-27 years) and 50 older adults (range: 57-81 years) completed a virtual-reality version of the RFT. Each participant determined the vertical for nineteen frame tilt angles ranging from -45° to 45° in 5° increments.

At five clockwise tilts (10°-30°) and one counterclockwise tilt (-15°), older adults showed higher median errors than young adults, with the largest difference at 15° (7.5° vs. 2°). The asymmetry index of the RFT error curve was symmetrically distributed around zero in young adults but significantly positive in older adults, particularly those older than 68 years. Analysis of visual cue selection revealed that, for clockwise tilts, young adults flexibly switched between edge-based and diagonal-based positioning strategies depending on frame tilt magnitude, whereas older adults predominantly relied on edge-based cues. For counterclockwise tilts, differences in cue use between cohorts were minor. The asymmetry index was independent of overall performance, showing no correlation with the mean RFT error in either group.

We propose that aging affects RFT performance through two dissociable mechanisms. A general decline in multisensory integration increases overall errors symmetrically across tilt angles. The clockwise-specific asymmetry, by contrast, may reflect age-related changes in lateralized visuospatial attention-specifically, the well-documented rightward attentional shift that accompanies healthy aging-which differentially affects the weighting of visual cues for clockwise vs. counterclockwise frame orientations.