Long-term adaptation to prism-induced inversion of the retinal images.
Level 3 - non-randomized controlled study
Controlled laboratory experimental study in healthy volunteers (graded by design analogy for non-clinical research)
PubMed 12037630 · doi:10.1007/s00221-002-1097-6
What was done
Healthy human participants (n=7) wore prism lenses for one week that continuously inverted their visual field by 180 degrees. A parallel control group (n=7) received intermittent exposure to the distorted central visual field. The researchers tracked the time course of visuomotor adaptation using naturalistic motor tasks and Cooper-Shepard mental rotation (MR) tests across days 1–7, evaluating changes in reaction times, MR linear regression slopes, Y-intercepts, and postadaptation motor performance.
What was found
On day 1 with prisms, MR reaction times remained similar to baseline but operated within a rotated spatial frame of reference, alongside dysmetric and irregular visuomotor performance. Visuomotor adaptation functions mostly plateaued by day 3. As natural motor proficiency increased, MR Y-intercepts noticeably decreased, while MR slopes remained stable through days 1–7 across both groups. The correlation between stimulus angle and reaction time increased over time. Postadaptation testing showed minimal and selective adaptation limited to natural motor tasks. No exact numerical values or statistical test parameters were reported in the abstract.
Why it matters
This study provides evidence that long-term visuomotor adaptation to inverted retinal images modulates the spatial planning and preparatory phases shared with mental rotation, without altering the underlying rate of mental transformation itself.
Limits
The total sample size was very small (n=14 across two groups). Allocation was not described as randomized, and the abstract omits quantitative effect sizes, confidence intervals, and statistical test values.
Cited by
- context Wearing inverting prism glasses causes the perceived visual field to flip right-side up after an adaptation period of continuous wear.