The role of visual field position in pattern–discrimination learning

Abstract

SUMMARYInvariance of object recognition to translation in the visual field is a fundamental property of human pattern vision. In three experiments we investigated this capability by training subjects to distinguish between random checkerboard stimuli. We show that the improvement of discrimination performance does not transfer across the visual field if learning is restricted to a particular location in the retinal image. Accuracy after retinal translation shows no sign of decay over time and remains at the same level it had at the beginning of the training. It is suggested that in two-dimensional translation invariance-as in three-dimensional rotation invariance-the human visual system is relying on memory-intensive rather than computation-intensive processes. Multiple position-and stimulusspecific learning events may be required before recognition is independent of retinal location.

Topographic Contribution of Early Visual Cortex to Short-Term Memory Consolidation: A Transcranial Magnetic Stimulation Study

“…This suggestion is in line with propositions of object substitution in visual memory after presentation of a competing stimulus (Giesbrecht and Di Lollo, 1998;Enns and Di Lollo, 2000). Furthermore, our finding of a lateralized TMS effect on memory performance suggested that the neural memory representation was retinotopically organized, with limited transfer of memorized information to other parts of the visual field (Karni and Sagi, 1993;Schoups et al, 1995;Dill and Fahle, 1997). This spatial specificity of our findings further supports the notion of a local neural representation of memory in visual cortex.…”

Category learning induces position invariance of pattern recognition across the visual field

“…This allows us to reconcile apparently contradictory findings of, on the one hand, a limited translation invariance of human object recognition observed in tasks involving pattern discrimination (Foster & Kahn 1985;Nazir & O'Regan 1990;Dill & Fahle 1997, 1998, and the robustness of recognition against spatial displacements found for familiar objects (Ellis et al 1989;Biederman & Cooper 1991;Stankiewicz & Hummel 2002) on the other hand. In concordance with the former, we observed an initial drop of performance as learning and test locations became dissociated from each other (cf.…”

Spatial constraints on learning in visual search: Modeling contextual cuing.

“…However, despite individuals' ability to recognize an object even when its projection on the retina varies significantly, several studies have shown that perceptual learning is not necessarily invariant to translation in the visual field (Dill & Fahle, 1997;Fahle, 1994;Fahle, Edelman, & Poggio, 1995;Fiorentini & Berardi, 1981;Karni & Sagi, 1991;Nazir & O'Regan, 1990;Ramachandran, 1976;Shiu & Pashler, 1992). In fact, response times and error rates tend to increase linearly with the degree of translation applied to a stimulus, which is taken as evidence that some type of shifting process is responsible for lining up visual input with stored memory (Foster & Kahn, 1985).…”

“…In fact, response times and error rates tend to increase linearly with the degree of translation applied to a stimulus, which is taken as evidence that some type of shifting process is responsible for lining up visual input with stored memory (Foster & Kahn, 1985). Dill and Fahle (1997), for example, trained observers to recognize particular novel stimuli (bilaterally symmetric 6 ϫ 6 matrices of dots) and discriminate them from distractors. They then translated the stimuli to a different visual field location and found that the learning did not transfer if the training was restricted to a particular location in the visual field.…”