Encoding differences in visual and haptic face recognition

In previous experiments, we provided further evidence that 3-D face stimuli can be learned and recognized by touch alone. Performance was significantly improved when haptic memory was refreshed during the experiment, indicating high memory demands due to the serial encoding process of haptic exploration. We also found that performance in a complementary visual experiment was better than in the haptic one. We suggested that these results arise from differences in encoding procedures (holistic in vision vs. serial in haptics). To test this hypothesis we designed the following two experiments which promoted serial encoding also in vision: Experiment 1 used the same old/new recognition task for which three faces were learned with three subsequent test-blocks. Participants used a mouse to move a Gaussian window which uncovered 2° of a photograph of the 3-D face. Recognition accuracy was low(d'=.98), equivalent to non-refreshed haptic performance, and significantly lower than for unrestricted visual recognition(d’=2.12). Using the same design in Experiment 2, memory was refreshed by repeated exposure to the learned faces. Performance increased significantly(d'=1.64) to levels of memory-refreshed haptic performance and unrestricted visual recognition. The performance differences in visual and haptic face recognition therefore might be attributed to modality-specific encoding strategies and memory demands