|Reference code: ||PT/FB/BL-2004-016.09|
|Location: ||Arquivo PCA - Pasta 24/2004|
|Perceptual memory in the human visual system|
|Publication year: ||2010|
It is a well established observation that plane inversion causes deterioration of performance in face discrimination tasks – the so-called face inversion effect (FIE). This phenomenon suggests that the human visual system contains specialized processing mechanisms that are more engaged by upright faces than by inverted faces or non-face objects. One prominent hypothesis proposes that such specialization results from
extensive practice with upright faces, leading to expertise for this canonical orientation. Here, we aimed to investigate perceptual learning for faces presented in multiple orientations, by conducting both psychophysics and functional magnetic resonance imaging (fMRI) experiments.
We conducted two psychophysics experiments in which participants performed a same / different discrimination task (DT) on pairs of faces: for orientations ranging between 0 and 300° over one session (Experiment 1) and for a single orientation over four training sessions (Experiment 2). We then conducted an fMRI experiment to investigate the neural correlates of face perception at multiple orientations.
A quadratic effect was observed across orientations for both reaction times and error rates, indicating a deterioration of performance away from 0° and towards 180°. In Experiment 2, we observed a main effect of session, indicating that participants became significantly faster and more accurate with training. Finally, when tested with a different orientation (240°) at the end of the last session, participants showed a similar
performance compared with the trained orientation (120°), suggesting that transfer of learning across orientations took place.
In summary, we have showed a consistent effect of face orientation in both behavioural and neuroimaging results. Specifically, we found that participants gave more errors and were slower in their responses as faces were rotated away from 0º. In addition, performance was improved when participants underwent periods of training, both for trained and untrained orientations. Consistently with the expertise hypothesis, we also
found a parametric modulation of fMRI activity in specialized visual brain areas, according to the quadratic behavioural effect of face orientation.
- Gomes CA, Mendes M, Figueiredo P. (2009) Perceptual learning for multiple face orientations. Perception. Vol. 38 Supp., p. 79.
- Gomes CA, Mendes M, Figueiredo P. (2009) Perceptual learning for multiple face orientations. APPE 2009, Lisboa, Portugal.
|Accessibility: ||Document does not exist in file|
|Secondary author(s): |
|Mendes, M., Silva, M. F., Xavier, J., Gomes, C.|
|Document type: |
|Number of reproductions: |
|Figueiredo, P., Mendes, M., Silva, M. F., Xavier, J., & Gomes, C. (2010). Perceptual memory in the human visual system. In Aquém e além do cérebro. Behind and beyond the brain. Proceedings of the 8th Symposium of Fundação Bial (p. 186). Porto: Fundação Bial.|
|Indexed document: ||No|
|Keywords: ||Face perception / Learning / Expertise / Psychophysics / Functional magnetic resonance imaging (fMRI)|
Perceptual memory in the human visual system