Haptic face recognition: Behavioural, neuropsychological, and neuroimaging perspectives

Very few studies have investigated face recognition by touch; yet this field of inquiry has the potential to offer valuable insights about both haptic and visual face recognition. The current thesis uses behavioural, neuropsychological case study, and a neuroimaging technique to collectively address four questions: How are faces haptically processed? Do haptic and visual face recognition share common mechanisms? Is face recognition multisensory? Is face recognition special? The results of these studies indicate that haptic face recognition relies more on configural than featural processing mechanisms; in contrast, haptic object recognition focuses more on features than on overall configuration. Such processing patterns are similar to what has been observed in visual face and nonface-object recognition. Moreover, when configural processing of faces is disrupted in the disorder known as prosopagnosia, similar deficits in haptic face recognition are also observed. The behavioural similarities documented between haptic and visual face recognition extend to, and are a result of, the common neural substrates shared by haptic and visual face recognition. Due to the functional and neuroanatomical correspondence between haptic and visual face recognition, we conclude that face recognition is a multisensory phenomenon. Finally, the thesis also offers significant new results based on haptic face-recognition paradigms that collectively address the continuing controversy whether or not faces are special.