Internal versus external features in triggering the brain waveforms for conjunction and feature faces in recognition

Abstract

Previous research has found that conjunction faces (whose internal features, e.g. eyes, nose, and mouth, and external features, e.g. hairstyle and ears, are from separate studied faces) and feature faces (partial features of these are studied) can produce higher false alarms than both old and new faces (i.e. those that are exactly the same as the studied faces and those that have not been previously presented) in recognition. The event-related potentials (ERPs) that relate to conjunction and feature faces at recognition, however, have not been described as yet; in addition, the contributions of different facial features toward ERPs have not been differentiated. To address these issues, the present study compared the ERPs elicited by old faces, conjunction faces (the internal and the external features were from two studied faces), old internal feature faces (whose internal features were studied), and old external feature faces (whose external features were studied) with those of new faces separately. The results showed that old faces not only elicited an early familiarity-related FN400, but a more anterior distributed late old/new effect that reflected recollection. Conjunction faces evoked similar late brain waveforms as old internal feature faces, but not to old external feature faces. These results suggest that, at recognition, old faces hold higher familiarity than compound faces in the profiles of ERPs and internal facial features are more crucial than external ones in triggering the brain waveforms that are characterized as reflecting the result of familiarity.

External (Versus Internal) Facial Features Contribute Most to Repetition Priming in Facial Recognition: ERP Evidence

“…Similar to previous findings in facial recognition (Nie, Jiang, et al, 2014), internal facial features would contribute more to repetition priming than external facial features, such that familiar internal feature faces would elicit much stronger N250r and N400 activations than would familiar external feature faces; and…”

“…We then compared the repetition priming contributions of internal and external facial features on brain activations via the four ERP components of interest. We had four hypotheses: Perceptual processing reflected by P100 activation and structural encoding reflected by N170 activation would not be susceptible to the experimental manipulations; N250r activation, reflecting the accessing of stored structural representations of a face in long-term memory, and N400 activation, an index of the process of retrieving relevant knowledge from long-term memory, would each be affected by the prime repetition of faces such that target faces would elicit stronger waveforms than prime faces, the two sub-components of N250r showing distinctly different activations; Similar to previous findings in facial recognition (Nie, Jiang, et al, 2014), internal facial features would contribute more to repetition priming than external facial features, such that familiar internal feature faces would elicit much stronger N250r and N400 activations than would familiar external feature faces; and Both N250r and N400 activations would be sensitive to the time interval between the prime and the target faces, such that larger amplitudes would be observed in the immediate repetition vs the delayed repetition condition. …”

“…To ensure that all facial images were from popular celebrities, we recruited 60 undergraduates who did not engage in the formal experiment in our current study to take a pretest assessing their familiarity with our prepared 450 images. The assessment for the facial images of celebrities followed the procedure adopted in the previous literature (Nie, Michael, et al, 2014; Reder et al., 2013). These students were instructed to assess each facial image on a five-point Likert scale with the following descriptors: 1 = “completely unfamiliar”, 2 = “unfamiliar”, 3 = “not sure”, 4 = “familiar”, and 5 = “completely familiar.” On the basis of these pretest scores, we selected 320 experimental facial stimuli, including 197 actors, 48 singers, 49 hosts, 13 athletes, 5 politicians, 4 economists, and 4 artists.…”

“…However, there were brain activation differences for facial memory comparisons between a whole familiar face and a new face with external facial features from a familiar face. Of note, these researchers demonstrated that these two types of reconstructions from internal and external facial features held similar familiarity in terms of behavioral recognition (Nie, 2018; Nie, Jiang, et al, 2014; Nie, Jiang, et al, 2015), but distinctly different familiarity in terms of neural activations (ERP signals) for which familiar internal feature faces evoked much stronger activations than familiar external feature faces (Nie, Jiang, et al, 2014).…”

“…For instance, some studies differentiated internal and external facial features in facial memory (Meinhardt-Injac et al., 2010; Nie, 2018; Nie, Jiang, et al., 2014; Nie, Jiang, et al., 2015). Internal features include the forehead, eyebrows, eyes, nose, cheeks, and mouth, while external features refer to hairstyle, ears, chin, and facial contours (Bartlett et al., 2009; Jones & Bartlett, 2009; Nie, 2018; Nie, Jiang, et al, 2014; Nie, Jiang, et al, 2015). Research on recognition of new faces that were reconstructed by altering internal or external features found that brain activation was similar for facial memory comparisons between a whole familiar face and a new face with internal facial features from a familiar face.…”