Karen Lander

The role of movement in the recognition of famous faces

The effects of movement on the recognition of famous faces shown in difficult conditions were investigated. Images were presented as negatives, upside down (inverted), andthresholded. Results indicate that, under all these conditions, moving faces were recognized significantly better than static ones. One possible explanation of this effect could be that a moving sequence contains more static information about the different views and expressions of the face than does a single static image. However, even when the amount of static information was equated (Experiments 3 and 4), there was still an advantage for moving sequences that contained their original dynamic properties. The results suggest that the dynamics of the motion provide additional information, helping to access an established familiar face representation. Both the theoretical and the practical implications for these findings are discussed.

Evaluating the effectiveness of pixelation and blurring on masking the identity of familiar faces

Two experiments are reported that assess how well the identity of highly familiar (famous) faces can be masked from short naturalistic television clips. Recognition of identity was made more difficult by either pixelating (Experiment 1) or blurring (Experiment 2) the viewed face. Participants were asked to identify faces from both moving and static clips. Results indicated that participants were still able to recognize some of the viewed faces, despite these image degradations. In addition, moving images of faces were recognized better than static ones. The practical and theoretical implications of these findings are discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.

Recognizing Famous Faces: Exploring the Benefits of Facial Motion

We report on two experiments that investigated the role of facial motion in the recognition of degraded famous face images. The results of these experiments suggest that seeing a face move is advantageous for the correct recognition of identity. This effect is not solely due to the extra static-based information contained in a moving sequence but is also due to additional dynamic information available from a moving face. Furthermore, famous faces were recognized more accurately when the original dynamic characteristics of the motion were maintained (Experiment 1), compared to when either the tempo or the direction of motion were altered (Experiment 2). It is suggested that there may be general benefit for viewing naturally moving faces, not specific benefit to any particular face identity. Alternatively, individual faces may have associated characteristic motion signatures.

`Putting the Face to the Voice': Matching Identity across Modality

Speech perception provides compelling examples of a strong link between auditory and visual modalities. This link originates in the mechanics of speech production, which, in shaping the vocal tract, determine the movement of the face as well as the sound of the voice. In this paper, we present evidence that equivalent information about identity is available cross-modally from both the face and voice. Using a delayed matching to sample task, XAB, we show that people can match the video of an unfamiliar face, X, to an unfamiliar voice, A or B, and vice versa, but only when stimuli are moving and are played forward. The critical role of time-varying information is underlined by the ability to match faces to voices containing only the coarse spatial and temporal information provided by sine wave speech [5]. The effect of varying sentence content across modalities was small, showing that identity-specific information is not closely tied to particular utterances. We conclude that the physical constraints linking faces to voices result in bimodally available dynamic information, not only about what is being said, but also about who is saying it.

Why are moving faces easier to recognize

Previous work has suggested that seeing a famous face move aids the recognition of identity, especially when viewing conditions are degraded (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). Experiment 1 investigated whether the beneficial effects of motion are related to a particular type of facial motion (expressing, talking, or rigid motion). Results showed a significant beneficial effect of both expressive and talking movements, but no advantage for rigid motion, compared with a single static image. Experiment 2 investigated whether the advantage for motion is uniform across identity. Participants rated moving famous faces for distinctiveness of motion. The famous faces (moving and static freeze frame) were then used as stimuli in a recognition task. The advantage for face motion was significant only when the motion displayed was distinctive. Results suggest that a reason why moving faces are easier to recognize is because some familiar faces have characteristic motion patterns, which act as an additional cue to identity.

The role of motion in learning new faces

Four experiments are reported that investigate the usefulness of rigid (head nodding, shaking) and nonrigid (talking, expressions) motion for establishing new face representations of previously unfamiliar faces. Results show that viewing a face in motion leads to more accurate face learning, compared with viewing a single static image (Experiment 1). The advantage for viewing the face moving rigidly seems to be due to the different angles of view contained in these sequences (Experiment 2). However, the advantage for nonrigid motion is not simply due to multiple images (Experiment 3) and is not specifically linked to forwards motion but extends to reversed sequences (Experiment 4). Thus, although we have demonstrated beneficial effects of motion for face learning, they do not seem to be due to the specific dynamic properties of the sequences shown. Instead, the advantage for nonrigid motion may reflect increased attention to faces moving in a socially important manner.

It's not what you say but the way you say it : Matching faces and voices

Recent studies have shown that the face and voice of an unfamiliar person can be matched for identity. Here the authors compare the relative effects of changing sentence content (what is said) and sentence manner (how it is said) on matching identity between faces and voices. A change between speaking a sentence as a statement and as a question disrupted matching performance, whereas changing the sentence itself did not. This was the case when the faces and voices were from the same race as participants and speaking a familiar language (English; Experiment 1) or from another race and speaking an unfamiliar language (Japanese; Experiment 2). Altering manner between conversational and clear speech (Experiment 3) or between conversational and casual speech (Experiment 4) was also disruptive. However, artificially slowing (Experiment 5) or speeding (Experiment 6) speech did not affect cross-modal matching performance. The results show that bimodal cues to identity are closely linked to manner but that content (what is said) and absolute tempo are not critical. Instead, prosodic variations in rhythmic structure and/or expressiveness may provide a bimodal, dynamic identity signature.

Relating visual and vocal attractiveness for moving and static faces

The relationship between visual and vocal attractiveness in males and females as evaluated by men and women was investigated. Participants rated the attractiveness of voices and static faces or voices and moving faces. Rubenstein (2005. Psychological Science, 16, 759–762) suggested that dynamic and static faces are judged by different evaluative standards. Results from the reported experiment suggest that for male participants there was a positive correlation between female vocal and visual (moving or static face) attractiveness. Women rated with higher voice attractiveness were rated as having more attractive faces. For female participants there was a positive correlation between male vocal and moving visual attractiveness but not between male vocal and static visual attractiveness. In addition, no significant correlation between the attractiveness of male static faces and that of male moving faces was found, highlighting differences in rated attractiveness when judging either moving or static faces (Rubenstein, A. J. 2005. Psychological Science, 16, 759–762). Finally, there was no correlation between vocal and visual attractiveness (moving or static) for same-sex judgements. Results are discussed with regard to perceptual and evolutionary perspectives.

The influence of positive and negative facial expressions on face familiarity

Recent studies have shown that smiling faces are judged as more familiar than those showing a neutral expression (Baudouin, Gilibert, Sansone, & Tiberghien, 2000). Here we compare judged familiarity of unknown and famous faces when displaying a positive, neutral, or negative expression. Our results confirm a smiling familiarity bias, with positive-expression faces judged as being more familiar. Importantly, we also show significantly reduced familiarity for negative-expression faces, compared with neutral- or positive-expression faces. This difference in judged familiarity is not due to differences in expression intensity, but instead related to expression valence. Results are discussed with regard to the independence of facial identity and expression processing, and in terms of factors that influence face familiarity and memory.

Exploring the role of characteristic motion when learning new faces

Previous research has shown that it is easier to recognize familiar faces when shown moving, rather than static, especially when viewing conditions are difficult (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). One possible theoretical reason for the moving-face advantage is that we learn “characteristic motion signatures” for familiar faces, associated with the face representation in memory. To examine this idea we investigated the role of motion at test when learning faces from either static images or moving sequences (Experiment 1). Results suggest that there is only an advantage for motion at test when the face is learned moving. In Experiment 2 we map the importance of facial motion as a face becomes increasingly familiar, on a television drama. We demonstrate that the beneficial effect of motion is not dependent on the amount of time the face is viewed. Results from both experiments support the idea of rapidly learned characteristic motion patterns.