An event-related potential study of contextual modifications in a face recognition task.

Event-related potentials (ERP) were recorded during a task involving the short-term recognition of unfamiliar faces. The purpose was to study the effects of changing the intrinsic context (facial expression) and/or the extrinsic context (background) between the encoding and recognition of a face. The new face caused an increase in the parietal N170 amplitude, but this component was not affected by contextual modifications. In contrast, the frontal N200 was very sensitive to context changes. There was also a well-defined, late parietal component modulated by the processing of information relevant to the face recognition decision. This late positive component reached its amplitude peak when the decision criterion was the strictest. The results obtain showed that ERP can be modulated by these context variations even though they are irrelevant to the task at hand.

Unconscious familiarity and local context effects on low-level face processing: a reconstruction hypothesis.

A common view in face recognition research holds that there is a stored representation specific to each known face. It is also posited that semantic or memory-based information cannot influence low-level face processing. The two experiments reported in this article investigate the nature of this representation and the flow of face information processing. Participants had to search for a particular primed face among other faces. In Experiment 1, the search was done in a context where distractors had either a different degree of fame or the same degree of fame. In Experiment 2, the target face was primed either with semantic information or without any information. Both experiments demonstrated that increasing the display set size lengthened face detection time. However, the lengthening was a function of face fame. The search context also had an effect on the slope of the famous face detection. The results are explained in terms of the idea that face representations are reconstructed and that high- and low-level information are integrated into the processing. The integration process is not a conscious one.

When the smile is a cue to familiarity.

The question discussed in the two following experiments concerns the effect of facial expressions on face recognition. Famous and unknown faces with neutral or smiling expression were presented for different inspection durations (15 ms vs 1000 ms). Subjects had to categorize these faces as famous or unknown (Experiment 1), or estimate their degree of familiarity on a rating scale (Experiment 2). Results showed that the smile increased ratings of familiarity for unfamiliar faces (Experiments 1 and 2) and for famous faces (Experiment 2). These data are discussed in the framework of current face-recognition models and are interpreted in terms of social value of the smile. It is proposed that the smiling bias found here acts at the level of the decision process.

Phonological and semantic priming: evidence for task-independent effects.

The questions asked in the present experiments concern the generality of semantic and phonological priming effects: Do these effects arise automatically regardless of target task, or are these effects restricted to target tasks that specifically require the retrieval of the primed information? In Experiment 1, subjects produced faster color matching times on targets preceded by a masked rhyming prime than on targets preceded by an orthographic control or an unrelated prime. This result suggests that automatic priming effects on the basis of phonological similarity can be obtained even when the target task does not make use of phonological information. This claim was reinforced in Experiment 2 in which a rhyme priming effect and a semantic priming effect were found in a semantic categorization task. In Experiment 3, the target task was phonological (rhyme detection), and, again, both phonological and semantic priming effects were observed. Finally, in Experiments 4 and 5, in a replication and an extension of Experiment 1, phonological and semantic priming effects were found in a color matching task, a task involving neither phonological nor semantic processing. These results are most straightforwardly interpreted by assuming that both semantic and phonological priming effects are, at least in part, due to automatic activation of memorial representations.

Encoding activity and face recognition.

A series of studies conducted over the past 20 years have explored the effects of various tasks on recognition memory for faces. Memory for faces appears better when the study task involves judgements about an abstract trait rather than a physical feature. The various situations in which these results were obtained raise important methodological questions regarding the learning conditions, whether incidental or intentional, and the duration of exposure to the stimulus during the study phase. We consider here two alternative explanations for the reported results. One concerns depth of processing and the other the opposition between component and holistic processing. Possible strategies for improving face recognition performance are considered.

Models of human memory.

The capacity to store and retrieve information is a property common to biological organisms and certain artefacts. Psychological models of human memory fall into two rival classes: a) "bionic" models which draw inspiration from the structural and functional properties of the central nervous system (computo bionic models); b) "symbolic information processing" models in which the inspiration for description and explanation of natural processes is drawn from the structural and functional properties of Von Neumann computers (computo-symbolic models).