Interference from familiar natural distractors is not eliminated by high perceptual load

A crucial prediction of perceptual load theory is that high perceptual load can eliminate interference from distractors. However, Lavie et al. (Psychol Sci 14:510–515, 2003) found that high perceptual load did not eliminate interference when the distractor was a face. The current experiments examined the interaction between familiarity and perceptual load in modulating interference in a name search task. The data reveal that high perceptual load eliminated the interference effect for unfamiliar distractors that were faces or objects, but did not eliminate the interference for familiar distractors that were faces or objects. Based on these results, we proposed that the processing of familiar and natural stimuli may be immune to the effect of perceptual load.     

Processing overlap-dependent distractor dilution rather than perceptual target load determines attentional selectivity

The perceptual load theory of attentional selection argues that the degree to which distractors interfere with target processing is determined by the “perceptual load” (or discrimination difficulty) of target processing: when perceptual load is low, distractors interfere to a greater extent than when it is high. A well-known exception is load-independent interference effects from face distractors during processing of name targets. This finding was reconciled with load theory by proposing distinct processing resources for faces versus names. In the present study, we revisit this effect to test (a) whether increasing the processing overlap (perceptual, lexical, conceptual) between potential targets and distractors would reinstate the classic load effect, and (b) whether this data pattern could be better explained by load theory or by a rival account that argues that distractor dilution rather than target load determines the degree of distractor interference. Over four experiments, we first replicate the original finding and then show that load effects grow with increasing processing overlap between potential targets and distractors. However, by adding dilution conditions, we also show that these processing overlap dependent modulations of distractor interference can be explained by the distractor dilution perspective but not by perceptual load theory. Thus, our findings support a processing overlap dilution account of attentional selection.     

Perceptual load effects on processing distractor faces indicate face-specific capacity limits

The claim that face perception is mediated by a specialized “face module” that proceeds automatically, independently of attention (e.g., Kanwisher, 2000) can be reconciled with load theory claims that visual perception has limited capacity (e.g., Lavie, 1995) by hypothesizing that face perception has face-specific capacity limits. We tested this hypothesis by comparing the effects of face and nonface perceptual load on distractor face processing. Participants searched a central array of either faces or letter strings for a pop star versus politician's face or name and made speeded classification responses. Perceptual load was varied through the relevant search set size. Response competition effects from a category-congruent or -incongruent peripheral distractor face were eliminated with more than two faces in the face search task, but were unaffected by perceptual load in the name search task. These results support the hypothesis that face perception has face-specific capacity limits and resolve apparent discrepancies in previous research.     

知觉负荷对面孔多重社会范畴加工的影响

为了考察知觉负荷理论对于面孔多重社会范畴加工机制解释的可能性, 我们采用两个反应时实验探讨了姓名判断是否会在不同的知觉负荷条件下受到面孔性别与种族信息的影响。实验1通过侧抑制范式考察姓名判断中面孔种族引发的干扰效应是否会受到知觉负荷水平的调节。结果发现, 姓名判断的反应时间会随着负荷水平的提高显著延长, 即面孔种族引发的干扰效应不会随着负荷水平的提高而消失。实验2继续通过侧抑制范式考察了姓名判断中面孔性别引发的干扰效应是否会在不同知觉负荷水平下出现差异。结果发现, 在低负荷水平下, 个体在不一致条件下的反应时长于一致条件下的反应时, 并且被试会倾向于将中性名字的性别判断为与面孔的性别一致。在高负荷水平下, 个体的反应时在一致和不一致条件下没有显著差异, 并且被试对中性名字的性别判断属于随机猜测水平。上述结果表明, 种族加工具有自下而上的强制性加工的特点; 性别加工是受到注意资源调节的自上而下加工, 具有一定的灵活性。     

Attentional spread in deaf and hearing participants: Face and object distractor processing under perceptual load

The case of human deafness constitutes a unique opportunity to examine possible consequences for perceptual processing due to altered sensory experiences. We tested whether deaf??in contrast to hearing??individuals are more susceptible to visual distraction from peripheral than from central face versus object stimuli. The participants were required to classify the gender of a target male or female symbol presented either alone (low perceptual load) or together with three filler symbols (high perceptual load), while ignoring gender-congruent or -incongruent face versus object distractors presented at central or peripheral positions. The gender classifications were affected by distractor gender under low, but not under high, perceptual load in hearing participants. In contrast, the responses of deaf participants were similarly influenced by distractor gender under both levels of perceptual load. There was no evidence for generally enhanced attention to the visual periphery in deaf individuals. Our results indicate that auditory deprivation may result in enhanced attentional capacities under high perceptual load.     

Recognizing the un-real McCoy: priming and the modularity of face recognition

Fodor (1983) has proposed that face perception is carried out by an informationally encapsulated module, whose operation is unaffected by context or expectancies. We tested the modularity hypothesis by examining whether discriminations between normal and distorted versions of famous faces can be primed, either by the name of an associated person (semantic context) or by a valid cue as to the identity of the target face (expectancy). A preliminary experiment showed that, in the absence of priming, discriminations between normal and distorted versions of a face were unaffected by whether the target faces were familiar or not, confirming that these judgments tap perceptual, not postperceptual (semantic), coding processes. In Experiment 1, accuracy was significantly higher when target face pairs were preceded by related name primes, as compared with unrelated ones. In Experiment 2, reaction times were significantly faster for targets preceded by a valid identity cue than for targets preceded by an invalid one. Neither effect could be explained as a speed—accuracy tradeoff. These results fail to support Fodor’s conjecture that face processing is encapsulated.     

The role of perceptual load in processing distractor faces

It has been established that successful ignoring of irrelevant distractors depends on the extent to which the current task loads attention. However, the previous load studies have typically employed neutral distractor stimuli (e.g., letters). In the experiments reported here, we examined whether the perception of irrelevant distractor faces would show the same effects. We manipulated attentional load in a relevant task of name search by varying the search set size and found that whereas congruency effects from meaningful nonface distractors were eliminated by higher search load, interference from distractor faces was entirely unaffected by search load. These results support the idea that face processing may be mandatory and generalize the load theory to the processing of meaningful and more complex nonface distractors.     

The role of attention and familiarity in face identification

How is attention allocated during face identification? Previous work using famous and unfamiliar faces suggests that either no attention or a special attentional mechanism is required. We used a conventional attentional blink (AB) procedure to measure face identification with temporarily reduced attention. The participants viewed a rapid series of face images with one embedded nonface abstract pattern (T1). They judged the texture of T1 and then detected a prespecified face (T2) presented at varying lags after T1. T2 was either famous or unfamiliar, as were distractor faces. Regardless of distractor type, detection of an unfamiliar T2 face was significantly impaired at short versus long T1-T2 lags, indicating an attentional requirement for face identification. Detection of a famous T2 face was unaffected by lag, suggesting that familiarity protects against atemporal attentional bottleneck These findings do not support propositions that face identification is "special" in its need for attentional control     

Ignoring famous faces: category-specific dilution of distractor interference

The extent to which famous distractor faces can be ignored was assessed in six experiments. Subjects categorized famous printed target names as those of pop stars or politicians, while attempting to ignore a flanking famous face distractor that could be congruent (e.g, a politician's name and face) or incongruent (e.g., a politician's name with a pop stars face). Congruency effects on reaction times indicated distractor intrusion. An additional, response-neutral flanker (neither pop star nor politician) could also be present. Congruency effects from the critical distractor face were reduced (diluted) by the presence of an intact anonymous face, but not by phase-shifted versions, inverted faces, or meaningful nonface objects. By contrast, congruency effects from other types of distracting objects (musical instruments, fruits), when printed names for these classes were categorized, were diluted equivalently by intact faces, phase-shifted faces, or meaningful nonface objects. Our results suggest that distractor faces act differently from other types of distractors, suffering from only face-specific capacity limits.     

Not to be and then to be: visual representation of ignored unfamiliar faces

Negative priming, the increase in response time and/or errors to targets previously encountered as distractors, is explained by inhibitory mechanisms that block the access of distractor representations to response systems. The processing of unfamiliar human faces was investigated using negative priming. Observers viewed a row of faces to decide whether 2 target faces were the same or different. Response latencies were longer when 1 or both targets had appeared as distractors on the immediately preceding trial--evidence that never-before seen faces are represented and require inhibition. Response latencies were shorter when face targets had appeared as distractors, either corrupted with high-frequency noise or contrast inverted--evidence that representations are facilitated. Finally, response latencies remained unaltered when face targets had appeared as upside-down distractors--evidence that not all distractor representations afford response priming. The visual system indeed represents ignored unfamiliar faces, but blocks these representations only if they vie with targets for the control of action.     

Does temporal integration of face parts reflect holistic processing?

We examined whether temporal integration of face parts reflects holistic processing or response interference. Participants learned to name two faces “Fred” and two “Bob.” At test, the top and bottom halves of different faces formed composites and were presented briefly separated in time. Replicating prior findings (Singer & Sheinberg, Vision Research, 46, 1838–1847, 2006), naming of the target half for aligned composites was slowed when the irrelevant half was from a face with a different name rather than from the original face. However, no interference was observed when the irrelevant half had a name identical to the name of the target half but came from a different learned face, arguing against a true holistic effect. Instead, response interference was obtained when the target half briefly preceded the irrelevant half. Experiment 2 confirmed a double dissociation of holistic processing versus response interference for intact faces versus temporally separated face halves, suggesting that simultaneous presentation of facial information is critical for holistic processing.     

知觉负载对负性分心面孔的知觉加工和记忆的影响

本研究采用视觉搜索和意外再认记忆任务,结合事件相关电位技术,考察知觉负载对负性分心面孔的知觉加工和记忆的影响。在视觉搜索任务中,行为上恐惧分心面孔在高负载下干扰任务。ERP结果上,恐惧比中性分心面孔诱发更大的N170和N250;在低负载下恐惧比中性分心面孔诱发更大的N700,在高负载下没有差异。在意外再认记忆中,个体对低负载下的恐惧分心面孔表现出记忆。这些结果说明负性分心物在早期是自动化加工;晚期加工受知觉负载的调节,负载越低对负性分心物的过滤越少,存在对负性分心物的记忆偏向。     

The other-race effect does not rely on memory: Evidence from a matching task

Viewers are typically better at remembering faces from their own race than from other races; however, it is not yet established whether this effect is due to memorial or perceptual processes. In this study, UK and Egyptian viewers were given a simultaneous face-matching task, in which the target faces were presented upright or upside down. As with previous research using face memory tasks, participants were worse at matching other-race faces than own-race faces and showed a stronger face inversion effect for own-race faces. However, subjects' performance on own and other-race faces was highly correlated. These data provide strong evidence that difficulty in perceptual encoding of unfamiliar faces contributes substantially to the other-race effect and that accounts based entirely on memory cannot capture the full data. Implications for forensic settings are also discussed.     

A bottleneck in face identification: repetition priming from flanker images

There is evidence that face processing is capacity-limited in distractor interference tasks and in tasks requiring overt recognition memory. We examined whether capacity limits for faces can be observed with a more sensitive measure of visual processing, by measuring repetition priming of flanker faces that were presented alongside a face or a nonface target. In Experiment 1, we found identity priming for face flankers, by measuring repetition priming across a change in image, during task-relevant nonface processing, but not during the processing of a concurrently-presented face target. Experiment 2 showed perceptual priming of the flanker faces, across identical images at prime and test, when they were presented alongside a face target. In a third Experiment, all of these effects were replicated by measuring identity priming and perceptual priming within the same task. Overall, these results imply that face processing is capacity limited, such that only a single face can be identified at one time. Merely attending to a target face appears sufficient to trigger these capacity limits, thereby extinguishing identification of a second face in the display, although our results demonstrate that the additional face remains at least subject to superficial image processing.     

Dissociating perceptual and representation-based contributions to priming of face recognition

Repetition priming of object identification refers to the phenomenon whereby experience with an object induces systematic changes in subsequent processing of that same object. This data-driven form of priming is distinct from conceptually-driven priming. To date, considerable controversy exists about whether data-driven priming reflects facilitation in perceptual processing or mediation by preexisting object representations. The present study concerned priming of recognizing familiar and unfamiliar faces and how this priming is influenced by face inversion, which interferes with perceptual face processing. Perceptual and representation-based loci conjointly contributed to priming; the perceptual locus was operative similarly for familiar and unfamiliar faces, whereas the representation-based locus was only invoked for familiar faces and resulted in a response-time reduction triple the magnitude of that from the perceptual locus. The results constrain theoretical accounts of data-driven priming by indicating that improved identification can result from the combination of perceptual and representation-based facilitation.     

The other-race effect does not rely on memory: Evidence from a matching task

Viewers are typically better at remembering faces from their own race than from other races; however, it is not yet established whether this effect is due to memorial or perceptual processes. In this study, UK and Egyptian viewers were given a simultaneous face-matching task, in which the target faces were presented upright or upside down. As with previous research using face memory tasks, participants were worse at matching other-race faces than own-race faces and showed a stronger face inversion effect for own-race faces. However, subjects' performance on own and other-race faces was highly correlated. These data provide strong evidence that difficulty in perceptual encoding of unfamiliar faces contributes substantially to the other-race effect and that accounts based entirely on memory cannot capture the full data. Implications for forensic settings are also discussed.     

Perceiving age and gender in unfamiliar faces: an fMRI study on face categorization

Efficient processing of unfamiliar faces typically involves their categorization (e.g., into old vs. young or male vs. female). However, age and gender categorization may pose different perceptual demands. In the present study, we employed functional magnetic resonance imaging (fMRI) to compare the activity evoked during age vs. gender categorization of unfamiliar faces. In different blocks, participants performed age and gender classifications for old or young unfamiliar faces (50% female respectively). Both tasks elicited activations in the bilateral fusiform gyri (fusiform face area, FFA) and bilateral inferior occipital gyri (occipital face area, OFA). Importantly, the same stimuli elicited enhanced activation during gender as compared to age categorization. This enhancement was significant in the right FFA and the left OFA, and may be related to increased configural processing. Our findings replicate and extend recent work, and shows that the activation of core components of the face processing network is strongly dependent on task demands.     

Own- and other-race categorization of faces by race,gender, and age

We investigated how visual experience with faces of a particular race affects subordinate group-level categorizations in Chinese and Israeli participants living in the respective countries. Categorization of faces by race, gender, and age was examined within subjects with participants who had only minimal experience with the other-race faces. As would be predicted by the previously documented other-race advantage effect, both Chinese and Israeli participants classified the race of the face more quickly and more accurately for other-race than for own-race faces. In contrast, the observers’ race did not interact with the race of the rated face either for gender or for age categorization. The absence of these interactions suggests that the physiognomic characteristics that determine the gender and age of a face are universal, rather than race specific. Furthermore, these data suggest that determining the race of a face is not imposed as a first step in face processing, preempting the perception of other category-defining physiognomic characteristics.     

Robust representations for faces: evidence from visual search.

We report evidence from visual search that people can develop robust representations for highly overlearned faces. When observers searched for their own face versus the face of an unfamiliar observer, search slopes and intercepts revealed consistently faster processing of self than stranger. These processing advantages persisted even after hundreds of presentations of the unfamiliar face and even for atypical profile and upside-down views. Observers not only showed rapid asymptotic recognition of their own face as the target, but could reject their own face more quickly as the distractor. These findings suggest that robust representations for a highly overlearned face may (a) mediate rapid asymptotic visual processing, (b) require extensive experience to develop, (c) contain abstract or view-invariant information, (d) facilitate a variety of processes such as target recognition and distractor rejection, and (e) demand less attentional resources.     

Perceptual asymmetries in face recognition

Four experiments were carried out to investigate perceptual asymmetries in face recognition. Perceptual asymmetries favoring the half-face on the observer's left were found under free viewing conditions for both unfamiliar faces (Experiment 1) and famous faces (Experiment 3). For unfamiliar faces, this asymmetry was not obtained when fixation was controlled by presenting faces tachistoscopically (Experiment 2). For famous faces, the perceptual asymmetry favoring the half-face normally seen on the left did not appear to be retained in memory (Experiments 3 and 4). Asymmetries in face perception have been explained in terms of a direct access model of laterally effects. However, these results raise the possibility that asymmetric scanning or attentional factors may be important.