Carry-over effects in face recognition: Processing mode or attentional window?

This study investigates whether or not the dominant processing mode (global or local) in a Navon task is carried over to a face recognition task when the dominant processing mode (configural or featural) in an encoding phase is manipulated. In Experiment 1, Navon figures that were equal in size to a facial photograph were prepared. Participants performed better on the face recognition task after reading large letters in the Navon figures than after reading small letters when configural processing was required in the encoding phase. In Experiment 2, Navon figures that were equal in size to the parts of a face were prepared. The performance after reading large letters did not differ from that after reading small letters. This suggests that both the dominant processing mode in Navon tasks and the size of Navon figures should be considered when discussing the effects of Navon tasks in face recognition.     

Local and global cross-modal influences between vision and hearing, tasting, smelling, or touching

It is suggested that the distinction between global versus local processing styles exists across sensory modalities. Activation of one-way of processing in one modality should affect processing styles in a different modality. In 12 studies, auditory, haptic, gustatory or olfactory global versus local processing was induced, and participants were tested with a measure of their global versus local visual attention; the content of this measure was unrelated to the inductions. In a different set of 4 studies, the effect of local versus global visual processing on the way people listen to a poem or touch, taste, and smell objects was examined. In all experiments, global/local processing in 1 modality shifted to global/local processing in the other modality. A final study found more pronounced shifts when compatible processing styles were induced in 2 rather than 1 modality. Moreover, the study explored mediation by relative right versus left hemisphere activation as measured with the line bisection task and accessibility of semantic associations. It is concluded that the effects reflect procedural rather than semantic priming effects that occurred out of participants' awareness. Because global/local processing has been shown to affect higher order processing, future research may activate processing styles in other sensory modalities to produce similar effects. Furthermore, because global/local processing is triggered by a variety of real world variables, one may explore effects on other sensory modalities than vision. The results are consistent with the global versus local processing model, a systems account (GLOMOsys; F?rster & Dannenberg, 2010).     

Holistic processing impairment can be restricted to faces in acquired prosopagnosia: Evidence from the global/local Navon effect

Previous studies have shown that acquired prosopagnosia is characterized by impairment at holistic/configural processing. However, this view is essentially supported by studies performed with patients whose face recognition difficulties are part of a more general visual (integrative) agnosia. Here, we tested the patient PS, a case of acquired prosopagnosia whose face‐specific recognition difficulties have been related to the inability to process individual faces holistically (absence of inversion, composite, and whole–part effects with faces). Here, we show that in contrast to this impairment, the patient presents with an entirely normal response profile in a Navon hierarchical letter task: she was as fast as normal controls, faster to identify global than local letters, and her sensitivity to global interference during identification of local letters was at least as large as normal observers. These observations indicate that holistic processing as measured with global/local interference in the Navon paradigm is functionally distinct from the ability to perceive an individual face holistically.     

Typical hierarchical processing in autistic adults

ABSTRACT

Previous research suggests that autistic individuals exhibit atypical hierarchical processing, however, most of these studies focused solely on children. Thus, the main aim of the current study was to investigate the presence of atypical local or global processing in autistic adults using a traditional divided attention task with Navon’s hierarchical figures. Reaction time data of 27 autistic and 25 neurotypical (NT) adults was analysed using multilevel modelling and Bayesian analysis. The results revealed that autistic, like NT, adults experienced a global precedence effect. Moreover, both autistic and NT participants experienced global and local interference effects. In contrast to previous findings with children, the current study suggests that autistic adults exhibit a typical, albeit unexpected, processing of hierarchical figures.     

Culture variation in the average identity extraction: The role of global vs. local processing orientation

ABSTRACT

Research has shown that observers often spontaneously extract a mean representation from multiple faces/objects in a scene even when this is not required by the task. This phenomenon, now known as ensemble coding, has so far mainly been based on data from Western populations. This study compared East Asian and Western participants in an implicit ensemble-coding task, where the explicit task was to judge whether a test face was present in a briefly exposed set of faces. Although both groups showed a tendency to mistake an average of the presented faces as target, thus confirming the universality of ensemble coding, East Asian participants displayed a higher averaging tendency relative to the Westerners. To further examine how a cultural default can be adapted to global or local processing demand, our second experiment tested the effects of priming global or local processing orientation on ensemble coding via a Navon task procedure. Results revealed a reduced tendency for ensemble coding following the priming of local processing orientation. Together, these results suggest that culture can influence the proneness to ensemble coding, and the default cultural mode is malleable to a temporary processing demand.     

The tendency of unconscious thought toward global processing style

This study explored whether unconscious thought has a tendency to process information globally. In three experiments, a Navon task was used to activate global or local processing styles. Findings showed that in the unconscious-thought groups, those performing the local Navon task presented a poorer decision-making performance when compared to those performing the global Navon task (Experiment 1); participants reported that their judgments were made based on partial attributes (Experiment 2), and evaluated a target individual mainly based on information consistent with stereotypes (Experiment 3). These results showed that when presented with distracter tasks, conscious thought activates local processing, which impairs its ability to process information globally. However, this impairment would not happen if global processing were activated instead. This study provides support to the idea that unconscious thought has a tendency to process information globally.     

Sensory and affective judgments of skin during inter- and intrapersonal touch

Here we report two experiments that investigated the tactile perception of one’s own skin (intrapersonal touch) versus the skin of other individuals (interpersonal touch). In the first experiment, thirteen female participants rated, along four perceptual attributes, the skin of their own palm and volar forearm, then that of several of the other participants. Ratings were made using visual analogue scales for perceived smoothness, softness, stickiness, and pleasantness. One’s own skin was rated less pleasant than the skin of others. For both intra- and interpersonal touch, the forearm skin was rated smoother, softer, less sticky and more pleasant than the palmar skin. In the second experiment, ten pairs of female participants rated each other’s palm and volar forearm skin, with the skin of the touched individual being assessed before and after the application of skin emollients that alter skin feel. As in the first experiment, the untreated skin of others was rated more pleasant than the participants’ own skin, and the forearm versus palm differences were replicated. However, the emollient had generally larger effects on self-assessments than the assessments of others, and the site effect showed greater positive sensory and pleasantness increases for palm versus volar forearm. The disparate results of the two experiments suggest that attention, influenced by the ecological importance of the stimulus, is more important to assessment of touched skin than ownership of the skin or the contribution to self-touch made by the additional receptors in the passively touched skin. In both experiments, the pleasantness of touched skin was associated with the skin’s perceived smoothness and softness, with weak trends toward negative associations with its perceived stickiness, consistent with prior research using inanimate surfaces (e.g., textiles and sandpapers).     

The effects of precedence on Navon-induced processing bias in face recognition

Macrae and Lewis (2002) showed that repeated reporting of the global dimension of Navon stimuli improved performance in a subsequent face identification task, whilst reporting the features of the Navon stimuli impaired performance. Using a face composite task, which is assumed to require featural processing, Weston and Perfect (2005) showed the complementary pattern: Featural responding to Navon letters speeded performance. However, both studies used Navon stimuli with global precedence, in which the overall configuration is easier to report than the features. Here we replicate the two studies above, whilst manipulating the precedence (global or featural) of the letter stimuli in the orientation task. Both studies replicated the previously reported findings with global precedence stimuli, but showed the reverse pattern with local precedence stimuli. These data raise important questions as to what is transferred between the Navon orientation task and the face-processing tasks that follow.     

Processing of compound visual stimuli by children with autism and Asperger syndrome

A typical modes of visual processing are common in individuals with autism. In particular, and unlike typically developing children, children with autism tend to process the parts of a complex object as a priority, rather than attending to the object as a whole. This bias for local processing is likely to be due to difficulties in assembling subparts into a coherent whole, as proposed by Frith ( 10 1989) using the term “weak central coherence” or WCC. This study was aimed to better characterize the processing of complex visual stimuli by children with autism. Thirteen children with autistic spectrum disorders were individually paired with children of two control groups, one matched on verbal mental age (VMA) and one matched on chronological age (CA). Participants from the three groups were tested in two tasks. The first task involved hierarchical global/local stimuli, inspired by Navon ( 30 1977). The second task employed compound face‐like or geometrical stimuli. This task emphasized the processing of configural properties of the stimuli (i.e., spatial relationships). Children from the three groups showed a perceptual bias favouring the global dimension of the stimuli in the first task. By contrast, children with autism were deficient compared to normal children for the processing of the configural dimensions of the stimuli in the second task. These results suggest that visual cognition of children with autism is characterized by a dissociation between global and configural processing, with global processing being preserved and configural processing being altered in these children, therefore delineating the extents and limits of the WCC theory (Frith, 10 1989).     

Past and present experiences with maternal touch affect infants’ attention toward emotional faces

Maternal touch is considered crucial in regulating infants’ internal states when facing unknown or distressing situations. Here, we explored the effects of maternal touch on 7-month-old infants’ preferences towards emotions. Infants’ looking times were measured through a two-trial preferential looking paradigm, while infants observed dynamic videos of happy and angry facial expressions. During the observation, half of the infants received an affective touch (i.e., stroke), while the other half received a non-affective stimulation (i.e., fingertip squeeze) from their mother. Further, we assessed the frequency of maternal touch in the mother-infant dyad through The Parent-Infant Caregiving Touch Scale (PICTS). Our results have shown that infants’ attention to angry and happy facial expressions varied as a function of both present and past experiences with maternal touch. Specifically, in the affective touch condition, as the frequency of previous maternal affective tactile care increased (PICTS), the avoidance of angry faces decreased. Conversely, in the non-affective touch condition, as the frequency of previous maternal affective tactile care increased (PICTS), the avoidance of angry faces increased as well. Thus, past experience with maternal affective touch is a crucial predictor of the regulatory effects that actual maternal touch exerts on infants’ visual exploration of emotional stimuli.     

Auditory attention to frequency and time: an analogy to visual local-global stimuli

Two priming experiments demonstrated exogenous attentional persistence to the fundamental auditory dimensions of frequency (Experiment 1) and time (Experiment 2). In a divided-attention task, participants responded to an independent dimension, the identification of three-tone sequence patterns, for both prime and probe stimuli. The stimuli were specifically designed to parallel the local-global hierarchical letter stimuli of [Navon D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353-383] and the task was designed to parallel subsequent work in visual attention using Navon stimuli [Robertson, L. C. (1996). Attentional persistence for features of hierarchical patterns. Journal of Experimental Psychology: General, 125, 227-249; Ward, L. M. (1982). Determinants of attention to local and global features of visual forms. Journal of Experimental Psychology: Human Perception and Performance, 8, 562-581]. The results are discussed in terms of previous work in auditory attention and previous approaches to auditory local-global processing.     

Local processing enhancements associated with superior observational drawing are due to enhanced perceptual functioning,not weak central coherence

Individuals with drawing talent have previously been shown to exhibit enhanced local visual processing ability. The aim of the current study was to assess whether local processing biases associated with drawing ability result from a reduced ability to cohere local stimuli into global forms, or an increased ability to disregard global aspects of an image. Local and global visual processing ability was assessed in art students and controls using the Group Embedded Figures Task, Navon shape stimuli, the Block Design Task and the Autism Spectrum Quotient, whilst controlling for nonverbal IQ and artistic ability. Local processing biases associated with drawing appear to arise from an enhancement of local processing alongside successful filtering of global information, rather than a reduction in global processing. The relationship between local processing and drawing ability is independent of individual differences in nonverbal IQ and artistic ability. These findings have implications for bottom-up and attentional theories of observational drawing, as well as explanations of special skills in autism.     

Same,same — but different: On the use of Navon derived measures of global/local processing in studies of face processing

Some studies have reported a significant correlation between face discrimination/recognition ability and indexes of global/local processing derived from the Navon paradigm. Other studies, however, have failed to find such a relationship. In this paper we examine three aspects related to the Navon paradigm that may have contributed to this discrepancy but which have been largely neglected: (i) the use of different types of compound stimuli across studies, (ii) differences between studies in the type of index derived from the Navon paradigm, and (iii) the reliability of these indexes. In a Navon experiment comparing performance with compound letters and compound shapes in normal participants, we find little consistency both within and across participants in how they perform with these stimulus types, despite the fact that both stimulus types give rise to the typical effects. In addition we find that many of the Navon derived indexes of global/local effects used in studies examining face processing have low reliability and do not measure the same aspects of global/local processing. Echoing the results from the normal participants, we also find little consistency in how a congenital prosopagnosic performs in the Navon paradigm. With compound letters, she responds much faster to local than to global aspects of the stimuli; a pattern not seen in a single of the normal participants. With compound shapes, however, she exhibits no such abnormality. These findings question the validity of the conclusions in studies relating Navon derived indexes of global/local processing to face processing.     

Investigating the stability of and relationships among global/local processing measures

Global/local stimuli have been used to estimate global processing biases in individuals and groups, as well as in response to various manipulations. Throughout the literature, multiple different versions of global/local stimuli have been used, such as traditional hierarchical letters and numbers (i.e., Navon letters), abstract hierarchical shapes, and high- and low-spatial-frequency gratings and faces. However, currently it is unclear how reliable or stable performance is on these measures within individuals over time, and whether these seemingly different measures are tapping into the same underlying process. As such, the purpose of the present study was to examine the stability of individual performance on three distinct global/local measures over time and to examine the relationships among the measures. In two studies, we examined the reliability of the biases within, and the relationships among, standard Navon letters in a traditional interference task, hierarchical shapes in a forced choice task, and superimposed high- and low-pass spatial frequency faces in a forced choice task. In both studies, participants completed all three of the tasks, and then returned 7–10 days later to again complete the same tasks. The degree of global/local bias within an individual was found to be highly reliable in the hierarchical shape task and the spatial frequency face task, but less reliable in the traditional Navon letter task. Interestingly, in both studies we found that none of the three measures of global bias were related to each other. Therefore, while these measures do appear to be reliable over time, they may be tapping into distinct aspects of global/local processing.     

Autism: Hard to Switch from Details to the Whole

It has long been proposed that individuals with autism exhibit a superior processing of details at the expense of an impaired global processing. This theory has received some empirical support, but results are mixed. In this research we have studied local and global processing in ASD and Typically Developing children, with an adaptation of the Navon task, designed to measure congruency effects between local and global stimuli and switching cost between local and global tasks. ASD children showed preserved global processing; however, compared to Typically Developing children, they exhibited more facilitation from congruent local stimuli when they performed the global task. In addition, children with ASD had more switching cost than Typically Developing children only when they switched from the local to the global task, reflecting a specific difficulty to disengage from local stimuli. Together, results suggest that ASD is characterized by a tendency to process local details, they benefit from the processing of local stimuli at the expense of increasing cost to disengage from local stimuli when global processing is needed. Thus, this work demonstrates experimentally the advantages and disadvantages of the increased local processing in children with ASD.     

Visual search for global/local stimulus features in humans and baboons

Fagot and Deruelle (1997) demonstrated that, when tested with identical visual stimuli, baboons exhibit an advantage in processing local features, whereas humans show the “global precedence” effect initially reported by Navon (1977). In the present experiments, we investigated the cause of this species difference. Humans and baboons performed a visual search task in which the target differed from the distractors at either the global or the local level. Humans responded more quickly to global than to local targets, whereas baboons did the opposite (Experiment 1). Human response times (RTs) were independent of display size, for both local and global processing. Baboon RTs increased linearly with display size, more so for global than for local processing. The search slope for baboons disappeared for continuous targets (Experiment 2). That effect was not due to variations in stimulus luminance (Experiment 3). Finally, variations in stimulus density affected global search slopes in baboons but not in humans (Experiment 4). Overall, results suggest that perceptual grouping operations involved during the processing of hierarchical stimuli are attention demanding for baboons, but not for humans.     

Testing day: The effects of processing bias induced by Navon stimuli on the strength of the Müller-Lyer illusion

Explanations for the cognitive basis of the Müller-Lyer illusion are still frustratingly mixed. To date, Day’s (1989) theory of perceptual compromise has received little empirical attention. In this study, we examine the merit of Day’s hypothesis for the Müller-Lyer illusion by biasing participants toward global or local visual processing through exposure to Navon (1977) stimuli, which are known to alter processing level preference for a short time. Participants (N = 306) were randomly allocated to global, local, or control conditions. Those in global or local conditions were exposed to Navon stimuli for 5 min and participants were required to report on the global or local stimulus features, respectively. Subsequently, participants completed a computerized Müller-Lyer experiment where they adjusted the length of a line to match an illusory-figure. The illusion was significantly stronger for participants with a global bias, and significantly weaker for those with a local bias, compared with the control condition. These findings provide empirical support for Day’s “conflicting cues” theory of perceptual compromise in the Müller-Lyer illusion.     

Positive Affect and Flexibility: Overcoming the Precedence of Global over Local Processing of Visual Information

Previous findings on the relationship between positive mood and global processing are often based on visual matching tasks that involve a choice between global and local strategies. Preferences for global processing in positive mood, however, do not imply a reduced ability to process locally. The present experiment tested the assumption that positive affect increases flexibility in cognitive processing as indicated by the ability to overcome global precedence, and to respond rapidly to non-dominant (local) features when the task necessitates it. Consistent with expectations, participants responded significantly faster to local targets after positive compared to neutral and negative prime words. The typical precedence of global over local processing observed after neutral and negative prime words was reversed after positive prime words. Findings support the assumption that positive affect increases cognitive flexibility. Furthermore, findings suggest that mood-related preferences in global versus local processing cannot be generalized to processing ability.     

Effects of processing bias on the recognition of composite face halves

Research has shown that face recognition accuracy can be improved by prior global processing and impaired by prior local processing (Macrae & Lewis, 2002). The aim of this study was to test the processing bias account of face recognition, using the composite face task (Young, Hellawell, & Hay, 1987), a test of featural recognition. Undergraduate volunteers (N=75) participated in a between-subjects design that tested their ability to recognize face halves within a composite, following either global or local Navon processing or a control task. Results showed that, as compared with the control task, local processing speeded ability to recognize face halves. These results provide support for the processing bias account of face recognition.