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Changing pre-existing, automatized motor skills often requires interference control. Prepotent response inhibition - one subdimension of inhibition - has been theorized to be particularly associated with successful interference control in motor skills. Recent evidence suggests that different inhibition subdimensions elicit distinct ERP patterns (with larger P3 components for response inhibition). Therefore, we examined whether a similar ERP pattern would arise in a task demanding participants to overcome interference emerging from strong motor automatisms. This was realized within a typing paradigm involving a letter switch manipulation which is able to produce strong, immediate interference effects. Most importantly, stimulus-locked ERP analyses revealed an enhanced P3 component at frontal, central and most pronouncedly parietal sites for interference trials, in line with previous reported patterns for response inhibition. Together, different analyses provide first insights into the electrophysiological correlates of motor skill change, corroborating the pivotal role of response inhibition for successful interference control., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We investigated the influence of Fourier power spectrum (1/f(p)) characteristics on face learning while recording ERPs that are associated with the representation of faces. Two image sets with an altered 1/f(p) characteristics were created. The first set consisted of stimuli with a STEEP SLOPE (1/f(3.5)) and therefore enhanced low spatial frequencies (LSF) and attenuated high spatial frequencies (HSF). The second set consisted of stimuli with a SHALLOW SLOPE (1/f(2)), similar to complex natural scenes and artwork, resulting in enhanced HSF and attenuated LSF. Faces with a SHALLOW SLOPE elicited larger N170 and N250 amplitudes and larger old/new effects for central positivity in comparison to unmodified faces. The opposite effect was observed for faces with a STEEP SLOPE that led to slower reaction times. This result suggests that diminishing the ratio of fine detail (HSF) to coarse structures (LSF) impairs face learning, whereas increasing it facilitates neurocognitive correlates of face learning., (Copyright © 2011 Elsevier B.V. All rights reserved.)

There is a continuing controversy in models of face identification concerning the level of access to names relative to semantic information. In order to determine whether names are accessed sequentially after or in parallel to semantic information, we studied participants' speeded decisions about famous faces that were primed by partial semantic or partial name information. Decisions that required the access to the celebrity's name (one or more forename syllables, Expt 1) were significantly primed by partial name primes (initials or name fragments). However, at variance with sequential stage models, no reliable priming was observed by partial semantic primes (information about nationality, occupation, or whether a person was dead or alive). Moreover, there was a clear and consistent priming effect by partial semantic primes if the task was a nationality (British or American) decision that required the access to semantic information (Expt 2), demonstrating the effectiveness of these primes. The effects of partial name primes on nationality decisions were less consistent, with a significant effect for name fragments but not initials. However, effects of name primes were generally greater for syllable decisions than nationality decisions, and effects of semantic primes were generally greater for nationality decisions than syllable decisions. Taken together, these results favour a model of parallel rather than sequential access and suggest some degree of independence in the access to personal semantics and names.

In order to determine the dissociability of face, voice, and personal name recognition, we studied the performance of 36 brain-lesioned patients and 20 control subjects. Participants performed familiarity decisions for portraits, voice samples, and written names of celebrities and unfamiliar people. In those patients who displayed significant impairments in any of these tests, the specificity of these impairments was tested using corresponding object recognition tests (with pictures of objects, environmental sounds, or written common words as stimuli). The results showed that 58% of the patients were significantly impaired in at least one test of person recognition. Moreover, 28% of the patients showed impairments that appeared to be specific for people (i.e., performance was preserved in the corresponding object recognition test). Three patients showed a deficit that appeared to be confined to the recognition of familiar voices, a pattern that was not described previously. Results were generally consistent with the assumption that impairments in face, voice, and name recognition are dissociable from one another. In contrast, there was no clear evidence for a dissociability between deficits in face and voice naming. The results further suggest that (a) impairments in person recognition after brain lesions may be more common than was thought previously and (b) the patterns of impairment that were observed can be interpreted using current cognitive models of person recognition (Bruce & Young, 1986; Burton, Bruce, & Johnston, 1990)., (Copyright 2000 Academic Press.)

We investigated whether an asymmetric relationship between the perception of identity and emotional expressions in faces (Schweinberger & Soukup, 1998) may be related to differences in the relative processing speed of identity and expression information. Stimulus faces were morphed across identity within a given emotional expression, or were morphed across emotion within a given identity. In Experiment 1, consistent classifications of these images were demonstrated across a wide range of morphing, with only a relatively narrow category boundary. At the same time, classification reaction times (RTs) reflected the increased perceptual difficulty of the morphed images. In Experiment 2, we investigated the effects of variations in the irrelevant dimension on judgments of faces with respect to a relevant dimension, using a Garner-type speeded classification task. RTs for expression classifications were strongly influenced by irrelevant identity information. In contrast, RTs for identity classifications were unaffected by irrelevant expression information, and this held even for stimuli in which identity was more difficult and slower to discriminate than expression. This suggests that differences in processing speed cannot account for the asymmetric relationship between identity and emotion perception. Theoretical accounts proposing independence of identity and emotion perception are discussed in the light of these findings.

This study investigated hemispheric asymmetries in repetition priming (Experiment 1) and associative priming (Experiment 2) in visual word recognition. Participants performed speeded lexical decisions for foveally presented target words that could be preceded by prime words presented to the left (LVF) or right (RVF) visual field. Experiment 1 demonstrated larger repetition priming in reaction times when prime words were presented to the RVF (left hemisphere). In contrast, no repetition priming was observed for pseudowords. Hemispheric asymmetries in word repetition priming may therefore reflect the superiority of the left hemisphere in activating lexical representations. Experiment 2 did not find any hemispheric asymmetries in associative priming. The results suggest that repetition priming and associative priming act on different levels in word recognition, for which different hemispheric asymmetries exist.

Effects of variation in an irrelevant stimulus dimension on judgments of faces with respect to a relevant dimension were investigated. Dimensions were identity, emotional expression, and facial speech. The irrelevant dimension was correlated with, constant, or orthogonal to the relevant one. Reaction times (RTs) were predicted to increase over these conditions to the extent that the relevant dimension could not be processed independently of the irrelevant one. RTs for identity judgments were independent of variation in expression or facial speech, but RTs for expression and facial speech judgments were influenced by identity variation. Facial speech perception was affected by identity even when variation in the mouth region was eliminated. Moreover, observers could judge speech faster for personally familiar faces than for unfamiliar faces. The results suggest asymmetric dependencies between different components of face perception. Identity is perceived independently of, but may exert an influence on, expression and facial speech analysis.

We investigated whether the recognition deficits of two patients with long-standing prosopagnosia would also extend to exemplars within visually homogeneous object categories other than faces. Categorical object recognition was unimpaired in both patients. One patient was impaired in recognizing exemplars within both "living" and "nonliving" object categories. In contrast, the other patient performed at normal levels in exemplar recognition. These results provide further evidence that prosopagnosia does not necessarily reflect a general disorder in exemplar recognition, but can be a face-specific deficit.

The phonological loop model for retention of auditory verbal material in working memory, developed by Baddeley, assumes that irrelevant speech and phonological similarity influence only one and the same element of the system--that is, the phonological short-term store. We tested this idea by recording event-related potentials (ERPs) to auditorily presented letters that were phonologically similar or dissimilar and were to be memorized in the presence of more or less disturbing irrelevant speech. Irrelevant speech and phonological similarity caused ERP effects with clearly different scalp topographies, indicating that these factors influence different brain systems and hence probably different cognitive elements. Moreover, ERPs indicated that the phonological similarity effect might involve processes at the level of phonological analysis. Our data also support recent suggestions that the irrelevant speech effect is not based on the phonological similarity between relevant and irrelevant material, but on the phonological variability within the irrelevant stream.

The current investigation measured the effects of increasing stimulus duration on listeners' ability to recognize famous voices. In addition, the investigation studied the influence of different types of cues on the naming of voices that could not be named before. Participants were presented with samples of famous and unfamiliar voices and were asked to decide whether or not the samples were spoken by a famous person. The duration of each sample increased in seven steps from 0.25 s up to a maximum of 2 s. Voice recognition improvements with stimulus duration were with a growth function. Gains were most rapid within the first second and less pronounced thereafter. When participants were unable to name a famous voice, they were cued with either a second voice sample, the occupation, or the initials of the celebrity. Initials were most effective in eliciting the name only when semantic information about the speaker had been accessed prior to cue presentation. Paralleling previous research on face naming, this may indicate that voice naming is contingent on previous activation of person-specific semantic information.

Evidence from brain-damaged patients suggests different memory systems for verbal and nonverbal stimuli which also have different neuroanatomical substrates. We explored whether the scalp topographies of event-related potentials (ERPs) might confirm the dissociability of these systems. Unfamiliar faces and names were presented in separate conditions, study blocks alternating with recognition blocks. During recognition the familiarity of each stimulus was rated on a 4-point scale. The amplitudes of the ERPs to the study items were monotonically related in size to the mean subsequent familiarity ratings. Memory-related ERP differences (Dm) were calculated by subtracting ERPs recorded during the study phase to items with low subsequent familiarity ratings from items with high familiarity ratings. The Dm for faces and names showed stimulus-specific scalp topographies between 400 and 800 ms. These findings confirm that memory for names and faces is mediated by at least partially different brain systems.

This study investigated the performance of left- (LBD) and right-brain-damaged (RBD) patients in recognizing personal names under different conditions of associative priming. Subjects performed speeded familiarity decisions for names of famous and unfamiliar persons. These target names were preceded by primes, either faces or names, which could be neutral, related (e.g. Gorbachev-Jelzin), or unrelated (e.g. Travolta-Carter). Overall impairments in name recognition were observed in both patient groups relative to controls but were more severe in LBD than in RBD patients. This suggests that, contrary to previous hypotheses, the recognition of personal names is more dependent on left hemisphere functioning. In controls and LBD patients, associative priming effects did not differ significantly between face and name primes. In RBD patients, however, associative priming from names was larger than priming from faces. This specificity of priming effects for names in RBD patients was tentatively related to their impairments in face recognition.

Covert face recognition was investigated in a patient with prosopagnosia without object agnosia. This patient performed well in various face processing tasks like expression analysis and feature processing and had relatively preserved semantic knowledge about persons, but was slightly impaired in the visual matching of unfamiliar faces. In face-name paired-associate relearning task, covert face recognition was demonstrated to be above-chance. However, as this task cannot be meaningfully applied to control subjects, results do not necessarily indicate that the degree of covert face recognition is normal. In fact, in contrast to control subjects, the patient showed significantly reduced associative priming of names by face primes as compared to name primes, suggesting a quantitative reduction of covert face recognition. It is argued that these results support the view that overt and covert face recognition are brought about by the same functional system (Farah, O'Reilly and Vecera, 1993).

This study investigated practice effects on reaction time (RT) in patients with unilateral brain damage and age-matched controls. Subjects performed a Sternberg-type stimulus recognition task. Both RT and RT variability decreased in all subjects from a short initial session to a second session, 1 to 3 days later. Within the second session, however, RT remained constant in the controls, whereas it was further reduced in the patients. These findings argue against the assumption that brain-damaged patients generally show smaller practice effects on RT than controls, and instead suggest that it may be essential to provide patients with sufficient practice opportunities. To locate the processing stage where practice is effective, analyses were performed also on the intercept and slope parameters of the RT function. It is argued that the differential practice effects were due to the speeding of perceptual and/or response-related stages, rather than gains in memory search speed.

To clarify whether the impairment of right-brain-damaged (RBD) patients in face recognition is related to perceptual or mnestic processing stages, we tested unilaterally lesioned patients and controls in a Sternberg-type memory search task. Subjects had to memorize sets of 1, 2, or 3 faces (or, in a control condition, digits) and were then to recognize these memorized stimuli among new ones by speeded choice reactions. In this task, deficits in stimulus encoding and memory search should show up in increased intercepts and slopes, respectively, of the RT function over memory set size. A face-specific impairment of the RBD patient group, consisting in longer reaction times and higher error rates, was confirmed but could not be unequivocally attributed to either stimulus encoding or memory search. However, inspection of individual data suggested that (1) some RBD patients are virtually unimpaired in face recognition and (2) if impairment after right hemisphere damage is present, it may selectively affect either stimulus encoding or memory search.

This study demonstrates that operant conditioning may increase the P300 component of the event-related potential above a level obtained without contingent training. An experimental group of subjects was rewarded for producing large P300 amplitudes and was compared with a yoked control group which was rewarded on a random basis. During training the experimental subjects increased both the amplitude of the P300 and of a subsequent frontal negative slow wave relative to the control group. These training effects were independent of prestimulus potential shifts and occurred likewise for target and nontarget stimuli.

ERPs elicited by photographs of unfamiliar faces were shown to be predictive for their later recognition. We established that these ERP differences were unrelated to fluctuations of attention or other non-specific factors during perceptual processing. Therefore they may be interpreted as manifestations of brain processes that correlate with memory encoding. The scalp topography of this ERP difference was bipolar with greater electrical positivity at frontal and greater negativity at parieto-temporal scalp sites. This topography appears to contrast with the more uniformly positive differences reported for verbal stimuli but is in accord with what might be expected for faces and complex visual stimuli.

The relative contributions of stimulus encoding and memory search to right hemisphere (RH) superiority in face recognition were investigated in a memory search task with lateralized probe stimulus presentation. RH superiority in reaction time and latency of a late positive ERP component was independent of stimulus degradations, but increased as a function of memory set size. These results suggest equal efficiency of the hemispheres in stimulus encoding, but RH superiority in memory search. In addition, a long-lasting ERP negativity contralateral to the stimulated hemifield is discussed with reference to models of hemispheric processing in hemifield studies.