Categorical perception for unfamiliar faces. The effect of covert and overt face learning.

Robust findings show that categorical perception (CP) occurs in identification of familiar faces. CP has also been observed for unfamiliar morphed faces after sufficient learning of the original, unmorphed faces has taken place. We previously suggested that CP arises when the activation of inconsistent visual and verbal representations creates a conflict between perceptual and category information. In the present study, we conducted two experiments in which the endpoint faces of an unfamiliar morphed continuum were presented in either a covert training regime (famous vs. nonfamous judgments) or an overt training regime (previously seen vs. unseen judgments). In both experiments, participants' reaction times to repeated targets decreased relative to reaction times to control items during training. After overt training, CP was observed for the previously unfamiliar faces. No CP was observed for covertly trained faces. We conclude that individual faces must be explicitly categorized before CP can be established for the morphed continuum between them.

What's in the name? Categorical perception for unfamiliar faces can occur through labeling.

The conditions under which categorical perception (CP) occurs for unfamiliar faces are unclear. Although CP is generally found only for familiar faces, it has been reported for unfamiliar faces after brief training (Levin & Beale, 2000) or even without any learning of the original faces (Campanella, Hanoteau, Seron, Joassin, & Bruyer, 2003). Three experiments investigated whether CP can be observed for an unfamiliar morphed face continuum without preexposure to the endpoints of the continuum (Experiment 1); with brief exposure to the endpoints (Experiment 2); or with exposure to named endpoints (Experiment 3). CP was always observed for matched pairs of famous faces. However, CP for unfamiliar faces was induced only when participants observed names paired with the endpoint faces before the start of the experiment. The results suggest that CP effects for unfamiliar faces can be observed extremely rapidly when clear category labels are presented.

Exploring the relationship between proper name anomia and word retrieval: a single case study.

We report the results of an investigation of the spoken word retrieval abilities of a patient, BG, with proper name anomia. Our investigations reveal that she is impaired in retrieving common nouns as well as proper names. Common noun retrieval was influenced by age-of-acquisition, word familiarity and name agreement. Cued retrieval of proper names was influenced by age-of-acquisition, although effects of other linguistic variables were not excluded. It is claimed that an explanation in terms of a 'continuum of word retrieval difficulty' rather than of proper names as 'pure referring expressions' can best account for the findings. However, this proposal is unlikely to be able to explain all cases of proper name anomia. Nonetheless, it is suggested that similar findings may be observed in other people with proper name anomia, and that it is necessary for future studies to investigate not only proper name but also common noun retrieval. We also provide evidence that Plausible Phonology and Specificity hypotheses of proper name anomia cannot account for BG's naming abilities.

Remembering and knowing in a patient with preserved recognition and impaired recall.

ROB is a patient who has a severe deficit in recalling recently presented verbal material following rupture and repair of an anterior communicating artery aneurysm [Hanley JR, Davies ADM, Downes J, Mayes A. Cognitive Neuropsychology 1994;11:543-78; Hanley JR, Davies ADM. In: Parkin A, editor. Case Studies in the Neuropsychology of Memory. Hillsdale, NJ: Lawrence Erlbaum, 1997. p. 111-26]. Despite this, her performance on tests of recognition memory is comfortably within the normal range. In the present series of experiments, we investigated whether or not ROB's performance on tests of recognition memory might be associated with a disproportionately large number of correct decisions made on the basis of familiarity rather than contextual retrieval [e.g. Mandler G. Psychological Review 1980;87:252-71]. Contrary to this hypothesis, the results showed that ROB made a high proportion of remember decisions relative to know decisions in recognition [cf. Gardiner JM. Memory & Cognition 1988;16:309-13] and produced a high recollection score when conscious recollection and familiarity were placed in opposition to one another [cf. Jacoby LL, Woloshyn V, Kelley C. Journal of Experimental Psychology: General 1989;118:115-25.]. ROB's recognition memory performance therefore appears to be qualitatively as well as quantitatively similar to that found in the normal population. As ROB has suffered damage to both the fornix and the anterior thalamus, the results of the present study are consistent with the claim that damage to the extended hippocampal system has a much more severe effect on recall than on recognition [Aggleton JP, Shaw C. Neuropsychologia 1996;34:51-62; Aggleton JP, Saunders RC. Memory 1997;5:49-71]. The present results provide no support, however, for the additional suggestion [Aggleton JP, Brown MW. Behavioral and Brain Sciences 1999;22:425-56.] that the extended hippocampal system is necessary for recognition memory decisions that are based on contextual retrieval.

Allograph errors and impaired access to graphic motor codes in a case of unilateral agraphia of the dominant left hand.

This paper describes the case of a unilateral agraphic patient (GG) who makes letter substitutions only when writing letters and words with his dominant left hand. Accuracy is significantly greater when he is writing with his right hand and when he is asked to spell words orally. GG also makes case errors when writing letters, and will sometimes write words in mixed case. However, these allograph errors occur regardless of which hand he is using to write. In terms of cognitive models of peripheral dysgraphia (e.g., Ellis, 1988), it appears that he has an allograph level impairment that affects writing with both hands, and a separate problem in accessing graphic motor patterns that disrupts writing with the left hand only. In previous studies of left-handed patients with unilateral agraphia (Zesiger & Mayer, 1992; Zesiger, Pegna, & Rilliet, 1994), it has been suggested that allographic knowledge used for writing with both hands is stored exclusively in the left hemisphere, but that graphic motor patterns are represented separately in each hemisphere. The pattern of performance demonstrated by GG strongly supports such a conclusion.

Why are familiar-only experiences more frequent for voices than for faces?

Hanley, Smith, and Hadfield (1998) showed that when participants were asked to recognize famous people from hearing their voice, there was a relatively large number of trials in which the celebrity's voice was felt to be familiar but biographical information about the person could not be retrieved. When a face was found familiar, however, the celebrity's occupation was significantly more likely to be recalled. This finding is consistent with the view that it is much more difficult to associate biographical information with voices than with faces. Nevertheless, recognition level was much lower for voices than for faces in Hanley et al.'s study, and participants made significantly more false alarms in the voice condition. In the present study, recognition performance in the face condition was brought down to the same level as recognition in the voice condition by presenting the faces out of focus. Under these circumstances, it proved just as difficult to recall the occupations of faces found familiar as it was to recall the occupations of voices found familiar. In other words, there was an equally large number of familiar-only responses when faces were presented out of focus as in the voice condition. It is argued that these results provide no support for the view that it is relatively difficult to associate biographical information with a person's voice. It is suggested instead that associative connections between processing units at different levels in the voice-processing system are much weaker than is the case with the corresponding units in the face-processing system. This will reduce the recall of occupations from voices even when the voice has been found familiar. A simulation was performed using the latest version of the IAC model of person recognition (Burton, Bruce, & Hancock, 1999) which demonstrated that the model can readily accommodate the pattern of results obtained in this study.

Ionizing radiation-induced mitogen-activated protein (MAP) kinase activation in DU145 prostate carcinoma cells: MAP kinase inhibition enhances radiation-induced cell killing and G2/M-phase arrest.

These studies examine the role(s) played by the mitogen-activated protein kinase (MAPK) pathway after exposure of DU145 prostate carcinoma cells to radiation. Radiation (2 Gy) was found to cause both immediate primary (0-30 min) and prolonged secondary activations (90-1440 min) of the MAPK pathway. These activations of the MAPK pathway were abolished by inhibition of epidermal growth factor receptor (EGFR) function. The secondary activation was also abolished by addition of a neutralizing monoclonal antibody against transforming growth factor alpha (TGFA). Activation of the MAPK pathway could be induced in nonirradiated cells by the transfer of medium from irradiated cultures. Neutralizing antibody to TGFA blocked this effect, indicating that radiation causes secondary activation of the MAPK pathway by release of TGFA in DU145 cells. Radiation induced a transient G(2)/M-phase growth arrest that was prolonged for up to 24 h by inhibition of the MAPK pathway. Inhibition of the MAPK pathway significantly increased the ability of radiation to cause apoptosis 24 h after exposure. The ability of DU145 cells to proliferate after irradiation became dependent on MAPK signaling. When cells were subjected to single doses or fractionated radiation exposure, continuous inhibition of the MAPK pathway significantly decreased clonogenic survival. Only a small fraction of this cell killing could be accounted for by apoptosis within the first 96 h. Thus inhibition of the MAPK pathway increased radiation-induced cell killing likely by both apoptotic and nonapoptotic mechanisms. Collectively, our findings indicate that disruption of the TGFA/EGFR/MAPK pathway may represent a strategy that could be exploited to manipulate prostate carcinoma growth and cell survival after irradiation.

Understanding memory for faces in Parkinson's disease: the role of configural processing.

It has previously been reported that unfamiliar face recognition memory is impaired in Parkinson's disease (PD) [(Dewick, H. C., Hanley, J. R., Davies, A. D. M., Playfer, J. R. & Turnbull, C. J., Perception and memory for faces in Parkinson's disease. Neuropsychologia, 1991, 29, 785-802), (Haeske-Dewick, H. C., Are perception and memory for faces influenced by a specific age at onset factor in Parkinson's disease? Neuropsychologia, 1996, 34, 315-320), (Levin, B. E., Llabre, M. M. & Weiner, W. J., Cognitive impairments associated with early Parkinson's disease. Neurology, 1989, 39, 557-561)]. In the work reported here, we consider the possible mechanisms that might underlie this impairment. 28 PD patients and 28 controls were given a two-part test of recognition memory for words and faces, and two perceptual tests to measure their configural and componential processing ability. We found that PD patients were significantly worse than controls on the recognition memory test for faces, but not when the stimuli were words. In addition, PD patients were significantly impaired relative to controls on the closure test (FCT) used to measure configural processing, but there was no difference between the two groups on a test of componential processing ability. Multiple regression analyses revealed that even after accounting for the influence of age, intelligence and level of depression, configural processing ability was the important predictor of unfamiliar face recognition memory in Parkinson's disease. There was no effect of Parkinson's disease specific variables on either face recognition or FCT performance. In addition, some recently diagnosed patients were poor at face recognition. It is suggested that face configuration skills may be affected very early in the course of Parkinson's disease, and that this may be connected to the fact that considerable nigrostriatal degeneration and alteration in brain neurotransmitter levels occur before the clinical symptoms of PD appear.

Detecting the faking of amnesia: a comparison of the effectiveness of three different techniques for distinguishing simulators from patients with amnesia.

This paper compared the effectiveness of three different procedures that have been put forward as possible ways of distinguishing patients with genuine memory problems from those who are attempting to simulate amnesia. The performance of 20 patients with amnesia was compared with the performance of 20 normal control individuals and 20 normal individuals who had been asked to simulate amnesia on the distraction/no distraction test (Baker, Hanley, Kimmance, & Slade, 1993), the coin-in-the-hand test (Kapur, 1994) and word fragment completion (Horton, Smith, Barghout, & Connolly, 1992). The distraction/no distraction test and the coin-in-the-hand test both proved successful in distinguishing patients with amnesia from simulators (p < .01). Excellent performance by virtually all patients with amnesia coupled with chance or below chance performance by 19/20 simulators on the coin-in-the-hand test was particularly striking. Consistent with the results of Horton et al. ( 1992), the word fragment completion test successfully discriminated between the performance of simulators and controls (p < .01). However, the fragment completion test proved incapable of distinguishing between the performance of patients with amnesia and simulators (p > .05). It is argued that there may be problems inherent in the use of tests designed to investigate implicit memory in attempts to detect malingering.

Proper name anomia and anomia for the names of people: functionally dissociable impairments?

This paper reviews the performance of 10 previously reported patients who have deficits in recalling the names of people, but whose performance in recalling common names is relatively well preserved. An analysis of face naming ability in these 10 patients reveals that the proportion of faces that a patient can name is closely related to whether or not the patient has a retrieval problem that also extends to the recall of other types of proper names such as the names of towns. This analysis suggests that names of faces are particularly difficult to recall relative to other types of proper names, and provides no support for the view that a specialised brain mechanism is involved in the retrieval of people's names.

In vivo overexpression of c-erbB-2 oncoprotein in xenografts of mice implanted with human colon cancer lines.

We have previously shown that c-erbB-2 oncoprotein encoded by the erbB-2 gene is overexpressed in human colorectal cancers that metastasis compared to those that are cured by surgery. To determine whether c-erbB-2 is also differentially expressed in vivo in metastasising and non-metastasising tumours, we developed models of colorectal cancer growth in nude mice. Human colon cancer cell lines, HCT116, KM12SM, LIM1215 and SW480, were injected into the caecum after characterising their morphology, doubling time, DNA flow-cytometry and expression of c-erbB-2. Six weeks later, xenografted tissues were fixed for histological analysis and detection of c-erbB-2 by immunohistochemistry, 78% (21/27) of mice developed caecal cancers. The caecal tumours derived from HCT116, KM12SM or LIM1215 were highly metastatic; 67 to 100% of them had liver metastases and lymph node involvement and 33 to 75% had lung tumours. Most of the tumours were c-erbB-2-positive. In contrast SW480 caecal tumours had only 33% lymph node involvement, but not liver or lung metastases. Only one SW480 caecal tumour and one lymph node metastasis expressed c-erbB-2. C-erB-2 was more frequently expressed in xenografted tissues in colon cancer primaries and secondaries of the highly metastatic cells (HCT116, KM12SM and LIM1215) compared to the cells (SW480) giving predominantly local growth. Our results suggest that c-erbB-2 gene may play an important role in the development of metastasis from colorectal cancer.

Orthographic analogies and developmental dyslexia.

Goswami (1986, 1988) has demonstrated that children can use orthographic analogies (particularly at the onset-rime level) between the spelling patterns in words to help to decode new words (e.g. using 'beak' to read 'peak'). This strategy has been shown in children as young as six years old. Since it is known that children with developmental dyslexia find it particularly difficult to read words that they have not been specifically taught (Lovett, Warren-Chaplin, Ransby & Borden, 1990), the present study investigated whether dyslexic children might be unable to use analogies. Employing a design similar to that used by Goswami (1988), it was hypothesized that dyslexics would find it difficult to transfer spontaneously knowledge of a 'clue' word to decode new words that could be read by analogy with the clue word. The results of Expt 1 indicated that the dyslexic readers read significantly fewer of the analogous words than a reading age-matched comparison group of younger children. Furthermore, none of the nine dyslexic children read as many of the analogous words as the lowest scoring control child. In a second experiment, a design similar to that of Muter, Snowling & Taylor (1994) was used with a new and larger sample of dyslexic children. In this experiment, all the children were brought to criterion in reading the clue words before the analogous words were presented. Once again, the dyslexic children read significantly fewer words that were analogous with the clue words than did a reading age-matched comparison group. The number of analogous words that the dyslexic children read was significantly correlated with their performance on a test that is sensitive to the ability to detect rhyme. It is argued that a failure to make analogies may be one of the main causes of the reading impairment experienced by children with developmental dyslexia.

Does articulatory suppression remove the irrelevant speech effect?

Salamé and Baddeley (1982) reported that the effect of irrelevant speech on the serial recall of visually presented sequences was abolished when subjects performed articulatory suppression during presentation and recall of the target items. They argued that this is because suppression isolates visually presented material from the phonological store, which they consider to be the locus of the irrelevant speech effect. In the present experiment, an alternative interpretation of Salamé and Baddeley's findings was investigated. Salamé and Baddeley used nine-item sequences, and observed very low levels of recall when articulation was suppressed. It is therefore possible that Salamé and Baddeley's failure to observe any additional effect of irrelevant speech reflects either a floor effect or else a strategic choice by subjects to abandon the use of a phonological memory code because of task difficulty. In the experiment reported here, this issue was investigated by using both six- and nine-item sequences. Results revealed no effect of irrelevant speech under articulatory suppression even at the shorter sequence length. The results therefore replicate and extend the findings of Salamé and Baddeley (1982), and provide support for their view that visually presented material must be articulated before it becomes susceptible to interference from irrelevant speech.

Putting faces to names.

An experiment is reported which investigated participants' ability to remember a person's face when they were presented with the person's name. During the learning phase, participants were shown 18 unfamiliar faces together with a name and occupation. At test, participants were presented with a name and were asked to indicate the face and occupation that had been presented with that name at learning. Results showed that participants' ability to remember the face was contingent upon their ability to remember the occupation that had been presented with the name. When participants were presented with a face and were asked to remember the name, performance was also contingent upon correctly remembering the associated occupation, consistent with the findings of McWeeny, Young, Hay & Ellis (1987). No such contingencies were apparent when participants were given an occupation and were asked to remember the associated name and face; participants frequently remembered the name but not the face, or the face without the name. These results are consistent with the serial access model of person identification proposed by Bruce & Young (1986), and with more recent developments proposed by Valentine, Brédart, Lawson & Ward (1991) and Craigie & Hanley (1993) in which there are no direct links between the representation of a person's name in memory and visual information about their facial appearance. The mnemonic strategies that were used by the participants during the learning phase of the experiment were also examined. These strategies help explain those few occasions on which participants appear to be able to link names to faces without identity-specific semantic information.

Reading speed in pure alexia.

This study investigated possible causes of differences in reading speed between two alexic patients who read words letter by letter. As both patients appeared to rely on serial left-to-right processing of letters within words, the difference in reading speed did not seem to be related to any differences in the extent to which the patients could recognize letters in words in parallel or 'ends-in'. Differences in reading speed also seemed to be unrelated to the patients ability to identify individual letters since their letter recognition accuracy was very similar. Furthermore, although patient PD was significantly slower at reading words aloud than patient DC, PD was in fact significantly quicker than DC on a test that has previously been used to assess letter recognition skills in letter-by-letter readers. It is therefore concluded that PD reads words more slowly because of an additional impairment at the level of the word form system. The results therefore reinforce the distinction between Type 1 and Type 2 letter-by-letter readers that was first drawn by Patterson and Kay.

A dissociation between the ability to print and write cursively in lower-case letters.

This paper reports the case of a patient with a peripheral spelling impairment who is much more severely impaired at writing in lower-case letters than in upper-case letters. This pattern can be observed when writing both words and single letters of the alphabet. Despite this, his problems in writing lower-case letters are no longer present when he is writing cursively. This case therefore indicates that the ability to print letters in lower-case can be selectively impaired in the absence of similar problems in printing upper-case letters or in writing lower-case letters cursively. In terms of the model of writing put forward by Ellis (1982, 1988), this suggests that allographic level representations for print handwriting styles can be functionally dissociated from allographic representations for cursive styles.

Studies of X-irradiated bladder cancer cell lines showing differences in p53 status: absence of a p53-dependent cell cycle checkpoint pathway.

Cell growth arrest is a common response to DNA damage by ionising irradiation and the p53 gene has been shown to play an important role in this mechanism, possibly in a tissue-specific manner. Mutations in the p53 gene are frequent in invasive bladder cancers, which are often treated by radiotherapy. In this paper we have investigated the growth response to X-irradiation of three bladder cancer cell lines with differing p53 status: UCRU-BL-17 overexpresses mutant p53, while UCRU-BL-13 and UCRU-BL-28 contain wt P53. We have also examined the expression of proteins reported to be part of the p53 control pathway in response to irradiation-induced DNA damage. No G1 arrest was detectable in any of the cell lines after ionising irradiation; furthermore, in a downstream event reported to be correlated with p53 function there was no increase in WAF-1 protein levels regardless of p53 status. Rather, ionising irradiation resulted in G2 arrest, but the extent of this was not related to p53 status. p16 levels were also not affected by irradiation. Our results suggest that the UCRU-BL-28 cell line may have a defect in the p53-cell control pathway upstream of p53, while UCRU-BL-13 cells may have a defect downstream between p53 and WAF-1.

The effect of environmental context on recall and category clustering scores following relational and individual item processing: a test of the outshining hypothesis.

This study investigated the effects of the reinstatement of environmental context on recall of a list of words after subjects had performed either relational processing or individual item processing on them at encoding (cf Einstein & Hunt, 1980). In the first experiment, subjects showed significantly less semantic category clustering when environmental cues were available to them at recall. This effect occurred regardless of encoding task, and suggests that subjects in the same context condition were using environmental cues to help them recall words from the list. Nevertheless, there was no effect of contextual reinstatement on the number of words recalled in either encoding condition. In Experiment 2, a list of words with a much less obvious categorical structure was used, which eliminated category clustering following individual item processing. Despite this, no beneficial effect of contextual reinstatement was seen on the number of words recalled by subjects who performed either the individual item or the relational processing task. In the relational processing group, contextual reinstatement once again significantly reduced the category clustering scores. The results of both experiments indicate that there are effects of contextual reinstatement on memory that are not necessarily apparent when overall level of recall is the dependent variable.

A dissociation between developmental surface and phonological dyslexia in two undergraduate students.

This study compares the nature of the reading deficit that was observed in two dyslexic undergraduate students who were severely impaired at reading and spelling compared with normal undergraduates. They both achieved the same (below average) score on the National Adult Reading Test and on the Schonell spelling test. One of them, however, was good at reading and spelling nonwords, had good phonological awareness skills, was better at reading regular than irregular words, and made phonologically accurate reading and spelling errors (i.e. was a surface dyslexic). The other had poor phonological awareness, produced relatively few phonologically accurate spelling errors, and was poor at reading and spelling nonwords (i.e. was a phonological dyslexic). It is particularly noteworthy that such a clear dissociation between surface and phonological forms of developmental dyslexia occurred in two subjects who were closely matched in terms of their overall reading and spelling ability, and also in terms of their memory span and vocabulary. It is argued that this study strengthens the evidence for the existence of qualitatively different types of developmental dyslexia. The findings are also consistent with the view that phonological awareness skills are more closely related to the operation of the phonological rather than the visual reading route.

Are names difficult to recall because they are unique? A case study of a patient with anomia.

According to Burton and Bruce (1992), names are more difficult to recall than biographical information about people, such as their occupation, because names are unique or highly distinctive. It follows from this that anomic patients who have great difficulty in recalling names should also find it difficult to recall other information that is unique to a particular individual. This paper attempts to evaluate this claim by examining the case of NP, a patient who has severe anomic word-finding difficulties following the rupture and repair of a posterior cerebral artery aneurysm. NP's ability to recall biographical information about people that she cannot name was investigated in a series of experiments. These revealed that she can answer specific questions about the occupations and appearance of well-known people and can recall distinctive meaningful information about them such as the identity of their spouse, even though she is unable to recall their name. It is argued that these results support the view that names are represented in a store separate from that for semantic information about people that we know. The findings are therefore consistent with the sequential stage model of face identification put forward by Bruce and Young (1986) and are explained in terms of the theory of speech production put forward by Levelt (1989).