TEACHING RECEPTIVE NAMING OF CHINESE CHARACTERS TO CHILDREN WITH AUTISM BY INCORPORATING ECHOLALIA

The facilitative effect of incorporating echolalia on teaching receptive naming of Chinese characters to children with autism was assessed. In Experiment 1, echoing the requested character name prior to the receptive naming task facilitated matching a character to its name. In addition, task performance was consistently maintained only when echolalia preceded the receptive manual response. Positive results from generalization tests suggested that learned responses occurred across various novel conditions. In Experiment 2, we examined the relation between task difficulty and speed of acquisition. All 3 participants achieved 100% correct responding in training, but learning less discriminable characters took more trials than learning more discriminable characters. These results provide support for incorporating echolalia as an educational tool within language instruction for some children with autism.     

Is the acquisition of basic-colour terms in young children constrained?

We investigated whether the learning of colour terms in childhood is constrained by a developmental order of acquisition as predicted by Berlin and Kay [1969 Basic Color Terms (Berkeley, CA: University of California Press)]. Forty-three children, aged between 2 and 5 years and grouped according to language ability, were given two tasks testing colour conceptualisation. Colour comprehension was assessed in a spoken-word-to-colour-matching task in which a target colour was presented in conjunction with two distractor colours. Colour naming was measured in an explicit naming task in which colours were presented individually for oral naming. Results showed that children's knowledge of basic-colour terms varied across tasks and language age, providing little support for a systematic developmental order. In addition, we found only limited support for an advantage for the conceptualisation of primary (red, green, blue, yellow, black, white) compared to non-primary colour terms across tasks and language age. Instead, our data suggest that children acquire reliable knowledge of nine basic colours within a 3-month period (35.6 to 39.5 months) after which there is a considerable lag of up to 9 months before accurate knowledge of the final two colours (brown and grey) is acquired. We propose that children acquire colour term knowledge in two distinct time frames that reflect the establishment of, first, the exterior (yellow, blue, black, green, white, pink, orange, red, and purple) and, second, the interior structure (brown and grey) of conceptual colour space. These results fail to provide significant support for the order predicted by Berlin and Kay, and suggest, instead, that the development of colour term knowledge is largely unconstrained.     

Implicit Memory and Anxiety: Perceptual Identification of Emotional Stimuli

The perceptual identification paradigm was used to examine implicit memory performance in high- and low-trait anxious subjects. A series of threat-related and neutral words was presented in different colours during the encoding phase. Subjects were required to encode the stimuli by naming the colour while ignoring the semantic content of the words (Experiment 1), by simply reading the words (Experiment 2) or by naming the colour of the words and the words themselves (Experiment 3). Experiment 1 demonstrated the predicted emotional Stroop effect, with high-trait subjects taking relatively longer than low-trait subjects to name the colour of the threat-related as compared to the neutral stimuli. All three experiments revealed a significant implicit memory effect overall, with more primed than unprimed words being correctly identified during the perceptual identification task. Subjects in all experiments also identified more of the threat-related than neutral words. Although Experiment 2 found that, overall, the high-trait subjects identified relatively fewer threat-related words than neutral words in comparison to the low-trait subjects, none of the experiments offered any support for the prediction of a threat-related implicit memory bias in hightrait anxiety.     

Theory of mind finds its Piagetian perspective: why alternative naming comes with understanding belief

In the last of a series of experiments 48 3–5-year old children were tested on an alternative naming game with “synonyms,” e.g., if puppet calls the depicted item a “rabbit” the child has to call it a “bunny,” or the child has to judge puppet’s performance when roles are reversed. The game was also played with categories (rabbit–animal), name/colour (rabbit–black), colour/colour (black–white), and part/part (head–tail). The younger children (≤3.5 years) had severe problems with “synonyms” and categories (alternative names for the items, <10% correct), but not with names and colours, only colours, or only parts (>80% correct). Children’s increasing success with age on the alternative names tasks was closely paralleled (.53≤r≤.72) by their mastery of the false belief task in which they had to predict that a mistaken story character would look for a desired object in the wrong location. For explaining the synchrony between alternative naming and understanding false belief we draw on the Piagetian idea that children come to represent perspective at some point in their development. To apply this idea to the alternative naming game we draw on the philosophical discussion about sortals (terms that specify what sort of object something is) creating perspective differences.     

Varieties of grapheme-colour synaesthesia: a new theory of phenomenological and behavioural differences

Recent research has suggested that not all grapheme-colour synaesthetes are alike. One suggestion is that they can be divided, phenomenologically, in terms of whether the colours are experienced in external or internal space (projector–associator distinction). Another suggestion is that they can be divided according to whether it is the perceptual or conceptual attributes of a stimulus that is critical (higher–lower distinction). This study compares the behavioural performance of 7 projector and 7 associator synaesthetes. We demonstrate that this distinction does not map on to behavioural traits expected from the higher–lower distinction. We replicate previous research showing that projectors are faster at naming their synaesthetic colours than veridical colours, and that associators show the reverse profile. Synaesthetes who project colours into external space but not on to the surface of the grapheme behave like associators on this task. In a second task, graphemes presented briefly in the periphery are more likely to elicit reports of colour in projectors than associators, but the colours only tend to be accurate when the grapheme itself is also accurately identified. We propose an alternative model of individual differences in grapheme-colour synaesthesia that emphasises the role of different spatial reference frames in synaesthetic perception. In doing so, we attempt to bring the synaesthesia literature closer to current models of non-synaesthetic perception, attention and binding.     

The influence of similarity on visual working memory representations

In verbal memory, similarity between items in memory often leads to interference and impaired memory performance. The present study sought to determine whether analogous interference effects would be observed in visual working memory by varying the similarity of the to-be-remembered objects in a colour change detection task. Instead of leading to interference and impaired performance, increased similarity among the items being held in memory led to improved performance. Moreover, when two similar colours were presented along with one dissimilar colour, memory performance was better for the similar colours than for the dissimilar colour. Similarity produced better performance even when the objects were presented sequentially and even when memory for the first item in the sequence was tested. These findings show that similarity does not lead to interference between representations in visual working memory. Instead, similarity may lead to improved task performance, possibly due to increased stability or precision of the memory representations during maintenance.     

A study of the effect of structural information and familiarity in form perception

Two experiments were carried out to investigate the influence of structural information and familiarity on the processing of visual forms. Pairs of “well” structured and nameable and “poorly” structured and non-nameable fragmented forms were employed as stimuli. The effects of structure and familiarity were assessed by manipulating the visual hemifield of presentation and the task. In Experiment 1 stimuli were judged as being either in the same orientation or mirror-reversed, a task that does not require high-level semantic information to be processed. Experiment 2 required physically identical forms to be matched, which may use either physical or name information. In Experiment 1 “same” judgements were equivalent for both types of stimuli, and “different' judgements were longer for the “poorly” structured (non-nameable) forms. In Experiment 2 there was little overall difference between “well” and “poorly” structured forms, though response times to “well” structured (nameable) forms were slowed for right-visual-field presentations. It is suggested that familiarity may not be sufficient to provide a perceptual advantage for nameable forms, as the advantage for nameable stimuli was confined to “same” judgements in Experiment 1 and response times were shorter for non-nameable stimuli in Experiment 2. Rather, performance depends upon factors such as the computation of global shape (due to structural properties of collinearity and closure) and on the use of different kinds or representations (physical versus name) in matching.     

Emotion and adherence to treatment in people with asthma: An application of the emotional Stroop paradigm

This study explored whether an emotional Stroop paradigm might represent an appropriate means of assessing individuals' emotional representations of asthma. In addition, the opportunity was taken to investigate whether emotional representations of asthma, as assessed by this method, were associated with adherence to inhaled preventative medication. An asthma Stroop task was devised which comprised three sets of stimuli: asthma symptom words, general negative words, and neutral words. Three groups of participants were compared on their performance on this task: individuals with asthma, individuals without asthma, and individuals without asthma who had been primed about the condition. It was found that individuals with asthma experienced significantly more interference when colour‐naming the asthma symptom words, but not when colour‐naming the general negative words. Furthermore, their performance on the asthma Stroop task was associated with self‐reported adherence levels. Specifically, individuals who reported the highest and lowest levels of adherence displayed more interference when colour‐naming the asthma symptom words than individuals with intermediate levels of adherence. It is concluded that the emotional Stroop paradigm might provide an objective and sensitive means of assessing individuals’ emotional representations of illness. Additionally, it is proposed that emotional responses to illness should be assessed and included in research designed to explain health behaviours and, furthermore, that such research should not assume that any relationship between emotional representations and health behaviours will be linear.     

Perceptual and categorical judgements of colour similarity

Consideration is given to the tasks that make judgements of colour similarity based on perceptual similarity rather than categorical similarity. Irrespective of whether colour categories are taken to be universal (Berlin & Kay, 1969) or language induced (Davidoff, Davies, & Roberson, 1999), it is widely assumed that colour boundaries, and hence categorical similarity, would be used when categorising colours. However, we argue that categorical similarity is more reliably used in implicit than in explicit categorisation. Thus, in Experiment 1, we found that category boundaries may be overridden in the explicit task of matching-to-sample: There was a similar strong tendency to ignore colour boundaries and to divide the range of coloured stimuli into two equal groups in both Westerners and in a remote population (Himba). In Experiment 2, we showed that a distinctive stimulus (focal colour) in the range affected the equal division in a matching-to-sample task. Experiment 3 tested the stability of a category boundary in an implicit task (visual search) that assessed categorical perception; only for this task was categorisation largely immune to range effects and largely based on categorical similarity. It is concluded that, even after colour categories are acquired, perceptual rather than categorical similarity is commonly used in judgements of colour similarity.     

Developmental differences in the use of task goals in a cued version of the stroop task

The ability of children (M= 8.8 years) and adults (M= 25.6 years) to maintain task goals was examined by comparing their performance on a cued version of the Stroop colour‐word task. The experimental task presented a cue on each trial that instructed the participant to either read aloud the forthcoming word or name the colour of the word's lettering. Participants were tested with each of two cue‐stimulus delays (1,000 and 5,000 ms). Analysis of error rates in the colour‐naming condition revealed that children experienced greater interference than adults at each of the cue‐stimulus delays. In an effort to separate the relative contributions of colour‐naming and word‐reading processes, additional analyses were performed based on the process dissociation procedure of Lindsay and Jacoby (1994) . While colour‐naming process estimates did not vary with age group or cue‐stimulus delay, word‐reading process estimates were found to vary with age group and cue‐stimulus delay. Specifically, adults were superior to children in the inhibition of irrelevant word information only during a long cue‐stimulus delay. Collectively, these findings indicate that children have difficulty maintaining task goals in order to suppress stronger, goal‐irrelevant responses.     

True and false memory for colour names versus actual colours: Support for the visual distinctiveness heuristic in memory for colour information

In a colour variation of the Deese–Roediger–McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., “blood, cherry, scarlet, rouge … ”); they later showed false memory for the critical colour name (e.g., “red”). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.     

Categorical perception of emotional facial expressions does not require lexical categories

Does our perception of others' emotional signals depend on the language we speak or is our perception the same regardless of language and culture? It is well established that human emotional facial expressions are perceived categorically by viewers, but whether this is driven by perceptual or linguistic mechanisms is debated. We report an investigation into the perception of emotional facial expressions, comparing German speakers to native speakers of Yucatec Maya, a language with no lexical labels that distinguish disgust from anger. In a free naming task, speakers of German, but not Yucatec Maya, made lexical distinctions between disgust and anger. However, in a delayed match-to-sample task, both groups perceived emotional facial expressions of these and other emotions categorically. The magnitude of this effect was equivalent across the language groups, as well as across emotion continua with and without lexical distinctions. Our results show that the perception of affective signals is not driven by lexical labels, instead lending support to accounts of emotions as a set of biologically evolved mechanisms.     

Influence of short-term memory codes on visual image processing: evidence from image transformation tasks.

Three experiments showed that phonological recording of visual stimuli in short-term memory (STM) affects coding in long-term memory (LTM) and therefore performance on tasks involving generation and manipulation of visual images of the stimuli. An image transformation task was devised. It consists of mentally subtracting a part of an image to discover in the remainder another object. In Experiment 1, Ss were required to learn a set of easily nameable visual stimuli and then perform the subtraction task on images retrieved from LTM. Performance was significantly better when initial learning was accompanied by articulatory suppression (AS). Experiment 2 confirmed that AS had no effect when the task was performed on an image of a just-presented stimulus. In Experiment 3, the nameability of the stimuli was manipulated. The results replicated the effect of AS for items that were easy to name but showed no effect of AS for stimuli that were difficult to name.     

Retrieval failure, rehearsal deficiency, and short-term memory loss in the aphasic adult

Studies show that aphasic patients typically are grossly impaired in short-term memory performance. Since aphasics generally experience difficulty in word retrieval, it is conceivable that short-term memory loss is partially the result of verbal rehearsal deficiency which, in turn, is caused by the word retrieval problem. This paper reports an experiment in which five aphasic adults were nonverbally to recall individualized lists of pictures they could easily name and lists of pictures they could not name. Final items in the two lists were recalled with equal accuracy; this was expected in that the recency effect usually reflects sensory rather than verbal storage. Initial items were recalled with greater accuracy than middle-list items in the nameable sets but not in the unnameable sets. This primacy effect suggests the aphasics rehearsed the nameable pictures, but both lists were recalled so poorly that rehearsal deficit was considered responsible for no more than a fraction of the aphasics' reduction in short-term memory.     

Colour specificity in episodic and in perceptual object recognition with enhanced colour impact

In three experiments we investigated the perceptual specificity of explicit (old-new object recognition) and implicit memory (word-picture matching) for colour. In order to enhance the impact of colour on processing, we increased the number of colours per object and we impaired shape information. We presented multicoloured pictures (Experiment 1), blurred and partially occluded pictures (Experiment 2) and coloured line drawings in visual noise (Experiment 3). Experiments 1 and 2 had an intentional study phase; the study phase of Experiment 3 was an incidental colour or category naming task. Changing colour from study to test always had negative effects on episodic recognition although colour was irrelevant. In contrast, in the matching task old pictures were generally matched faster than new ones independent of their colour congruence. In Experiment 3, an additional small advantage of congruent colours and of semantic processing occurred. We conclude that two different memory representations contribute to these tasks. Changes of an achromatic, more abstract representation, that is used in normal object recognition, and a representation of the specific exemplar that includes colour. This latter token is used in episodic recognition as well as in unusual perceptual tasks (Experiment 3).     

Semantic negative priming in picture categorization and naming

Ignoring a particular stimulus can hamper subsequent attended processing of the same stimulus, a phenomenon known as 'negative priming'. Previous research has yielded partial support for the claim that the effect results from the attentional inhibition of central representations, as suggested by the fact that it appears to extend to semantic associates of ignored stimuli. In the current experiment, participants categorized or named pictorial stimuli with superimposed distractor pictures; the effect of unrelated, identical, or categorically related previously ignored pictures was investigated. Furthermore, visual similarity between categorically related picture pairs was manipulated in the naming task. The results indicated negative priming from identical ignored pictures irrespective of task. However, semantic negative priming was observed in the categorization task only. In the naming task, even visual overlap between categorically related picture pairs failed to induce negative priming. These findings argue against a central locus of the negative priming effect.     

Does maintenance of colour categories rely on language? Evidence to the contrary from a case of semantic dementia

Recent neuropsychological evidence, supporting a strong version of Whorfian principles of linguistic relativity, has reinvigorated debate about the role of language in colour categorisation. This paper questions the methodology used in this research and uses a novel approach to examine the unique contribution of language to categorisation behaviour. Results of three investigations are reported. The first required development of objective measures of category coherence and consistency to clarify questions about healthy control performance on the freesorting colour categorisation task used in previous studies. Between-participant consistency was found to be only moderate and the number of colour categories generated was found to vary markedly between individuals. The second study involved longitudinal neuropsychological examination of a patient whose colour categorisation strategy was monitored in the context of a progressive decline in language due to semantic dementia. Performance on measures of category coherence and consistency was found to be relatively stable over time despite a profound decline in the patient's colour language. In a final investigation we demonstrated that, for both the patient and controls, between- and within-participant consistency were higher than expected by (a) random sorting and (b) sorting perceptually similar chips together. These findings indicate that the maintenance of colour categorisation need not depend on language.     

Investigating the effects of multiple primes: An analysis of theoretical mechanisms

Is the size of a semantic-priming effect a function of the strength of the semantic context? This issue was examined in four studies using a single categorically related prime as the weaker context and four categorically related primes as the stronger context. Results indicate that, independently of prime-target SOA, four primes provide a larger priming effect than a single prime in a lexical-decision task, but not in a naming task. These data provide further support for the argument that different mechanisms mediate priming in the two tasks. In particular, only the lexical-decision task appears to be susceptible to higher-level processes that can be influenced by the number of primes. Priming in a naming task appears to be driven by more automatic processes. Possible accounts of this multiple-prime advantage in lexical-decision tasks are considered.     

Visual discrimination of spectral distributions

Human observers seem to be able to use different features that classify materials with a large degree of accuracy. In this paper, we look at human perception of statistical properties of the spectral distribution in a scene. We investigated whether human observers can discriminate just as accurately between coloured textures that have a spectral distribution due either to shading only or to both shading and specular reflectance as between uniform colours. Thresholds for the discrimination of coloured textures are about 15 times as high as thresholds for the discrimination of uniform colours, provided there is a sharp transition between the two colours. However, the coloured texture thresholds are only 1.5 times higher when we introduce a gradual transition between the two colours. There are also distinct qualitative differences in discrimination thresholds for different base colours. These differences cannot be predicted from discrimination thresholds for uniform colours. Human observers are surprisingly good at discriminating between a material edge and a shadow edge in complex scenes. Statistical differences in the orientation of the colour distributions in colour space might be used to accomplish this. In a second experiment we investigated how well observers can discriminate between two linear distributions in colour space that have the same base colour but different orientations. When we vary the line-length in R, G, B space, thresholds cannot be predicted completely by the conservation of the average distance between the two distributions. This means that observers use not only the maximum colour difference in the stimulus to do the task, but other cues are also involved.