Testing for symmetry in the conditional discriminations of language-trained chimpanzees

If subjects are taught to match Stimulus A to B and then, without further training, match B to A, they have passed a test of symmetry. It has been suggested that non-humans' lack of success on symmetry tests might be overcome by giving them a history of symmetry exemplar training, that is, by directly teaching a large number of conditional relations (e.g., AB, CD, EF,...) and also directly training the "reverse" of these relations (e.g., BA, DC, FE,...). The chimpanzee subjects of the present study, Sherman, Austin, and Lana, had already received extensive symmetry exemplar training as a result of attempts to teach a selection-based language system of lexigrams. The present study systematically subjected 2 of these chimps (Sherman and Lana), for the first time, to standard symmetry tests in controlled conditions. Both chimps failed the tests, even when their correct responses on test trials were reinforced. The findings do not support the exemplar training hypothesis, and cast doubt upon whether the chimps can pass tests of stimulus equivalence.     

One Frog, Two Frog, Red Frog, Blue Frog: Factors Affecting Children's Syntactic Choices in Production and Comprehension

Two experiments are reported which examine children's ability to use referential context when making syntactic choices in language production and comprehension. In a recent on-line study of auditory comprehension, Trueswell, Sekerina, Hill, and Logrip (1999) examined children's and adults' abilities to resolve temporary syntactic ambiguities involving prepositional phrases (e.g., “Put the frog on the napkin into ¨”). Although adults and older children used the referential context to guide their initial analysis (pursuing a destination interpretation in a one-frog context and a modifier interpretation in a two-frog context), 4 to 5-year olds' initial and ultimate analysis was one of destination, regardless of context. The present studies examined whether these differences were attributable to the comprehension process itself or to other sources, such as possible differences in how children perceive the scene and referential situation. In both experiments, children were given a language generation task designed to elicit and test children's ability to refer to a member of a set through restrictive modification. This task was immediately followed by the “put” comprehension task. The findings showed that, in response to a question about a member of a set (e.g., “Which frog went to Mrs. Squid's house?”), 4- to 5-year-olds frequently produced a definite NP with a restrictive prepositional modifier (e.g., “The one on the napkin”). These same children, however, continued to misanalyze put instructions, showing a strong avoidance of restrictive modification during comprehension. Experiment 2 showed that an increase in the salience of the platforms that distinguished the two referents increased overall performance, but still showed the strong asymmetry between production and comprehension. Eye movements were also recorded in Experiment 2, revealing on-line parsing patterns similar to Trueswell et al.: an initial preference for a destination analysis and a failure to revise early referential commitments. These experiments indicate that child–adult differences in parsing preferences arise, in part, from developmental changes in the comprehension process itself and not from a general insensitivity to referential properties of the scene. The findings are consistent with a probabilistic model for uncovering the structure of the input during comprehension, in which more reliable linguistic and discourse-related cues are learned first, followed by a gradually developing ability to take into account other more uncertain (or more difficult to learn) cues to structure.     

Is inhibition of return a reflexive effect?

The inhibition of return (IOR) phenomenon is routinely considered an effect of reflexive attention because the paradigm used to generate IOR employs peripheral cues that are uninformative as to where a target will appear. Because the cues are spatially unreliable it is thought that there is no reason for attention to be committed volitionally to them, and hence, the IOR effect is considered reflexive. What has been generally overlooked, however, is that the cues provide reliable temporal information as to when a target will occur. This predictive information is used by participants to prepare volitionally for when a target is likely to appear. We investigated whether the IOR effect is a product of the volitional application of attention to peripheral cues for the use of their temporal information. To test this idea we rendered the temporal information provided by peripheral cues unreliable. While this eliminated participants using the cues volitionally, it did not abolish the IOR phenomenon. These data demonstrate two new findings. First, the IOR effect is fundamentally a reflexive phenomenon. Second, when peripheral cues are not used volitionally, the IOR effect is attenuated. Together, the present findings indicate that the IOR effect can be modulated by volitional (top-down) processes but it is not the product of them. We argue that an intimate link between fronto-parietal regions and the superior colliculus provide a functional neural mechanism for this volitional effect to impact IOR.     

Speech and non-speech processing in people with specific language impairment: a behavioural and electrophysiological study

McArthur and Bishop (2004) found that people with specific language impairment (SLI) up to 14 years of age have poor behavioural frequency discrimination (FD) thresholds for 25-ms pure tones, while people with SLI upto 20 years of age have abnormal auditory N1--P2--N2 event-related potential (ERP) responses to the same tones. In the present study, we extended these findings to more complex non-speech and speech sounds by comparing younger (around 13 years) and older (around 17 years) teenagers with SLI and controls for their behavioural FD thresholds and N1-P2 ERPs to 25 and 250-ms pure tones, vowels, and non-harmonic complex tones. We found that a subgroup of people with SLI had abnormal responses to tones and vowels at the level of behaviour and the brain, and that poor processing was associated with the spectral complexity of auditory stimuli rather than their phonetic significance. We suggest that both the age of listeners and the sensitivity of psychoacoustic tasks to age-related changes in auditory skills may be crucial factors in studies of sound processing in SLI.     

Spoken Idiom Recognition: Meaning Retrieval and Word Expectancy

This study investigates recognition of spoken idioms occurring in neutral contexts. Experiment 1 showed that both predictable and non-predictable idiom meanings are available at string offset. Yet, only predictable idiom meanings are active halfway through a string and remain active after the string’s literal conclusion. Experiment 2 showed that the initial fragment of a predictable idiom inhibits recognition of a word providing a congruous, but literal, conclusion to the expression. No comparable effects were obtained with non-predictable idioms. These findings are consistent with the view that spoken idiom identification differs from word recognition and occurs word-by-word, just as with other familiar, multi-lexical phrases.The present study was supported by PRIN 2003–2004. We would like to thank Corrado Cavallero, Simona Collina, Melinda Tucker and Francesco Zardon for their valuable help.     

The developing constraints on parsing decisions: the role of lexical-biases and referential scenes in child and adult sentence processing

Two striking contrasts currently exist in the sentence processing literature. First, whereas adult readers rely heavily on lexical information in the generation of syntactic alternatives, adult listeners in world-situated eye-gaze studies appear to allow referential evidence to override strong countervailing lexical biases (Tanenhaus, Spivey-Knowlton, Eberhard, and Sedivy, 1995). Second, in contrast to adults, children in similar listening studies fail to use this referential information and appear to rely exclusively on verb biases or perhaps syntactically based parsing principles (Trueswell, Sekerina, Hill, and Logrip, 1999). We explore these contrasts by fully crossing verb bias and referential manipulations in a study using the eye-gaze listening technique with adults (Experiment 1) and five-year-olds (Experiment 2). Results indicate that adults combine lexical and referential information to determine syntactic choice. Children rely exclusively on verb bias in their ultimate interpretation. However, their eye movements reveal an emerging sensitivity to referential constraints. The observed changes in information use over ontogenetic time best support a constraint-based lexicalist account of parsing development, which posits that highly reliable cues to structure, like lexical biases, will emerge earlier during development and more robustly than less reliable cues.     

Grammatical language impairment and the specificity of cognitive domains: relations between auditory and language abilities

Grammatical-specific language impairment (G-SLI) in children, arguably, provides evidence for the existence of a specialised grammatical sub-system in the brain, necessary for normal language development. Some researchers challenge this, claiming that domain-general, low-level auditory deficits, particular to rapid processing, cause phonological deficits and thereby SLI. We investigate this possibility by testing the auditory discrimination abilities of G-SLI children for speech and non-speech sounds, at varying presentation rates, and controlling for the effects of age and language on performance. For non-speech formant transitions, 69% of the G-SLI children showed normal auditory processing, whereas for the same acoustic information in speech, only 31% did so. For rapidly presented tones, 46% of the G-SLI children performed normally. Auditory performance with speech and non-speech sounds differentiated the G-SLI children from their age-matched controls, whereas speed of processing did not. The G-SLI children evinced no relationship between their auditory and phonological/grammatical abilities. We found no consistent evidence that a deficit in processing rapid acoustic information causes or maintains G-SLI. The findings, from at least those G-SLI children who do not exhibit any auditory deficits, provide further evidence supporting the existence of a primary domain-specific deficit underlying G-SLI.     

Seeing to hear better: evidence for early audio-visual interactions in speech identification

Lip reading is the ability to partially understand speech by looking at the speaker's lips. It improves the intelligibility of speech in noise when audio-visual perception is compared with audio-only perception. A recent set of experiments showed that seeing the speaker's lips also enhances sensitivity to acoustic information, decreasing the auditory detection threshold of speech embedded in noise [J. Acoust. Soc. Am. 109 (2001) 2272; J. Acoust. Soc. Am. 108 (2000) 1197]. However, detection is different from comprehension, and it remains to be seen whether improved sensitivity also results in an intelligibility gain in audio-visual speech perception. In this work, we use an original paradigm to show that seeing the speaker's lips enables the listener to hear better and hence to understand better. The audio-visual stimuli used here could not be differentiated by lip reading per se since they contained exactly the same lip gesture matched with different compatible speech sounds. Nevertheless, the noise-masked stimuli were more intelligible in the audio-visual condition than in the audio-only condition due to the contribution of visual information to the extraction of acoustic cues. Replacing the lip gesture by a non-speech visual input with exactly the same time course, providing the same temporal cues for extraction, removed the intelligibility benefit. This early contribution to audio-visual speech identification is discussed in relationships with recent neurophysiological data on audio-visual perception.     

The role of specific consequences in the maintenance of three types of questions

This research replicated and extended a study by Williams, Donley, and Keller (2000). In that study, children with autism received a box with an object inside and learned to ask “What's that?,” “Can I see it?,” and “Can I have it?” to have the name of the object, to see the object, and to get the object, respectively. The purpose of the present research was to determine if the three questions (a) were three independent repertoires of behavior, (b) constituted three instances of a single functional response class, or (c) belonged to a chain of behavior. The 3 boys with autism who participated responded independently to each question when the consequences for each question were altered. This indicates that the three target responses were three independent repertoires of behavior, each one reinforced and maintained with its specific consequences. Thus, this procedure serves to teach children with autism to ask questions with flexibility according to a variable context.     

On defining words, some scenarios and vectors in the 'autobiography' of C. G. Jung

Having first considered recent research into the circumstances surrounding the production and publication of the 'autobiography' of Jung, the author concludes that in spite of its being the work of several authors, it nevertheless constitutes a whole. Taken from whichever angle, they all point to Jung's particular inquiry into the unconscious, as it emerges through Jung's own words. The author goes on to suggest both a lateral and a structural reading of MDR (Memories, Dreams, Reflections) which in turn reveals, on the basis of the several dreams reported, the central 'fantasy' which inspired Jung's research and his oeuvre. Finally, he discusses the idea of the collective or impersonal unconscious and highlights the emphasis Jung places on processes which unfold according to rhythms which are associated with distinct scales, depending on whether they are those of the individual, the clan or the culture.