Articulatory length and phonological similarity in span tasks: A reply to Baddeley and Andrade

We report a partial replication of previous results by Caplan, Rochon, and Waters (1992), using methods that address objections raised by Baddeley and Andrade (this issue) and that improve on several techniques used by them. The results cast doubts on the role of articulation in determining the word length effect in span, and hence on the role of articulation in rehearsal.     

Interference and the representation of order within associations

In the presence of interference, recall of pairs can critically depend on the diagnostic power of memory of the order of items within the pair. Models of pair memory make different assumptions about whether and how such order information is stored, from convolution-based models, which assume no explicit storage of order, to matrix models and several models that assume a pair is learned by concatenating the representations of the constituent items, which lead to perfect within-pair order memory (given retrieval of the pair). Here we investigate memory for associations and within-pair order by examining the relationship between forward and backward probes of pairs subject to order-dependent associative interference in a double-function list paradigm. Associative interference disrupted the high correlation between forward and backward recall accuracy that is typically observed in standard paired-associate learning, challenging matrix and concatenation-based models. However, participants could overcome some interference due to within-pair order ambiguity, challenging directionally ambiguous convolution-based models. Unexpectedly, the test-retest correlation was reduced for pairs under the influence of interference compared to control pairs. This finding is incompatible with all existing implementations of the model classes we consider. Any model must include an assumption that order encoding (but not retrieval) is unreliable, and the form of this additional mechanism may depend intimately on how a given model is designed. In sum, our findings suggest that within-pair order memory is neither poor nor perfect, pointing to a fallible mechanism for within-pair order learning in verbal association-memory tasks.     

The effect of noun animacy on the processing of unambiguous sentences: evidence from French relative clauses

Two experiments, one using self-paced reading and one using eye tracking, investigated the influence of noun animacy on the processing of subject relative (SR) clauses, object relative (OR) clauses, and object relative clauses with stylistic inversion (OR-SI) in French. Each sentence type was presented in two versions: either with an animate relative clause (RC) subject and an inanimate object (AS/IO), or with an inanimate RC subject and an animate object (IS/AO). There was an interaction between the RC structure and noun animacy. The advantage of SR sentences over OR and OR-SI sentences disappeared in AS/IO sentences. The interaction between animacy and structure occurred in self-paced reading times and in total fixation times on the RCs, but not in first-pass reading times. The results are consistent with a late interaction between animacy and structural processing during parsing and provide data relevant to several models of parsing.     

Linking associative and serial list memory: Pairs versus triples

Paired associates and serial list memory are typically investigated separately. An "isolation principle" (J. B. Caplan, 2005) was proposed to explain behavior in both paradigms by using a single model, in which serial list and paired associates memory differ only in how isolated pairs of items are from interference from other studied items. In the present study, 2 experiments identify a critical dissociation between the 2 paradigms, challenging this unified account. Specifically, forward and backward probes were highly correlated for pairs and less so for short lists (triples). The authors asked whether the isolation principle could quantitatively accommodate this type of dissociation. A simulation confirmed that a single model incorporating the isolation principle can adequately explain this and other dissociations, supporting the common processes view.     

The relationship between age, verbal working memory, and language comprehension

A structural modeling approach was used to examine the relationships between age, verbal working memory (vWM), and 3 types of language measures: online syntactic processing, sentence comprehension, and text comprehension. The best-fit model for the online-processing measure revealed a direct effect of age on online sentence processing, but no effect mediated through vWM. The best-fit models for sentence and text comprehension included an effect of age mediated through vWM and no direct effect of age. These results indicate that the relationship among age, vWM, and comprehension differs depending on the measure of language processing and support the view that individual differences in vWM do not affect individuals' online syntactic processing.     

Sex differences in cognitive strategic preference among medical students

The cognitive strategic preferences of first-year medical students (42 men and 31 women) were assessed using the Word-Shape Sorting Test, on which subjects may adopt a verbal or visuospatial approach to problem-solving. 24 (77%) women, but only 25 (60%) men, exhibited a clear preference for a particular information-processing strategy. Some factors contributing to confusion in the literature on cognitive style are discussed.     

Intrusions and perseverations

Twenty-two subjects with presumed senile dementia of the Alzheimer's type (SDAT), twenty-two with dementia other than SDAT, twenty with aphasia, and seventeen healthy controls over 50 years of age were examined for intrusions and perseverations. Perseverations were defined as the immediate inappropriate repetition of a prior response whereas intrusions were defined as the inappropriate repetition of prior responses after intervening stimuli. Intrusions and perseverations occurred in demented and aphasic subjects, but were rare in controls. Intrusions occurred most often in SDAT or Wernicke aphasia, but also in dementia other than SDAT. Intrusions were not correlated with dementia severity. Intrusions are a useful sign of dementia, but they cannot be considered pathognomonic of SDAT. They appear to arise when subjects are unable to access correct responses from long-term memory and instead substitute erroneous responses selected from short-term memory. Perseverations were most common in the Wernicke aphasics and subjects with dementia due to communicating hydrocephalus. Although frontal lobe dysfunction is prominent in communicating hydrocephalus, it is absent in cases of Wernicke aphasia. Thus, we have confirmed prior suggestions that perseveration can occur in the absence of frontal lobe injury. Failure to self-monitor speech as well as an inability to change mental set probably plays an important role in the genesis of perseverations. There was no statistically significant correlation between dementia severity and number of perseverations. Low correlations were found between intrusions and perseverations suggesting that these seemingly similar behaviors are distinct and are probably produced by separate neuropsychological mechanisms.     

The effects of feature necessity and extrinsicity on gradedness of category membership and class inclusion relations*

Two theories of differences among natural language categories in graded membership and strength of class inclusion are contrasted. The two sets of hypotheses tested were: (1) that categories represented by features which many people believe to be necessary would have less graded memberships, and stronger class inclusion, than those represented by features which few people believe to be necessary, and (2) that categories which people believe are represented primarily by intrinsic features (i.e. features that are true of an entity in isolation; see Barr & Caplan, 1987) would have less graded structures, and stronger class inclusion, than those which people believe are represented primarily by extrinsic features (i.e. features representing relations between an entity and other entities). The findings suggest that feature necessity and feature extrinsicity have independent effects on gradedness of category membership and on class inclusion.