Mental playmates: Siblings, executive functioning and theory of mind

This study assessed the theory of mind (ToM) and executive functioning (EF) abilities of 124 typically developing preschool children aged 3 to 5 years in relation to whether or not they had a child-aged sibling (i.e. a child aged 1 to 12 years) at home with whom to play and converse. On a ToM battery that included tests of false belief, appearance-reality (AR) and pretend representation, children who had at least 1 child-aged sibling scored significantly higher than both only children and those whose only siblings were infants or adults. The numbers of child-aged siblings in preschoolers' families positively predicted their scores on both a ToM battery (4 tasks) and an EF battery (2 tasks), and these associations remained significant with language ability partialled out. Results of a hierarchical multiple regression analysis revealed that independent contributions to individual differences in ToM were made by language ability, EF skill and having a child-aged sibling. However, even though some conditions for mediation were met, there was no statistically reliable evidence that EF skills mediated the advantage of presence of child-aged siblings for ToM performance. While consistent with the theory that distinctively childish interaction among siblings accelerates the growth of both TOM and EF capacities, alternative evidence and alternative theoretical interpretations for the findings were also considered.

Spatially localized distortions of event time

A fundamental question about the perception of time is whether the neural mechanisms underlying temporal judgements are universal and centralized in the brain or modality specific and distributed []. Time perception has traditionally been thought to be entirely dissociated from spatial vision. Here we show that the apparent duration of a dynamic stimulus can be manipulated in a local region of visual space by adapting to oscillatory motion or flicker. This implicates spatially localized temporal mechanisms in duration perception. We do not see concomitant changes in the time of onset or offset of the test patterns, demonstrating a direct local effect on duration perception rather than an indirect effect on the time course of neural processing. The effects of adaptation on duration perception can also be dissociated from motion or flicker perception per se. Although 20 Hz adaptation reduces both the apparent temporal frequency and duration of a 10 Hz test stimulus, 5 Hz adaptation increases apparent temporal frequency but has little effect on duration perception. We conclude that there is a peripheral, spatially localized, essentially visual component involved in sensing the duration of visual events.

A misspelt youth: Spelling and orthographic learning in university students as a function of spelling-sound consistency

Pseudowords with inconsistent vs. consistent spellings (e.g., nurch, with rhyme neighbours search, lurch & perch, vs. mish, with neighbours dish, wish) were presented with definitions for naming either twice or 6 times. In an oral spelling test, there were main and interactive effects of consistency and the number of training trials on accuracy and main effects only on response latency, with the improvement in accuracy from 2 to 6 training trials greater for the more poorly learned inconsistent items. Of most interest, the smaller effect of training on accuracy in the consistent condition was reliable; contrary to the most obvious prediction of dual route spelling models that the sublexical procedure should produce correct spellings for consistent items early in training. In a second task students wrote spellings of multisyllabic words containing unstressed indeterminate (schwa) vowels. In their errors on the schwa vowel, students showed sensitivity to the most common spelling overall but also they were influenced by differences in schwa spellings in English words as a function of the number of syllables and schwa position. These results indicate that dual route models of spelling will need to accommodate the consistency of spellings within categories defined by lexical structure variables.

Inhibition, encoding specificity, and response availability revisited

In the think/no-think paradigm people practice “suppressing” a learned response to a cue. Practice at suppression appears to produce a long-lasting inhibition of the suppressed response, as evidenced by a subsequent failure to recall the response to an extralist (associatively related, non-studied) cue. Critical to this interpretation is the assumption that suppression practice is necessary. A series of interference paradigms, which do not involve suppression practice and which are structurally similar to the think/no-think paradigm, provide evidence against the inhibition interpretation. Additional evidence against inhibition derives from our demonstrations herewith that the findings from the think/no-think paradigm can be replicated without any apparent suppression requirement. Furthermore, the results from all of these paradigms can be explained by the same simple principle. Namely, that when an item exists in an extended associative network, strengthening the item makes it interfere with the recall of other items in the network.

Quantifying the complexity of relative clause and cleft sentences

Explanations of the difficulty of relative-clause sentences implicate complexity but the measurement of complexity remains controversial. Four experiments investigated how far relational complexity (RC) theory, that has been found valid for cognitive development and human reasoning, accounts for the difficulty of 16 types of English, object- and subject-extracted relative-clause constructions. RC corresponds to the number of nouns assigned to thematic roles in the same decision. Complexity estimates based on RC and those based on maximal integration cost (MIC) were strongly correlated and accounted for similar variance in sentence difficulty (subjective ratings, comprehension accuracy, reading times). Consistent with RC theory, sentences that required more than 4 role assignments in the same decision were extremely difficult for many participants. Performance on nonlinguistic relational tasks predicted comprehension of object-extracted sentences, before and after controlling for subject-extractions. Working memory tasks predicted comprehension of object-extractions before controlling for subjectextractions. The studies extend the RC approach to a linguistic domain.

The good and the bad: Acquisition of likes and dislikes in affective learning

Affective learning, the acquisition of likes and dislikes, was investigated in two experiments using verbal ratings and affective priming as indices of affective change. In both experiments, neutral geometric shapes were paired with pleasant or unpleasant pictures in a picture-picture conditioning procedure to acquire positive and negative valence. Experiment 1 found the acquisition of positive valence; however, this valence change was lost after extinction training. Experiment 2 used more salient pictures as unconditioned stimuli. Positive and negative valence was acquired during paired presentations and retained across extinction training. The results of Experiment 2 are consistent with dual process accounts, which claim that evaluative conditioning is distinct from Pavlovian conditioning because it is resistant to extinction.