Articulatory and Phonological Determinants of Word Length Effects in Span Tasks

Several previous studies have shown that memory span is greater for short words than for long words. This effect is claimed to occur even when the short and long words are matched for the number of syllables and phonemes and so to provide evidence for subvocal articulation as being one mechanism that underlies memory span (Baddeley, Thomson, & Buchanan, 1975). The three experiments reported in this paper further investigate the articulatory determinants of word length effects on span tasks. Experiment 1 replicated Baddeley et al.'s finding of an effect of word length on auditory and visual span when the stimuli consist of words that differ in terms of the number of syllables. Experiments 2 and 3 showed that the effects of word length are eliminated when the words in the span task are matched for the number of syllables and phonemes but differ with respect to the duration and/or complexity of their articulatory gestures. These results indicate that it is the phonological structure of a word and not features of its actual articulation that determines the magnitude of the word length effect in span tasks.     

Gaining knowledge via other minds: Children's flexible trust in others as sources of information

In five experiments, we examined 3‐ to 6‐year‐olds’ understanding that they could gain knowledge indirectly from someone who had seen something they had not. Consistent with previous research, children judged that an informant, who had seen inside a box, knew its contents. Similarly, when an informant marked a picture to indicate her suggestion as to the content of the box, 3‐ to 4‐year‐olds trusted this more frequently when the informant had seen inside the box than when she had not. Going beyond previous research, 3‐ to 4‐year‐olds were also sensitive to informants’ relevant experience when they had to look over a barrier to see the marked picture, or ask for the barrier to be raised. Yet when children had to elicit the informant's suggestion, rather than just consult a suggestion already present, even 4‐ to 5‐year‐olds were no more likely to do so when the informant had seen the box's content than when she had not, and no more likely to trust the well‐informed suggestion than the uninformed one. We conclude that young children who can ask questions may not yet fully understand the process by which they can gain accurate information from someone who has the experience they lack.     

BEHAVIORAL MOMENTUM IN THE TREATMENT OF NONCOMPLIANCE

Behavioral momentum refers to the tendency for behavior to persist following a change in environmental conditions. The greater the rate of reinforcement, the greater the behavioral momentum. The intervention for noncompliance consisted of issuing a sequence of commands with which the subject was very likely to comply (i.e., high-probability commands) immediately prior to issuing a low-probability command. In each of five experiments, the high-probability command sequence resulted in a “momentum” of compliant responding that persisted when a low-probability request was issued. Results showed the antecedent high-probability command sequence increased compliance and decreased compliance latency and task duration. “Momentum-like” effects were shown to be distinct from experimenter attention and to depend on the contiguity between the high-probability command sequence and the low-probability command.     

Understanding the central processing limit in consistent-mapping visual search tasks

Effects of load (i.e., the number of stimuli in the display) have been observed in multiple-frame studies using a consistent mapping of stimuli to responses (e.g., Fisher, 1982, 1984). In a series of four experiments, it is shown that these effects are not the consequence of differences across the high- and low-load conditions in either decision noise or peripheral masking. Additionally, it is shown that of two modes of limited capacity (a limited-channel and divided-capacity model) considered as possible explanations of load effects in tasks where subjects are required to locate a target, only one--the limited-channel model--is consistent with the results from all three location tasks. Finally, it is argued that the limited-channel model predicts not only the behavior observed in the four consistent-mapping experiments reported in this article but also the behavior observed in several related consistent-mapping tasks (Kleiss & Lane, 1986; Shiffrin & Gardner, 1972).