Selective attention by children and adults to pictures specified by color

Four conditions were used to investigate developmental trends in the ability to establish and use a color set to direct the selective processing of pictures. In three conditions, 6-year-old, 9-year-old, and adult subjects viewed a series of pairs of pictures, with one red and one black line drawing in each pair. Subjects were asked to look either at the red pictures only, the black pictures only, or both pictures. In a fourth condition, subjects viewed a series of singly presented red and black pictures. Pictures of both colors were included in a subsequent recognition memory test. At all ages recognition memory was comparable for pictures of each color in the both and single conditions but was higher for pictures of the specified color in the selective red and selective black conditions. There was no evidence at any age that memory for pictures of the specified color was decreased by the presence of the second picture. These results, showing roughly comparable selectivity at all ages, were discussed in relation to findings of developmental trends in selective attention on more “traditional” central-incidental learning tasks.     

Some articulatory correlates of perceptual isochrony

Given sequences of digits with temporally equidistant acoustic onsets, listeners do not perceive them as isochronous (Morton, Marcus, & Frankish, 1976). In order for the sequences to be perceptually isochronous, systematic departures from acoustic isochrony must be introduced. These acoustic departures are precisely those that talkers generate when asked to produce an isochronous sequence (Fowler, 1979), suggesting that listeners judge isochrony based on acoustic information about articulatory timing. The present experiment was an attempt to test directly whether perceptually isochronous sequences have isochronous articulatory correlates. Electromyographic potentials were recorded from the orbicularis oris muscle when speakers produced sequences of monosyllables “as if speaking in time to a metronome.” Sequences were devised so that lip-muscle activity was related to the syllable-initial consonant, the stressed vowel, or the stressed vowel and final consonant. Results indicate that isochronous muscular activity accompanies both isochronous and anisochronous acoustic signals produced under instructions to generate isochronous sequences. These results support an interpretation of the perceptual phenomenon reported by Morton et al. to the effect that listeners judge isochrony of the talker’s articulations as they are reflected in the acoustic signal.     

The availability explanation of excessive plausibility assessments

The assessment of hypotheses in hypothesis generation involves a comparison between those hypotheses that have been generated (specified) and those that are not generated (unspecified). Experiment 1 was an investigation of an “availability explanation” for subjects' overconfidence in the probability of specified hypotheses. The conjecture is that subjects have difficulty retrieving unspecified hypotheses from memory. Therefore, the underpopulated set of unspecified hypotheses is assessed as less probable then it actually is and the specified set is assessed as more probable. Two manipulations to increase the availability of unspecified hypotheses were investigated. One involved explicitly requesting subjects to populate the unspecified set; the other was a computer presentation of candidate unspecified hypotheses. Results of experiment 1 were that assessment overconfidence for both experimental groups was reduced. The results support the conjecture that the availability heuristic is at least partially responsible for subjects' overconfidence. The main result of experiment 2 was that the overconfidence bias persisted with different assessment methods for both subject-generated and experimenter-supplied hypotheses.     

Performance of dyslexic children on speech perception tests

Several researchers who have compared the performance of dyslexic and normal-reading children on a variety of different tasks have suggested that dyslexic children may have subtle deficits in the phonemic analysis of spoken as well as written language. Thus it is of interest to know how children who have extraordinary difficulty learning to read can perform explicity auditory-phonetic tasks. Seventeen dyslexic children (10 years of age) and a group of 17 controls were administered tests of identification and discrimination of synthesized voiced stop consonants differing in place of articulation. These were tests of the type used to study categorical perception in adults, adapted for use with young children. Significant differences between dyslexics and controls were found in both kinds of tasks; the pattern of identification and discrimination differences suggests an inconsistency in the dyslexics' phonetic classification of auditory cues. A significant relationship was found between reading level and speech discrimination.     

Infant emotion and the vocal affect lexicon

The role of the vocal channel of emotion expression in infancy has been neglected in developmental theory. The present review describes the ontogenetic course of vocal emotional expression as exhibited by human and infrahuman primate young and considers its dynamic relationship to the facial and bodily components of expression. The infant's encoding of negative and positive emotion expression is discussed within a developmental framework. In addition, this review assesses the impact of early social influences. It is concluded that early patterns of infant vocal emotional expression are probably biogenetically determined and that there may be certain universal vocal signals. However, data derived from studies of dyadic interaction indicate that the transition from raw affect expression in early infancy to a more modulated pattern later on is a product not only of neuromuscular maturation but of maternal coaching in affective expression as well.     

Medication effects in the classroom: Three naturalistic indicators

Hyperactive and comparison boys participated in 5-week summer enrichment programs that included classroom activities and structured assessments of peer interaction patterns. During the 3rd and 4th weeks of these programs, a double-blind, methylphenidate-placebo crossover design was implemented within the hyperactive group. Three heterogeneous indicators of everyday behaviors were obtained: number of negative incidents noted by staff, quality of handwriting, and number of times the teacher called the boys' names aloud in the classroom. Medication effects emerged for each of these indicators. When hyperactive boys were taking placebos, they were involved in more negative incidents, their handwriting was poorer, and their names were called more frequently than when the boys were taking methylphenidate. Interrelationships among the measures suggest moderate cross-situational generality of medication responsiveness. Discussion focused on the bandwidth of medication effects and the need to examine the social ramifications of child treatments.This research was supported in part by NIMH grant 29475 and NIDA grant 01070. We gratefully acknowledge the participation of the data coders and the many summer school staff. Special thanks go to Mike Berlin, Barry E. Collins, and Sharon Dotemoto. Methylphenidate and placebo were supplied by Ciba-Geigy, Summit, New Jersey.     

Sentence processing: Evidence against the serial,independent stage assumption

The assumption that the processing stages involved in sentence comprehension are serially and independently executed was tested in two separate experiments using two new sentence types. One experiment was a sentence-picture verification task, the other was not. In Experiment I, subjects viewed sentences such as It's false that the dots are red and indicated, by pressing the appropriate response key, which of two colors would make the sentence true. In Experiment II, subjects verified sentences such as It isn't true that the dots aren't red against pictures of colored dots. On the strength of Sternberg's additive factor method, present findings challenge the validity of the serial, independent stage assumption, and results are alternatively discussed in terms of a capacity sharing model.This research was supported by PHS research grant MH 23401 to Sam Glucksberg, principal investigator.     

The effects of reward on tutor's behaviors in a cross-age tutoring context

Utilizing a cross-age tutoring context, this study examined the effects of reward on the teaching behaviors of the tutor, the tutor's subsequent motivation to continue to teach during a free choice period, and the social interaction between a tutor and a tutee. Third-grade boys and girls (n = 96) who exhibited a positive reinforcement style were asked to teach six addition problems to a first-grade boy or girl (n = 96). The children were randomly assigned to pairs and to one of the three reward conditions. In the performance-contingent reward condition, the tutors were promised a toy if the first-grader learned all of the arithmetic problems. In the noncontingent reward condition, the tutors were promised a toy for teaching the first-grader. In the no reward condition, the tutors taught the first-grader without promise of a toy. The results indicated that the social interaction was rated lower for the children in the performance-contingent group and that the tutors in this group spent less time teaching during the free choice period. However, neither the tutor's teaching style nor the tutee's post-test performance was adversely affected by the reward.     

Dynamic processes in music perception

A schema-based theory of music perception that describes the dynamic interaction between the musical event and the listener’s knowledge of the underlying regularities in tonal music is proposed. Three properties of musical schema are evaluated in a recognition memory experiment: (1) The schema engages a subset of the abstract knowledge system that is determined by the predominant key of the musical sequence, (2) the schema evaluates both interval relations and the functions of the sounded elements within the established tonal framework, and (3) the schema interacts continuously with the musical event in time to process pitch information in its temporal context. Listeners are required to identify the serial position of a chord that is changed between two successive chord sequences that are otherwise identical. The experiment measures the magnitude and the temporal extent of the disruptive effect of including in the sequence an element outside the tonal framework. The results show temporally specific effects on memory for pitch relations consistent with the operation of a musical schema. Comparisons are made with schema-based theories applied in other perceptual and cognitive domains.     

Hemiplegic writing in severe aphasia

Three patients with severe aphasia and right hemiplegia are described who could write to dictation with the right arm using a limb prosthesis though agraphic with the "intact" left hand. The phenomenon of "hemiplegic writing" is explained as an access to submerged or preprocessing levels in language and action structure, through the use of older proximal motor systems. This interpretation has implications for our understanding of language and brain function, as well as for approaches to the treatment of patients with severe language disorders.