Development of selective listening and hemispheric asymmetry.

In 2 experiments binaural and dichotic tasks of varying complexity were given to 64 7- and 9-yr-old children to investigate the interaction of laterality and selective attention. One of each digit pair was spoken by a male and the other by a female. Ss recalled 3 of the digits spoken in a specified voice. With the attended voice in one ear, performance improved relative to the binaural condition in both age groups. However, when location and voice cues were uncorrelated, the younger Ss' performance was more adversely affected. The right ear advantage (REA) increased as a function of task difficulty. With slow presentation rates, the REA remained constant with age but decreased with age in the faster conditions, which was opposite to the predicted increase in cerebral asymmetry of language function with age. The 7-yr-olds responded according to their perceptual asymmetry, recalling right-ear items whether the attended voice was in the left or right ear. The developmental changes in selective attention are explained by a capacity model. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of directed attention on cerebral asymmetries in normal and learning-disabled children.

Using a dichotic listening task employing both undirected and directed attention conditions, cerebral asymmetries were examined in matched populations of 32 normal and 32 learning-disabled (LD) children (ages 7 yrs 6 mo–13 yrs 2 mo). The analysis of recall performance indicated that development was not a significant factor in either group; both the normal and LD Ss showed a right-ear effect, although the LD Ss performed at a degraded level and were unable to demonstrate a right-ear advantage (REA) when attention was directed to the left ear, unlike normal Ss, who produced the REA despite the directed attention conditions. Results suggest that LD children probably do not suffer from developmental delays but rather from a defect in callosal functioning that interferes with their ability to process verbal information simultaneously. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric specialization and ear advantages in processing speech.

Reviews research on the hemispheric asymmetry model of relative ear advantages in the processing of auditory stimuli. Physiological studies of activation of the hemispheres in humans support left-hemisphere speech-processing specialization and contralateral sound field dominance. Electrophysiological studies in animals, effects of commissurotomy, hemispherectomy, and unilateral temporal lobe lesions on dichotic performance in humans, as well as stimulus dominance effects in intact Ss indicate that the assumption of ipsilateral sensory pathway suppression during competitive stimulation is unwarranted. Dichotic presentation is not necessary to produce a right-ear advantage (REA), and selective attention to one or the other ear frequently tends to alter the magnitude of the REA. A modified structural model that incorporates the effects of directed attention is proposed. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory attention in hyperactive children: Effects of stimulant medication on dichotic listening performance.

Administered dichotic digit tasks requiring free report and selective listening, respectively, to 20 6–16 yr old hyperactive children. Ss received methylphenidate before 2 experimental sessions and a placebo before 2 control sessions. The stimulant did not improve free-report performance significantly; rather it facilitated or impaired performance, depending on how it affected the order in which stimuli were reported. Similarly, medication had no effect on overall selective-listening performance, but it increased the difficulty of switching attention from one ear to the other. Results demonstrate that stimulants may act to maintain selective attention and to inhibit channel switching. Listening asymmetry, that is, right-ear superiority, was influenced by task variables but not by stimulant medication. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous and exogenous control of attention in dichotic listening.

Dichotic listening to verbal stimuli results in a right ear advantage (REA), indicating a left hemisphere processing superiority. The magnitude of the REA can be modulated by instructions to direct attention to the left or right ear stimulus. A previous study from our laboratory showed that presenting a prime syllable before the presentation of the dichotic syllables increases reports of the nonprimed syllable, apparently a negative priming effect that inhibits attention to the distracting prime representation. The present study combined attention instruction and priming, making up a 3 × 3 factorial design. The prime stimulus was a single consonant-vowel syllable presented binaurally just before onset of the dichotic consonant-vowel syllables. Results showed that both instructions and priming manipulations had an effect on which dichotic stimulus was selected. There was also a significant interaction between attention instruction and priming manipulation, indicating that the mechanism for instructed attention and the mechanism for negative priming work on the same level of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allocation of attention in dichotic listening: Differential effects on the detection and localization of signals.

In 2 dichotic listening experiments, 96 normal right-handed adults attended selectively to the left and right ear and divided their attention equally between both ears. Participants listened for specified targets and reported the ear of entry. The material consisted of pairs of consonant–vowel syllables in Experiment 1 and pairs of rhyming consonant–vowel–consonant words in Experiment 2. Both experiments yielded a right-ear advantage for detection and for localization. Attention instructions had no effect on detection. However, focusing attention on 1 ear increased the number of targets attributed to that ear while decreasing the number of targets attributed to the opposite ear. The dissociation between detection and localization indicates that volitional shifts of attention influence late (response selection) processes rather than early (stimulus identification) processes. Selective-listening effects can be accounted for by a 2-stage model in which a fixed input asymmetry is modulated by a biased selection of responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of attention and unilateral neglect on auditory stream segregation.

Two pairs of experiments studied the effects of attention and of unilateral neglect on auditory streaming. The first pair showed that the build up of auditory streaming in normal participants is greatly reduced or absent when they attend to a competing task in the contralateral ear. It was concluded that the effective build up of streaming depends on attention. The second pair showed that patients with an attentional deficit toward the left side of space (unilateral neglect) show less stream segregation of tone sequences presented to their left than to their right ears. Streaming in their right ears was similar to that for stimuli presented to either ear of healthy and of brain-damaged controls, who showed no across-ear asymmetry. This result is consistent with an effect of attention on streaming, constrains the neural sites involved, and reveals a qualitative difference between the perception of left- and right-sided sounds by neglect patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asymmetric switch cost and backward inhibition: Carryover activation and inhibition in switching between tasks of unequal difficulty.

Asymmetric switch cost, observed when switching between tasks varying in difficulty, shows that the difference between repeat and switch trials is greater when switching to the easier task. Early explanations of this effect attributed this pattern to both positive priming of the difficult task and negative priming of the easier task, but more recent models have focused only on activation processes. The role of inhibition in asymmetric switch cost was examined using backward inhibition, a more direct measure of task-set inhibition. The results indicated asymmetric backward inhibition, with greater sequential inhibition of the easier task (i.e., easy-difficult-easy sequences). Switch costs, however, showed both typical and reversed asymmetry (greater cost when switching from the easy to the difficult task), depending on the relative difficulty of task pairs. This pattern of results indicates that switch costs are attributable to both activation and inhibition processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modal attention asymmetry in patients with schizophrenia and bipolar disorder.

This cross-sectional study examined modal attention asymmetries in patients with schizophrenia (n?=?47) and bipolar disorder (n?=?42), as contrasted to a matched-sample comparison group of normal participants (n?=?89). A test of continuous auditory and visual attention was the primary measure. The data were analyzed from 2 experimental conditions: simple modal responses (auditory and visual) and modal switching responses (ipsimodal and cross-modal switching). In the simple modal condition, patients with schizophrenia demonstrated a visual over auditory asymmetry; patients with bipolar disorder showed no differences. In modal switching conditions, however, patients with bipolar disorder displayed a significant auditory over visual asymmetry. No main effect was detected between medications and attention functioning. Results are discussed in light of differentiating these 2 populations on the basis of modal specificity of attention functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrapair imagery effects in verbal discrimination and incidental associative learning.

Administered 4 study-test trials to 80 17-38 yr. Old students on a verbal discrimination learning (vdl) task where the items varied in imagery (i) value. Ss were then tested for incidental associative learning. The 32-pair mixed list consisted of 8 pairs of high-i and 8 pairs of low-i nouns, and 16 pairs in which 1 item was high-i and the other low-i. For 1/2 of the latter pairs the high-i word was correct. Significantly more errors occurred during vdl with homogeneous low-i pairs than with the other 3 pair types, which did not differ reliably from each other. Incidental associative learning was highest for homogeneous high-i pairs, and stimulus i was more effective than response i when the stimuli had been wrong but not when they had been right during prior vdl. The latter condition was characterized particularly by sharply depressed performance on high-i-low-i pairs. The vdl results are discussed in terms of imagery and frequency hypotheses, and the associative memory data in terms of the effects of the experimental conditions on the amount of attention devoted to 1 or both members during vdl. (french summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GeneUp: a program to select short PCR primer pairs that occur in multiple members of sequence lists

A computer program is presented that selects a small set of short primer pairs for PCR to sample all the sequences in a user-specified list of mRNAs. Such primer pairs could be used to increase the probability of sampling mRNAs of particular interest in differential display and to generate simplified hybridization probes for DNA chips or arrays. The program uses simulated PCR to find pairs of primers that sample more than one sequence in the list. A small set of such primer pairs is selected that give maximal coverage of the sequences in the list. Primer pairs are excluded that: (i) generate simulated PCR products of the same size from a number of sequences in the list, (ii) can easily form primer dimers, (iii) are outside a specified range of G + C content or (iv) occur in another list of undesirable sequences, such as rRNAs and Alu repeats. Five lists consisting of from 48-285 cDNA sequences were used to test the program. A small number of pairs of primers, 8-10 bases in length, were selected that fit the above criteria and that generate one or more simulated PCR products in all or most of the cDNAs in each list.     

Perception and conservation of length: Piaget and Taponier revisited.

Reports a developmental comparison of judgments of length made by 40 5-yr-olds, 40 8-yr-olds, and 40 adults (mean age, 27 yrs). Ss judged relative lengths of lines presented in pairs via animated films both in static views and under several transformation conditions. The secondary illusion found by Piaget was not replicated, but children were superior to adults in judging static unequal-length line pairs. In the transformation conditions, most 8-yr-olds and adults conserved length, whereas most 5-yr-olds did not. For lines that lengthened during displacement, no age differences were found. Results indicate greater interdependence of judging accuracy in the 2 conditions than suggested by Piaget's hypothesis and cast doubt on typical explanations of failure to conserve. Fine-grain analyses of accuracy data suggest that several stimulus factors and age shifts in guessing strategies are involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of three strategies of attention in dichotic monitoring.

Investigated 3 strategies of attention in 108 Ss in 3 age groups (7, 11, and 20 yrs). Ss monitored lists of monaural and dichotic words and responded manually to target words. Target detection rates in unequal division of attention (Exp I) showed that selection of the relevant input improved with age. The degree of attenuation of the irrelevant input was dependent on which ear was being ignored, but this effect interacted with age. The 7-yr-olds could not attend effectively to left-ear items. Exp II simplified the focusing strategy by eliminating response requirements to the irrelevant input. Selectivity improved with this strategy, particularly in 7-yr-olds. Equal division of attention between the 2 ears (Exp III) revealed a constant right-ear advantage in each age group. Differentiation of the 3 voluntary strategies improved between ages 7 and 11. In adults, the 3 strategies were clearly distinguished. Results are interpreted in terms of a multiprocess model of attention: Perceptual factors such as dichotic interaction and hemispheric asymmetry were strategy dependent but not age dependent. Voluntary selective attention was age dependent and affected the degree to which hemispheric asymmetry could be overcome. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recency judgments in children: A production deficiency in the use of redundant background cues.

Presented 8 20-picture lists to 40 2nd and 40 4th graders, and each list followed by 3 test pairs, each pair repeating 2 list items. Ss were required to pick the item they had seen more recently on the list. Background color cues were provided, and half the Ss were instructed in using the cues to simplify the task. Difficulty of the recency judgments was also varied by increasing the separation between the 1st presentation of the tested items from 3 to 9 items. The wider the separation, the better the judgment of relative recency. On cue problems, training improved the performance of 2nd graders but not 4th graders. The developmental implications of the study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sources of variability in sex-linked personality attributes: A twin study.

31 pairs of monozygotic (MZ) and 28 pairs of dizygotic (DZ) same-sex, adolescent twins completed Spence and Helmreich's Personal Attributes Inventory, which contains separate scales tapping Masculinity (instrumental traits), Femininity (expressive traits), and bipolar Masculinity–Femininity. Sex-adjusted intraclass correlations were computed for the MZ and DZ twin pairs. Significant twin-pair resemblance was found for Masculinity and Femininity, but not for Masculinity–Femininity. MZ resemblance for Masculinity was greater than DZ resemblance, suggesting a genetic component to masculinity development, but no genetic influence was detected in Femininity. All 3 traits showed substantial within-families variability, and it is concluded that future research should give equal attention to nonshared developmental influences that operate to make siblings dissimilar and to shared developmental influences. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A temporal distinctiveness theory of recency and modality effects.

Conducted 4 experiments with 40 undergraduates and 60 Ss drawn from a university community to confirm the qualitative and quantitative predictions of a temporal distinctiveness theory of contextually cued retrieval from memory as applied to recency and modality (auditory vs visual) effects on the recall of a list of word pairs. Results of Exp I demonstrated that increasing the length of the temporal isolation of the last word pair aurally presented increased recall of the item; increase in recall of the last item was smaller or absent for the visual presentation of the pairs. Exp II indicated that as the number of word pairs isolated at the end of the list increased, the size of the modality effect decreased. Temporal distinctiveness between the 1st and 2nd pairs in Exp III revealed auditory superiority in recall of the 1st pair, an effect that was eliminated in Exp IV when isolated interval occurred between the 3rd and 4th presentation of a 6-item word pair list. A mathematical model of the quantitative predictions of the theory is appended. (46 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Congruency, attentional set, and laterality effects with emotional words.

The present study investigated the influence of attention and word-emotion congruency on auditory asymmetries with stimuli that include verbal and emotional components. Words were presented dichotically to 80 participants and were pronounced in either congruent or incongruent emotional tones. Participants were asked to identify the presence of a target word or emotion under 1 of 2 conditions. The blocked condition required detection of a word or emotional target in separate blocks. In the randomized condition, the target was changed across trials by means of a postcue. A right-ear advantage (REA) and a left-ear advantage (LEA) were found for word and emotion targets, respectively. However, the finding of a Condition × Stimulus Type × Ear × Congruency interaction indicated that in the randomized condition, a REA was obtained for words when the stimuli were congruent and a LEA was observed for emotions when the stimuli were incongruent. The findings suggest that randomizing the target reduced the influence of the attentional set established by blocking the target. It is likely that this promoted the detection of hemispheric interference in the randomized condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual processing and infant ocular latencies in the overlap paradigm.

Young infants have repeatedly been shown to be slower than older infants to shift fixation from a midline stimulus to a peripheral stimulus. This is generally thought to reflect maturation of the neural substrates that mediate the disengagement of attention, but this developmental difference may also be attributable to young infants' slower processing of the midline stimulus. This possibility was tested with 3- and 7-month-old infants in 2 experiments in which the degree of familiarity of the midline stimulus was manipulated across repeated trials. The results of these experiments demonstrated that the processing of midline content does affect infants' ocular latencies to a peripheral stimulus but that developmental differences in such processing do not account for developmental differences in disengagement seen across the 1st year. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of recent practice on task switching.

Four experiments investigated the effect of recent selective practice on the cost of switching between 2 tasks afforded by letter-digit pairs: alphabet arithmetic and shape comparison. Experiments 1 and 2 found a greater cost associated with switching to the more recently practiced task: evidence that task-set inertia contributes to switching costs. Experiment 3 found this effect to be limited to trials on which a recently trained stimulus followed another such stimulus: a result problematic for all current theories of task-set priming. Experiment 4 showed that the effect of recent practice was eliminated by active preparation for a task switch: It appears that endogenous task-set preparation reduces the effects of task-set inertia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The associative deficit in older adult memory: Recognition of pairs is not improved by repetition.

This study used a novel experimental paradigm that combined associative recognition and list discrimination to study the associative deficit in older adults’ memory (M. Naveh-Benjamin, 2000). Participants viewed 2 lists of word–face pairs and were tested on recognition of pairs from the second study list. Older and young adults’ recognition was increased by repetition of individual items, but repetition of pairs of items increased recognition in young adults only. This provides converging evidence that older adults do not form associative links between items within pairs and supports the hypothesis that an associative deficit contributes to age-related memory decline. (PsycINFO Database Record (c) 2010 APA, all rights reserved)