Temporal precision of coding as a basic factor of laterality effects in the retention of verbal auditory stimuli.

It is proposed that the encoding of temporal or sequential information is of crucial importance for the explanation of the laterality effect. Evidence favoring this hypothesis is provided by reanalysing the experiment recently published by Mainka and Hörmann (1971). These investigators instructed Ss in a dichotic listening experiment to attend exclusively to material presented either to the right or the left ear. In the present paper free recall performance for words presented to the right and to the left ear was analysed separately with respect to the correspondence between the sequence of presentation and that of recall. It was found that the sequence of presentation and the sequence of recall correspond to a greater extent in the case of right ear material.It is suggested that the well-known laterality effect can be accounted for by assuming differences in the temporal precision of encoding the items presented to the right and left side. This interpretation is substantiated by a review of the research literature. It was assumed that this different accuracy in encoding the sequential aspects of a series of verbal items should result in a different speed in the retrieval of this series. This expectation was confirmed by the data of the experiment of Mainka and Hörmann. Thus, the encoding of temporal or sequential information is supposed to be effected primarily by the left hemisphere.     

Reliability and magnitude of auditory laterality effects: the influence of attention

Three experiments investigated the effect of attention on the reliability and magnitude of laterality effects in a dichotic listening task. In Experiment 1, 40 undergraduate students were randomly assigned to either a free-recall or focused-attention condition. In Experiment 2, 40 undergraduate students completed a dichotic listening task with exogenous cueing. They were randomly assigned to either a 150-ms stimulus onset asynchrony (SOA) or a 450-ms SOA condition. In Experiment 3, 20 participants completed a task where the SOA for the exogenous cue was randomized on a trial to trial basis. Results indicated that focused attention increased the magnitude of the laterality effect. Contrary to predictions, this finding was not due to reduced variability in the focused-attention task compared to the free-recall task. In addition, a cueing tone was only effective at directing attention in Experiment 3. Specifically, a significant right ear advantage observed at the 150-ms SOA was reduced at the 450-ms SOA. It appears that, in Experiment 3, the tone was effective at controlling attention because it reduced the systematic bias that has been suggested to account for the laterality effects observed in dichotic tasks.     

Awareness of the influence as a determinant of assimilation versus contrast

In the present study, subjects had to generate an evaluative judgment about a target person on the basis of his behaviour that had both positive and negative implications. In a previous phase of the study that was ostensibly unrelated to the judgment task, the relevant trait categories were primed. Subsequently, half of the subjects were reminded of the priming episode. Consistent with earlier research (e.g. Lombardi, Higgins and Bargh, 1987; Newman and Uleman, 1990) that used memory of the priming events as a correlational measure, a contrast effect was found under the ‘reminding’ condition and assimilation resulted when subjects were not reminded of the priming episode. This pattern of results is interpreted as the consequence of corrective influences.     

Neuroimaging the serial position curve. A test of single-store versus dual-store models

Neuroimaging data could help clarify the long-standing dispute between dual-store and single-store models of the serial position curve. Dual-store models assume that retrieval from late positions is dependent on short-term memory (STM), whereas retrieval from early positions is dependent on long-term memory (LTM). Single-store models, however, assume that retrieval processes for early and late items are similar, but that early items are more difficult to discriminate than late items. The present study used functional magnetic resonance imaging to examine this question. Ten young adults were scanned while they recognized items from early or late serial positions. Recognition of early items uniquely activated brain areas traditionally associated with LTM, namely, regions within the hippocampal memory system. None of these areas was activated for retrieval of late items. These results indicate differential use of LTM retrieval processes, and therefore support dual-store models over single-store models.     

Cross-modal correlation of auditory and visual language laterality tasks: a serendipitous finding

Two experiments were conducted to investigate whether auditory and visual language laterality tasks test the same brain processes for verbal functions. In the first experiment, 48 undergraduate students (24 males, 24 females) completed both an auditory monitoring task and a visual monitoring task, with the Waterloo Handedness Questionnaire administered between the two tasks. The visual task was an analogue of the dichotic listening task used. It was hypothesized that a significant cross-modal correlation would be found, indicating that the dichotic listening task and the visual analogue task do, in fact, test the same brain processes for verbal functions. Results revealed a right ear advantage in the auditory task, a left visual field advantage (LVFA) in the visual task, and a cross-modal correlation of asymmetries of -.09. The LVFA observed in the visual task was replicated in Experiment 2, thus establishing its legitimacy. Results are discussed in relation with the type of processing that might produce such an unexpected finding on the visual task.     

Happiness versus sadness as a determinant of thought confidence in persuasion: a self-validation analysis

The present research introduces a new mechanism by which emotion can affect evaluation. On the basis of the self-validation hypothesis (R. E. Petty, P. Bri?ol, & Z. L. Tormala), the authors predicted and found that emotion can influence evaluative judgments by affecting the confidence people have in their thoughts to a persuasive message. In each study, participants first read a strong or weak persuasive communication. After listing their thoughts about the message, participants were induced to feel happy or sad. Relative to sad participants, those put in a happy state reported more thought confidence. As a consequence, the effect of argument quality on attitudes was greater for happy than for sad participants. These self-validation effects generalized across different emotion inductions, different persuasion topics, and different measures of thought confidence. In one study, happy and sad conditions each differed from a neutral affect control. Most important, these metacognitive effects of emotion only occurred under high elaboration conditions. In contrast, individuals with relatively low motivation to think showed a main effect of emotion on attitudes, regardless of argument quality.     

Lateral masking as a determinant of global dominance.

The term compound letter refers to a large (global) letter made up of small (local) letters. Reaction time to identify local letters is longer when local and global letters are different than when they are the same (the global dominance effect). The possible contribution of lateral masking to this effect was investigated. Lateral masking denotes reduced probability of identifying a stimulus when it is closely surrounded by other stimuli (as is the case for the local items in a compound stimulus). Three experiments were conducted in which the dependent measure was percentage of correct responses, rather than reaction time. In experiment 1 compound letters were used; accuracy of performance yielded evidence of global dominance such as obtained with reaction time measures. In experiments 2 and 3 the strength of lateral masking in geometrical forms was varied by varying the density of their component items. In agreement with earlier suggestions based on indirect evidence, the results directly implicated lateral masking as an important determinant of global dominance. However, lateral masking could not account fully for the experimental outcome. Factors beyond lateral masking, such as global precedence in the processing sequence or inhibitory interactions among low and high spatial-frequency components of the compound images are required in order to provide a comprehensive account of global dominance effects.     

Auditory location in the irrelevant sound effect: The effects of presenting auditory stimuli to either the left ear, right ear or both ears

Two experiments used both irrelevant speech and tones in order to assess the effect of manipulating the spatial location of irrelevant sound. Previous research in this area had produced inconclusive results (e.g., Colle, 1980). The current study demonstrated a novel finding, that sound presented to the left ear produces the greatest level of disruption. These results were explained in terms of hemispheric specialisation for processing of some supra-linguistic components in the unattended sound. Results also supported previous research by demonstrating that both forms of irrelevant sound disrupted performance on serial memory tasks (Bridges & Jones, 1996; Colle & Welsh, 1976; Jones, Alford, Bridges, Tremblay, & Macken, 1999; Jones, Miles, & Page, 1990).     

Thought confidence as a determinant of persuasion: the self-validation hypothesis

Previous research in the domain of attitude change has described 2 primary dimensions of thinking that impact persuasion processes and outcomes: the extent (amount) of thinking and the direction (valence) of issue-relevant thought. The authors examined the possibility that another, more meta-cognitive aspect of thinking is also important-the degree of confidence people have in their own thoughts. Four studies test the notion that thought confidence affects the extent of persuasion. When positive thoughts dominate in response to a message, increasing confidence in those thoughts increases persuasion, but when negative thoughts dominate, increasing confidence decreases persuasion. In addition, using self-reported and manipulated thought confidence in separate studies, the authors provide evidence that the magnitude of the attitude-thought relationship depends on the confidence people have in their thoughts. Finally, the authors also show that these self-validation effects are most likely in situations that foster high amounts of information processing activity.     

Children's understanding of death as the cessation of agency: a test using sleep versus death

An important problem faced by children is discriminating between entities capable of goal-directed action, i.e. intentional agents, and non-agents. In the case of discriminating between living and dead animals, including humans, this problem is particularly difficult, because of the large number of perceptual cues that living and dead animals share. However, there are potential costs of failing to discriminate between living and dead animals, including unnecessary vigilance and lost opportunities from failing to realize that an animal, such as an animal killed for food, is dead. This might have led to the evolution of mechanisms specifically for distinguishing between living and dead animals in terms of their ability to act. Here we test this hypothesis by examining patterns of inferences about sleeping and dead organisms by Shuar and German children between 3 and 5-years old. The results show that by age 4, causal cues to death block agency attributions to animals and people, whereas cues to sleep do not. The developmental trajectory of this pattern of inferences is identical across cultures, consistent with the hypothesis of a living/dead discrimination mechanism as a reliably developing part of core cognitive architecture.