Is the growth of subjective time in humans a linear or nonlinear function of real time?

The difficulties of deciding whether subjective time grows as a linear or nonlinear function of real time are discussed, and two experiments are presented to address this question. In Experiment 1, people received a 10-s standard duration and then had to judge what proportion other durations (ranging from 1 to 10 s) were of the standard. Counting was prevented by a concurrent task. The relation between judged and actual proportions was linear. In Experiment 2, people were required to average together three tone durations (mean duration 600 ms) and to judge whether subsequently presented comparisons were or were not the average. The spacing of the tone durations had no effect on judgements, suggesting a linear underlying time scale.     

Is the growth of subjective time in humans a linear or nonlinear function of real time?

The difficulties of deciding whether subjective time grows as a linear or nonlinear function of real time are discussed, and two experiments are presented to address this question. In Experiment 1, people received a 10-s standard duration and then had to judge what proportion other durations (ranging from 1 to 10 s) were of the standard. Counting was prevented by a concurrent task. The relation between judged and actual proportions was linear. In Experiment 2, people were required to average together three tone durations (mean duration 600 ms) and to judge whether subsequently presented comparisons were or were not the average. The spacing of the tone durations had no effect on judgements, suggesting a linear underlying time scale.     

Attention and the right-ear advantage: What is the connection?

Dichotic listening originally was a means of studying attention. Half a century ago Doreen Kimura parlayed the dichotic method into a noninvasive indicator of lateralized cerebral language representation. The ubiquitous right-ear advantage (REA) for verbal material was accepted as a concomitant of left-sided language lateralization and preferential conduction of right-ear messages to the left hemisphere. As evidence has accumulated over the past 50years showing the REA to be dynamic and modifiable, the concept of attention has become essential for interpreting the findings. Progress in understanding the role of attention has been manifested as a transition from efforts to document attention effects to efforts to characterize their mechanisms. We summarize the relevant evidence, trace the evolution of explanatory models, and outline contemporary accounts of the role of attention in dichotic listening.     

Attention deficits: is there a right hemisphere specialization for simple reaction time, sustained attention, and phasic alertness?

Impairments of attentional focus often are claimed to be associated with lesions of the right hemisphere. Although some studies comparing right- and left-brain-damaged patients have supported this idea, others have not found differences between these patients in various attention tasks. The present study was carried out in order to further investigate the putative role of the right hemisphere in a simple reaction time task, a sustained attention task, and a phasic alertness task. Subjects were 46 patients with right-hemisphere lesions and 37 patients with left-hemisphere lesions. Results showed no difference between right- and left-brain-damaged patients in simple reaction time, in speed of response over time (sustained attention), and in the capacity to prepare to an uncoming stimulus (phasic alertness). Future studies will have to use a more precise categorization of lesions than only right-versus left-brain damage.     

The evolution of foresight: What is mental time travel, and is it unique to humans?

In a dynamic world, mechanisms allowing prediction of future situations can provide a selective advantage. We suggest that memory systems differ in the degree of flexibility they offer for anticipatory behavior and put forward a corresponding taxonomy of prospection. The adaptive advantage of any memory system can only lie in what it contributes for future survival. The most flexible is episodic memory, which we suggest is part of a more general faculty of mental time travel that allows us not only to go back in time, but also to foresee, plan, and shape virtually any specific future event. We review comparative studies and find that, in spite of increased research in the area, there is as yet no convincing evidence for mental time travel in nonhuman animals. We submit that mental time travel is not an encapsulated cognitive system, but instead comprises several subsidiary mechanisms. A theater metaphor serves as an analogy for the kind of mechanisms required for effective mental time travel. We propose that future research should consider these mechanisms in addition to direct evidence of future-directed action. We maintain that the emergence of mental time travel in evolution was a crucial step towards our current success.     

Self-reflection and well-being: is there a healthy amount of introspection?

Both extremely high and extremely low self-reflection have been considered as risk factors for psychological maladjustment. Therefore, from an integrating perspective medium amounts of self-reflection may constitute "healthy introspection." To test this hypothesis, self-reflection and psychological well-being were measured with self-report tests given a pooled sample of 647 subjects. A regressive relationship with self-reflection as a quadratic predictor of well-being was estimated using the LMS method for nonlinear structural equation modeling. No evidence for a curvilinear effect was detected in the total sample or in subgroups. Alternative theoretical assumptions are discussed on a psychological and operational level.     

Shape constancy and theory of mind: is there a link?

In three experiments, children aged between 4 and 7 years viewed a circular disc oriented at a slant. The disc was made of luminous material and situated in a darkened chamber. Children of all ages exaggerated the circularity of the disc when they knew that the object was really a circle (the circle task), and the effect was greatest in the younger members of the sample. Crucially, however, a group of children in Experiment 3 who viewed an identical shape that they knew emanated from an actual ellipse did not exaggerate circularity. In the second experiment, children tackled three standard theory of mind tasks in addition to the circle task mentioned above. A significant correlation emerged (even with age partialed) between the extent of exaggeration made by those who knew that the shape was a circle and ability to pass the theory of mind tests. It seems knowledge of reality contaminates judgements of appearance in the circle task. This might be the same bias that features in realist errors in theory of mind tasks.     

Teaching maxi- and minicomputer programming at the same time: Is there an advantage?

A course is described that provides concurrent and equal coverage of maxi- and minicomputer systems. The results of student evaluations are provided.     

Do monkeys think in metaphors? Representations of space and time in monkeys and humans

Research on the relationship between the representation of space and time has produced two contrasting proposals. ATOM posits that space and time are represented via a common magnitude system, suggesting a symmetrical relationship between space and time. According to metaphor theory, however, representations of time depend on representations of space asymmetrically. Previous findings in humans have supported metaphor theory. Here, we investigate the relationship between time and space in a nonverbal species, by testing whether non-human primates show space–time interactions consistent with metaphor theory or with ATOM. We tested two rhesus monkeys and 16 adult humans in a nonverbal task that assessed the influence of an irrelevant dimension (time or space) on a relevant dimension (space or time). In humans, spatial extent had a large effect on time judgments whereas time had a small effect on spatial judgments. In monkeys, both spatial and temporal manipulations showed large bi-directional effects on judgments. In contrast to humans, spatial manipulations in monkeys did not produce a larger effect on temporal judgments than the reverse. Thus, consistent with previous findings, human adults showed asymmetrical space–time interactions that were predicted by metaphor theory. In contrast, monkeys showed patterns that were more consistent with ATOM.     

Delusional disorder and delusions: is there a risk of violence in social interactions about the core symptom?

Delusional disorders are rare, but psychoses with prominent and persistent delusions are less so. A small but significant association between psychosis and violence is often mediated by delusions in such illnesses. Traditionally, delusions have been viewed as “incorrigible”, but there is evidence that they change over time. During development of a scale for measuring delusions, it was found that people who acted violently on their “most important” delusion were more likely to have modified that belief after a mild form of challenge to it. When cognitive–behaviour therapy (CBT) is used for schizophrenia, attempts to modify psychotic symptoms are generally included. Could studies of CBT provide further information about possible risks of social interactions about delusions? In the UK, 2000 people with schizophrenia have been in randomized controlled trials of CBT with a goal of symptom modification. These studies were examined for evidence of violence during the treatment. There was none. Given the period prevalence of violence among people with psychosis, this is surprising. In these studies, however, both challenge to delusions and change in them was minimal and in the context of a safe clinical relationship. Challenge to delusions may, however, occur in a variety of social situations. There are no systematic data on lay challenge to them, but it seems likely that some in the sufferer's social circle will do so vigorously. Relatives, friends, and acquaintances are the people most vulnerable to the most serious violence by someone with psychosis. Study of how people interact in these circumstances and whether their interactions are relevant to modification of delusions would be worthwhile. Could those close to a sufferer learn skills for responding to such pathological beliefs that could be protective against violence, perhaps derived from the principles of CBT?. Copyright © 2006 John Wiley & Sons, Ltd.     

Professional judgement in the assessment of risk: is there a role for systemic practice?

Risk assessment is an example of professional decision‐making pared to its stark essentials. Political pressures towards accountability and the need for defensible decisions encourage a ‘tick‐box’ approach to risk assessment, but this can create unrealistic expectations of certainty. In practice, as technological approaches produce ever more complex formal tools for assessing risk, their effectiveness remains dubious while our human decision‐making apparatus is marginalized. This article examines whether we should respect our ability to apprehend complex multi‐stranded narrative realities intuitively, with the hope that such intuitions might contribute to professional decision‐making. This idea is explored with reference to a case study.     

Omissions and semantic errors in aphasic naming: is there a link?

Within a discrete two-stage model of lexicalization, semantic errors and errors of omission are assumed to be independent events. In contrast, cascading and interactive models allow for an influence of word form on lexical selection and thus for an inherent relationship in accounting for both error types. A group of 17 aphasic patients was assessed with a naming test controlling for semantic competition of the target items. Semantic errors were more frequent for targets with many competitors than for targets with few competitors while omissions were more frequent when few competitors were available. However, the overall sums of errors in both item groups were comparable. These results imply a common source of both error types and thus speak against a strictly serial model of naming.     

Set-size effects in primary memory: An age-related capacity limitation?

Set size was varied as a factor in the primary memory paradigm developed by Wickens and colleagues (Wickens, Moody, & Dow, 1981; Wickens, Moody, & Vidulich, 1985). In Experiment 1, using adults and teenagers, no proactive interference (PI) was observed at set size 4, consistent with previous research, but PI was observed at set size 10. In Experiment 2, with adults, PI was observed at set sizes 6, 8, and 10, but not at set size 4. These results are consistent with the hypothesis that sets of more than 4 items overload primary memory, so that some items have to be retrieved from secondary memory. In Experiment 3, 8- to 9-year-olds were used with set sizes of 2 and 4. Proactive interference was observed with the larger, but not with the smaller, set. This suggests that primary memory was overloaded by 4 items at this age, indicating that its capacity increases with age.     

Why do the effects of delaying reinforcement in animals and delaying feedback in humans differ? A working-memory analysis

Animal research has shown that reinforcement is substantially less effective when it is delayed, but in studies of human motor learning delays in providing feedback typically have much less effect. One possible explanation is that in human research participants know the response to be learned and can thus focus on it during the delay; that is not the case in experiments on animals. We tested this hypothesis using a task in which participants had minimal information on what movement was correct and found that, as in animal experiments, participants learned only when feedback was immediate. A second experiment confirmed that the effects of the delay depended on how many responses had to be held in working memory: the greater the memory load, the poorer the learning. The results point to the importance of activity during a delay on learning; implications for the teaching of motor skills are discussed.     

Why do the effects of delaying reinforcement in animals and delaying feedback in humans differ? A working-memory analysis

Animal research has shown that reinforcement is substantially less effective when it is delayed, but in studies of human motor learning delays in providing feedback typically have much less effect. One possible explanation is that in human research participants know the response to be learned and can thus focus on it during the delay; that is not the case in experiments on animals. We tested this hypothesis using a task in which participants had minimal information on what movement was correct and found that, as in animal experiments, participants learned only when feedback was immediate. A second experiment confirmed that the effects of the delay depended on how many responses had to be held in working memory: the greater the memory load, the poorer the learning. The results point to the importance of activity during a delay on learning; implications for the teaching of motor skills are discussed.     

Do humans and nonhuman animals share the grouping principles of the iambic–trochaic law?

The iambic–trochaic law describes humans’ tendency to form trochaic groups over sequences varying in pitch or intensity (i.e., the loudest or highest sounds mark group beginnings), and iambic groups over sequences varying in duration (i.e., the longest sounds mark group endings). The extent to which these perceptual biases are shared by humans and nonhuman animals is yet unclear. In Experiment 1, we trained rats to discriminate pitch-alternating sequences of tones from sequences randomly varying in pitch. In Experiment 2, rats were trained to discriminate duration-alternating sequences of tones from sequences randomly varying in duration. We found that nonhuman animals group sequences based on pitch variations as trochees, but they do not group sequences varying in duration as iambs. Importantly, humans grouped the same stimuli following the principles of the iambic–trochaic law (Exp. 3). These results suggest the early emergence of the trochaic rhythmic grouping bias based on pitch, possibly relying on perceptual abilities shared by humans and other mammals, whereas the iambic rhythmic grouping bias based on duration might depend on language experience.     

Zeading and reazing: which is faster? The position of the diverging letter in a pseudoword determines reading time

We present evidence that (a) at least some components of the reading process are serial and (b) pseudoword reading is affected by lexical knowledge, even in a transparent orthographic system like Italian. Pseudowords deriving from five-letter words by changing either the first or the fourth letter were presented for reading aloud. Results showed an effect of the position of the diverging letter: Early diverging pseudowords were read more slowly than late diverging pseudowords. The dual-route cascaded (DRC) model (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001) successfully simulated the behavioural data.     

Zeading and reazing: Which is faster? The position of the diverging letter in a pseudoword determines reading time

We present evidence that (a) at least some components of the reading process are serial and (b) pseudoword reading is affected by lexical knowledge, even in a transparent orthographic system like Italian. Pseudowords deriving from five-letter words by changing either the first or the fourth letter were presented for reading aloud. Results showed an effect of the position of the diverging letter: Early diverging pseudowords were read more slowly than late diverging pseudowords. The dual-route cascaded (DRC) model (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001 Coltheart, M., Rastle, K., Perry, C., Langdon, R. and Ziegler, J. 2001. DRC: A dual route cascaded model of visual word recognition and reading aloud. Psychological Review, 108: 204–256. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) successfully simulated the behavioural data.