Tuesday, June 30, 2009

Developmental changes in time attitudes

From BPS blog


Kevin McGrew PhD
Educational/School Psych.
IAP (www.iapsych.com)

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Monday, June 29, 2009

Temporal g or temporal resolution power hypothesis: IQ Brain Clock support

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Temporal g...or...the temporal resolution power hypothesis (TRP). Lets hear it for the IQ Brain Clock!

I've previously blogged, with considerable excitement, about recent research that has suggested that the temporal resolution of one's internal "brain clock" may be more closely associated with intelligence scholars search for the neural underpinnings of general intelligence (g). Traditionally, and overwhelmingly, intelligence scholars have studied and focused on mental reaction time, largely based on the seminal work of Arthur Jensen. Then, along came recent research led primarily by mental timing scholar Rammsayer and colleagues...research that suggested that temporal g (vs. reaction time g) may be more important in attempts to identify the underlying mechanism of neural efficiency.. the focus of the search for the "holy grail" of general intelligence for decades.

The following just published journal article continlues to add to the evidence that temporal processing, temporal g, and/or temporal resolution, may be critically important in understanding human intellectual performance. Below is the article reference, abstract, and my paraphrased comments from a reading of the article.
  • Troche, S & Rammsayer, T. (2009). Temporal and non-temporal sensory discrimination and their predictions of capacity-and speed-related aspects of psychometric intelligence. Personality and Individual Differences,47, 52–57

The temporal resolution power hypothesis explains individual differences in psychometric intelligence in terms of temporal acuity of the brain. This approach was supported by high correlations between temporal discrimination and psychometric intelligence. Psychometric intelligence, however, was frequently found to be related to non-temporal discrimination (e.g., frequency, intensity, brightness discrimination). The present study investigated 100 female and 100 male participants with the aim to elucidate the functional relations between psychometric intelligence and temporal and non-temporal discrimination ability. Supporting the assumption of dissociable mechanisms, non-temporal discrimination predicted directly capacity – but not speed-related aspects of psychometric intelligence whereas temporal discrimination predicted both aspects. A substantial correlation between temporal and non-temporal discrimination suggested that general discrimination ability might account for the relations of psychometric intelligence to temporal and non-temporal discrimination abilities. Findings point to an internal structure of general discrimination ability with some dimensions of discrimination more predictive to certain aspects of psychometric intelligence than others.
Introduction/background summary

The neural efficiency hypothises, based on Jensen's model of neuronal oscillations, has stood front and center as the defacto explanation of individual differences in processing speed and psychometric intelligence. This model suggestes that individuals differ in the rate of rate of oscillation between refractory and excitatory states of neurons. The efficieny of oscillation rate, in turn, determines the speed/efficiency of transmission of neurally encoded information. The bottom line is that individuals with higher neural oscilate rates are believed to process information more efficiently, which leads to better intellectual performance.

In contrast, according to the articles authors, the more recent "temporal resolution power (TRP) hypothesis also refers to a hypothetical oscillatory process in the brain to account for the relationship between efficiency and speed of information processing as well as psychometric intelligence (Rammsayer & Brandler, 2002, 2007). According to this view, higher neural temporal resolution leads to faster information processing and to better coordination of mental operations resulting in better performance on intelligence tests. Rammsayer and Brandler (2002) proposed that psychophysical timing tasks, assessing temporal sensitivity and timing accuracy, are the most direct behavioral measures of TRP. The TRP hypothesis has been supported by subsequent studies which found substantial correlations between psychometric intelligence and timing performance (Helmbold, Troche, & Rammsayer, 2006, 2007; Rammsayer & Brandler, 2007)." Most of these studies have been described previously at the IQ Brain Clock blog under the label temporal g.

An important issue for the TRP hypothesis to address is the fact that the most frequently used mental timing tasks also imply some form of simple sensory discrimination (together with the timing component). In order for the TRP hypothesis to have merit, the model must address (explain) the established relation between sensory discrmination and psychometric (tested) intelligence not only for the temporal domain but also for other non-temporal sensory dimensions. As summarized by the author, "associations with psychometric intelligence were shown for color (r = .08 to r = .32; Acton & Schroeder, 2001), pitch (r = .42 to r = .54; Raz, Willerman, & Yama, 1987), or texture and shape in the tactile modality (r = .08 to r = .29; Stankov, Seizova-Cajic´, & Roberts, 2001)."

Purpose of study

The purpose of the current study was to disentagle the relations between temporal processing and sensory discrmination via the evaluation and testing of two different structural models. As described by the authors, "the first model expanded the investigation of Helmbold et al. (2006) to the level of latent variables by factorizing various non-temporal and temporal discrimination tasks. It is assumed that temporal and non-temporal discrimination abilities predict psychometric intelligence as two dissociable factors which, however, can be related to each other. The TRP hypothesis postulates that TRP affects both capacity- and speed-related aspects of psychometric intelligence (Helmbold & Rammsayer, 2006)."

Alternatively "Model 2 proceeds from Spearman’s (1904) assumption that a general discrimination ability predicts psychometric intelligence. In accordance with this view, temporal discrimination constitutes a factor indissociable from non-temporal discrimination. In other words, temporal and non-temporal discrimination tasks build a common factor referred to as GDA."

Method summary

The subjects were 100 male and 100 female volunteers (18 to 30 years of age; mean ± SD = 22.2 ± 3.3 years). The sample comprised 93 university students, 89 vocational school students and apprentices, while the remaining participants were working individuals of different professions. All participants reported normal hearing and normal or corrected-to-normal sight. The authors employed structural equation modeling (SEM) methods to evaluate and compare the two models.

Capacity and speed components of psychometric IQ (g) were measured with 12 subtests of the Berlin model of intelligence structure (BIS) test (Jäger, Süß, & Beauducel, 1997). Four temporal (temporal generalization, duration, temporal-order judgment, rhythm perception) and three non-temporal sensory discrimination tasks (pitch discrimination, intensity discrimination, rightness discrimination) were used to operationally define temporal processing and sensory discrimination, respectively.

Conclusions/discussion summary (emphasis added by blogmaster)

Evaluation and comparison of the two models suggested the following conclusions (as per the authors)
  • The relation between non-temporal discrimination and speed was completely mediated by temporal discrimination. The association between temporal discrimination and capacity was twofold. There was a weak but reliable direct association as well as a stronger indirect relation mediated by non-temporal discrimination.
  • Although Model 1 revealed a high correlation between temporal and non-temporal discrimination, the different relations of temporal and non-temporal discrimination to speed and capacity suggest that the two factors are dissociable. Our finding of a strong correlational link between temporal discrimination ability and psychometric intelligence is in line with the outcome of previous studies investigating the TRP hypothesis...according to this account, higher TRP entails increased speed and efficiency of information processing resulting in higher scores on both speed- and capacity-related intelligence tests. Thus, our finding that Model 1 fitted the data well is in line with the TRP hypothesis.
  • The present results corroborate Helmbold and Rammsayer’s (2006) finding of a stronger relationship between temporal discrimination ability and capacity compared to speed. On the contrary, shared variance with non-temporal discrimination accounted for the association between capacity and temporal discrimination whereas the direct link between temporal discrimination and capacity was rather weak. Thus, the strong relation between TRP and psychometric intelligence is probably due to the fact that TRP, when measured as a factor derived from temporal discrimination tasks, taps both temporal and unspecific discrimination abilities. From this perspective, time-related aspects of TRP may account for the association to speed whereas rather unspecific discrimination-related aspects mainly account for the association with capacity.
  • The more parsimonious Model 2 should be preferred over Model 1. Model 2 suggests that temporal and non-temporal discrimination tasks constitute a common factor of unspecific, general discrimination performance referred to as GDA. The close association between this factor and psychometric intelligence is supported by the outcome of previous studies.
  • The finding, that both temporal and non-temporal discrimination share a common source, supports the notion that general discrimination ability is somehow associated with higher-order mental ability.
  • The finding of a close association between GDA and psychometric intelligence suggests, that already at a very early sensory stage of information processing, higher neural efficiency can be observed as a correlate of psychometric intelligence
  • The high correlations between GDA and speed- as well as capacity-related aspects of psychometric intelligence, as revealed by Model 2, emphasize the importance of sensory performance as a correlate of higher-order mental ability. Nevertheless, differential relations between temporal and non-temporal discrimination and aspects of psychometric intelligence, as suggested by Model 1, may help to elucidate the internal structure of GDA. This is, certain sensory processes appear to be more predictive for certain aspects of psychometric intelligence than others. Such a conclusion is in line with the results of Stankov et al. (2001) who reported differential relations between cognitive abilities and aspects of tactile and kinesthetic perceptual processing. In the face of the available data, mapping of differential relationships between distinct sensory performances and components of psychometric intelligence represent a promising strategy to further explore the significance of sensory processes for human mental abilities.

Bottom line: This study continues to support the importance of temporal g, temporal processing, or the TRP hypothesis in explaining neural efficiency, which in turn is believed to play a major role in facilitating better (higher) intellectual performance. Understanding the interal IQ Brain Clock, and interventions/treatements that may help "fine tune" the brain clock (increase its timing resolution), appears an important avenue to pursue both for theoretical and applied (cognitive enhancement interventions) research. To pat myself on the back, I've previously summarized the potential link between increased resolution of the brain clock and higher cognitive functioning in prior professinal presentations (click here to visit a SlideShare PPT show)

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Cool neuron images

Thanks to MIND HACKS for the FYI about this site


Kevin McGrew PhD
Educational/School Psych.
IAP (www.iapsych.com)

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Thursday, June 25, 2009

Brain Fitness Webinar with Dr. Elkhonon Goldberg and Alvaro Fernandez. Kindle Book. Twitter Discussion.

Interesting activities at SHARP BRAINS. 

Kevin McGrew PhD
Educational/School Psych. 

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Brain Fitness Webinar
with Elkhonon Goldberg & Alvaro Fernandez.
Kindle Book. Twitter Discussion.

June 2009
Book Cover
SharpBrains' new book continues to get excellent endorsements:

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-- Doc Gurley, Internist Physician and Robert Wood Johnson Fellow, full book review Here
FREE Brain Fitness Webinar
Alvaro Fernandez and Dr. Elkhonon Goldberg, co-authors of The SharpBrains Guide to Brain Fitness, will cover the main highlights from this new book and address the questions submitted by readers.

When: Tuesday July 21st, 10am Pacific Time; 1pm Eastern Time
How to Register: Click HERE for more information and to Register
  Related Announcements
- A Kindle edition is now available HERE.

- The print edition of the book is available HERE.

- Alvaro Fernandez will facilitate a twitter-based book club over the summer. If you have a twitter account, please follow alvarof for more instructions.

- If your organization is interested in ordering the book in bulk at 40-60% discount depending on volume, please contact us HERE.
Have a stimulating summer!,

- The SharpBrains Team

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Saturday, June 20, 2009

Mental time travel



Kevin McGrew PhD
Educational/School Psych.
IAP (www.iapsych.com)

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Wednesday, June 17, 2009

More on schizophrenia and the mental clock

This is a follow-up post to a prior post re: a study (published in Brain and Cognition) linking mental timing and schizophrenia. I've now read the article closer and would like to share a little more of the content from the authors (prior post only included the abstract)

In the introduction, the authors state that the research literature suggests that:
Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to dysfunctions in the timing of perceptual, cognitive, and motor processes (Bressler, 2003; Paulus & Braff, 2003; Phillips & Silverstein, 2003; Tononi & Edelman, 2000). These impairments of neural timing have also been associated with ‘‘disturbances of consciousness,” and may give rise to the expression of clinical symptoms associated with both positive (e.g., hallucinations, delusions) and negative (e.g., psychomotor poverty, poverty of speech) subtype classifications of the disorder (Andreasen, 1999; Hyde, Ziegler, & Weinberger, 1993; McGlashan & Hoffman, 2000).
Support for these conceptualizations is emerging with evidence that brain structures and neurotransmitter systems – such as dopamine, glutamate, and serotonin – that are directly linked to neural timing processes are also impaired in schizophrenia (Andreasen, 1999; Andreasen et al., 1998; Buhusi & Meck, 2007; Cheng, Ali, & Meck, 2007; Rao, Mayer, & Harrington, 2001; Rao et al., 1997; Volz et al., 2001). Despite the growing interest and centrality of these time-dependent conceptualizations of the pathophysiology of schizophrenia, there remains a paucity of research directly examining overt timing performance in the disorder. In addition, the majority of studies that have examined timing behavior in schizophrenia have employed temporal durations in the range of several seconds (Densen, 1977; Johnson & Petzel, 1971; Tysk, 1983a, 1983b, 1990; Volz et al., 2001; Wahl & Sieg, 1980), requiring higher cognitive processes beyond initial sensory registration for temporal encoding (Fraisse, 1984; Michon, 1985; Rammsayer & Lima, 1991). Thus, the aim of the present study was to delineate deficits of temporal perception from more generalized cognitive impairments in schizophrenia by assessing duration estimates in both the millisecond and seconds range using a well-established task of time perception.
The primary purpose of the study was to move beyond prior studies that primarily focused on time estimation in the range of several secondsto time at the level of milliseconds. Also, the theoretical mental clock model used in this study was the classic pacemaker-accumulator model. One task frequently used in mental timing research is the temporal bisection task. The authors provide a nice description of this task:

a temporal bisection task was used to assess the timing of brief auditory durations (i.e., 300–600 ms) in individuals with schizophrenia and non-psychiatric control participants. The temporal bisection procedure required participants to first encode short and long anchor durations to which intermediate durations were subsequently compared and classified as most similar to either the short or the long anchor. The bisection point therefore refers to the duration at which short and long classifications are made with equal probability. In addition to brief durations in the millisecond range, participants in the present study were also required to estimate auditory durations in a second task employing intervals in the range of several seconds (i.e., 3–6 s).
Temporal bisection is unique to other tasks of time estimation with respect to its predictions and the inferences that can be drawn from temporal performance. In a simple timing task involving the estimation of a presented duration, differences in clock rate are reflected in performance differences. Specifically, a faster ‘‘internal clock” would result in the accumulation of a larger number of clock ‘‘pulses” during the timed interval, such that the summation of pulses would correspond to a longer duration than actually presented. A similar outcome would be observed for a slowed clock, with underestimations resulting from the accumulation of fewer pulses than would be needed to represent the presented duration
In the summary, the authors concluded that the timing deficits associated with schizophrenia are due primarily to perceptual or "clock" processes, and not other processes such as attention. Also implicated was the reference memory component of the pacemaker accumulator model.

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Thursday, June 04, 2009

Individual differences in rhtyhm perception and beat production

I received an advanced copy of a interesting manuscript accepted for publication by J. Grahn and D. McAuley, two researchers studying mental timing, and rhythm perception and beat production in particular.  The title of their "in press" article is Neural bases of individual differences in beat perception.  Since the manuscript has not gone through the final editing stage, I currently cannot make it available for viewing.  At this time I'm just providing a "sneak peak" via a copy of the abstract on the accepted version of the manuscript.  Dr. Grahn is listed under the Mental Timing Scholars blogroll at this blog.  Copies of other related publications by these researchers can be found at their professional web pages.  I'll be keeping an eye open for the formal publication

When people listen to music, they often move their body in time with the beat. However, people differ widely in their tendency to ‘feel a beat’. Why? Here we combined functional magnetic resonance imaging with a timing task that is diagnostic of individual differences in beat perception and compared the brain activity of individuals who readily perceive an implied beat with those who do not. Activation in auditory and motor areas was correlated with individual differences in beat perception, even when participants performed a timing task in which no behavioral differences occurred. The results support two conclusions. First, beat perception is mediated by the activation of cortical circuits involved in rhythm production. Second, some individuals more readily engage these
cortical beat-based circuits when making timing judgments than do others.

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Wednesday, June 03, 2009

Is grey the new gold?



Kevin McGrew PhD
Educational/School Psych.
IAP (www.iapsych.com)

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Monday, June 01, 2009

GLASCOW comma scale prediction research

Thanks to BRAIN INJURY blog foe this post.


Kevin McGrew PhD
Educational/School Psych.
IAP (www.iapsych.com)

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