Merging the senses into a robust percept

To perceive the external environment our brain uses multiple sources of sensory information derived from several different modalities, including vision, touch and audition. All these different sources of information have to be efficiently merged to form a coherent and robust percept. Here we highlight some of the mechanisms that underlie this merging of the senses in the brain. We show that, depending on the type of information, different combination and integration strategies are used and that prior knowledge is often required for interpreting the sensory signals.     

Components of attentional bias to threat in high trait anxiety: Facilitated engagement, impaired disengagement, and attentional avoidance

There is a wealth of evidence demonstrating enhanced attention to threat in high trait anxious individuals (HTA) compared with low trait anxious individuals (LTA). In two experiments, we investigated whether this attentional bias is related to facilitated attentional engagement to threat or difficulties disengaging attention from threat. HTA and LTA undergraduates performed a modified exogenous cueing task, in which the location of a target was correctly or incorrectly cued by neutral, highly and mildly threatening pictures. Results indicate that at 100 ms picture presentation, HTA individuals more strongly engaged their attention with and showed impaired disengagement from highly threatening pictures than LTA individuals. In addition, HTA individuals showed a stronger tendency to attentional avoidance of threat at the 200 and 500 ms picture presentation. These data provide evidence for differential patterns of anxiety-related biases in attentive processing of threat at early versus later stages of information processing.     

A hierarchical model of operational anticipation windows in driving an automobile

Driving an automobile is an example of a goal-directed activity with high complexity in which different behavioral elements have to be integrated and brought into a sequential order. On the basis of the reafference principle and experimental results on temporal perception and cognitive control, we propose a hierarchical model of driving behavior, which can also be adapted to other goal-directed activities. Driving is conceived of as being controlled by anticipatory neuronal programs; if these programs are disrupted by unpredictable stimuli, which require an instantaneous reaction, behavioral control returns after completion of the reactive mode to the anticipatory mode of driving. In the model different levels of anticipation windows are distinguished which, however, are interconnected, in a bi-directional way: (a) Strategic level with a representation of the driving activity from the beginning to reaching the final goal; (b) Segmented tactical level with the sequence of necessary milestones to reach the goal; (c) Maneuver level where actions like passing another car or keeping a lane are controlled; (d) Short-term integration level of a few seconds which allows immediate anticipations; and (e) Synchronization level for sensorimotor control and complexity reduction within neuronal assemblies. A flow diagram schematically describes different driving situations stressing the anticipatory mode of control. In a pilot experiment with 20 subjects using a virtual driving situation in a car simulator predictions of the model could be verified, i.e., subjects showed a significant preference for the anticipatory mode of driving.     

Do the Wechsler scales underestimate the difference between verbal and performance abilities in children with language–related disorders?

The present paper examines the validity of the Wechsler scales with children with language-related disorders, with whom the scales were not originally normed. The general question is whether we can take measures of IQ, normed with a normal sample, and then validly use them as indicators of the same constructs with samples significantly different from the normed sample. In previous papers it was pointed out that the pattern structurally simple > moderately complex > complex tests can be observed in their IQ profiles within both the Verbal scale and the Performance scale. In this paper, it is hypothesized that this scatter of scores leads to an underestimation of the global V-P IQ differences for children with language-related disorders because there are more structurally complex tests on the Performance scale than on the Verbal scale. To test this hypothesis, "purer" V-P IQ differences were calculated by comparing the scores on Verbal and Performance tests of equal structural complexity. WPPSI and WISC-R data from four groups of children were analyzed: language-impaired children (n = 128), reading-impaired children (n = 112), children from dyslexic families (n = 51), and normal children (n = 49). When the effect of the difference in structural complexity was controlled for, it was found that the distribution of the revised V-P IQ difference was significantly more toward the negative end of the spectrum than the traditional V-P IQ differences for language-impaired and reading-impaired children, and approaching a significant level for children from dyslexic families. As hypothesized, there were no significant differences between the two distributions of V-P IQ differences for normal children. Practical and theoretical implications are discussed.     

Duration processing in children as determined by time reproduction: implications for a few seconds temporal window

From research carried out over recent years using different experimental paradigms, it has become apparent that central information processing is temporally segmented into sequential units of a few seconds. This segmentation presumably reflects a neuronal process of temporal integration (TI) which automatically binds successive events into temporal units. Support for such TI comes, for example, from studies on temporal reproduction where standards up to approximately 2-3 s are reproduced veridically. Using this paradigm of temporal reproduction, we investigated the effect of normal cognitive development of sensory modality and of the range of presented standards on TI. Sixty children aged 6-7, 9-10 and 13-14 years reproduced visual or auditory standard durations ranged from 1 to 5.5 s or from 1 to 3 s. The results showed that durations of approximately 2 s were reproduced correctly, whereas those longer than 2.5 s were under-reproduced in the three age groups. For standards shorter than 2 s substantial age-related differences were revealed: the youngest group displayed significant over-reproduction comparing to older subjects. These observations indicate that the upper limit for TI is a stable feature across the different age groups. Furthermore an age-related modulation within the temporal window of the operating TI seems to be linked to cognitive development.     

Constructing Czechoslovakia: the meaning of "intelligence" in Czechoslovak educational discourse, 1900-1939

Before World War II, Czechoslovakia went through its constituting process, including the development of an educational system. We made an analysis of Czechoslovak discussions about educational uses of intelligence tests from a discourse-theoretic and social constructionist perspective. In particular, we examined which connotations became associated with the concept "intelligence" in educational scientific publications about possible educational uses of the newly introduced tests in the years 1900-1939. Results substantiate the inextricable entwining of the meaning of "intelligence" with the unique characteristics of the historical situation in Czechoslovakia before World War II.     

Cognition,construction of knowledge,and teaching

The existence of objective knowledge and the possibility of communicating it by means of language have traditionally been taken for granted by educators. Recent developments in the philosophy of science and the historical study of scientific accomplishments have deprived these presuppositions of their former plausibility. Sooner or later, this must have an effect on the teaching of science. In this paper I am presenting a brief outline of an alternative theory of knowing that takes into account the thinking organism's cognitive isolation from reality. This orientation was proposed by Vico at the beginning of the 18th century, disregarded for two hundred years, and then propounded independently by Piaget as a developmentally grounded constructivist epistemology. The paper focuses specifically on the adaptive function of cognition, Piaget's scheme theory, the process of communication, and the subjective perspective on social interaction. In the concluding section it then suggests some of the consequences the shift of epistemological presuppositions might have for the practice of teaching.The only truly ubiquitous factor in cognitive developments — be it in the history of science or in the ontogeny of mind — are of a functional, not a structural kind.Piaget and Garcia, 1983, p. 38I am indebted to Jack Lochhead and John Clement for their helpful critical comments on the draft of this paper. The work that led to it was supported in part by NSF Grants to IBR. University of Georgia, and SRRI, University of Massachusetts.     

Changes in verbal child-mother interactions with increasing language skills of the child

Protocols of language interactions between mothers and children are analyzed. The children ranged in age from 2,2 years to 5,0 years. Systematic changes in the interactions were found with the increasing level of language skills of the child. Mothers generally proved to be very sensitive measuring instruments of the language capacities of their children and they adapted their verbal utterances to these capacities. The syntactical forms as well as the communicated contents of the message were changing with increasing language skill. Nonhuman environmental influences on the language behaviors were studied in part and changes in the use of these situational resources by the mothers were observed. Individual differences in the teaching methods of the mothers as well as in the reactions of the children are discussed.