Identification Of Multidimensional Stimuli Research Articles

Event-Related Brain Potentials: Report Order and Task Switch on Multidimensional Stimuli Identification

An experiment was conducted to evaluate the effect of order of reporting stimulus dimension in multidimensional stimulus identification using a switch-task paradigm. Participants were required to identify each two-dimensional symbol by pushing the corresponding buttons on the keypad on which there were two columns representing the two dimensions, part and shape. The two orders of report were Order Part/Shape and Order Shape/Part. There was a task cue prior to each presentation of a symbol indicating the particular report order the participants should perform. The cue changed randomly. Both behavioral data and event-related potentials were recorded from 12 college students. Analysis of behavioral data showed switch cost indicated by increase in response time was greater for Order Shape/Part, a less appropriate order of reporting dimensional values, than Order Part/Shape (88 msec. vs 9 msec. for response time for the first stimulus dimension; 96 msec. vs -1 msec. for response time total). Neural activities under Order Shape/Part and Order Part/Shape were different, and it seems plausible that participants put more effort into selection and showed more related semantic activation in Order Shape/Part than in Order Part/ Shape which fits the Chinese adjective-then-noun language habit.

Event-Related Potential as a Measure of Effects of Report Order and Training on Identification of Multidimensional Stimuli

This experiment investigated effects of report order and training on multidimensional stimulus identification. Subjects were required to identify each two-dimensional symbol. There were two orders of reporting the two dimensions of a stimulus. Subjects performed the task for three practice sessions. Both behavioral data and event-related potentials were recorded. Analysis showed order of report had no significant effect on behavior data. But when participants responded in Order Shape/ Part, they showed more N2 inhibition for Order Part/Shape. The P3 mean amplitude was marginally significantly greater for Order Part/Shape than Order Shape/Part. This indicated Order Part/Shape, according to natural language habits, was more appropriate and less cognitively demanding than Order Shape/Part. For the two report orders, along with reduction of reaction time, amplitude of N1 and N2 increased with practice. Amplitude of P2 decreased with practice, and no P3 habituation was found. ERP data indicated no habituation effect. Results suggested neural activity depended not only on perceptual mechanism but also on extent of learning.

Effects of order of report and stimulus type on multidimensional identification.

An experiment was conducted to investigate the effect of order of report and stimulus type on multidimensional stimulus-identification performance. Analysis showed that the proper order of reporting dimensional attributes depended on stimulus type. If the dimensions were independent heterogeneous attributes, the effect of order of report was not significant. If homogeneous attributes were involved, they should be reported consecutively. The order in which the color attributes should be reported depended on the characteristics of the stimulus dimensions. If there was a natural language-appropriate order of reporting the dimensional attributes, the color attribute should be used as an adjective and reported first. Otherwise, reporting color attribute later seemed to have an advantage because color is less vulnerable to memory deterioration.

EFFECTS OF ORDER OF REPORT AND STIMULUS TYPE ON MULTIDIMENSIONAL IDENTIFICATION

An experiment was conducted to investigate the effect of order of report and stimulus type on multidimensional stimulus-identification performance. Analysis showed that the proper order of reporting dimensional attributes depended on stimulus type. If the dimensions were independent heterogeneous attributes, the effect of order of report was not significant. If homogeneous attributes were involved, they should be reported consecutively. The order in which the color attributes should be reported depended on the characteristics of the stimulus dimensions. If there was a natural language-appropriate order of reporting the dimensional attributes, the color attribute should be used as an adjective and reported first. Otherwise, reporting color attribute later seemed to have an advantage because color is less vulnerable to memory deterioration.

Effects of duration of stimulus and variability of foreperiod on the identification of multidimensional stimuli.

Two experiments were conducted to investigate the effects of duration of stimulus and variability of foreperiod on the identification of multidimensional stimuli. Statistical analysis showed that performance speed and accuracy deteriorated as duration of stimulus was severely limited. Further, subjects seemed to change the allocation of attentional resources according to the attributes of stimulus. They tended to distribute more attentional resources to the less salient attribute which resulted in a statistically nonsignificant effect of order of report under time stress. Variability of foreperiod had very little effect on performance and may not be important to consider in reactions. Implications of these results for the design of multidimensional displays and for human information processing were discussed.

Multidimensional stimulus identification: instructing subjects in the order of reporting stimulus dimensions.

Two experiments were conducted to investigate the effects of order of report on identification of multidimensional stimuli under various experimental conditions. Statistical analysis showed that order of report affected speed of identification. Subjects responded faster if a natural and more appropriate way of reporting stimulus dimensions was used. Further, subjects reacted more slowly if they were free to report stimulus dimensions in any order than when they were forced to report in a particular order. Their performance was even worse when order of report was a with-in-subject factor. Response competition and response inhibition were proposed as possible explanations of the results. The implications of the results for multidimensional identification tasks are to designate an appropriate order of reporting stimulus dimensions and to instruct subjects to respond in that order.

Effects of practice on identification of multidimensional stimuli.

This study investigated the effects of practice on the identification of multidimensional stimuli. Subjects were instructed to perform a two dimensional identification task. The stimuli could be identified either physically or connotatively. There were two orders of reporting the two dimensions of a stimulus. Analysis showed that method of identification and order of report significantly affected speed of identification. Physical identification was faster than identification of meaning. An appropriate order of report shortened response times, and increased practice reduced response times. Practice in multidimensional identification seemed to follow the same laws and trends of unidimensional performance. The effects of practice on multimensional identification could be represented by straight lines if response times were plotted against the logarithm of the number of trials as noted in unidimensional performance. Further, practice attenuated initial differences in response times between physical identification and identification of meaning.

A Connectionist Model of Choice and Reaction Time in Absolute Identification

A connectionist architecture is developed that can be used for modeling choice probabilities and reaction times in identification tasks. The architecture consists of a feedforward network and a decoding module, and learning is by mean-variance back-propagation, an extension of the standard back-propagation learning algorithm. We suggest that the new learning procedure leads to a better model of human learning in simple identification tasks than does standard back-propagation. Choice probabilities are modeled by the input-output relations of the network and reaction times are modeled by the time taken for the network, particularly the decoding module, to achieve a stable state. In this paper, the model is applied to the identification of unidimensional stimuli; applications to the identification of multidimensional stimuli—visual displays and words—is mentioned and presented in more detail in other papers. The strengths and weaknesses of this connectionist approach vis-a-vis other approaches are discussed

On exemplar-based exemplar representations: Reply to Ennis (1988).

The multivariate theory of similarity discussed by Ennis (1988) entails the assumption that individual category exemplars are themselves represented psychologically as distributions of individual exemplars. The potential utility of this exemplar-distribution approach for theories relating selective attention, similarity, and categorization is briefly discussed. Nosofsky (1986) proposed and tested a unified quantitative approach to modeling performance in tasks of multidimensional stimulus identification and categorization. The approach was based on the assumption that both identification and categorization decisions are governed by similarity comparisons with individually stored exemplars. By modeling patterns of identification confusions, a multidimensional scaling solution for the exemplars was derived. This solution was then used in conjunction with the exemplar-similarity model to predict performance in four separate categorization conditions with the same set of stimuli. A key component assumption was that selective attention processes may systematically modify distances among exemplars in the multidimensional psychological space.