Influence Response Times Research Articles

Influence of macroinitiator’s glass transition temperature on the response times of polymer dispersed liquid crystals

Glass transition temperature (Tg), an important parameter of polymer, was reported to have great influence on the electro-optical properties of polymer dispersed liquid crystals (PDLCs). In this study, macroinitiators with different Tg were synthesised by reversible addition fragmentation chain transfer polymerisation, and used to prepare PDLCs with different Tg block chains. The effect of different Tg of the block chains on response times was investigated. It was found that rise time decreased and decay time increased with the decrease of the block chain’s Tg. We proposed a possible mechanism by which Tg of the block chains influence response times.

Do You ‘See’ What I ‘See’? Differentiation of Visual Action Words

Dickinson and Szeligo (Can J Exp Psychol 62(4):211-222, 2008) found that processing time for simple visual stimuli was affected by the visual action participants had been instructed to perform on these stimuli (e.g., see, distinguish). It was concluded that these effects reflected the differences in the durations of these various visual actions, and the results were compared to participants' subjective ratings of word meaning but it was also possible that word characteristics like length might have influenced response times. The present study takes advantage of word length differences between French and English visual action words in order to address this issue. The goals of the present study were to provide evidence that (1) the processing time differences previously found were due to differences in the cognitive actions represented by these words (and not due to characteristics to the words themselves), and (2) that individuals subjectively differentiate visual action words in such a way that allows for predictable differences in behaviour. Participants differentiated 14 French visual action words along two dimensions. Four of these words were then used in the instructions for a size-discrimination task. Processing time depended on the visual action word in the instruction to the task and differed in a predictable manner according to word meaning but not word length.

Using Paradata to Explore Item Level Response Times in Surveys

SummaryWe analyse item level keystroke data from cycle 6 of the National Survey of Family Growth, which is a survey on fertility and related topics that is conducted in the USA. The National Survey of Family Growth is conducted among both males and females by using computer-assisted personal visit interviews and an audio computer-assisted self-interviewing component for the most sensitive topics. Our analyses focus on the time taken to answer a question as a function of item level characteristics, respondent characteristics and interviewer characteristics. Using multilevel models, we explore how these factors influence response times. Our exploratory study suggests that factors at all three levels (item, respondent and interviewer) influence response times. These results demonstrate that question features that explain variation in response times can be automatically derived from standard computer-assisted personal interviewing paradata. The effects of respondent characteristics that we observe are in line with prior findings from more controlled studies conducted in supervised telephone facilities. Some demographic characteristics of interviewers contributed to the variation in response times, though they failed to explain large portions of the between-interviewer variance.

Dynamic Accommodation Responses Following Adaptation to Defocus

Adaptation to defocus is known to influence the subjective sensitivity to blur in both emmetropes and myopes. Blur is a major contributing factor in the closed-loop dynamic accommodation response. Previous investigations have examined the magnitude of the accommodation response following blur adaptation. We have investigated whether a period of blur adaptation influences the dynamic accommodation response to step and sinusoidal changes in target vergence. Eighteen subjects (six emmetropes, six early onset myopes, and six late onset myopes) underwent 30 min of adaptation to 0.00 D (control), +1.00 D or +3.00 D myopic defocus. Following this adaptation period, accommodation responses to a 2.00 D step change and 2.00 D sinusoidal change (0.2 Hz) in target vergence were recorded continuously using an autorefractor. Adaptation to defocus failed to influence accommodation latency times, but did influence response times to a step change in target vergence. Adaptation to both +1.00 and +3.00 D induced significant increases in response times (p = 0.002 and p = 0.012, respectively) and adaptation to +3.00 D increased the change in accommodation response magnitude (p = 0.014) for a 2.00 D step change in demand. Blur adaptation also significantly increased the peak-to-peak phase lag for accommodation responses to a sinusoidally oscillating target, although failed to influence the accommodation gain. These changes in accommodative response were equivalent across all refractive groups. Adaptation to a degraded stimulus causes an increased level of accommodation for dynamic targets moving towards an observer and increases response times and phase lags. It is suggested that the contrast constancy theory may explain these changes in dynamic behavior.

Positive and negative associations underlying ambivalent attitudes

In two studies, we compared the strength of positive and negative associations of ambivalent attitudes to those of nonambivalent attitudes. In Study 1, results from an implicit association task showed that, in contrast to nonambivalent attitudes, ambivalent attitudes were characterized by strong positive and negative associations. In Study 2 responses to ambivalent attitude objects were faster following a positive as well as following a negative prime, compared to a non-word prime, whereas for neutral attitude objects prime type did not influence response times. Results provide direct evidence for the assumption that both positive and negative associations of ambivalent attitudes are relatively strong. Implications for attitude strength and attitude structure are discussed.

Goal-driven selective attention in patients with right hemisphere lesions: how intact is the ipsilesional field?

Patients with right hemisphere (RH) lesions often display a spatial bias in attention towards the ipsilesional hemifield. The behavioural manifestations of this spatial bias are typically interpreted as reflecting increased or enhanced attention for stimuli within the 'intact' ipsilesional field, and impaired attentional functioning within the contralesional field. In the healthy brain, goal-driven and stimulus-driven attentional processes interact to determine which stimuli should be prioritized for selection. Although unilateral brain damage increases the relative attentional salience of stimuli within the ipsilesional field, it might also cause problems in filtering or attenuating task-irrelevant information. We examined whether goal-driven attention modulates the processing of ipsilesional and contralesional information in 6 patients with unilateral brain damage following RH stroke (5 male, 1 female; mean age 60.8 years) and a group of age and sex-matched controls. We used a flanker task in which participants made speeded judgements on a central target item (a coloured letter). On each trial the target was flanked by a coloured letter in the left and right hemifields. In separate blocks, participants were instructed to judge either the identity or the colour of the central target and to ignore the flankers. The flanker on one side could be congruent, incongruent or neutral with respect to the target, on either the letter or the colour dimension, whereas the flanker on the other side was always neutral on both dimensions. Healthy controls showed significant interference from incongruent flankers on either side. Crucially, however, this effect only occurred for the task-relevant dimension [F(2,10) = 24.60; P < 0.001]. For patients, however, both the task-relevant and task-irrelevant dimensions of ipsilesional flankers interfered with response times [task-relevant: F(2,10) = 7.50, P < 0.05; task-irrelevant: F(1,5) = 6.20, P < 0.05]. Conversely, contralesional flankers influenced response times only when the target and distractor were incongruent on the task-relevant dimension [F(2,10) = 4.85; P < 0.05]. Our findings demonstrate that following RH damage, goal-driven biases cannot constrain the processing of task-irrelevant features of ipsilesional stimuli. We speculate that a lateralized bias in spatial attention leads to unselective prioritization of all feature-based attributes of stimuli appearing within the ipsilesional hemifield, whether or not they are relevant to performance. Attentional selection for ipsilesional stimuli in disorders such as spatial neglect and extinction may not therefore be entirely normal, as previously assumed.

Congruity effects evoked by subliminally presented primes: automaticity rather than semantic processing.

In a size judgment task on words denoting concrete objects, subliminally presented stimuli that preceded the targets influenced response times and were dependent on whether responses to the prime and the target were congruent or incongruent (Experiment 1). These findings, mirroring S. Dehaene et al. (1998), imply that primes are unconsciously categorized and processed to the response stage. However, the effect does not generalize to primes that are not in the response set (Experiment 2), and even exposure to primes not in the response set in an interleaved naming-size judgment task fails to induce it (Experiment 3). However, the effect generalizes from lowercase primes to the same set of uppercase targets (Experiment 4), suggesting an abstract level of operation. The findings suggest that rather than resulting from unconscious prime categorization, the congruity effect results from automatized stimulus-response mappings. Potential differences between the number and the word domain are discussed.

The Semantic Simon Effect

Three experiments are reported in which a semantic variant of the Simon paradigm was used. In Experiment 1, participants saw Dutch and English words that corresponded to names of animals (e.g. DOG) or occupations (e.g. TEACHER). Participants were instructed to respond by saying ANIMAL or OCCUPATION, depending on whether the presented word was a Dutch or English word (i.e. relevant stimulus feature) but irrespective of whether the word was the name of an animal or an occupation (i.e. irrelevant stimulus feature). Results showed that responses were facilitated when the correct response corresponded to the name of the semantic category of the presented word (e.g. saying “ANIMAL” to DOG) compared to when it was the name of a different semantic category (e.g. saying “OCCUPATION” to DOG), even though the semantic category of the presented word was irrelevant and had to be ignored. Category membership also influenced response times when letter case (upper- or lower-case: Experiment 2) and grammatical category (noun or adjective: Experiment 3) had to be determined in order to select a category label as a response. The semantic Simon effect offers a new tool that can be used to study automatic semantic processing.

Perception of traffic guidance signs containing conflicting symbol and direction information

Information pictographs (airport and ski trail symbols) and corporate logos (Amtrak, Montreal Metro), all with directional quality were paired with route guidance arrows. The resulting signs were rated on semantic differential adjective scales. In addition, the response times to the same signs were measured. Concordant signs, for which symbol and route arrow directions agree, were judged to be more clear, unified, valuable, and strong than signs using discordant symbols and arrows. Response times were slower for discordant airport and Amtrak signs than for the comparable concordant signs; however, concordance did not influence response times to the skier or the metro symbols. It was concluded that agreement between symbol and arrow direction is an important element in decreasing perceptual conflict within a sign. A second conclusion was that unless such agreement can be achieved, prominent arrowlike logos (e.g., Amtrak, airport) should be avoided in highway guidance signs because of their adverse effect o...

An audible train warning for track maintenance personnel

British Rail track maintenance staff currently use a portable warning device to provide audible warning of approaching trains. The audible signal comprises a train warning signal, which is continuous and the same signal broken into a series of discrete ‘bleeps’ to signify that it is safe to work. If the audible signal ceases entirely when bleeping then men could continue to work without protection. The study reported in this paper was in two parts. The first part, a laboratory study, compared response times to the sudden disappearance of the bleeping signal for four different lengths of interval between bleeps. The second part, a field study, sought to establish how operational conditions influenced response times for the interval with the shortest response time in the laboratory. The main recommendation from the study was that the interval should be shortened from the 7 s specified at the time the study was undertaken, to 2 s, in order to facilitate quicker responses to the absence of the bleeping signal.

Using semantic memory to find vs create a mood

Ss produced words from semantic memory which satisfied certain constraints. In Experiment I, a noun category plus a number and a letter were presented (e.g., ANIMAL-I-D, FRUIT-P-3), and S produced an instance of the category which had the given letter in the position designated by the given number. Faster responses occurred when the position cue occurred before the letter rather than after it. In Experiments II and III, Ss saw only a number and a letter (e.g., l-D, P-3) and were required to produce any word that had the given letter in the position designated by the given number. Order of the position and letter cues did not influence response times. The effect of order in one case and not the other strongly suggests that producing a word that satisfies certain semantic constraints involves a different process from producing a word that satisfies only certain orthographic restrictions.