Visual onset and offset latencies

An experiment was designed to test the hypothesis that the latency of response to the offset of light can sometimes be shorter than the latency of response to the onset. The subjects' task involved the temporal order discrimination of the offset of one light and the onset of another. The results indicated that offsets were perceived about 40 ms earlier than onsets. Reasons were suggested for the shorter onset latencies found by other investigators, and a model was proposed to account for changes in the relative latencies of onsets and offsets as a function of stimulus duration and intensity.     

Frequencies and latencies in detecting two-flash stimuli

Dark-adapted Ss responded as soon as they detected near-threshold stimuli, which usually comprised two flashes that were equal in luminance and duration. The percentage of trials on which the S responded and the median latency of responses were determined as functions of the interval between flash onsets. At short intervals: the percentage was independent of the interval and attributable to the stimulus energy alone (Bloch’s law); the latency increased gradually to the value for the first flash alone and was attributable to not only the energy, but also to its temporal distribution. At long intervals: the percentage decreased to a steady level that was either equal to or higher than the value for the first flash; the latency increased to a peak and then decreased to the value for the first flash; both response measures suggested inhibition and probability summation between the flashes.     

Response latencies in short-term memory

This paper deals with the problem of the interpretation of response latencies in short-term memory. A paired-associate study using a probe technique was conducted with the main experimental variation the length of the recall interval (1, 2, or 4 sec.). While shortening the interval had a statistically significant effect on recall probability the interaction between recall interval and probe position was negligible. While traditionally response latency is considered a measure of associative strength, such an interpretation seems inappropriate here. As an alternative, latencies may reflect more criterion values than sensitivity as these measures are interpreted in signal-detection theory.     

Response latencies in human matching-to-sample

Optimum characterization of individual information-processing skills requires isolation of assessable components. In matching-to-sample, three elementary processes might be separated if a proposed model of serial, selfterminating search were supported: registration of the stimulus in short-term memory, comparison of the two registered stimuli, and execution of the identifying response. Support for the model was obtained when response latencies were examined as a function of left-to-right position of the target stimulus in a display, but quantitative estimates of components could not be made because of interactions between tasks and the linearity of the scanning process. A second experiment, which varied the number of comparison stimuli, yielded highly linear functions whose slopes and intercepts violated certain aspects of the model. Data on eye movements obtained in a third experiment again supported the basic model but indicated that median response latencies represent a confounding of optimal and suboptimal performances.     

Response latencies in naming objects

After some preliminary analysis of what is involved in naming objects, in which the possible role of classificatory systems in the memory store is discussed, it is shown experimentally that there are consistent differences between the times taken to respond to presented objects by uttering their names, variations between the performances of different individuals being outweighed by variations due to the different objects. Moreover, there is a high consistency between different individuals as to the ordering of objects in respect of their naming latencies. It is further shown that a high correlation exists between the time taken to name an object and the frequency with which its name occurs in the language as a whole, as estimated in the Thorndike-Lorge Word List. Some implications of these findings are discussed, especially with reference to possible mechanisms by which presented objects are visually identified, and the appropriate names retrieved from the “word-store.”     

Response latencies and the computerized assessment of intelligence

A study was undertaken to examine the relationship between response latencies to verbal ability test items administered by computer and overall verbal intelligence test scores. Sixty-four undergraduate students responded to a test of verbal ability under four conditions of alternate test forms (A or B) and modes of administration (computerized vs paper-and-pencil). The response latencies recorded during computerized testing, averaged for each subject, showed a negative correlation with overall test scores as would be predicted from a speed-of-information-processing perspective of human intelligence (Jensen, 1982a, b; Vernon, 1983). This inverse relationship was evident in every condition of test form and mode of administration, thereby demonstrating the generalizability of these findings. Discussion considered the implications of test speededness for the results of this study and provided suggestions for future research employing response latency data as a means for studying the cognitive processes underlying intelligent behaviour.     

Social facilitation

The effects of the presence of another individual and evaluation apprehension were independently manipulated within a 3 (alone, mere presence, observation) × 4 (none, low, medium, high evaluation) factorial design. Ten subjects (five male, five female) were randomly assigned to each of the 12 conditions. Subjects' behavioral performance on a hidden-word task and a measure of autonomic arousal were the main dependent variables. Analysis of variance results showed a significant performance difference on the hidden-word task among the four evaluation apprehension conditions as predicted. No significant effects were found for the palmar sweat conductivity measures. The results add support for the concept of evaluation apprehension as the mediating variable in producing social-facilitation effects, and suggest that arousal as an intervening variable may be multidimensional.The author wishes to thank Joseph E. McGrath, James H. Davis, and Samuel S. Komorita for their helpful comments on a previous draft of this article.     

Social facilitation

Video-recording procedures have been used in previous research as a motivational manipulation. The present study investigated the permanent recording of behavior as a manipulation of evaluation apprehension and its effects upon behavioral performance and upon autonomic arousal. Twenty-four subjects (12 males, 12 females) were randomly assigned to one of four conditions formed by completely crossing two levels of audience status (peer or authority) with two levels of behavioral record (non-permanent or permanent). Another 24 subjects were assigned to an external control group to the 2×2 design. Subjects' performance on a hidden-word task and their arousal level (as assessed by the Palmar Sweat Index) were measured. Analyses of variance results showed a significant performance (p<.05) and a significant arousal (p<.05) difference between the behavioral record conditions as predicted. The control group was also found to be significantly (p<.05) different from the experimental groups on the behavioral performance measure. The results were related to previous research findings and interpreted within the context of the evaluation apprehension notion presented within social facilitation research.The author would like to thank Angelia Mellors, Valerie K. Golish, and Judy Cohen for serving as experiments, and Susan L. Doman and Cheryl Primmer for scoring the PSI measures.     

Word age-of-acquisition,reading latencies and auditory recognition

Current Psychology - This paper reports two experiments concerning the effects of word age-of-acquisition on word naming speed and auditory recognition of words presented at a low volume. The first...     

Ultrastable stimulus-response latencies: Acquisition and stimulus control

Modifications were made to Kristofferson’s (1976) response-stimulus synchronization procedure which resulted in a further reduction in the estimate of minimum S-R latency variance. Minimum variances near 50 msec² were obtained whether mean latency was 310 or 550 msec. Within this range, latency distributions were the same, symmetrical and sharp-peaked, and unlike typical RT. All responses fell within a 50-msec time window. This independence of mean latency and latency variance was present throughout acquisition. A special technique allowed isolation of the controlling stimulus for synchronization timing, and showed that subjects were able to transfer control to another modality with no loss of performance. Results are discussed in terms of support for the notion of nonvariable, internally timed delays which can be inserted in the S-R chain. These delays are easily adjustable, but, once set, are deterministic. The role of feedback in acquisition and maintenance of synchronization performance is also examined.     

Clause boundaries and recognition latencies for words in sentences

In 35 sessions of 10 trials apiece, each of eight Ss viewed and judged a display which produced simultaneous brightness contrast. All Ss were given an instructional set toward realistic perception. Members of one subgroup were informed as to the magnitude of their judgments; members of another were not. For every S, there occurred highly significant changes in magnitude of simultaneous brightness contrast over time. There were wide individual differences in the nature of the changes, not all of which were decremental. No significant differences were found as between informed and noninformed groups. The results are viewed as giving limited support to the notion of learning in the perception of simultaneous brightness contrast.     

Response amendment latencies during discrete arm movements

Examinations of the ability to rapidly modify ongoing movements have found that amendment latencies are shorter when a visual stimulus specifies an increase in movement velocity as compared to when a movement reversal is required. Our present study examined the hypothesis that amendment latencies for both continue and reverse instructions are dependent on the muscle activation state when the amendment is produced. Visual stimuli representing continue and reverse instructions wer represented at four different phases of a discrete arm movement, with amendment latencies measured to modified electromyographic (EMG) patterns. Amendment latencies for the continue instruction were shortest when the stimulus was presented early in the movement and increased when the stimulus was presented later in the response. The opposite trend was true for the reversal condition with long latencies occurring when the stimulus was presented early in the movement. Our findings support the notion that amendment latencies are directly related to the active state of the motor system when the modification is required, and the nature of the amendment to be generated.     

Response latencies of rats during behavioral thermoregulation

The cutaneous thermal stimulation that elicits behavioral thermoregulatory behavior was investigated in these experiments. In Experiment I, rats were placed in a cool environment and allowed to barpress for 3-sec bursts of radiant heat reinforcement. In various phases of the study, rats could earn different intensities of anterior, posterior, or whole-body radiation. Identical response rates were exhibited at each intensity for all exposure conditions; this information, when considered with existing literature on behavioral and neurophysiological studies, suggests that the rat’s thermoregulatory behavior depends on information carried by nonmyelinated fibers that supply thermoreceptors in the skin. Experiment II investigated the hypothesis that cooling of the skin is the stimulus that elicits each thermoregulatory response. Time series measures of skin temperature fluctuations and reaction times (RTs) were obtained. Tails of the RT distributions were shown to conform to exponential probability density functions, and mean RT varied linearly over the domain of reinforcement intensities used. A computer simulation model that describes temperature gradients across layers of skin was employed to estimate temperature fluctuations at the level of the cool receptors. Comparison of simulated skin temperatures with obtained RTs suggests that momentary thermoregulatory behavior is controlled mainly by cooling skin temperature.     

Naming and equivalence: Response latencies for emergent relations

In an attempt to distinguish between associative network and verbal mediation accounts of equivalence formation, three experiments were carried out in which conditional stimulus relations were established and response latencies assessed during tests for emergent relations. In Experiment 1, three groups of adults were trained with six three-member classes of visual stimuli, using different kinds of stimuli for each group: readily nameable pictograms, which were “preassociated” (Group 1); equally nameable but “non-associated” pictograms (Group 2); or non-associated “abstract” stimuli, designed to discourage the use of verbal mediators (Group 3). For those trained with pictograms, equal response latencies were observed on all tested relations, viz. trained associations, symmetry, transitivity, and transitivity with symmetry, but for subjects given abstract stimuli response latencies were greater on tests requiring transitivity. In Experiment 2 this result was replicated with methodological refinements, using only groups trained with preassociated pictograms or abstract stimuli. In Experiment 3 subjects were pretrained to label abstract stimuli with either individual names or class names. Latencies were longer for tests involving transitivity in the case of those subjects using individual names, but equal response latencies were observed on all four types of test for those using class names. The results suggest that equivalence classesMaybe supported by either an associative network or by verbal mediation, depending on stimulus conditions and the subsequent strategies employed by subjects.     

Effect of stimulus duration on perceptual onset and offset latencies

The effects of stimulus duration on perceptual onset and offset latency were compared in vision and audition. It was found that perceptual onset latency was independent of stimulus duration but that the perceptual offset latency was longer for brief stimuli than for stimuli that exceeded a critical duration. For stimuli longer than the critical duration, the perceptual onset and offset latencies were equal: The same temporal relationships were found in both modalities. The results indicate that for any specific stimulus parameters, reduction of stimulus duration results, ultimately, in a perception of fixed duration.     

Response latencies to the onset and offset of visual stimuli

Simple response times (RTs) are known to be slower to the offset of a visual stimulus than to its onset. This is called the onset advantage. In the first of four experiments, we discovered that a spurious onset advantage can be produced by the long persistence of P31 phosphor. In the remaining three experiments, we found that offset RTs were slower only when they were made in a context in which responses to the abrupt onset of some stimuli had to be suppressed. We tested this hypothesis of response suppression in two ways: (1) by mixing regular onset trials with other trials on which a response to an onset had to be suppressed, and (2) by ramping the emergence of "offset" stimuli over time, so that offsets were the only abrupt events in the display. In both cases, we found that the onset advantage depended critically on whether the responses were made in a context of response suppression. We conclude that the onset advantage is mediated not by sensory factors such as visible persistence, but by response programming factors that are strongly affected by contextual events.     

Decision latencies for phonological and semantic information in object identification

Several on-line studies in the literature have been cited in support of a two-stage model of name-retrieval in which semantic processing precedes and mediates access to phonology. Because of inconsistencies in prior studies an off-line experiment was designed to provide converging evidence on this issue. An experiment is reported in which young and elderly adults were required to give speeded judgments of whether a pictured object matched a named category, a named physical attribute, or a rhyming cue. Latencies for the young adults were fastest for category judgments and slowest for rhyming judgments. For the elderly adults physical attributes and rhyming judgments were equivalent. Results are discussed in terms of "lemma" theory in object naming.