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To assess the relation between the probability of individual interresponse times (IRTs) and the magnitude of contingent reinforcing brain stimulation, a schedule was used which restricts reinforcer presentation to responses spaced by a minimum temporal interval. The probability of IRTs falling in the region of the criterion interval increased monotonically with current amplitude across a wide range of scheduled intervals. These results contrast with IRT performance under continuous and variable-interval schedules, where a wide variety of idiosyncratic functional relations has been found. Use of the IRT schedule thus helps to clarify the function of brain stimulation magnitude in free-operant responding, providing an alternative datum to potentially confounded average response rate measures. The scheduled spacing of responses also allows an analysis in terms of the discrimination of temporal intervals. As brain stimulation magnitude increased, IRT distributions showed more discrete peaking near the criterion interval, and thus finer temporal discrimination. IRTs following a reinforced response were paced more accurately than IRTs following a nonreinforced response, pointing to the discriminative function of reinforcer presentation (proportional to brain stimulation magnitude) in temporal discrimination procedures. A signal detection analysis indicated that an animal's bias toward emission of subcriterion IRTs increases along with temporal discrimination accuracy in proportion to brain stimulation magnitude.

Current conceptions about the nature of educational exceptionality are examined. These very different conceptions have formed the basis for three types of remedial approaches to the same manifest educational handicaps. In some instances these recommended approaches are either theoretically or practically incompatible. Criteria for the evaluation of the effects of remediation are seen to vary in terms of the generality or specificity of the outcome and the temporal interval between the remedial effort and the desired effect.

6 Os estimated stereoscopic depth as a function of the duration of the half-images, the temporal interval between presentations of the half-images, and the magnitude and direction of the disparity carried by the target. The results indicate that all Os reported qualitative and quantitative depth estimates for identical experimental conditions and that the magnitude of the depth effect varied directly with disparity.

Summary Eight mediation paradigms were evaluated by comparing test-trial responses following mediation presentation with test-trial responses following control presentation. CCCs of low association value were used as the learning materials in one experiment, and CVCs of 100% association value in a second experiment. Response-equivalence paradigms and one stimulus-equivalence paradigm yielded mediated facilitation with both types of learning materials. When CVCs were used, two chaining models also showed mediated facilitation. Forward associations and minimal temporal separation of the A and C items, as they probably existed implicitly and explicitly during the second acquisition stage, led to mediated facilitation only when CCCs were the learning materials. With more meaningful materials these two variables were considerably less potent. Two additional experiments were performed to replicate the results of Paradigm II, which yielded negative results in Exp. I and positive results in Exp. II. The data corroborated the earlier conclusions that mediated facilitation was more likely to be observed with learning materials of higher meaningfulness. Selections of C as the test-trial alternative which made the “best pair” with the stimulus were reliably above an a priori chance level for all paradigms. In addition, the eight paradigms showed significant differences in this factor (response availability) which seemed to be predictable from the temporal interval separating presentation of C in the acquisition stages and its appearance of a test-trial alternative.

Thresholds for the auditory discrimination of mean interpulse interval were determined as a function of the number of intervals and of temporal variability, or “jitter.” Interval discrimination at low pulse frequencies is relatively independent of the number of pulses and of jitter. By contrast, interval discrimination at high pulse frequencies is extremely dependent upon the number of pulses and the level of jitter. The precision of interval discrimination achieved suggests that pulse interval discrimination for high pulse frequencies is carried out by a spectral analysis, rather than by a temporal analysis, of auditory information.

Three logic functions are introduced, two of which are functions in two-variables, named sequential logic product and sequential logic sum, while the third, depending on only one variable, is termed sequential logic negation. An algebraic theory is developed for logic processes where time plays an essential part; the connection is pointed out between sequential logic and the algebraic theory of multiple-state finite automata. This connection finally leads to new methods of analysis, as well as of synthesis, for finite automata operating according to given sequential equations; these methods offer certain advantages over standard procedures. Results obtained are likely to be useful in the theory of digital computers.

The accuracy of discrimination of small changes in sound level was examined as a function of the magnitude, temporal, and dimensional aspects of the variation between two reference testing conditions. Precision of sound level discrimination declined as: the magnitude of the sound level difference between the two reference conditions increased and as the frequency of occurrence of shifting between the two reference conditions increased. Of lesser importance was the temporal interval between successive discriminations, variation in the audio‐frequency of the reference signals, and the predictability of the to‐be‐presented testing conditions. The results are considered in terms of a preliminary analysis of psychological dimensions in auditory discrimination.

The purposes of the present experiment were to provide information on rate of information processing in visual perception and to determine the degree to which the “sequential blanking” effect found by Mayzner. Tresselt, and Cohen (1966) constituted a limitation on rapid sequential input rates. A 10-channel tachisto scope was employed that permitted controlled durations of each of the 10 channels and the 9 inter channel intervals. The S’s task was one of visual search or detection in which he searched for a target letter among noise letters. A temporal interval forced-choice procedure was used. In addition to varying the rate at which letters were sequentially presented, various irregular temporal spatial orders of presentation of the letter sequences were employed and the direction and orientation of the display in the visual field was varied as was also the spacing between adjacent stimuli. No evidence of “sequential blanking” was found either in terms of the detection criterion or in the Ss’ phenomenal reports. Detection performance was as good at a rate of 2 1/2 msec per letter as it was at a rate of 30 msec per letter.

The relaxation characteristics of solutions of the Soviet-made polymethine dye No. 3955 in various solvents were determined. A suitable selection of the solvent made it possible to vary the temporal correlation interval from 45 to 11 psec and the reduction in the temporal interval increased the spectral correlation interval. Under certain conditions the width and structure of the emission spectrum in one axial period remained constant throughout a giant pulse.

Two experiments studied the effect of a reaction time response (RT) on visual form recognition threshold when the temporal interval separating the RT stimulus and the recognition stimulus was short. In Experiment 1 an initial RT response to an auditory signal did not impair the subsequent forced-choice visual form recognition threshold. Interstimulus intervals (ISI) of 0, 50, 100, 150, and 200 msec were used; S was always aware of the ISI under test. In Experiment 2 a visual stimulus was used to elicit the R T response; this shift to an intramodal stimulus did not alter the recognition threshold. These data were interpreted as supporting the hypothesis that two stimulus events can be processed simultaneously even when the temporal interval between them is short.

It is hypothesized that the probability of detecting a signal in a vigilance task depends upon its temporal location with respect to the preceding series of signals. Probability of detection should be at a maximum when the signal occurs after a temporal interval which is equivalent to the mean of the intervals between the preceding signals detected. The experimental results support this hypothesis.

Let A be some temporally indefinite statement. Then we can in general form another statement asserting that A holds (obtains) at the particular time t. Correspondingly, we introduce the statement-forming operation R, the operation of temporal realization. We shall write “R t (A)” to be read “A is realized at the time t”, which is to represent the explicit statement that A holds (obtains) specifically at the time t. Thus if t 1 is 3 p. m. Greenwich time on January 1, 2000, and p 1 is the (temporally indefinite) statement, “All men are (i. e., are now) playing chess”, then “R t (p 1)” is the statement “It is the case at 3 p. m. Greenwich time on January 1, 2000 that all men are (now) playing chess”, or equivalently simply, “All men are playing chess at 3 p. m. Greenwich time on January 1, 2000”. Again, if p 2 is the statement “All men will play chess tomorrow”, then “R t 1 (p 2)” is the statement “It is the case at 3 p. m. Greenwich time on January 1, 2000 that all men will be playing chess tomorrow”.

All the tense logics we have dealt with so far have been two-valued in a fairly definite sense, that is, they are all based on the classical propositional calculus. In terms of model theory, this is reflected in the way we evaluate the propositional connectives ∼, ⊃, v, ≡ in tense structures — the truth-values of complex formulas built with these connectives are calculated at each moment in a tense-structure according to the classical, two-valued prescription.

WHAT are the primary tests (in the sense described on p. 71) for temporal interval? To say that an event occurred n units of time after another event is to say that if a true clock recorded a certain reading at the place of the first event at the instant of its occurrence, then a true clock previously synchronised with the former would record a reading greater by n units at the place of the second event at the instant of its occurrence. Statements about temporal interval are statements about what would have been or would be the behaviour of true clocks.

Summary.-32 Ss, 16 in an experimental group and 16 in a control group, gave two verbal estimates of each of 8 standard intervals ranging from 300 to 1000 rnsec. in 100-msec. steps. The experimental group reproduced each standard 12 times before verbally estimating it, while the control group had no prior experience with the standards to be verbally estimated. The mean reliability of the verbal estimates of the experimental group was significantly higher (p < .02) than that of the control group. This finding was held to account for the high reliability coefficients reported for the method of verbal estimation by a number of comparative studies employing several methods on the same group of Ss. The result suggests that serial position of the measuring methods may spuriously inflate the reliability coefficients of the method of verbal estimation when that method is used subsequent to the method of reproduction. The principal mechods employed in the study of time estimation are the methods of reproduction, production and verbal estimation. In the meihod of reproduction (MR) E operatively demonscrates a standard interval, which S actempcs to reproduce physically. S's judgment is called a reproduccion. In the method of production (MP) S physically produces a temporal interval as an estimate of a standard which has been verbally stated buc not demonstrated by E. S's judgment is called a production. In the method of verbal estimation (ME) S verbally estimates a standard which has been operatively demonstrated by E. S's judgment is called a verbal estimate (Bindra & Waksburg, 1956). Differences in reliability among the principal methods have been the topic

Publisher Summary This chapter highlights developmental changes in memory and the acquisition of language. It highlights the relationship between short-term or immediate memory and language acquisition, in addition to issues involving longer-term memory. The term immediate or short-term memory has had several uses. For some, it has had a purely temporal definition, referring to any remembering that occurs within some specific short temporal interval of the original experience. It represents the first stage of processing between perception and subsequent higher order processing, and is largely oriented toward preserving transient features of the environment long enough so that relatively slow mental processes have a chance to operate upon environmental input. Much attention has been given to the potential role of developmental changes in immediate-memory span for language acquisition. There are obvious ways in which the ability to produce or to understand sentences depends upon the ability to remember temporarily certain constituents while processing others. The other obvious parameter that involves immediate memory is structural complexity. The differences in strategies for language acquisition may be related to characteristics of both short- and long-term memory organizations.

In a series of cases the laws of logic can take the form of assertions not about the properties of terms and sentences but about objects to which the terms and sentences relate (i.e., the form of ontological assertions). For example, the assertions “From the sentence ∼ (XY) follows the sentence ∼ Xv ∼ Y” can take the form “If the situation ∼ (XY) happens, then the situation ∼ Xv ∼ Y happens”.

Simple combinational logic systems of the type described in chapter 3 are not adequate if we wish to design logic systems which are required to initiate or respond to a sequence of events or if the response to an input must depend in some way on the inputs which have occurred previous to the current input. In cases such as this, the use of some form of memory element is necessary. Systems described in this section will make use of various types of bistable memory element.

A schedule of reinforcement was used in which reinforcement was delivered to only those responses with associated interresponse times (IRTs) falling within a prescribed temporal interval. For each of three different groups of rats, a different value was used for the lower bound of the reinforcement interval. In all cases, the width of the interval was equal to the lower bound. This schedule was put into effect following regular reinforcement of all IRTs. The probability of short IRTs, and the mode and interquartile range of the IRT distributions were computed as a function of the number of sessions exposure to the IRT reinforcement schedule.

The contingent negative variation (CNV), a cerebral DC shift in man, has been linked in the literature to the psychological concept “expectancy.” In a study of the relationship between developing accuracy of interval estimation and CNV amplitude, absolute error of interval estimation was found to decrease exponentially while CNV amplitude could best be described by a quadratic (inverted-U) function. It was concluded that the relationship between CNV amplitude and “expectancy” is not one-to-one, and that these data, with those from a number of other investigations, support the hypothesis that the various portions of the brain act differentially and at various times during learning.

The present study investigated the relationship between a temporal interval’s perceived length and the amount of stimulus and stimulus change within that interval. In three separate tests, completely filled intervals were found to be significantly overestimated by the Ss in comparison with empty intervals. In contrast to this, interrupted or divided intervals were underestimated.

The effect of broadband (125–8000 cps) background noise on the dichotic temporal interval between two clicks required to report them as two was investigated. As noise level is increased up to 30 dB SL (re monaural threshold), the dichotic temporal interval required for a report of two (Δt) is decreased. For noise levels from 30–50 dB SL, the dichotic temporal interval for a report of two increases. The extent of this reversal seems related to mask level, although the effect of noise in decreasing Δt is not related to signal‐to‐noise ratio. With narrow‐band low‐pass noise, the Δt required for a report of two continues to decrease as noise level increases up to 50 dB SL, whereas a narrow‐band high‐pass noise shows the same reversal as does the broadband noise. Increasing the click level without adding any background noise decreases the Δt required for a report of two. Additional experiments that elucidate these findings are presented.