CS Duration Research Articles

The role of the CS and its relationship to the CR in avoidance conditioning

Two studies are reported which are concerned with the role of the CS and its relationship to the CR in the standard avoidance learning situation. Study I demonstrates that the decrement associated with a trace CS is greatly reduced in one-way avoidance as compared with two-way. The suggestion is made that the differences in CS effects is attributable to differences in task complexity. Study 2 varied CS duration and the CS-CR termination contingency. Rapid acquisition of the avoidance response was obtained only when the CS remained on for the entire CS-US interval unless terminated by a response. The results were discussed with respect to the theoretical aspects of maintenance and emergence of the avoidance response.

Heart-rate response during aversive conditioning.

36 rats were used to determine the effects of: (a) footshock before specific training, (b) CS duration (6 vs 60 sec.), and (c) form of aversive conditioning (CER vs CAR) on heart rate both during the presentation of the CS and between presentations. All three tested variables were effective in modifying the heart-rate response to the CS while only CS duration altered heart rates between CS presentations.

The role of the cs and avoidance period duration in discriminated avoidance conditioning.

In an experiment investigating the effect of CS duration on discriminated bar-press conditioning, subjects were assigned to one warning period duration (1.5, 5.0 or 15.0 sec.) on the first day of avoidance training, and to one of the three durations on the second day of training. On each day avoidance behaviour was greatly influenced by the duration of the CS (warning) period, but the duration on day I had no effect on the second day's avoidance performance. Groups receiving no CS during training, although provided an avoidance contingency, showed little conditioning, but produced highly significant amounts of intertrial responding. In a second experiment, subjects receiving CS on day I were shifted to no CS on day II. Avoidance performance on day II was not significantly different from the day II performance of subjects in Experiment I having two training sessions with the CS present or absent on both days.

Quantitative adjustment in magnitude of the hemidecorticate learning deficit by CS duration manipulation

The instrumental learning deficit of the functionally hemidecorticated rat is shown to be subject to systematic alterations in magnitude by changes in the CS duration, with the eventual approximation of normal and hemidecorticate learning. The data is considered as further evidence on the quantitative nature of the hemidecorticate learning impairment, and suggests two forms of cortical stimulus encoding mechanisms. The one relates to the pick-up and association of the critical stimulus elements with the reinforcement contingencies and is described as an incoding function; the other concerns the sampling and subsequent gating-out of non-critical stimulus elements and is described as an outcoding function. Two forms of redundancy of cortical networks are discussed as the basis for the quantitative deviations from the normal which the hemidecorticate manifests on both encoding processes.

Effects of CS Presence and Duration on Suppression of Positively Reinforced Responding in the Rat

The variable of CS duration preceding unavoidable electric shock was investigated with rats as Ss. For the 6 durations examined from 3.75 to 60 sec, suppression of positively reinforced bar-pressing in the presence of CS was complete. While response suppression between CS presentations was initially severe, it gradually dissipated as the experiment progressed. A separate group of rats received unavoidable shocks not preceded by a stimulus. General suppression of responding throughout the session was more severe than with the cued-shock groups, and recovery was slower. The difference in the effects of uncued shock and cued shock was confirmed when stimulus presentation conditions were reversed between the subject groups.

The interaction effects of CS intensity and CS-UCS interval in human eyelid conditioning.

The joint effects of low CS intensity and CS‐UCS interval (ISI) on human eyelid conditioning performance were investigated. Five paid subjects were run in 36 test sessions, in a within‐subjects design in which six CS intensities were varied orthogonally to three CS durations. Conditioning performance was measured by the percentage of conditioned responses corrected for spontaneous blinks, and by d'CR, a measure based upon a signal detection analysis. Both measures yielded similar results which showed a continued shift toward longer optimum ISIs with decreases in CS intensity, i.e. the optimum ISI shifted from 0·5 sec. to 2·0 sec. A partial explanation of this finding was based on a consideration of neurophysiological and reaction‐time studies.

Similarity of cardiac CR forms in the rhesus monkey during several experimental procedures.

Cardiac rates of rhesus monkeys were observed in a variety of different conditioning procedures, each of which involved a visual stimulus (CS) followed by an electric shock (US). With a 30-sec CS, cardiac rate accelerated rapidly after CS onset, reached a maximum in the middle of CS, and decelerated thereafter, with a terminal CS rate often at the level of, or below, pre-CS levels. A similar biphasic cardiac rate response in CS was also observed under subsequent exposure to intermittent pairings of CS and US, avoidance of US, response-produced termination of US, and when CS-US pairings were superimposed upon an avoidance baseline, even when CS duration was varied from 12 to 60 seconds. The unusual regularity of cardiac rate responses in several different procedures may result from one or more of these factors: (a) characteristics of the rhesus monkey, (b) initial exposure to Pavlovian conditioning, or (c) the uniformity of measurement of cardiac rate employed in this study.

Interstimulus interval and CS duration effects in differential conditioning.

Interstimulus interval and CS duration effects in differential conditioning.

Effect of change in duration of CS upon extinction of an avoidance CR.

Effect of change in duration of CS upon extinction of an avoidance CR.

Response-contingent CS termination as a factor in avoidance conditioning

Four groups of five dogs each underwent acquisition and extinction of a conditioned leg flexion avoidance response. The CS-US interval was 4.0 sec for all groups, but CS duration was either.5, 1.0, 2.0 or 4.0 sec for each group. Responses occurring prior to CS offset terminated the CS. There was no evidence that CS termination facilitated acquisition of the avoidance response. There was slight evidence that the 4.0 sec group took longer to extinguish the avoidance response.

A portable solid-state stimulus programmer

This paper describes a miniature solid-state timing device particularly useful for presenting repetitive signal sequences in classical conditioning experiments. The device uses transistors, silicon-controlled rectifiers, and four-layer diodes, and is powered by 20-hour rechargeable nickel-cadmium batteries. Visual monitoring is provided for the unelapsed ITI and battery charge. Ranges are; ITI, 15 sec. to 5 min., ISI, 0–50 secs., CS duration, 0.5 to 30 sec., US duration, 0.5 to 30 sec. The CS and US durations are adjustable and the onset of the latter may be at any time after the CS onset. Cycling is continuous and automatic; the outputs are in the form of relay closures.

Fear conditioning as a function of CS duration during acquisition and suppression tests

The effects of CS duration during fear conditioning were assessed using a secondary punishing technique. CS duration was not found to be an influencing variable. Inadequacies of the secondary punishment procedure utilized by Mowrer and his colleagues were noted and it was suggested that more ex­ tensive comparisons be made of the CER technique with an improved secondary punishing procedure. In investigating critical parameters of fear condi­ tioning, Mowrer & Aiken (1954) and Mowrer & Solomon (1954) used the technique of conditioned suppression via a secondary punisher. In this procedure a rat is trained to make an operantbarpressona CRF schedule for food. Concurrently, but in a different environment, a CS (light) is presented immediately prior to shock, i.e., a fear conditioning procedure. After several training sessions in each situation, the CS is used as a secondary punisher by being made contingent on the bar press. The fear arousing capacity of the light is inferred from the amount of response suppression which occurs during the secondary punishment phase. This procedure differs from the more widely used conditioned emotion response (CER) procedure (Estes & Skinner, 1941) in that in the CER technique the presen­ tation of feared stimulus is not contingent upon S's re­ sponse. It is programmed independently of the food rein­ forcement schedule. The amount of response suppres­ sion which occurs while the conditioned stimulus is pres­ ent is taken as an index of its fear arousing capacity. Kimble (1961, p. 270) states that ... the function relating strength of fear to the time separating neutral and noxious stimuli resembles thatfor other classically conditioned responses. However, this generalization has a very limited empirical support being based pri­ marily on studies of avoidance conditioning rather than fear conditioning per se. Those experiments which have studied fear conditioning using a CER procedure have typically found optimal durations to be considerably longer than the .5 sec. which Kimble implies. Libby (1951) found that response suppression increased with increases in CS duration up to 7 sec., but observed no increases between 7 sec. and 30 sec., i.e., the function was a negatively accelerated increasing one which was asymptotic around 7 sec. Using pigeons, Lyon (1963) found that as the CS duration increased from 100 to 300 sec., the amount of suppression increased. Simi­ larly, Stein et al (1958) and Carlton & Didamo (1960) found relative CS duration to be an important parameter of conditioned suppression. The purpose of the present experiment was to de­ termine if similar results would be obtained if the CS

MODIFICATION OF VERBAL INTERACTIONS IN TRIAD GROUPS: PRELIMINARY REPORT.

Studies of group behavior within an operant conditioning fmmework have been relstively sparse. The studies that have been performed (e.g., Cieutat, 1959; Oakes, Drogc, & August, 1960) have demonstrated that verbal conditioning principles can be employed ro manipulate simultaneously the duration of talking by several Ss. The purpose of the present study was to investigate the conditions under which the verbal interactions in triads of Ss could be modified. The assumption was made that the verbal behavior of a given S is regulated at least to some extent by the verbal behavior of other Ss in the group. A series of 5 reinforcement programs was investigated to determine to what extent manipulation of the verbal behavior of 2 Ss in a triad group (Non-critical Ss or NCSs) would have on the third S (Critical S or CS). 90 Ss (in 30 triads) were placed in individual isolation booths and given psychiatric case histories to discuss. The reinforcement was points which registered on their counters contingent upon duration of talking and the person to whom they talked. The points were exchangeable for gifts at [he end of the experimental session. The best reinforcement procedure involved direct manipulation of CS's behavior. Reinforcement programs involving simultaneous manipulation of the NCSs in addition to the CS failed to produce changes in the CS's duration of talking. The reinforcement programs were also unsuccessful in producing increases in the amount of talking by the NCSs to the CS although there were substantial decrements in the interactions between NCSs. Because of the large variabiliry among triads of Ss, results are tentative. The study susgesred that the effectiveness of any reinforcement program may be dependent upon a number of variables, such as the operant level of talking by CS, the operant duration of talking directed by the NCSs to CS, the sex of the members composing the triads, and possibly the length and/or number of conditioning sessions. These are variables which have to be taken into account in subsequent research.

CS duration and task Instructions as determiners of extinction of the conditioned eyelid response

Eyelid responses were conditioned while a simultaneous sound intensity judgment was performed. All Ss received eyelid or sound instructions, oriented toward either the eyelid or sound task, and either a 550 or 2550 msec, acquisition CS. Performance in acquisition and extinction decreased with sound task instructions, but showed no significant effect of duration of CS in acquisition or extinction.

Frequency of reinforcement as a parameter of conditioned suppression.

Two pigeons were trained on a multiple VI-1; VI-4 min schedule for food reinforcement until a stable differential rate of response was established. Each component of the multiple schedule was in effect for 10 min and was separated from the other by 1 min time out. An Estes-Skinner conditioned suppression procedure was superimposed on each component of the schedule. The relative magnitude of the suppression behavior was measured during its acquisition and extinction, and at CS durations of 100, 200, and 300 sec. The initial magnitude of the suppression behavior was less severe on the VI-1 baseline than on the VI-4, and it extinguished more rapidly on the VI-1. As the relative duration of the CS was increased, the suppression behavior became less severe on both baselines, but the initial differential magnitude in the suppression remained intact.

Delayed Avoidance Conditioning: Warning Stimulus (CS) Duration

A first step in the study of this problem was an examination of temporal parameters. In this study, CS durations longer than 5 sec. were employed in order to explore the possibility that prolongation of the CS might facilitate acquisition in the Skinnex box. Although previous results obtained with the shuttle-box suggested that short CS durations are more favorable for avoidance acquisition (Solomon & Brush, 1956; Woodward, 1954), performance in the Skinner and shuttle-box is sufficiently cl~ss~m~lar to merit questioning the generality of the results obtained with the latrer. Moreover, Meyer, el al. (1960) reported that the use of a CS of less than 5 sec. failed to facilitate acquisition in the Skinner box. This finding suggested that, if CS duration has any relevance to acquisition, the effects must be related to a range of durations of longer than 5 sec. Two experiments are reported. In Exp. 1, rats were trained with varied CS durations. During testing the CS was constant for all animals in order to assess differences resulting from the previous training without biasing latency requirements of the avoidance response. In Exp. 2, the longest CS duration was decreased gradually in order to mitigate the disruptive effects of an abrupt change in latency requirements.

Interhemispheric transfer of tactile conditioned responses in corpus callosum-sectioned cats.

ArticlesINTERHEMISPHERIC TRANSFER OF TACTILE CONDITIONED RESPONSES IN CORPUS CALLOSUM-SECTIONED CATST. H. Meikle JR., J. A. Sechzer, and Eliot StellarT. H. Meikle JR., J. A. Sechzer, and Eliot StellarPublished Online:01 Jul 1962https://doi.org/10.1152/jn.1962.25.4.530MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited BySomatosensory receptive fields of fibres in the rostral corpus callosum of the catBrain Research, Vol. 441, No. 1-2Cortical evoked potential changes during classical conditioning of morphine dependence in ratsExperimental Neurology, Vol. 81, No. 3Cerebral hemispheres and selective attentionActa Psychologica, Vol. 46, No. 1Visual processing in the split-brain cat: Analysis of the single-hemisphere deficitExperimental Neurology, Vol. 49, No. 1Visual processing in the split-brain cat: One versus two hemispheresExperimental Neurology, Vol. 33, No. 2Interaction between the hemispheres in unimanual somesthetic learningExperimental Neurology, Vol. 30, No. 1Task difficulty and lateralization of learning in the functional split-brain ratPhysiology & Behavior, Vol. 5, No. 4Quantitative differences in performance on abstract discriminations using one or both hemispheresExperimental Neurology, Vol. 26, No. 1Quantitative adjustment in magnitude of the hemidecorticate learning deficit by CS duration manipulationPhysiology & Behavior, Vol. 4, No. 5The effects of forebrain commissurotomies on the rate of learning a dark-light discrimination by catsBrain Research, Vol. 14, No. 3The role of the cortex in acquisition and retention of a classically conditioned passive avoidance responsePhysiology & Behavior, Vol. 4, No. 4Interocular transfer in the hooded ratPhysiology & Behavior, Vol. 4, No. 4The hemidecorticate learning deficit: Evidence for a quantitative impairmentPhysiology & Behavior, Vol. 4, No. 1Electrophysiological studies of learning in split brain catsElectroencephalography and Clinical Neurophysiology, Vol. 23, No. 6Localisation of a memory trace in the intact ratPhysiology & Behavior, Vol. 1, No. 2 More from this issue > Volume 25Issue 4July 1962Pages 530-543 https://doi.org/10.1152/jn.1962.25.4.530PubMed14472200History Published online 1 July 1962 Published in print 1 July 1962 Metrics

CERの測定

Brady and others measured the effects of convulsive shock on behavior using CER (Conditioned Emotional Response). But the nature of the CER has not thoroughly been examined, although there were many experiments cencerning the problem since it was first reported by Estes and Skinner in 1941. The present study was designed to investigate the nature of CER.About 120 albino rats were trained in the Skinner box. After the accomplishment of the bar-pressing learning, they were conditioned the fear by the combination of buzzer (CS) and the electric shock (UCS) in a grid box. The effects of the following two variables were examined. The first was the duration of the CS (buzzer) which was changed from 15 to 180sec. The second was the number of shock which was changed from 2 to 8. Sixteen groups, consisted of 7 rats each, were used owing to the combination of the two variables.After the conditioning of the fear response, Ss were given extinction trials in the Skinner box presenting only the CS. Results were given in the inflexion ratio of the number of the bar-pressing. A modified formula was used in computing the IR. The IR may represent the direct effect of CS and IR′ the post effect.The main results were as follows:1) IR and IR′ increase as the function of the duration of the buzzer. They increase as the duration increases and reach the maximum at 30sec., and then decrease as the duration increases.2) IR reaches the maximum when the number of shock is four, and IR′ reaches the maximum when the number is two. Both IR and IR′ decrease when the number of the shock increases.3) There may be the optimal points of the duration and number of CS for the effects of CER. Insufficiency as well as excess of the duration and the number of CS the decrease of the effects may result from.