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D A Siddle

Publications and source records attributed to D A Siddle.

At least 37 records · Page 2Linked to original sources
PubMed1991

Orienting, habituation, and resource allocation: an associative analysis.

This paper addresses the question of the most appropriate theoretical account of the phenomena of orienting and habituation. Several lines of evidence are reviewed. First, it is argued that the effects of stimulus omission require a comparator theory in which it is asserted that responses to iterated events result from a comparison between predicted and actual stimulus input. Second, the data from studies in which paired stimulus events are employed seem, at least at first sight, to be best explained in terms of a comparator theory in which a key role is ascribed to associative processes. Third, secondary task probe reaction time data indicate that events that elicit orienting also command processing resources, and that habituation involves changes in the manner in which events are processed. Finally, recent data on the effects of intermodality change indicate that electrodermal responses are larger on the change trial than on the first habituation training trial; these results seem problematical for noncomparator theories. However, other data on the context-specificity of habituation and on the effects of stimulus miscuing cast doubt on the usefulness of an associative analysis as a general account of habituation phenomena. Nevertheless, the weight of evidence seems to indicate that an adequate theory of human habituation must include a comparison process and must acknowledge that orienting and habituation involve a re-allocation of attentional resources.

Arousal↗
PubMed1990

Stimulus miscuing and dishabituation: electrodermal activity and resource allocation.

The present research investigated the effects of miscuing a shock stimulus on dishabituation of the skin conductance response and on the allocation of processing resources. In both experiments, a control group received 21 S1-S2 pairings intermixed with 23 S3-alone presentations. For the experimental group, S2 was miscued on trials 11 and 22 by its presentation following S3. In Experiment 1 (N = 48), S2 was a shock that was either "clearly discernible" or "uncomfortable but not painful". The results indicated increased electrodermal responding when S2 was miscued by S3 and subsequent dishabituation when S2 again followed S1 on the next trial. Miscuing produced dishabituation with both a high- and low-shock S2. A continuous measure of S2 expectancy revealed that expectancy of S2 in the presence of S1 declined as a result of miscuing. Experiment 2 (N = 36) employed reaction time to a white noise probe stimulus as the dependent variable. The critical data came from probes presented 300 ms following S2 onset on the S1-S2 trial immediately following miscuing. They indicated that miscuing produced slowed reaction time to probes presented during S2 on the following S1-S2 trial. Thus, the miscuing of S2 by S3 appears to result in an increase in processing resources devoted to S2, even when S2 is presented in its usual position following S1. The results are discussed in terms of current theories of associative learning.

Adult↗
PubMed1989

The effect of context change on long-term habituation of the skin conductance response to signal and non-signal stimuli in humans.

The present experiment investigated the role of contextual cues in long-term habituation of the skin conductance response. Subjects (N = 65) first underwent a habituation training session in which they received 15 presentations each of a signal and a non-signal stimulus. Signal value was induced by a motor response requirement to stimulus offset. In a test session one week later, the effect of context change on long-term habituation was examined by presenting the habituation stimuli in either the same or in a changed context. Although both short-term (within-session) and long-term (between-session) habituation were demonstrated, the results provided no evidence for context-dependency of long-term habituation. Moreover, there was no evidence of differential long-term habituation as a function of signal value in either the same- or changed-context conditions. The data are discussed in terms of Wagner's (1978) priming theory, and the methodological implications of the experimental manipulations of context change and signal value induction are explored.

Adolescent↗
PubMed1989

Effects of fear-relevance on electrodermal safety signal learning.

Safety signal learning in human subjects was investigated using a conditioned inhibition procedure with a shock unconditioned stimulus (US). The conditioned stimulus (CS) duration, and thus the CS-US interval, varied randomly from 20 to 50 s. Conditioning was assessed by change in tonic skin conductance level (SCL). Experiment 1 demonstrated reliable learning of a conditioned inhibition (A+/AB-) discrimination, in terms of both self-reported shock expectancy and change in SCL, in subjects who were able to report correctly the stimulus contingency. There was, however, no evidence of transfer of inhibitory properties from the safety signal B to a separately trained excitor. Experiment 2 compared two groups in which the safety signal was either fear-relevant (picture of snake or spider) or fear-irrelevant (flower or mushroom). As in previous research, there was no effect of fear-relevance on safety-signal learning. The results are discussed in terms of preparedness theory and excitatory conditioning with fear-relevant stimuli.

Cognition↗
PubMed1989

Restoration of stimulus associability, electrodermal activity, and processing resource allocation.

Four experiments investigated Pearce and Hall's (1980) proposal that a decrease in the predictive accuracy of a stimulus restores stimulus associability as reflected by increased orienting and controlled processing. The experiments examined the effects of miscuing or omission on stimulus associability as assessed by stimulus expectancy, electrodermal responding, and reaction time (RT) to a secondary task probe stimulus. In Experiments 1 and 2, a control group received 21 S1-S2 trials intermixed with 21 S3-alone presentations. For the experimental group, S2 was miscued by its presentation following S3 on two trials. In Experiments 1 and 2a, S1, S2, and S3 were moderate intensity stimuli, but in Experiment 2b, shock was used as S2. Experiment 1 (N = 24) demonstrated that, although there was uncertainty about whether S2 would follow S3 when S3 was re-presented following miscuing, skin conductance responses to S3 did not differ according to whether or not it had miscued the previous S2. Experiment 2a (N = 48) and Experiment 2b (N = 24) demonstrated that RT to white noise probe stimuli presented during the S3-alone presentation immediately following miscuing did not differ between experimental (miscuing) and control (no miscuing) groups. In Experiments 3 and 4, a control group received 23 S1-S2 trials. For the experimental group, S2 was omitted on two trials. In Experiment 3 (N = 24) S1 and S2 were of moderate intensity, whereas in Experiment 4 (N = 24) shock was used as S2. Reaction time to white noise probes presented during S1 did not differ according to whether or not the previous S2 was omitted. Thus, despite evidence of a reduction in the predictive accuracy of both S3 following miscuing and S1 following omission, there was no evidence of restoration of the associability of either S1 or S3. The results are discussed in terms of current theories of associative learning.

Adolescent↗
PubMed1989

Effects of conditioned stimulus fear-relevance and preexposure on expectancy and electrodermal measures of human Pavlovian conditioning.

The present research investigated the effects of fear-relevance of the conditioned stimulus (CS) and CS preexposure on human electrodermal conditioning and on a continuous measure of expectancy of the unconditioned stimulus (US). Both experiments employed 20 preexposure, 8 acquisition, and 8 extinction trials in a differential Pavlovian conditioning paradigm with shock as the US. In Experiment 1 (N = 48), electrodermal conditioning was retarded by CS preexposure, but was not influenced by fear-relevance of the CS. Expectancy of the US was retarded by preexposure only in the fear-relevant condition. In Experiment 2 (N = 48), the CS/US contingencies was embedded in a visual masking task. Preexposure retarded both electrodermal conditioning and US expectancy. Neither measure was influenced by fear-relevance of the CS. However, fewer subjects in the preexposure condition learned the CS/US relationship and those who did, did so on later trial than those in the no-preexposure condition. Thus, the results indicated clear retardation of conditioning as a result of preexposure, but no reliable effect of fear-relevance.

Adolescent↗
PubMed1989

Stimulus miscuing, electrodermal activity, and the allocation of processing resources.

The present research investigated the effects of stimulus miscuing on electrodermal responding, dishabituation, stimulus expectancy, and the allocation of processing resources as assessed by reaction time to a secondary task probe stimulus. In both experiments, a control group received 33 S1-S2 pairings intermixed with 33 S3-alone presentations. For the experimental group, S2 was miscued by its presentation following S3 on 4 trials. Experiment 1 (N = 24) demonstrated reliable electrodermal responding when S2 was miscued by S3 and subsequent dishabituation when S2 was re-presented following S1 on the next trial. A continuous measure of S2 expectancy revealed that S2 was not expected to follow S3 on miscuing trials. On re-presentation trials, S2 was not expected to follow S1. Experiment 2 (N = 24) employed probe reaction time as the dependent variable. White noise probe stimuli of 500-ms duration were presented 300 ms following the onset of S2 on miscued trials and on re-presentation trials. Reaction time to probes presented during miscued presentations of S2 was slower in the experimental group than in the control group. Reaction time on S2 re-presentation trials was also slower in the experimental group than in the control group. The results are interpreted to indicate that both the miscuing of S2 by S3 and its re-presentation following S1 on the next trial command processing resources. The results are discussed in terms of current theories of associative learning.

Adolescent↗
PubMed1988

Avoidance learning, Pavlovian conditioning, and the development of phobias.

This paper examines the role of Pavlovian conditioning in the acquisition, maintenance and elimination of human phobias. Because many conceptualizations of human fears and phobias are based on data from studies of avoidance learning in animals, we first review theories of avoidance. Our conclusion is that none of the extant theories provides an adequate account of avoidance learning, and we propose a model of avoidance that involves Pavlovian, but not instrumental learning. We then analyse critically arguments that Pavlovian conditioning plays only a small role in the aetiology of fears. Finally, the paper examines the implications of a conditioning model of avoidance for the study of human fears and phobias.

Animals↗
PubMed1987

The effects of signal value on short- and long-term habituation.

The present study examined the effects of signal value on short- and long-term habituation of the skin conductance response. Subjects (N = 48) attended the laboratory at the same time of day on two consecutive days. Day 1 comprised pretraining and training phases, and day 2 comprised the test phase. In the pretraining phase subjects received one presentation each of a tone and a vibration stimulus. In the training and test phases subjects received a randomly ordered sequence of 15 tones and 15 vibrations. All stimuli were of 4 s duration. During the training phase Groups E1 and E2 performed a motor response to the offset of one of the stimuli whereas a third group (Group C) did not. Neither Group E1 nor Group C performed the motor task during the pretraining and test phases. Both between- and within-group analyses of the training phase data indicated that responses were larger and habituation was slower to signal stimuli. Analyses of the test phase data and comparison of pretraining and test phase data indicated that long-term habituation occurred only to nonsignal stimuli. The results are discussed in terms of Wagner's (1978) theory of habituation.

Adolescent↗
PubMed1985

Effects of conditioned stimulus preexposure on human electrodermal conditioning.

Two experiments investigated the effects of conditioned stimulus (CS) preexposure on Pavlovian differential conditioning and extinction of the skin conductance response. In both experiments, half the subjects were exposed to 20 presentations each of the CS+ and CS-, and the other half were exposed to control stimuli. CS duration was 8 sec. The unconditioned stimulus in Experiment 1 (N = 48) was a 1000 Hz tone of 80 dB which signalled a reaction time requirement, and in Experiment 2 (N = 48), it was a 1 sec burst of white noise at 105 dB. The results of Experiment 1 indicated that no-preexposure groups displayed more CS+/CS- differentiation than preexposure groups during acquisition and more resistance to extinction, at least for the first interval anticipatory response. In addition, the results of Experiment 2 indicated that no-preexposure groups displayed more differentiation than preexposure groups in terms of the second interval anticipatory response. These data constitute a demonstration of the latent inhibition effect with human subjects, and imply that there is an intrinsic relationship between the orienting response and the conditioning process.

Acoustic Stimulation↗
PubMed1985

The effects of anticipated information on skin conductance and cardiac activity.

This experiment examined electrodermal and cardiac activity within a two-stimulus anticipation paradigm. A warning stimulus informed subjects (N = 24) whether an imperative stimulus to follow would contain two or four letters (low or high information conditions) and whether this stimulus would be presented for 60 or 75 msec (short or long duration). The subject's task was to identify as many of the letters in the imperative stimulus as possible. Although the amount of information conveyed by the warning stimulus was identical throughout the experiment (2 bits), skin conductance responses during the warning stimulus-imperative stimulus interval were larger prior to the high information imperative stimulus than prior to the low. Cardiac activity was not affected by the experimental manipulations. The implications of these findings for theories of the orienting response are discussed, particularly with reference to the view that orienting reflects an activation of the information processing system.

Adolescent↗