Stimulus Contiguity Research Articles

Action–Sound Coincidences Suppress Evoked Responses of the Human Auditory Cortex in EEG and MEG

The N1 auditory ERP and its magnetic counterpart (N1[m]) are suppressed when elicited by self-induced sounds. Because the N1(m) is a correlate of auditory event detection, this N1 suppression effect is generally interpreted as a reflection of the workings of an internal forward model: The forward model captures the contingency (causal relationship) between the action and the sound, and this is used to cancel the predictable sensory reafference when the action is initiated. In this study, we demonstrated in three experiments using a novel coincidence paradigm that actual contingency between actions and sounds is not a necessary condition for N1 suppression. Participants performed time interval production tasks: They pressed a key to set the boundaries of time intervals. Concurrently, but independently of keypresses, a sequence of pure tones with random onset-to-onset intervals was presented. Tones coinciding with keypresses elicited suppressed N1(m) and P2(m), suggesting that action-stimulus contiguity (temporal proximity) is sufficient to suppress sensory processing related to the detection of auditory events.

Implicit memory for novel associations between pictures: effects of stimulus unitization and aging.

Studies of implicit memory for novel associations have focused primarily on verbal materials and have highlighted the contribution of conceptually unitized representations to such priming. Using pictorial stimuli in a perceptual identification task, we examined whether new association priming can occur at a purely perceptual level. By manipulating the spatial contiguity of stimuli, we also evaluated whether such priming requires the creation of perceptually unitized representations. Finally, we examined the status of such priming in aging. In Experiment 1, we found that spatial contiguity of stimuli is not necessary for novel pictorial association priming to emerge, although such contiguity does enhance the magnitude of associative priming. In Experiment 2, we found that new association priming is age invariant, regardless of spatial contiguity. In Experiment 3, we provide additional evidence that pictorial association priming is perceptually based. These findings expand the scope and delineate the conditions of novel association priming and inform theories about the nature of implicit memory for new associations.

Stimulus competition in pre/post and online ratings in an evaluative learning design

Evaluative learning is said to differ from Pavlovian associative learning in that it reflects stimulus contiguity, not contingency. Thus, evaluative learning should not be subject to stimulus competition, a proposal tested in the current experiments. Participants were presented in elemental and compound training phases with pictures of shapes as CSs. Each shape/pair of shapes was followed by a picture of a happy or an angry face as the US. In Experiments 1 and 2, evaluative ratings were collected before and after the experiment, and, in Experiment 3, participants provided evaluations online. Stimulus competition was evident in all experiments confirming that evaluative learning is sensitive to stimulus contingencies.

Segmentation and the pairing hypothesis.

The effect of stimulus contiguity and response contingency on responding in chain schedules was examined in two experiments. In Experiment 1, four pigeons were trained on two simple three-link chain schedules that alternated within sessions. Initial links were correlated with a variable-interval 30s schedule, and middle and terminal links were correlated with interdependent variable-interval 30s variable-interval 30s schedules. The combined duration of the interdependent schedules summed to 60s. The two chains differed with respect to signaling of the schedule components: a two-stimulus chain had one stimulus paired with the initial link and one stimulus paired with both the middle and the terminal link, while a three-stimulus chain had a different stimulus paired with the each of the three links. The results showed that the two-stimulus chain maintained lower initial-link responding than the three-stimulus chain. In Experiment 2, four pigeons were exposed to three separate conditions, the two- and three-stimulus chains of Experiment 1 and a three-stimulus chain that had a 3s delay to terminal-link entry from the middle-link response that produced it. The two-stimulus chain maintained lower initial-link responding than the three-stimulus chain, as in Experiment 1, and a similar initial-link responding was maintained by the two-stimulus chain and the three-stimulus chain with the delay contingency. The results demonstrate that a stimulus noncontiguous with food can maintain responding that is sometimes greater than a stimulus contiguous with food, depending on the response contingency for terminal-link entry. The results are contrary to the pairing hypothesis of conditioned reinforcement.

Neuronal Synchrony: A Versatile Code for the Definition of Relations?

Neuronal Synchrony: A Versatile Code for the Definition of Relations?

Emergent Conditional Discriminations in Children and Adults: Stimulus Equivalence Derived from Simple Discriminations

This study examines whether trained and derived simple discriminations lead to conditional relations between discriminative stimuli of the same and opposite (S+, S−) functions. After being trained on an arbitrary X-Y task (X1-Y1, X2-Y2) and on two simple discrimination tasks (A1+/A2− and B1+/B2−), children (Experiment 1) and adults (Experiment 2) were tested on the formation of novel simple discriminations (A3+/A2− and B3+/B2−) and conditional stimulus relations between all directly and indirectly paired A stimuli and between all directly and indirectly paired B stimuli (A1-A2-A3, B1-B2-B3). Subjects who formed these sets also received A2-X1 and B1-X2 training followed by a series of probes to assess the formation of two five-member stimulus equivalence classes (A1-A2-A3-X1-Y1, B1-B2-B3-X2-Y2). A modest majority of the children matched the directly paired stimuli (A2-A1, B2-B1 and A1-A2, B1-B2; A2-A3, B2-B3 and A3-A2, B3-B2) with one another while only a few of them also matched the indirectly paired stimuli with one another (A1-A3, B1-B3 and A3-A1, B3-B1). Those who did also related all the A and B stimuli with the designated X and Y stimuli. By contrast, all normal adults matched all paired and conditionally linked stimuli with one another. Present findings and those of related studies on stimulus equivalence are discussed from a stimulus contiguity perspective.

Reversal of Emergent Simple Discrimination in Children: A Component Analysis

The conditions for reversing emergent simple discriminations in children through stimulus contiguity were examined. Experiment 1 involved two phases, Baseline and Reversal. Baseline started with a color discrimination training, red omega (S +) vs yellow omega (S−). This task was followed by three tests (no programmed consequences), one with red omega (S+) vs yellow omega (S−), one with red lambda vs yellow pi, and one with black lambda vs black pi. Reversal involved the same sequence but with reversed contingencies for the training task, yellow omega (S+) vs red omega (S−). The test results in Baseline and in Reversal were positive for most children. Experiments 2-4 examined aspects of the protocol that may have contributed to the successful reversal of the form discrimination. These additional data indicate that for most children, the reversed emergent discrimination performance was a function of color-form contiguity in Baseline and in Reversal rather than of the contingency reversal.

Stability of Emergent Simple Discriminations in Young Children

This study compared two procedures for establishing and reversing stimulus control transfer across simple discriminations in children. One procedure, stimulus contiguity, started with training of a color discrimination task, red omega (S +) vs yellow omega (S −). This task was followed by two nonreinforced tests, one with colored forms, red lambda and yellow pi; and one with black forms, lambda and pi. Children who selected the lambda on both tests received a reversal task. Two types of reversals were used: one in which the contingencies for red and yellow were reversed (Reversal 1) and one in which the forms were presented with opposite colors, yellow lambda and red pi (Reversal 2). The second procedure, match-to-sample training, was the same except that the colors and forms were conditionally related to one another. The results showed that (a) both procedures were more effective in establishing than in reversing stimulus control transfer, (b) Stimulus Contiguity was more effective than match-to-sample training, and (c) both procedures were more effective in changing the form discrimination with Reversal 1 than with Reversal 2.

NMDA receptor antagonist MK-801 blocks learning of conditioned stimulus-unconditioned stimulus contiguity but not fear of conditioned stimulus in goldfish (Carassius auratus L.).

NMDA receptor antagonist MK-801 blocks learning of conditioned stimulus-unconditioned stimulus contiguity but not fear of conditioned stimulus in goldfish (Carassius auratus L.).

NMDA receptor antagonist MK-801 blocks learning of conditioned stimulus-unconditioned stimulus contiguity but not fear of conditioned stimulus in goldfish (Carassius auratus L.).

The blockade of learning of Pavlovian fear conditioning by the N-methyl-D-aspartic acid (NMDA)-receptor antagonist MK-801 was examined in 166 goldfish. In previously untrained fish, MK-801 blocked learning of a light-off or a tone conditioned stimulus (CS) paired with an electrical shock unconditioned stimulus (US). Pretraining on the light-off CS did not affect the rate of learning of the tone CS but protected the tone learning from disruption by MK-801. Switching from the light-off to the tone CS changed the identity of the CS but not its temporal contiguity with the US. Pretraining consisting of pseudoconditioning of the light-off CS did not protect subsequent tone learning from blockade by MK-801. Thus, the NMDA receptor functions are necessary for learning related to the temporal contiguity of the CS and US but not to the identity of the CS as a cue to the occurrence of the fearful effects of the US.

Periodic Reinforcement and Second-Order Schedules

In two experiments, rats were trained initially on a recycling conjunctive schedule in which a food pellet was delivered after 30 s provided at least one response had occurred; otherwise the next cycle began immediately. This produced low rate responding characterized by either a pause-respond-pause pattern or else a pause-respond pattern. The schedule then was changed so that half of the intervals ended with the presentation of a brief stimulus instead of food. Patterning after food was little affected, whereas patterning after the brief stimulus varied across rats. Generally, a short pause after the brief stimulus was followed by an initial increase in responding that led to either a fairly constant rate, or else to a decrease in rate throughout the interval. In later conditions, when the incidence of response-food and response- stimulus contiguity were manipulated separately, only the former increased response rate; this was so even when the brief stimulus was paired with food in some conditions. Rate increases were accompanied by changes in patterning across all intervals. These results do not support a simple conditioned reinforcement interpretation of the control acquired by a brief stimulus on a second-order schedule with fixed-interval components. Rather, they suggest that a number of interrelated variables combine to maintain responding. These variables include response-reinforcer contiguity, the temporal location of the response dependency, and the contingency between the brief stimulus and the reinforcer.

Some Current Issues in Children's Selective Attention

A large part of the history of learning theory of the last 25 years consists of devising ways to deal with stimulus selectivity. Earlier theories that assumed contiguity of stimulus and response to be a sufficient condition for formation of an association were found wanting. This paper has described some of the ways theorists have attacked the problem. These theoretical solutions were of two general types--two-stage theories with stimulus selection preceding association and theories that altered associative processing. Both types of theories successfully handled selective phenomena, and there is no clear basis at present for preferring one or the other. A question generally neglected by early attention theorists concerns the nature of a stimulus. How is the stimulus complex available to a subject divided into cues or elements that can be selectively responded to? Related questions are whether the experimenter's perception of stimulus elements correspond to the subject's view, and whether elements are perceived the same by all subjects. The answer to the last two questions appears to be in the negative. Recent research relative to these questions with children, adults, and nonhuman organisms is reviewed.

Three main factors in rat shuttle behavior: their pharmacology and sequential entry in operation during a two-way avoidance session.

The effects of eserine (0.1 mg/kg), nicotine (0.2 mg/kg), atropine (2 mg/kg), methylatropine (5 mg/kg), clonidine (0.2 mg/kg), phenoxybenzamine (10 mg/kg), apomorphine (0.5 mg/kg), and haloperidol (0.5 mg/kg), i.p., on shuttle responses to a buzzer (SBs) were studied on four different behavioral paradigms in rats: (a) D test: 50 buzzers and 25 shocks at random intervals and in random order; (b) DP test: 50 buzzers paired on all trials with shocks irrespective of the performance of SBs (Pavlovian conditioning); (c) DC test: 50 buzzers followed at a randomly variable interval by shocks unless there was an SB; (d) DPC test: 50 buzzer-shock trials omitting shocks every time there was an SB (two-way avoidance). Shock-induced drive was assumed to equally pervade all four situations; stimulus contiguity ('pairing') was present only in the DP and DPC tests; and the avoidance 'contingency' was present only in the DC and DPC paradigms. An analysis of the distribution of SB performance in control animals over the 10 successive blocks of 5 buzzers of each session revealed that the response level was similar for all tests during the first 2 blocks; that of the DC and DPC groups increased above the level of the other two from the third block on; and from the fifth block on, SB performance was higher in the DPC than in the DC group and in the DP over the D group. At all blocks the sum of SBs obtained in the D test, plus DP-D, plus DC-D, gave a value quite close to that experimentally determined in the DPC group. This was interpreted as showing that during the first 10 buzzers drive was the main (or the only) factor influencing SB performance in all groups; after the third block of 5 buzzers 'contingency' became a factor on its own; and 'pairing' assumed some control over SB behavior only from the fifth block on. Eserine depressed SBs in the D test, starting from the first block of buzzers; its effect was antagonized by atropine and by methylatropine. Clonidine depressed responding in the DP and DPC paradigms, and its effect was blocked by phenoxybenzamine. Nicotine, eserine, and apomorphine increased, and atropine, methylatropine, and haloperidol decreased SB performance in both the DC and the DPC test; the effect of the two former substances could be antagonized by any of the two anticholinergic agents, and haloperidol antagonized that of apomorphine. The possibilities are discussed of: (a) a peripheral cholinergic mechanism which inhibits drive; (b) a similar mechanism which favors operation of the 'contingency' factor; (c) a dopaminergic mechanism in 'contingency'; (d) a central adrenergic inhibitory mechanism in 'pairing'.

Cognitive conditioning: imagined stimulus contiguity and the third interval conditional GSR.

The effect of repeatedly imagining paired or unpaired CSs and USs on the frequency of post-CS responses during real extinction was studied. Four groups of 10 Ss first received a model tone and shock. For two of the groups the stimuli were paired (delayed conditioning paradigm). For the others the stimuli were arranged in a long trace paradigm. The Ss then received a series of commands requiring them to imagine receiving paired CSs and USs, or to imagine the events singly. Then 10 real tone extinction trials were given. The groups which received delayed conditioning model stimuli were more responsive than trace groups, and groups which had imagined paired stimuli were more responsive than their unpaired controls. Cognitively oriented explanations of these findings were discussed.

The role of instrumental responding and contiguity of stimuli in the development of infant secondary reinforcement

Ten-month-old infants received contingent pairings of a tone (T+) and food reinforcer. Groups S r and S D received the food on an FI 23-sec schedule for target touching, the former group receiving T+ immediately after the response and 1.5 sec prior to food and the latter group receiving T+ at the end of the intertrial interval. Group SC received food reinforcers 1.5 sec after T+ with no response required. A second tone (T n) was heard by all groups once during each intertrial interval, at randomly determined points. All groups subsequently were given a spatial discrimination task, receiving T+ for one alternative and T n for the other. Group S r gave significantly more responses for T+ than for T n, but neither of the other two groups produced a superiority for T+. Thus, both contiguity with a primary reinforcer and the presence of an operant during training appear to be necessary for a neutral signal to acquire the ability to enhance responding.

Effects of Spatial Separation of Stimulus, Response, and Reward in Discrimination Learning by Children

RAMEY, CRAIG T., and GOULET, L. R. Effects of Spatial Separation of Stimulus, Response, and Reward in Discrimination Learning by Children. CmnLD DEVELOPMENT, 1971, 42, 978-982. 90 male schoolchildren of 3 age levels were tested on a 2-choice visual discrimination task that varied in spatial contiguity of stimulus, response, and reward. Separation of stimulus from response and reward was found to retard learning.

EFFECTS OF SPATIAL SEPARATION OF STIMULUS, RESPONSE, AND REWARD IN DISCRIMINATION LEARNING BY CHILDREN

RAMEY, CRAIG T., and GOULET, L. R. Effects of Spatial Separation of Stimulus, Response, and Reward in Discrimination Learning by Children. CmnLD DEVELOPMENT, 1971, 42, 978-982. 90 male schoolchildren of 3 age levels were tested on a 2-choice visual discrimination task that varied in spatial contiguity of stimulus, response, and reward. Separation of stimulus from response and reward was found to retard learning.

Contiguity and imbeddedness factors in the discriminative learning of retardates

Previous studies show that imbedding a reward within a stimulus and spatial contiguity of stimulus and reward are factors which facilitate 2-choice discriminations. In the present study, the separate and joint effects of the two factors on discriminative learning are studied in a factorial design. Reward imbeddedness was manipulated by presenting the reward within a hollow box and was compared with a nonimbeddedness situation in which the reward was placed in a foodwell under the box. Contiguity was arranged by presenting copies of the discriminative stimulus in the goal situation (either the box or the foodwell) and was compared with noncontiguity in which the reward alone was presented in the goal situation Contiguity facilitates learning but imbeddedness does not reliably improve learning. The two factors interact significantly and in a direction which is consistent with previous findings.

An olfactory discrimination apparatus: Modification of the basic “wind-tunnel” design

A modified “wind-tunnel” olfactory discrimination apparatus for rats is described and evaluated. The apparatus, constructed of Teflon, features a precise stimulus delivery system that is easy to build, and a high contiguity of stimulus, manipulandum and reward. Discrimination between odorants to a high performance criterion is obtained within 3–6 h of shaping and training.

Elicitation and reinforcement as separate stimulus functions.

3 groups of 16 rats were trained to discriminate between two distinctive end boxes. Two groups discriminated between goal boxes while the third group discriminated between start boxes. These stimuli were then tested as secondary reinforcers in a T-maze. The groups trained to discriminate between goal boxes showed a statistically significant preference for the goal box previously associated with reinforcement. The third group showed no preference. It was concluded that discrimination training is not sufficient to establish an Sr without contiguity of stimulus and reward.