The organization of classical and instrumental conditional reactions

This paper makes a theoretical analysis of the process of formation of neural associations among sensory changes produced in the brain by environmental stimuli; it also analyzes the origin of classical and instrumental conditional reactions. It has been proposed that sensory traces of stimuli “intermingle,” forming patterns of associations in “polymodal” structures of the brain. The sensory traces of stronger stimulus dominate over the sensory traces of weaker stimulus in the pattern. An activation of a pattern of associations by any of the stimuli involved releases a reaction typical of the stronger stimulus (called a reinforcing or unconditional stimulus) before the latter is presented. That type of reaction, called classical conditional reaction, is dispensable; it is one of post-reinforcement origin and therefore, is not represented in the pattern of associations. When a physiological act, such as a definite movement (e.g., pressing a bar) must precede the obtaining of the reinforcing stimulus, this physiological act, called an instrumental conditional reaction, is also evoked each time the pattern of associations has been activated. The instrumental conditional reaction is indispensable and, because of its pre-reinforcement origin, belongs, through its sensory feedback, to the pattern of associations.     

Stimulus–classification and stimulus–action associations: Effects of repetition learning and durability

It has been shown that acquired stimulus–response bindings result from at least two types of associations from the stimulus to the task (stimulus–task or stimulus–classification; S–C) and from the stimulus to the motor response (stimulus–response or stimulus–action; S–A). These types of associations have been shown to independently affect behaviour. This finding suggests that they are processed in different pathways or different parts of a pathway at the neural level. Here we test a hypothesis that such associations may be differentially affected by repetition learning and that such effects may be detected by measuring their durability against overwriting. We show that both S–C and S–A associations are in fact strengthened when learning is boosted by increasing repetitions of the primes. However, the results further suggest that associations between stimuli and actions have less durable effects on behaviour and that the durability of S–C and S–A associations is independent of repetition learning. This is an important finding for the understanding of the underlying mechanisms of associative learning and particularly raises the question of which processes may affect flexibility of learning.     

The effects of brief and extended stimulus availability on preference

The effects of stimulus availability on preference were evaluated using two conditions of a modified preference assessment. Different preference hierarchies were found in 15-s access conditions than in 15-min access conditions. Subsequent comparisons of a short-availability high-preference stimulus and a long-availability high-preference stimulus verified differential preferences for stimuli based on duration of availability.     

Antecedent effects of observing peer play

The relative reinforcing value of toys was assessed in the absence of, and immediately following, participant observation of a peer manipulating one of the toys. Preference assessments were used to identify preference hierarchies. Reinforcer assessments were conducted with a high-preference item, a low-preference item, and a control. Each participant allocated responding toward the high-preference item during baseline. When reinforcer assessment sessions were preceded by a peer observation period, 3 of the 4 participants shifted allocation to the toy manipulated by the peer. The 4th participant shifted allocation only when the high-preference stimulus was replaced with a medium-preference stimulus. These data suggest that, among preschoolers, response allocation is influenced by observations of peers playing.     

Across-task priming revisited: response and task conflicts disentangled using ex-Gaussian distribution analysis

The differential effects of task and response conflict in priming paradigms where associations are strengthened between a stimulus, a task, and a response have been demonstrated in recent years with neuroimaging methods. However, such effects are not easily disentangled with only measurements of behavior, such as reaction times (RTs). Here, we report the application of ex-Gaussian distribution analysis on task-switching RT data and show that conflict related to stimulus-response associations retrieved after a switch of tasks is reflected in the Gaussian component. By contrast, conflict related to the retrieval of stimulus-task associations is reflected in the exponential component. Our data confirm that the retrieval of stimulus-task and -response associations affects behavior differently. Ex-Gaussian distribution analysis is a useful tool for pulling apart these different levels of associative priming that are not distinguishable in analyses of RT means.     

A comparison of methods for assessing preference for social interactions

Researchers have evaluated a variety of methods for assessing preference for social interactions, and generally have found that such assessments accurately identify differentially reinforcing, preferred interactions. However, few researchers have compared methods for assessing preference for social interactions, and none have done so with participants across different skill levels. The current study compared the stability and validity of hierarchies produced by social interaction preference assessments (SIPA) and picture-based multiple stimulus without replacement preference assessments (MSWO) with 8 individuals diagnosed with autism spectrum disorder (ASD). The MSWO most often produced valid hierarchies for participants who could match, identify, and tact pictures of social interactions and that the SIPA most often produced valid hierarchies for participants who could not identify or tact pictures of social interactions. A vocal paired-stimulus preference assessment (PSPA) was also conducted with a subset of participants who communicated vocally, and it produced valid hierarchies. Considerations and recommendations for selecting a method of assessing preference for social interactions are discussed.     

A replication of the response‐restriction preference assessment

We replicated the response‐restriction (RR) preference assessment and compared results in terms of preference hierarchies to those from free‐operant and multiple stimulus without replacement (MSWO) formats with six children with autism spectrum disorders (ASDs). We also assessed social validity of each format with teachers and clinicians who work with children with ASDs. Complete hierarchies were produced in four of 18 assessments and with MSWO and RR formats only. Results of the social validity assessment varied across raters, with each preference assessment format receiving the highest rating from at least one rater. Results are discussed in terms of practical recommendations and relative to the preference assessment literature as a whole.     

Web‐based stimulus preference assessment and reinforcer assessment for videos

This study replicated and extended the use of a web‐based multiple‐stimulus‐without‐replacement preference assessment (Curiel, Curiel, Li, Deochand, & Poling, 2018) by adding a web‐based single‐operant reinforcer assessment. Five adults diagnosed with autism spectrum disorder participated in this study. The web‐based program identified preference hierarchies for 4 of the 5 participants, and the single‐operant reinforcer assessment confirmed that the highly preferred videos functioned as reinforcers. Advantages of computer‐based stimulus preference and reinforcer assessments are discussed.     

Probabilistic multidimensional scaling: Complete and incomplete data

Simple procedures are described for obtaining maximum likelihood estimates of the location and uncertainty parameters of the Hefner model. This model is a probabilistic, multidimensional scaling model, which assigns a multivariate normal distribution to each stimulus point. It is shown that for such a model, standard nonmetric and metric algorithms are not appropriate. A procedure is also described for constructing incomplete data sets, by taking into consideration the degree of familiarity the subject has for each stimulus. Maximum likelihood estimates are developed both for complete and incomplete data sets. This research was supported by National Science Grant No. SOC76-20517. The first author would especially like to express his gratitude to the Netherlands Institute for Advanced Study for its very substantial help with this research.     

Stimulus control of free-operant avoidance: The contribution of response rate and incentive relations between multiple-schedule components

The associations formed in the components of a multiple schedule can be classified as (1) stimulus-response (S-R) associations and (2) stimulus-reinforcer (S-S^R) associations. The present experiments sought to determine the individual contribution of these S-R and S-S^R associations to stimulus control by manipulating them independently. Responses postponed shocks by 25 sec in the presence of a tone alone and a light alone in all experiments. The contingencies programmed in the absence of both tone and light established a reference for the S-R and S-S^R associations in tone and in light. All four possible combinations of signalling response increase or decrease together with incentive increase or decrease were studied. Although the influence of the contingencies operating in the absence of tone and light was difficult to detect from response rates in tone or light, presenting tone and light together revealed clear effects. Response rates in tone and light together relative to those in either alone depended upon the contingency operating in the absence of tone and light. Stimulus-response and stimulus-reinforcer associations appeared to counteract each other when in opposition and combine together to enhance each other when in agreement. This suggested that the associations of a stimulus to response and to incentive combine algebraically in determining stimulus control. An algebraic analysis in terms of the S-R and S-S^R associations conditioned to the stimulus elements comprising the training and test stimuli accounted for the observed patterns of data.     

SHOULD MARITAL RELATIONS BE NON‐HIERARCHICAL?

The paper explores an egalitarian norm widely accepted today, which I call the Marital Non‐Hierarchy Standard. According to this standard, marital relationships should be non‐hierarchical; neither partner may be more dominant than the other. The Marital Non‐Hierarchy Standard is exceptional: in almost all associations, including many financial, professional, educational and recreational ones, in almost all spheres of life, some hierarchies, within certain limits, are widely believed to be morally legitimate. I argue that in marital relations, too, some hierarchies should be accepted as morally legitimate. It might be argued that marital relations should be loving, and love requires that lovers will have the same degree of power. However, contemporary analyses of love show that love is consistent with (some) hierarchies. It might also be argued that justice requires that lovers will have equal power. However, theories of distributive justice such as Rawls's, Sen's, Dworkin's, and almost all others allow some marital hierarchies. Thus, both the love requirement and the justice requirement allow some hierarchical marital relationships and conflict with the Marital Non‐Hierarchy Standard. Until other justifications for this standard are presented, it is unclear why it should be endorsed.     

Contextual potentiation of acquired behavior after devaluing direct context-US associations

In two experiments, water-deprived rats were exposed to tone-footshock pairings in a particular conditioning context. In Experiment 1, the training parameters were selected on the basis of parametric pilot data so as not to produce direct associations between the conditioning context and footshock. Despite independent evidence of no appreciable direct association between the conditioning context and footshock, animals tested in the conditioning context exhibited more lick suppression to the tone than other animals tested with the tone outside of the conditioning context. Thus, the conditioning context potentiated suppression to the tone in the absence of appreciable fear of the conditioning context. In Experiment 2, training parameters were used that permitted the formation of direct associations between the conditioning context and footshock; however, for half the animals, these associations to the context were then extinguished. With the tone absent, a comparison of extinguished animals tested either in the conditioning context or outside the conditioning context detected no differences in suppression, demonstrating the effectiveness of the extinction manipulation. However, other animals also subjected to extinction of direct context-footshock associations displayed greater suppression to the tone within the conditioning context than comparable animals tested outside the context. Collectively the data indicate that the superior retention-test performance seen within the training context can arise both from the commonly assumed direct associations between the training context and the unconditioned stimulus and from the potentiation by the training context of the associations between the nominal conditioned stimulus and unconditioned stimulus.     

Effects of stimulus–stimulus short-term memory associations in a Simon-like task

The Simon effect refers to faster responding when an irrelevant stimulus location corresponds with the response to a relevant stimulus attribute than when it does not. We investigated whether a memory-based Simon-like effect would occur when the irrelevant spatial attribute was associated with the stimulus during a prior task. In a first task, an association between colour and location was formed by requiring participants to count the occurrences of two colour stimuli, each of which was always presented in a left or right location. In a second task, the colour stimuli were presented centrally and mapped to left and right keypresses, with the mapping being inconsistent or consistent with the prior colour-location associations. A Simon-like effect was evident at the start of the second task, with performance being better when the established colour–position associations were consistent with the colour–response mapping than when they were not. This result indicates that stimulus–stimulus short-term memory associations formed during the first task transferred to the second task. For the remainder of the second task, the data showed a more conservative speed–accuracy criterion for the inconsistent condition than for the consistent condition, though a processing efficiency measure suggested that the prior stimulus–stimulus short-term associations may also continue to directly influence performance. Results suggest that simple declarative knowledge, as represented by stimulus–stimulus STM links, exerts less persistent transfer effects than procedural knowledge as provided by stimulus–response STM links.     

Element pretraining influences the content of appetitive serial compound conditioning in rats

Four experiments with rat subjects in a Pavlovian appetitive conditioning procedure examined the effects of prior pairings of S2 with the unconditioned stimulus (US) on the nature of the associations formed in S1----S2----US serial compound conditioning. Experiments 1 and 2 showed that prior training of S2 prevented the acquisition of stimulus-stimulus (S-S) associations between S1 and stimulus features of S2, but enhanced the acquisition of stimulus-response (S-R) associations between S1 and the emotional conditioned response (CR) evoked by S2. Experiments 3 and 4 showed that the effects of S2 pretraining were not due to S2 training itself, but rather to its endowing S2 with the ability to evoke a strong CR during the early stages of serial compound conditioning. In Experiment 3, suppression of the CR to a pretrained S2 during serial compound conditioning permitted the establishment of S-S associations. In Experiment 4, the induction of a CR in the presence of an untrained S2 during serial compound conditioning prevented the acquisition of S-S associations. Implications of these data for our understanding of compound conditioning are discussed.     

Transfer of orthogonal stimulus–response mappings to an orthogonal Simon task

When up–down stimulus locations are mapped to left–right keypresses, an overall advantage for the up–right/down–left mapping is often obtained that varies as a function of response eccentricity. This orthogonal stimulus–response compatibility (SRC) effect also occurs when stimulus location is irrelevant, a phenomenon called the orthogonal Simon effect, and has been attributed to correspondence of stimulus and response code polarities. The Simon effect for horizontal stimulus–response (S–R) arrangements has been shown to be affected by short-term S–R associations established through the mapping used for a prior SRC task in which stimulus location was relevant. We examined whether such associations also transfer between orthogonal SRC and Simon tasks and whether correspondence of code polarities continues to contribute to performance in the Simon task. In Experiment 1, the orthogonal Simon effect was larger after practising with an up–right/down–left mapping of visual stimuli to responses than with the alternative mapping, for which the orthogonal Simon effect tended to reverse. Experiment 2 showed similar results when practice was with high (up) and low (down) pitch tones, though the influence of practice mapping was not as large as that in Experiment 1, implying that the short-term S–R associations acquired in practice are at least in part not modality specific. In Experiment 3, response eccentricity and practice mapping were shown to have separate influences on the orthogonal Simon effect, as expected if both code polarity and acquired S–R associations contribute to performance.     

Ontogenetic differences in the association of gustatory and tactile cues with lithium chloride and footshock

Using a double dissociation design with 15% sucrose solution and exposure to a heat lamp (34 degrees C) as CSs and 0.3 M LiCl and 1-mA footshock as USs, the present study found 15-day-old rats to show selective associations similar to those found in adults. Five-day-old pups, however, expressed similar sucrose aversions when this solution was paired with either LiCl or footshock, whereas they expressed heat aversions after heat-LiCl but not heat-shock pairings. Results are discussed with respect to previous data on selective associations in pups, current theories on selective associations, and ontogenetic differences in stimulus selection.     

Executive control in the Simon effect: an electromyographic and distributional analysis

Manual responses to lateralized stimuli are faster for spatially congruent stimulus-response associations than for incongruent associations, even if the stimulus location is irrelevant. This effect, however, decreases as reaction time increases. Recent data suggest that such a decrease reflects online, within-trial executive control. The present study was aimed at testing this hypothesis by analyzing the electromyographic activity of muscles involved in response execution. We focused on the particular trials in which an activation of the muscle involved to the incorrect response preceded the execution of the correct response. A sequential effect analysis, along with an analysis of the reaction time distributions, revealed that after such dual-activation trials, executive control was reinforced. In addition, a distribution analysis of the reaction times associated with such trials compared to the trials without incorrect activation, revealed online, within-trial changes in executive control. Arguments against a late motor locus of the effect of the irrelevant stimulus location are also provided. These results are discussed in terms of current models of cognitive control.     

Evaluating and reporting data quality in eye movement research

In order to judge the degree of confidence one should have in the results of an experiment using eye movement records as data, it is necessary to have information about the quality of the eye movement data themselves. Suggestions are made for ways of assessing and reporting this information. The paper deals with three areas: characteristics of the eye movement signal, algorithms used in reducing the data, and accuracy of the eye position data. It is suggested that all studies involving eye movement data should report such information. Appendices include linear interpolation algorithms for mapping from the eye movement signal to stimulus space and a way of obtaining an index of accuracy for each data point.     

The influence of cue-task association and location on switch cost and alternating-switch cost.

Task-switching performance is strongly influenced by whether the imperative stimulus uniquely specifies which task to perform: Switch cost is substantial with bivalent stimuli but is greatly reduced with univalent stimuli, suggesting that available contextual information influences processing in task-switching situations. The present study examined whether task-relevant information provided by task cues influences the magnitude of switch cost in a parallel manner. Cues presented 500 ms prior to a trivalent stimulus indicated which of three tasks to perform. These cues either had a preexisting association with the to-be-performed task (verbal cues), or a recently learned association with the task (spatial and shape cues). The results paralleled the effects of stimulus bivalence: substantial switch cost with recently learned cue-task associations and greatly reduced switch cost with preexisting cue-task associations. This suggests that both stimulus-based and cue-based information can activate the relevant task set, possibly providing external support to endogenous control processes. Alternating-switch cost, a greater cost for switching back to a recently abandoned task, was also observed with both preexisting and recently learned cue-task associations, but only when all tasks were presented in a consistent spatial location. When spatial location was used to cue the to-be-performed tasks, no alternating-switch cost was observed, suggesting that different processes may be involved when tasks are uniquely located in space. Specification of the nature of these processes may prove to be complex, as post-hoc inspection of the data suggested that for the spatial cue condition, the alternating-switch cost may oscillate between cost and benefit, depending on the relevant task.