Influence of visual stimulus mode on transfer of acquired spatial associations.

Associations between corresponding stimulus–response locations are often characterized as overlearned, producing automatic activation. However, 84 practice trials with an incompatible mapping eliminate the benefit for spatial correspondence in a transfer Simon task, where stimulus location is irrelevant. The authors examined whether transfer occurs for combinations of physical-location, arrow-direction, and location-word modes in the practice and transfer sessions. With 84 practice trials, the Simon effect was reduced for locations and arrows, and there was complete transfer across these modes; location words showed little transfer within or between modes. These results suggest that the acquired short-term associations were based on visual-spatial stimulus codes distinct from semantic-spatial codes activated by the words. With 600 practice trials, words showed transfer to word and arrow but not location Simon tasks, suggesting that arrows share semantic-spatial codes with words. Reaction-time distribution functions for the Simon effect showed distinct shapes for each stimulus mode, with little impact of the practiced mapping on the shapes. Thus, the contribution of the short-term location associations seems to be separate from that of the long-term associations responsible for the Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validity and boundary conditions of automatic response activation in the Simon task.

Three experiments were conducted to determine whether spatial stimulus-response compatibility effects are caused by automatic response activation by stimulus properties or by interference between codes during translation of stimulus into response coordinates. The main evidence against activation has been that in a Simon task with hands crossed, responses are faster at the response location ipsilateral to the stimulus though manipulated by the hand contralateral to the stimulus. The experiments were conducted with hands in standard and in crossed positions and electroencephalogram measures showed coactivation of the motor cortex induced by stimulus position primarily during standard hand positions with visual stimuli. Only in this condition did the Simon effect decay with longer response times. The visual Simon effect appeared to be due to specific mechanisms of visuomotor information transmission that are not responsible for the effects obtained with crossed hands or auditory stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of an irrelevant location dimension as a function of the relevant stimulus dimension.

The effect of an irrelevant location dimension on choice reactions to the relevant stimulus dimension was examined. Exp 1 used variations of the spatial Stroop task and the Simon task that differed in whether the relevant dimension (location name or color) was similar to the irrelevant location dimension. Congruity of the stimulus dimensions and stimulus–response (S–R) mapping had additive effects in the Simon task but overadditive effects in the Stroop task. Exps 2–4 showed that each pattern could be obtained for both tasks, suggesting that dimensional similarity is not crucial; overadditivity occurred only when stimulus identification was prolonged. Results can be interpreted in terms of the relative timing of activation for the relevant and irrelevant information, if it is assumed that the activation function for irrelevant location varies across different S–R mappings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Response-Discrimination Account of the Simon Effect.

Simon effects might partly reflect stimulus-triggered response activation. According to the response-discrimination hypothesis, however, stimulus-triggered response activation shows up in Simon effects only when stimulus locations match the top-down selected spatial codes used to discriminate between alternative responses. Five experiments support this hypothesis. In Experiment 1, spatial codes of each response differed by horizontal and vertical axis position, yet one axis discriminated between alternative responses, whereas the other did not. Simon effects resulted for targets on discriminating axes only. In Experiment 2, both spatial axes discriminated between responses, and targets on both axes produced Simon effects. In Experiment 3, Simon effects resulted for a spatial choice-reaction task but not for a go/no-go task. Even in the go/no-go task, a Simon effect was restored when a two-choice reaction task preceded the go/no-go task (Experiment 4) or when participants initiated trials with responses spatially discriminated from the go response (Experiment 5). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mixing location-relevant and location-irrelevant choice-reaction tasks: Influences of location mapping on the Simon effect.

The Simon effect refers to the finding that reaction times are faster when stimulus and response locations correspond than when they do not in tasks where stimulus location is defined as irrelevant. The authors examined the Simon effect for situations in which location-irrelevant trials were intermixed with trials for which stimulus location was relevant. Compatible mapping of the location-relevant trials enhanced the Simon effect relative to an unmixed condition, whereas incompatible mapping reversed the Simon effect. The reversal with incompatible mapping remained evident when task uncertainty was removed by use of a precue and was larger than the reversed effect produced by making incongruent trials more frequent than congruent trials. This result suggests that both attentional biases and task-defined associations contribute to the reversal of the Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial coding and central patterns: Is there something special about the eyes?

In this study we investigated in a Simon-like task whether task-irrelevant spatial information, delivered by centrally presented patterns, interfered with response selection in the same way as laterally presented stimuli. Second, we asked whether such interference was equal for different kinds of stimuli. Participants were required to respond to the colour of two framed squares, two arrows, or two schematic eyes by pressing one of two lateralized response keys. The results consistently show that the Simon effect occurs independently of the nature of the stimulus, as classically reported for lateralized stimuli. Response times were influenced by the direction and frame-relative position of the stimuli, being faster for responses corresponding to the direction indicated by the stimuli than for noncorresponding responses regardless of stimulus types. Contrary to findings with lateralized nondirectional stimuli, such an effect increased with increasing RTs indicating that for centrally presented patterns the extraction of spatial information is time consuming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The prepared emotional reflex: Intentional preparation of automatic approach and avoidance tendencies as a means to regulate emotional responding.

Advance preparation of action courses toward emotional stimuli is an effective means to regulate impulsive emotional behavior. Our experiment shows that performing intentional acts of approach and avoidance in an evaluation task influences the unintended activation of approach and avoidance tendencies in another task in which stimulus valence is irrelevant. For the evaluation-relevant blocks, participants received either congruent (positive-approach, negative-avoidance) or incongruent (positive-avoidance, negative-approach) mapping instructions. In the evaluation-irrelevant blocks, approach- and avoidance-related lever movements were selected in response to a stimulus feature other than valence (affective Simon task). Response mapping in the evaluation task influenced performance in the evaluation-irrelevant task: An enhanced affective Simon effect was observed with congruent mapping instructions; in contrast, the effect was reversed when the evaluation task required incongruent responses. Thus, action instructions toward affective stimuli received in one task determined affective response tendencies in another task where these instructions were not in effect. These findings suggest that intentionally prepared short-term links between affective valence and motor responses elicit associated responses without a deliberate act of will, operating like a “prepared reflex.” (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer of magnitude and spatial mappings to the SNARC effect for parity judgments.

Left–right keypresses to numerals are faster for pairings of small numbers to left response and large numbers to right response than for the opposite pairings. This spatial numerical association of response codes (SNARC) effect has been attributed to numbers being represented on a mental number line. We examined this issue in 3 experiments using a transfer paradigm. Participants practiced a number magnitude-judgment task or spatial stimulus–response compatibility task with parallel or orthogonal stimulus–response dimensions prior to performing a parity-judgment task. The SNARC effect was enhanced following a small–left/large–right magnitude mapping but reversed following a small–right/large–left mapping, indicating that associations between magnitude and response defined for the magnitude-judgment task were maintained for the parity-judgment task. The SNARC effect was unaffected by practice with compatible or incompatible spatial mapping for the parallel spatial task but was larger following up–right/down–left mapping than up–left/down–right mapping for the orthogonal spatial task. These results are inconsistent with the SNARC effect being due to a horizontal number line representation but consistent with a view that correspondence of stimulus and response code polarities contributes to the effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correspondence effects for objects with opposing left and right protrusions.

Choice reactions to a property of an object stimulus are often faster when the location of a graspable part of the object corresponds with the location of a keypress response than when it does not, a phenomenon called the object-based Simon effect. Experiments 1–3 examined this effect for variants of teapot stimuli that were oriented to the left or right. Whether keypress responses were made with fingers within the same hand or between different hands was also manipulated. Experiment 1 showed that, for judgments of stimulus color and upright-inverted orientation, the Simon effect for intact teapots occurred in the direction of the spout location and was larger for within- than between-hand response modes. In Experiments 2 and 3, teapots with the handle or spout removed showed separate contributions of each component to the Simon effect. In Experiment 4, we clarified a discrepancy between our findings of object-based Simon effects and a previously reported absence of effect with color judgments for door-handle stimuli. We obtained an object-based Simon effect with respect to handle position when the bases of the door handles were centered but not when the handles were centered. The findings that object-based Simon effects occur with color judgments and when responses are fingers on the same hand are in closer agreement with a location coding account than with a grasping affordance account. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Influence on Simon and SNARC effects of a nonspatial stimulus-response mapping: Between-task logical recoding.

In 4 experiments, we intermixed trials in which the stimulus color was relevant with trials where participants had to judge the stimulus shape or parity and found that the logical-recoding rule (Hedge & Marsh, 1975) applied to the relevant dimension in a task can generalize to the irrelevant dimension of the other task. The mapping assigned to participants in color-relevant trials modulated the Simon and SNARC (spatial-numerical association of response codes) effects (Simon & Small, 1969; Dehaene, Bossini, & Giraux, 1993) observed in shape- and parity-relevant trials. Standard effects were obtained when color-relevant trials required participants to respond by pressing a key of the same color as the stimulus, whereas an alternate-color mapping caused either the disappearance or reversal of the effects. The present results demonstrate that for between-task transfer effects to occur the critical dimensions in the two alternative tasks do not have to share the same representation nor need the stimuli of the two tasks have any feature in common. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locus of the single-channel bottleneck in dual-task interference.

Two experiments used the locus-of-cognitive-slack method to determine whether dual-task interference occurs before or after the response selection stage. The experiments used the overlapping tasks paradigm, in which 2 signals, each requiring a different speeded choice response, are presented in rapid succession. In Exp 1, stimulus–response (S–R) compatibility was manipulated by varying whether Task 2 stimuli were mapped onto their responses by a rule or arbitrarily. Compatibility effects were additive with the effects of degree of task overlap, manipulated by varying the stimulus onset asynchrony between the signals. Exp 2 examined 2 additional forms of S–R compatibility: symbolic compatibility (arrows vs letters) and spatial compatibility (the "Simon" effect). Effects of symbolic compatibility were additive with effects of degree of task overlap, whereas the effects of spatial compatibility and degree of task overlap were underadditive. It is argued that only a central-bottleneck model provides a consistent account of these results. The nature of the central bottleneck is considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The object-based Simon effect: Grasping affordance or relative location of the graspable part?

Reaction time is often shorter when the irrelevant graspable handle of an object corresponds with the location of a keypress response to the relevant attribute than when it does not. This object-based Simon effect has been attributed to an affordance for grasping the handle with the hand to the same side. Because a grasping affordance should differentially affect keypress responses only when they are made with different hands, we conducted three experiments that measured the object-based Simon effect for frying pan stimuli using between- and within-hand response sets. When the relevant stimulus dimension was color, neither the object-based Simon effect nor the location-based Simon effect varied across response sets. When upright-inverted orientation judgments were made for the frying pan and for nongraspable stimuli derived from it, there again was no significant difference in size of the between- and within-hand Simon effects for any of the stimuli. The results provide evidence that the Simon effect for graspable frying pan stimuli is because of relative location of the handle and not to a grasping affordance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Involvement of retrosplenial cortex in forming associations between multiple sensory stimuli.

The retrosplenial cortex (RSP) is highly interconnected with medial temporal lobe structures, yet relatively little is known about its specific contributions to learning and memory. One possibility is that RSP is involved in forming associations between multiple sensory stimuli. Indeed, damage to RSP disrupts learning about spatial or contextual cues and also impairs learning about co-occurring conditioned stimuli (CSs). Two experiments were conducted to test this notion more rigorously. In Experiment 1, rats were trained in a serial feature negative discrimination task consisting of reinforced presentations of a tone alone and nonreinforced serial presentations of a light followed by the tone. Thus, in contrast to prior studies, this paradigm involved serial presentation of conditioned stimuli (CS), rather than simultaneous presentation. Rats with damage to RSP failed to acquire the discrimination, indicating that RSP is required for forming associations between sensory stimuli regardless of whether they occur serially or simultaneously. In Experiment 2, a sensory preconditioning task was used to determine if RSP was necessary for forming associations between stimuli even in the absence of reinforcement. During the first phase of this procedure, one auditory stimulus was paired with a light while a second auditory stimulus was presented alone. In the next phase of training, the same light was paired with food. During the final phase of the procedure both auditory stimuli were presented alone during a single session. Control, but not RSP-lesioned rats, exhibited more food cup behavior following presentation of the auditory cue that was previously paired with light compared with the unpaired auditory stimulus, indicating that a stimulus-stimulus association was formed during the first phase of training. These results support the idea that RSP has a fundamental role in forming associations between environmental stimuli. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Exposure to a rhythmic auditory stimulus facilitates memory formation for the passive avoidance task in the day-old chick.

Previous research regarding the beneficial effects of auditory stimuli on learning and memory in humans has been inconsistent. In the current study, day-old chicks were used to reduce the impact of individual differences on responses. Chicks were trained on a passive avoidance task and exposed to various auditory stimuli. Exposure to a complex rhythmic sequence for 1 min strongly facilitated chicks' long-term memory. The optimal time of presentation of the stimulus was between 10 min before and 20 min after training. Moreover, the enhancing effect was not generalized to the other auditory stimuli tested. It is suggested that this effect may be due to arousal because arousal hormones are critical to long-term memory formation. This study indicates that the temporal characteristics and type of stimulus may be important considerations when investigating the effects of auditory stimuli on cognitive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference effects in the Stroop and Simon paradigms.

The possibility that Stroop and Simon effects reflect the same cognitive processes was tested in 3 experiments with 62 adult Ss. The words LEFT and RIGHT were shown left and right of screen center. Similar levels of interference were found for a Simon task (keypress to meaning of word) and a spatial Stroop task (name its location). A reverse Simon task (keypress to word location) showed minimal interference from the irrelevant word, but in a reverse spatial Stroop task (read the word aloud) interference from the irrelevant location was sizeable. This poses difficulty for translational accounts of Stroop interference. Presenting LEFT and RIGHT laterally balanced by a color-name foil yielded a Simon effect inconsistent with an orienting response hypothesis. With bilateral stimuli in a reverse Simon task, interference was marked, supporting an integrative account of Stroop and Simon effects in terms of cognitive activation and the salience of irrelevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Simon Effect in Pigeons.

Pigeons pecked left versus right keys contingent upon the color presented at 1 of those locations. Spatial-response latencies were shorter when the color appeared at the same location as the required response than at the opposite location. This Simon effect occurred when the stimulus on the alternative key was constant, varied from trial to trial, or changed when the color cue appeared and when the reinforcement probability for correct responses was the same on corresponding as on noncorresponding trials. Humans performing the same task by touching the keys also showed the Simon effect. These findings demonstrate that for pigeons, too, a relevant symbolic cue activates a spatial code that produces faster responses at the location corresponding with the activated code. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of motivation and orientation in sensory preconditioning.

Explored the effect of hunger on sensory preconditioning. Ss were 17 male cats. An appetitive task was used to test for sensory preconditioning effects in order to avoid complications arising from differences of drive state during preconditioning and testing for preconditioning. It was found that hunger facilitated the association between paired auditory and visual stimuli, but not between stimuli presented separately and in random order. Examination of the orientation responses of Ss during preconditioning indicate that the auditory stimulus becomes an arousing cue that signals the onset of the visual stimulus. It is suggested that the orientation responses produced as a consequence of this cue function are responsible for the association of the auditory and visual stimuli. (French summary) (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming processes in the Simon task: More evidence from the lexical decision task for a third route in the Simon effect.

Recently, it was proposed that the Simon effect would result not only from two interfering processes, as classical dual-route models assume, but from three processes. It was argued that priming from the spatial code to the nonspatial code might facilitate the identification of the nonspatial stimulus feature in congruent Simon trials. In the present study, the authors provide evidence that the identification of the nonspatial information can be facilitated by the activation of an associated spatial code. In three experiments, participants first associated centrally presented animal and fruit pictures with spatial responses. Subsequently, participants decided whether laterally presented letter strings were words (animal, fruit, or other words) or nonwords; stimulus position could be congruent or incongruent to the associated spatial code. As hypothesized, animal and fruit words were identified faster at congruent than at incongruent stimulus positions from the association phase. The authors conclude that the activation of the spatial code spreads to the nonspatial code, resulting in facilitated stimulus identification in congruent trials. These results speak to the assumption of a third process involved in the Simon task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of stimulus modality and task condition on blink startle modification and on electrodermal responses

Participants in Experiments 1 and 2 performed a discrimination and counting task to assess the effect of lead stimulus modality on attentional modification of the acoustic startle reflex. Modality of the discrimination stimuli was changed across subjects. Electrodermal responses were larger during task-relevant stimuli than during task-irrelevant stimuli in all conditions. Larger blink magnitude facilitation was found during auditory and visual task-relevant stimuli, but not for tactile stimuli. Experiment 3 used acoustic, visual, and tactile conditioned stimuli (CSs) in differential conditioning with an aversive unconditioned stimulus (US). Startle magnitude facilitation and electrodermal responses were larger during a CS that preceded the US than during a CS that was presented alone regardless of lead stimulus modality. Although not unequivocal, the present data pose problems for attentional accounts of blink modification that emphasize the importance of lead stimulus modality.     

Stimulus control of avoidance behavior in rats following differential or nondifferential Pavlovian training along dimensions of the conditioned stimulus.

Assigned 36 male albino Holtzman rats, following 2-way avoidance training with an auditory CS, to 1 of 6 Pavlovian manipulations: discrimination or equivalence training along frequency or intensity dimensions, nominal single stimulus training, or unsignalled shocks only. Subsequently, Ss received separate generalization tests when frequency and/or intensity were varied. Intradimensional discrimination training tended to steepen generalization gradient and resulted in a peak shift away from the negative CS (safety signal) within the frequency continuum. Pseudodiscrimination equivalence training typically reduced stimulus control, even when training and test stimuli were not along the same dimension. These modifications of avoidance generalization gradients through interpolated noncontingent training provide additional evidence of the transfer of Pavlovian control to instrumental behavior. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)