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.     

Determinants of Two-Choice Reaction-Time Patterns for Same-Hand and Different-Hand Finger Pairings

Several studies of two-choice reaction times have compared situations in which the alternative responses are fingers from one hand (the same-hand pairing) or one finger from each hand (the different-hand pairing). Two patterns of results have been obtained: (a) equivalent reaction times for the same-hand and different-hand pairings and (b) faster reaction times for the different-hand pairing. Previously, these outcomes have been attributed to the adoption of different response-preparation strategies when response pairs are constant (low response-pair uncertainty) versus when they are varied from trial to trial (high response-pair uncertainty). However, response-pair uncertainty has been confounded with whether only the two relevant fingers were placed on response keys or whether more than two fingers were. Experiment 1 of the present study demonstrated that finger placement, rather than response-pair uncertainty, determines which reaction-time pattern is obtained. Experiments 2 and 3 investigated the nature of the finger-placement effect by placing the fingers that were irrelevant for the task on response keys or on immovable blocks. The experiments indicated that the crucial factor is the number of fingers on active response keys, with the type of preparation being different when only two fingers are on keys rather than when more than two fingers are.     

Spatial Compatibility Effects With Unimanual and Bimanual Wheel-Rotation Responses: An Homage to Guiard (1983)

ABSTRACT. Y. Guiard (1983) reported a prescient study of compatibility effects in response times for clockwise/counterclockwise wheel rotations to stimuli in left/right locations. Left-right coding of responses predominated in his study, but some results suggested that unimanual versus bimanual operation was also a factor. The authors report 3 experiments directly examining whether there is a difference in spatial compatibility effects obtained with wheel-rotation responses executed bimanually or unimanually (with left or right hand). Adopting a right-to-clockwise or left-to-counterclockwise mapping was advantageous for top, side, and bottom hand placements. This benefit interacted neither with unimanual or bimanual responding nor with the response hand. The results confirm that the critical relation is between the wheel and stimulus position, and is not effector dependent. This finding is in agreement with results from studies using discrete keypress responses, emphasizing that spatial coding of stimuli, actions, and their goals is of central importance in response-selection decisions.     

A feature-integration account of sequential effects in the Simon task

Recent studies have shown that the effects of irrelevant spatial stimulus-response (S-R) correspondence (i.e., the Simon effect) occur only after trials in which the stimulus and response locations corresponded. This has been attributed to the gating of irrelevant information or the suppression of an automatic S-R route after experiencing a noncorresponding trial—a challenge to the widespread assumption of direct, intentionally unmediated links between spatial stimulus and response codes. However, trial sequences in a Simon task are likely to produce effects of stimulus- and response-feature integration that may mimic the sequential dependencies of Simon effects. Four experiments confirmed that Simon effects are eliminated if the preceding trial involved a noncorresponding S-R pair. However, this was true even when the preceding response did not depend on the preceding stimulus or if the preceding trial required no response at all. These findings rule out gating/suppression accounts that attribute sequential dependencies to response selection difficulties. Moreover, they are consistent with a feature-integration approach and demonstrate that accounting for the sequential dependencies of Simon effects does not require the assumption of information gating or response suppression.     

The role of joint attention in the development of infants' play with objects

Year-old infants' play was scored within and outside joint attention with mother and when alone for four levels of maturity: stereotypical, inappropriate relational, appropriate relational, functional. Maternal sensitivity within joint attention was rated on two measures: following infants' interests and scaffolding infants' activities. Infants' play was more advanced with mother than when alone. With mother, infants had more functional and appropriate relational play within joint attention and more stereotypical play outside joint attention, indicating more advanced play within joint attention and more immature play outside joint attention. Functional play within joint attention, but not outside joint attention, correlated with functional play when alone. Mothers' ability to scaffold infants' activities within joint attention may be particularly facilitative to infants' advanced play.     

Stimulus-response compatibility with pure and mixed mappings in a flight task environment

The present study examined the stimulus-response compatibility (SRC) effect in a simulated flight environment. Experiments 1 and 2 tested the effect with pure and mixed mappings in flight tasks by using attitude displays with inside-out and outside-in formats, whereas Experiments 3 and 4 used a simplified display and tasks. The SRC effect was obtained with mixed mappings when responses were turns of a flight yoke (Experiments 1-3). In contrast, the SRC effect was absent with mixed mappings when they were buttonpresses (Experiment 4). Analyses of sequential effects suggest that the reduction in Experiments 1-3 can be attributed to reduction in the frequency of trials for which the congruent mapping repeats, but the elimination in Experiment 4 cannot be. Implications of the findings are discussed in the context of aviation cockpit design.     

Mixing location-irrelevant and location-relevant trials: influence of stimulus mode on spatial compatibility effects

The performance advantage for spatially compatible mappings of physical locations to keypress responses, relative to incompatible mappings, is eliminated when stimulus color, rather than location, is relevant on half of the trials. In Experiment 1, we compared the effects of mixing for different stimulus modes (physical locations, arrow directions, and location words) to determine whether this elimination of the stimulus-response compatibility (SRC) effect would generalize to other stimulus modes. The SRC effect was unaffected when the location information was conveyed by arrows and was amplified when the location information was conveyed by words. In Experiment 2, we used vocal left-right responses instead of keypresses, and the SRC effects for all three stimulus modes were enhanced by mixing. In both experiments, for all stimulus modes, mixing reduced or reversed correspondence effects for trials on which the location information was irrelevant when the mapping for those trials on which it was relevant was incompatible. These findings suggest that when trial types are mixed, direct activation of the corresponding response, regardless of mapping, does not occur for physical locations mapped to keypresses. However, such activation does occur when stimuli or responses are verbal, apparently because performance is mediated in part by activation of a verbal name code for the stimulus.     

Dual-task performance with ideomotor-compatible tasks: is the central processing bottleneck intact, bypassed, or shifted in locus?

The present study examined whether the central bottleneck, assumed to be primarily responsible for the psychological refractory period (PRP) effect, is intact, bypassed, or shifted in locus with ideomotor (IM)-compatible tasks. In 4 experiments, factorial combinations of IM- and non-IM-compatible tasks were used for Task 1 and Task 2. All experiments showed substantial PRP effects, with a strong dependency between Task 1 and Task 2 response times. These findings, along with model-based simulations, indicate that the processing bottleneck was not bypassed, even with two IM-compatible tasks. Nevertheless, systematic changes in the PRP and correspondence effects across experiments suggest that IM compatibility shifted the locus of the bottleneck. The findings favor an engage-bottleneck-later hypothesis, whereby parallelism between tasks occurs deeper into the processing stream for IM- than for non-IM-compatible tasks, without the bottleneck being actually eliminated.     

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.     

No overall right-left prevalence for horizontal and vertical Simon effects

The present study confirmed that there is no overall right-left prevalence effect for Simon tasks, in which stimulus location is irrelevant, when (1) the stimulus and response sets vary along both horizontal and vertical dimensions simultaneously, (2) the stimulus set varies along both dimensions, but the response set varies along only one dimension, and (3) the stimuli and responses vary in one of four possible locations and responses are made by a unimanual joystick movement. In all experiments, Simon effects of similar magnitude were evident for both the horizontal and the vertical dimensions. The findings suggest that the right-left prevalence effect observed with two-dimensional location-relevant tasks is not due to stronger overall automatic activation of horizontal codes but to different translation efficiencies in intentional response selection processes.