Development of the acquisition and control of action-effect associations

Voluntary action is anticipatory and, hence, must depend on associations between actions and their perceivable effects. We studied the acquisition of action-effect associations in 4-5-vs. 7-year-old children. Children carried out key-pressing actions that were arranged to produce particular auditory effects. In a subsequent test phase, children were to press keys in response to the previous effect sounds, with the sound-key mapping being either consistent or inconsistent with previous key-sound practice. As the processes underlying voluntary action controls are known to significantly improve between 4 and 7 years of age, it was expected that younger children were more prone to automatic effects of acquired sound-key associations. This hypothesis was confirmed, but reaction times and accuracy measures showed different and dissociable patterns. Four-year-olds but not 7-year-olds were more likely to commit an error--i.e., to perform a sound-compatible rather than the correct action--if the sound-key mapping was inconsistent with previous practice. This effect strongly depended on previous practice, suggesting that it reflects long-term learning. In contrast, reaction time effects of mapping consistency did not depend on previous experience but only on the consistency between stimulus and action effect in the present task. Taken altogether, the results suggest that children acquire response-effect associations automatically and that younger children are more likely to suffer from frequent goal neglect; i.e., they tend to forget the current action goal, so that their behavior is dominated by automatic, stimulus-triggered response tendencies.     

Backward-compatibility effects with irrelevant stimulus-response overlap: the case of the SNARC effect

In 3 dual-task experiments, the relationship between primary-task response (R1) and secondary-task response (R2) was varied. In general, R1-left responses were faster when followed by the word one, and right responses were faster when followed by the word two. This backward-compatibility (BWC) effect indicated (a) that activation of R2 was not delayed until R1 selection was completed, and (b) that activation of the vocal responses was accompanied by the automatic activation of magnitude codes, known to be associated with spatial left-right codes (spatial-numerical association of response codes [the SNARC effect]). These findings supported the hypotheses (a) that BWC effects persist even with irrelevant R1-R2 overlap, (b) that the SNARC effect is based on associations between magnitude and spatial representations underlying response processing, and (c) that the production and perception of magnitudes relies on common codes.     

Symbolic control of visual attention: The role of working memory and attentional control settings

This study examined how 1 symbol is selected to control the allocation of attention when several symbols appear in the visual field. In Experiments 1-3, the critical target feature was color, and it was found that uninformative central arrows that matched the color of the target were selected and produced unintentional shifts of attention (i.e., involuntary, initiated slowly, producing long-lasting facilitatory effects). Experiment 4 tested whether such selection is the result of an attentional filter or of a competition bias due to a match of incoming information against integrated object representations stored in working memory. Here, the critical feature was shape and color was irrelevant, but matching color arrows were still selected. Thus, features of objects in working memory will bias the selection of symbols in the visual field, and such selected symbols are capable of producing unintentional shifts of attention. ((c) 2003 APA, all rights reserved)     

Fitting the psychometric function

A constrained generalized maximum likelihood routine for fitting psychometric functions is proposed, which determines optimum values for the complete parameter set--that is, threshold and slope--as well as for guessing and lapsing probability. The constraints are realized by Bayesian prior distributions for each of these parameters. The fit itself results from maximizing the posterior distribution of the parameter values by a multidimensional simplex method. We present results from extensive Monte Carlo simulations by which we can approximate bias and variability of the estimated parameters of simulated psychometric functions. Furthermore, we have tested the routine with data gathered in real sessions of psychophysical experimenting.     

Moving through virtual reality without moving?

Virtual reality (VR) technology is increasingly used in spatial cognition research, as it offers high experimental control and interactivity in naturalistic multi-modal environments, something that is difficult to achieve in real-world settings. Even in the most sophisticated and costly VR systems, people do not necessarily perceive and behave as they would in the real world. This might be related to our inability to use embodied (and thus often highly automated and effective) spatial orientation processes in VR. While real-world locomotion affords automatic and obligatory spatial updating of our self-to-surrounding relationships, such that we easily remain oriented during simple perspective changes, the same is not necessarily true in VR. This can lead to striking systematic and qualitative errors such as failures to update rotations ("Nonturner" behavior). Here, we investigated whether rich naturalistic visual stimuli in immersive VR might be sufficient to compensate for the lack of physical motion. To this end, 24 participants performed point-to-origin tasks after visually simulated excursions along streets of varying curvature in a naturalistic virtual city. Most (21/24) participants properly updated simulated self-motions and showed only moderate regression toward mean pointing responses. 3/24 participants, however, exhibited striking "Nonturner" behavior in that they pointed as if they did not update the visually simulated turns and their heading had not changed. This suggests that our immersive naturalistic VR stimuli were an improvement over prior optic flow stimuli, but still insufficient in eliciting obligatory spatial updating that supported correct point-to-origin responses in all participants.     

Eye movements and display change detection during reading

In the boundary change paradigm (Rayner, 1975), when a reader's eyes cross an invisible boundary location, a preview word is replaced by a target word. Readers are generally unaware of such changes due to saccadic suppression. However, some readers detect changes on a few trials and a small percentage of them detect many changes. Two experiments are reported in which we combined eye movement data with signal detection analyses to investigate display change detection. On each trial, readers had to indicate if they saw a display change in addition to reading for meaning. On half the trials the display change occurred during the saccade (immediate condition); on the other half, it was slowed by 15-25 ms (delay condition) to increase the likelihood that a change would be detected. Sentences were presented in an alternating case fashion allowing us to investigate the influence of both letter identity and case. In the immediate condition, change detection was higher when letters changed than when case changed corroborating findings that word processing utilizes abstract (case independent) letter identities. However, in the delay condition (where d' was much higher than the immediate condition), detection was equal for letter and case changes. The results of both experiments indicate that sensitivity to display changes was related to how close the eyes were to the invalid preview on the fixation prior to the display change, as well as the timing of the completion of this change relative to the start of the post-change fixation.     

Parafoveal processing of word n + 2 during reading: do the preceding words matter?

We used the boundary paradigm (Rayner, 1975) to test two hypotheses that might explain why no conclusive evidence has been found for the existence of n + 2 preprocessing effects. In Experiment 1, we tested whether parafoveal processing of the second word to the right of fixation (n + 2) takes place only when the preceding word (n + 1) is very short (Angele, Slattery, Yang, Kliegl, & Rayner, 2008); word n + 1 was always a three-letter word. Before crossing the boundary, preview for both words n + 1 and n + 2 was either incorrect or correct. In a third condition, only the preview for word n + 1 was incorrect. In Experiment 2, we tested whether word frequency of the preboundary word (n) had an influence on the presence of preview benefit and parafoveal-on-foveal effects. Additionally, Experiment 2 contained a condition in which only preview of n + 2 was incorrect. Our findings suggest that effects of parafoveal n + 2 preprocessing are not modulated by either n + 1 word length or n frequency. Furthermore, we did not observe any evidence of parafoveal lexical preprocessing of word n + 2 in either experiment.     

Attentional control of the creation and retrieval of stimulus–response bindings

Two experiments studied the degree to which the creation and retrieval of episodic feature bindings is modulated by attentional control. Experiment 1 showed that the impact of bindings between stimulus and response features varies as a function of the current attentional set: only bindings involving stimulus features that match the current set affect behavior. Experiment 2 varied the time point at which new attentional sets were implemented—either before or after the processing of the to-be-integrated stimuli and responses. The time point did not matter, suggesting that the attentional set has no impact on feature integration proper but controls which features get access to and can thus trigger the retrieval of bindings.     

Plural self-awareness

It has been claimed in the literature that collective intentionality and group attitudes presuppose some “sense of ‘us’” among the participants (other labels sometimes used are “sense of community,” “communal awareness,” “shared point of view,” or “we-perspective”). While this seems plausible enough on an intuitive level, little attention has been paid so far to the question of what the nature and role of this mysterious “sense of ‘us’” might be. This paper states (and argues for) the following five claims: (1) it is neither the case that the sense in question has the community (or “us”) in its content or as its object nor does the attitude in question presuppose a preexistent community (or “us”) as its subject. (2) The “sense of ‘us’” is plural pre-reflective self-awareness. (3) Plural pre-reflective self-awareness plays the same role in the constitution of a common mind that singular pre-reflective self-awareness plays in the individual mind. (4) The most important conceptions of plural subjects, collective persons, or group agents in the current literature fail to recognize the nature and role of plural self-awareness, and therefore fall short in important respects. (5) In spite of the striking similarities between the plural and the singular mind, there are important differences to consider. The authority of the singular first person point of view has no equivalent in the plural case.     

The Guise of the Bad in Augustine’s Pear Theft

In the second book of his Confessions, Augustine of Hippo presents his famous juvenile Pear Theft as an apparent case of acting under the guise of the bad. At least since Thomas Aquinas’ influential interpretation, scholars have usually taken Augustine’s detailed discussion of the case to be dispelling this “guise of the guise of the bad”, and to offer a solid “guise of the good”-explanation. This paper addresses an important challenge to this view: Augustine offers two different “guise of the good”-explanations in his text rather than just one, and the two explanations seem to be mutually exclusive. A number of more recent attempts to reconcile Augustine’s two lines of explanation are discussed and found wanting, and a new suggestion is made. The proposed solution focuses on the Pear Theft as a joint action, and it departs from the Aquinian interpretation in that it accounts for a way in which the “guise of the bad”-hypothesis survives the explanation.