Processing load impairs coordinate integration for the localization of touch

• Published in: Attention, perception & psychophysics Vol. 76; no. 4; pp. 1136 - 1150
• Main Authors: Badde, Stephanie, Heed, Tobias, Röder, Brigitte
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2014; Springer; Springer Nature B.V
• Subjects: Adolescent; Adult; Analysis of Variance; Behavioral Science and Psychology; Biological and medical sciences; Cognitive Processes; Cognitive Psychology; Coordinate transformations; Cues; Female; Fundamental and applied biological sciences. Psychology; Hand; Humans; Influence; Judgment; Male; Memory; Pattern Recognition, Physiological - physiology; Perception; Posture; Posture - physiology; Psychology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Short Term Memory; Space Perception - physiology; Stimuli; Tactile perception; Task Performance and Analysis; Touch - physiology; Touch Perception - physiology; Web services; Young Adult; Spatial localization; Touch; Automaticity; Human; Tactile sensitivity; Information processing; Perception; Cognition; Space perception; Localization; Mental load; Automatic processing
• ISSN: 1943-3921; 1943-393X; 1943-393X
• DOI: 10.3758/s13414-013-0590-2

To perform an action toward a touch, the tactile spatial representation must be transformed from a skin-based, anatomical reference frame into an external reference frame. Evidence suggests that, after transformation, both anatomical and external coordinates are integrated for the location estimate. The present study investigated whether the calculation and integration of external coordinates are automatic processes. Participants made temporal order judgments (TOJs) of two tactile stimuli, one applied to each hand, in crossed and uncrossed postures. The influence of the external coordinates of touch was indicated by the performance difference between crossed and uncrossed postures, referred to as the crossing effect . To assess automaticity, the TOJ task was combined with a working memory task that varied in difficulty (size of the working memory set) and quality (verbal vs. spatial). In two studies, the crossing effect was consistently reduced under processing load. When the load level was adaptively adjusted to individual performance (Study 2), the crossing effect additionally varied as a function of the difficulty of the secondary task. These modulatory effects of processing load on the crossing effect were independent of the type of working memory. The sensitivity of the crossing effect to processing load suggests that coordinate integration for touch localization is not fully automatic. To reconcile the present results with previous findings, we suggest that the genuine remapping process—that is, the transformation of anatomical into external coordinates—proceeds automatically, whereas their integration in service of a combined location estimate is subject to top-down control.