Stimulus and response chunking in the Hebb Digits task

Using the Hebb Digits task, an incidental sequential learning paradigm, the effects of chunking of both the presentation and response phases of performance were examined. In the first experiment, consistent stimulus chunking increased learning, and performance was at an equivalent level to this when consistent chunking of both stimuli and responses was present. Consistent chunking of the responses alone did not significantly improve learning over a baseline condition where neither stimuli nor responses were chunked. The disruption of response organization in a second experiment, through a random response condition, failed to impact learning in non-chunked and stimulus chunked conditions. A third experiment found that response chunking did benefit learning in a condition where stimuli were presented in random chunks. A final experiment suggested extended processing of the digits could not account for performance gains in the stimulus chunking condition. Overall, the results suggest that the enhanced effects of chunking on learning were stimulus-driven rather than response-driven, except under conditions that constrained a consistent pattern of stimulus organization.     

‘Goals’ are not an integral component of imitation

Several theories suggest that actions are coded for imitation in terms of mentalistic goals, or inferences about the actor’s intentions, and that these goals solve the correspondence problem by allowing sensory input to be translated into matching motor output. We tested this intention reading hypothesis against general process accounts of imitation using the pen-and-cups task. The task has three components: participants place a pen in one of two cups, using their right or left hand, and one of two grips. Previous research has revealed a colour minimum error pattern; when one of the components is differentially coloured (e.g., one cup is red and the other blue), accuracy is greatest on the coloured dimension. We found the colour minimum error pattern, not only in the standard version of the task, where participants imitate the actions of a human model, but also in three novel variants of the task, in which participants responded on the basis of spatial or arbitrary stimulus–response mappings to ‘geometric’, non-biological stimuli. These stimuli do not afford the attribution of intentions, and therefore our results support generalist theories of imitation by showing that the colour minimum error pattern is due, not to intention reading, but to the operation of task-general processes of perception, attention and motor control.     

Seeing Where the Stone Is Thrown by Observing a Point-Light Thrower: Perceiving the Effect of Action Is Enabled by Information,Not Motor Experience

People are very adept at perceiving biological motion (e.g., Johansson, 1973 Johansson, G. (1973). Visual perception of biological motion and a model for its analysis. Perception & Psychophysics, 14(2), 201–211.[Crossref], [Web of Science ®] , [Google Scholar]). This ability has been an essential life skill to members of this social species. The human niche during the ice age was socially coordinated hunting for big game. Being able to judge the location targeted by the throw of a conspecific would be a valuable perceptual ability that we now study to investigate 2 competing theories of biological motion perception: Common Coding (CC; Prinz, 1997 Prinz, W. (1997). Perception and action planning. European Journal of Cognitive Psychology, 9(2), 129–154.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) and Kinematic Specification of Dynamics (KSD; Runeson & Frykholm, 1983 Runeson, S., & Frykholm, G. (1983). Kinematic specification of dynamics as an informational bias for person-and-action perception: Expectation, gender recognition, and deceptive intent. Journal of Experimental Psychology: General, 112, 585–615.[Crossref], [Web of Science ®] , [Google Scholar]). The 2 theories diverge in attributing perceptual ability to either motor or visual experience, respectively. To test predictions of the CC theory, we performed 3 experiments to manipulate observers' specific motor experience while they judged the targeted location of throwing by watching point-light displays. In Experiment 1, we tested whether the identity of the thrower in the display mattered. In Experiment 2, we tested whether the motor expertise of the observer mattered. In Experiment 3, we tested whether the gender/style of throwing demonstrated by the point-light thrower mattered. The combined results failed to support CC theory, suggesting that motor experience is not required for the perception of action. Because all participants judged the target location of throwing quite well, KSD theory suggests that the kinematic information available in the displays may have enabled the perception. We performed Experiment 4 to analyze the information. We found that the judgment pattern exhibited by the observers in both Experiments 1 and 2 was well predicted by the KSD theory. Thus, we concluded that the perception of biological motion is enabled by visual information and improved by visual experience.     

The Clinic and the Tearoom

Although the clinical and the sexual are commonly treated as antithetical realms of experience, queer commentary teaches that the clinic is a positively sexual space and that clinical intimacy is a creative form of sexual intimacy. Contrary to writers such as Engelhardt, the clinic is a space where queer publics are forged, and the barriers between moral friends and moral strangers potentially dissolve, but only to the extent that one is disposed to allow oneself to enjoy experiences of identification that confound the ideals of human dignity typically invoked in writings about sexual ethics on the one hand and clinical medical ethics on the other hand.     

Temporal Regularity of Tapping by the Left and Right Hands in Timed and Untimed Finger Tapping

The temporal characteristics of repetitive finger tapping by the left and right hands were examined in two experiments. In the first experiment, interresponse intervals (IRIs) were recorded while right-handed male subjects tapped in synchrony with an auditory timing pulse (the synchronization phase) and then attempted to maintain the same tapping rate without the timing pulses (the continuation phase). The left and right hands performed separately, at four different rates (interpulse intervals of 250, 500, 750, and 1500 ms). There was no asymmetry of the asynchronies of the timing pulses and the associated responses in the synchronization phase or of the IRIs in either phase, but there was an asymmetry in the temporal dispersion of the responses in both phases. In the second experiment, right-handed males tapped separately with each hand at three different speeds: as quickly as possible, at a fast but steady rate, and at a slow rhythmical rate. The speed asymmetry present when tapping as quickly as possible (with the preferred hand tapping more quickly) was reduced when tapping at the fast steady rate and was absent when tapping at the slow rhythmical rate. The temporal dispersion of the IRIs produced by the nonpreferred hand was greater than the temporal dispersion of those produced by the preferred hand in all speed conditions. These results show smaller temporal dispersion of tapping by the preferred hand in right-handed males under different conditions, including submaximal speeds at which both hands respond at the same rate. This suggests that the motor system controlling the preferred hand in right-handers has more precise timing of response output than that controlling the nonpreferred hand.     

Gross Motor Performance in Minimally Brain Injured Children

As a pre-requisite to curriculum development, the characteristics of the gross motor performance of special education classes of minimally brain injured boys and girls were described. In general, age changes in mean performance were linear, the scores of the boys being the superior. The level of performance very closely resembled that of comparison groups of educable mentally retarded children from the same school districts.