On the inference of personal authorship: enhancing experienced agency by priming effect information

Three experiments examined whether the mere priming of potential action effects enhances people's feeling of causing these effects when they occur. In a computer task, participants and the computer independently moved a rapidly moving square on a display. Participants had to press a key, thereby stopping the movement. However, the participant or the computer could have caused the square to stop on the observed position, and accordingly, the stopped position of the square could be conceived of as the potential effect resulting from participants' action of pressing the stop key. The location of this position was primed or not just before participants had to stop the movement. Results showed that (subliminal as well as supraliminal) priming of the position enhanced experienced authorship of stopping the square. Additional experimentation demonstrated that this priming of agency was not mediated by the goal or intention to produce the effect.     

Choosing the shortest way to Mum: auditory guided rotation in 6- to 9-month-old infants

The purpose of this study was to investigate the use of auditory information for rotation of the shortest way in twelve 6- to 9-month-old sighted infants. Behavior was manipulated by means of an auditory stimulus presented in four different directional angles (90°, 112.5°, 135°, and 157.5°) to the right and to the left behind the infants, and in one non-directional angle (180°). Infants lay in a prone position and had magnetic trackers fastened to the head and body which measured their rotation direction and angular velocity. The results showed that infants not only consistently chose the shortest over the longest way, but also rotated with a higher peak angular velocity as the angle to be covered between themselves and the goal increased. The results did not show significant preferences for one particular rotation direction. The study can contribute to the understanding of the auditory system as a functional listening system where auditory information is used as a perceptual source for prospectively guiding behavior in the environment.     

EthoVision: A versatile video tracking system for automation of behavioral experiments

The need for automating behavioral observations and the evolution of systems developed for that purpose is outlined. Video tracking systems enable researchers to study behavior in a reliable and consistent way and over longer time periods than if they were using manual recording. To overcome limitations of currently available systems, we have designed EthoVision, an integrated system for automatic recording of activity, movement, and interactions of animals. The EthoVision software is presented, highlighting some key features that separate EthoVision from other systems: easy file management, independent variable definition, flexible arena and zone design, several methods of data acquisition allowing identification and tracking of multiple animals in multiple arenas, and tools for visualization of the tracks and calculation of a range of analysis parameters. A review of studies using EthoVision is presented, demonstrating the system’s use in a wide variety of applications. Possible future directions for development are discussed.     

Index for Volume 20

Sixteen adult subjects served in an experiment in which the writing of six unfamiliar graphemes was practiced. To investigate the learning process, we analyzed the absolute and relative changes of movement time of the first three consecutive segments as a function of practice. The results showed that movement time of all three segments decreased. This decrease was significantly less in the first segment than it was in the second and third segment, however. We interpret these effects of practice, from an information-processing viewpoint, as follows: (a) Initially separate response segments become integrated in more comprehensive response chunks, and (b) the preparation of later segments of the grapheme is realized more and more during the real-time execution of the initial segment. The results further revealed that these learning effects were more pronounced in graphemes composed of familiar segments than in graphemes that contained unfamiliar segments. Finally, it turned out that similarity between initial and final segments hindered the writing speed of the first segment; the effect of similarity was independent of the above-mentioned effects of practice. The latter effect is interpreted as confirming evidence for the view that the preparation of later segments of a grapheme is reflected by changes of movement time of the first segments of a grapheme.     

Being flexible or rigid in goal-directed behavior: When positive affect implicitly motivates the pursuit of goals or means

Building on previous research on the role of positive affect as implicit motivator we investigated both flexibility and rigidity in goal-directed behavior. Given that goal-directed behavior can be represented in terms of goals or means, we suggest that goal-directed behavior is more flexible in switching means when positive affect implicitly motivates a person to reach the goal, but is more rigid in switching means when positive affect implicitly motivates a person to perform a specific means. Three experiments corroborated this idea: the speed of switching from a learned goal-directed means to a new means was facilitated when positive affect was attached to the representation of the goal, whereas this switching was slowed down when positive affect was attached to the representation of the learned means. Together, these findings provide new insights into the occurrence of flexibility and rigidity in implicitly motivated goal-directed behavior.     

Androgenetic alopecia: stress of discovery

The psychological problems of men in the initial stages of alopecia androgenetica (hereditary male hair loss) have seldom been studied. We evaluated two groups of 80 men with alopecia androgenetica in Stages II to IV, indicating the amount of hair loss (overall N=160; for Group I: M=48 yr., SD=18.2; for Group II: M=50 yr., SD=18.0) who visited a dermatology clinic for benign dermatological complaints but not for hair loss, by questionnaires and interview, retrospectively. As predicted, hair problems were reported to be significantly greater overall at the moment of discovery of hair loss than later. About half of the men reported feeling annoyed to very annoyed about the discovery of hair loss. For those patients, provision of information by internet might facilitate a visit to the dermatologist.