The effect of mechanical context on attentional cost in unimanual coordination

The purpose of this study was to address the attentional cost of sensorimotor coordination by determining if changes to the mechanical context of movement would influence the ability to attend and respond to an alternate stimulus. Nine right-handed participants performed rhythmic pronation and supination movements of the forearm in time with an auditory metronome. A secondary task, consisting of a pedal response to visual probe stimuli, was employed to infer the attentional cost of the coordination task. When the axis-of-rotation (AOR) was placed below the long axis of the forearm, the average time to react (RT) to the probe stimuli was greater for the supinate-on-the-beat condition than for the pronate-on-the-beat condition. Conversely, with the AOR above the forearm, RT for the pronate-on-the-beat pattern was greater than that for the supinate-on-the-beat pattern. Thus, changing the mechanical context of an upper limb coordination task altered the central processing cost required to maintain pattern stability. This finding provides further evidence that the attentional resources required to produce a particular movement are determined by the ease with which the action is executed by the sensorimotor system.     

Process demands of rejection mechanisms of recognition memory

A surge of research has been conducted to examine memory editing mechanisms that help distinguish accurate from inaccurate memories. In the present experiment, the authors examined the ability of participants to use novelty detection, recollection rejection, and plausibility judgments to reject lures presented on a recognition memory test. Participants studied a list of word pairs that were arranged in a category relationship (both words from the same category) or an unrelated relationship (both words from different categories) under full or divided attention. At test, participants were given a yes/no recognition test in which they were to respond after seeing the test items for 400 ms or 2,800 ms. Some of the test items were rearranged word pairs that were consistent with the study relationship, whereas others were inconsistent with the study relationship. The results demonstrate that the participants required full attention at study to use novelty detection, recollection rejection, and plausibility judgments to reject lures. Moreover, the results indicate that a long response deadline at test was needed for participants to use both recollection rejection and plausibility judgments to reject lures.     

Drinking motives as mediators in the relation between personality disorder symptoms and alcohol use disorder

Research shows high comorbidity between Cluster B Personality Disorders (PDs) and Alcohol Use Disorders (AUDs). Studies of personality traits and alcohol use have identified coping and enhancement drinking motives as mediators of the relation among impulsivity, negative affectivity or affectivity instability, and alcohol use. To the extent that certain PDs reflect extreme expression of these traits, drinking motives were hypothesized to mediate the relation between PD symptoms and presence/absence of an alcohol use disorder (AUD). This hypothesis was tested using a series of cross-sectional and prospective path models estimating the extent that coping and enhancement drinking motives mediated the relation between cluster A, B, and C PD symptom counts and AUD diagnosis among a sample of 168 young adults between ages 18 and 21. Enhancement motives mediated the cross-sectional relation between Cluster B symptoms and AUD. Prospectively, enhancement motives partially mediated the relation between Cluster B personality symptoms and AUD through the stability of Year 1 AUD to Year 3 AUD. Results suggest that enhancement motives may be especially important in understanding the relation between Cluster B personality disorders and AUDs.     

Desgabets on Cartesian Minds

George Berkeley maintains both anti-abstractionism (that abstract ideas are impossible) and idealism (that physical objects and their qualities are mind-dependent). Some scholars (including Atherton, Bolton, and Pappas) have argued, in different ways, that Berkeley uses anti-abstractionism as a premise in a simple argument for idealism. In this paper, I argue that the relation between anti-abstractionism and idealism in Berkeley's metaphysics is more complex than these scholars acknowledge. Berkeley distinguishes between two kinds of abstraction, singling abstraction and generalizing abstraction. He then rests his case for idealism, not on the denial of the possibility of generalizing abstraction, but rather on the denial of the possibility of singling abstraction. Moreover, Berkeley's argument does not rest on a blanket rejection of all forms of singling abstraction. Rather, the fundamental anti-abstractionist assumption, for his purposes, is the claim that primary qualities cannot be mentally singled out from secondary qualities. Crucially, the claim that the existence of physical objects cannot be mentally singled out from their being perceived is not a premise in, but rather a consequence of, Berkeley's argument for idealism. Berkeley's argument therefore avoids circularity inasmuch as it appeals to the impossibility of singly abstracting one idea in order to establish the impossibility of singly abstracting another.     

No evidence of age-related increases in unconscious plagiarism during free recall

In three experiments younger and older participants took part in a group generation task prior to a delayed recall task. In each, participants were required to recall the items that they had generated, avoiding plagiarism errors. All studies showed the same pattern: older adults did not plagiarise their partners any more than younger adults did. However, older adults were more likely than younger adults to intrude with entirely novel items not previously generated by anyone. These findings stand in opposition to the single previous demonstration of age-related increases in plagiarism during recall.     

Prepared movements are elicited early by startle

A startle stimulus has been shown to elicit a ballistic response in a reaction time (RT) task at very short latencies without involvement of the cerebral cortex (J. Valls-Sole, J. C. Rothwell, F. Gooulard, G. Cossu, & E. Munoz, 1999). The present authors examined the nature of the startle response. A simple RT task was used in which 8 participants performed arm extension movements to 3 target distances (20 degrees, 40 degrees, and 60 degrees ) in a blocked design. An unpredictable startling acoustic stimulus (124 dB) replaced the imperative stimulus in certain trials. The authors verified the presence of a startle response independent from the prepared response by observing electromyographic (EMG) activity in sternocleidomastoid and orbicularis oculi muscles. Findings indicated that when the participant was startled, the intended voluntary response was produced at significantly shorter response latencies. Furthermore, the kinematic variables of the observed response during startle trials for all 3 target distances were mostly unchanged. The EMG characteristics of the responses were not modified, indicating that the response produced was indeed the prepared and intended response.