Multiple memory stores and operant conditioning: a rationale for memory's complexity

Why does the brain contain more than one memory system? Genetic algorithms can play a role in elucidating this question. Here, model animals were constructed containing a dorsal striatal layer that controlled actions, and a ventral striatal layer that controlled a dopaminergic learning signal. Both layers could gain access to three modeled memory stores, but such access was penalized as energy expenditure. Model animals were then selected on their fitness in simulated operant conditioning tasks. Results suggest that having access to multiple memory stores and their representations is important in learning to regulate dopamine release, as well as in contextual discrimination. For simple operant conditioning, as well as stimulus discrimination, hippocampal compound representations turned out to suffice, a counterintuitive result given findings that hippocampal lesions tend not to affect performance in such tasks. We argue that there is in fact evidence to support a role for compound representations and the hippocampus in even the simplest conditioning tasks.     

How mechanical context and feedback jointly determine the use of mechanical variables in length perception by dynamic touch

Earlier studies have revealed that both mechanical context and feedback determine what mechanical invariant is used to perceive length by dynamic touch. In the present article, the authors examined how these two factors jointly constrain the informational variable that is relied upon. Participants were to judge length while wielding a rod or while holding it stationary. In two experiments, it was tested whether perceptual learning effects in the wielding condition transferred to the holding condition and vice versa. There was an asymmetry in transfer across mechanical conditions: Improvements in the holding context transferred to the wielding condition, but not vice versa. Examining the individuals’ exploitation of mechanical variables, we found that, after feedback, participants changed in information usage in both mechanical conditions. For many participants, these changes were not confined to the mechanical context in which the feedback was provided. Indeed, feedback in one mechanical context brought about changes in information usage that often manifested themselves in the other mechanical condition. The authors explore the implications of these findings for research on perceptual learning in dynamic touch and the salience hypothesis.     

Electrophysiological examination of embodiment in vision and action

A wealth of behavioral data has shown that the visual properties of objects automatically potentiate motor actions linked with them, but how deeply are these affordances embedded in visual processing? In the study reported here, we used electrophysiological measures to examine the time course of affordance resulting from the leftward or rightward orientation of the handles of common objects. Participants were asked to categorize those objects using a left- or right-handed motor response. Lateralized readiness potentials showed rapid motor preparation in the hand congruent with the affordance provided by the object only 100 to 200 ms after stimulus presentation and up to 400 ms before the actual response. Examination of event-related potentials also revealed an effect of handle orientation and response-hand congruency on the visual P1 and N1 components. Both of these results suggest that activity in the early sensory pathways is modulated by the action associations of objects and the intentions of the viewer.     

Redundant sensory information does not enhance sequence learning in the serial reaction time task

In daily life we encounter multiple sources of sensory information at any given moment. Unknown is whether such sensory redundancy in some way affects implicit learning of a sequence of events. In the current paper we explored this issue in a serial reaction time task. Our results indicate that redundant sensory information does not enhance sequence learning when all sensory information is presented at the same location (responding to the position and/or color of the stimuli; Experiment 1), even when the distinct sensory sources provide more or less similar baseline response latencies (responding to the shape and/or color of the stimuli; Experiment 2). These findings support the claim that sequence learning does not (necessarily) benefit from sensory redundancy. Moreover, transfer was observed between various sets of stimuli, indicating that learning was predominantly response-based.     

Perceived parenting and separation-individuation in Belgian college students: associations with emotional adjustment

The present study examined associations among perceived parenting, separation-individuation, and emotional adjustment in a convenience sample of college students in Belgium (N=350; 68% female; aged 18 to 26). In line with a conceptual model advanced in the literature, factor analysis supported the distinction between three dimensions of separation-individuation: overdependence and healthy separation (both of which had already been described in earlier research) and a new dimension, labeled excessive autonomy. Path analysis findings were consistent with a mediational model in which lower quality of perceived parenting predicted more excessive autonomy, which in turn predicted poorer emotional adjustment. In addition, healthy separation predicted superior emotional adjustment, whereas overdependence was not associated with this particular type of adjustment. Implications for current understanding of the process of separation-individuation in college students and of excessive autonomy, in particular, are discussed.     

Breaking and creating habits on the working floor: A field-experiment on the power of implementation intentions

Previous research has shown that implementation intentions are effective tools to promote new behavior. The present study aimed to provide the first evidence that conscious planning is an effective tool in replacing well-learned habits with new habits. This was tested in a field-experiment on repetitive behavior in the domain of recycling, using 109 employees of a tele-company as participants. Recycling behavior of the participants was observed by the actual amount of paper and the number of plastic cups in their personal wastebaskets. Following a pre-measure, participants were assigned to either implementation intention conditions, conditions in which an eye-catching facility was placed to promote recycling behavior, or control conditions. Recycling behavior was substantially improved in the facility as well as the implementation intention conditions in week 1 and week 2 and still 2 months after the manipulation. These data supported our hypothesis that planning breaks down unwanted habits and creates new ones.     

Dancing shapes: a comparison of luminance-induced distortions

We present an illusory display in which a grid of outlined squares is positioned in front of a moving luminance gradient. Observers perceive a strong, illusory, 'wavelike' motion of the superimposed squares. We compared luminance effects on dynamic and static aspects of this illusion. The dynamic aspect was investigated by means of a temporal gradient, which induced an illusory pulsing of the outlined squares. The static aspect was investigated in two different ways. In one experiment, the outlined squares were positioned on a spatial gradient, which caused the squares to look like trapezoid shapes. In another experiment, the squares were positioned on different luminance fields, which affected their apparent size. In all experiments, luminance settings were the same, and observers were asked to indicate the direction and strength of the induced distortions. The overall results show large agreements between the dynamic distortion and the first-mentioned static distortion, whereas different tendencies emerged for the second static distortion. In a second series of experiments, we examined these distortions for various ranges of the luminance gradient and for border gradients as well. On the basis of these data, we explored how the directions of the perceived distortions of the single-gradient displays examined in this paper could be related to each other.     

Heavy drinking in college students: who is at risk and what is being done about it?

Problem drinking and related consequences are a major social issue plaguing college campuses across the United States. Each year, alcohol is responsible for fatalities, assaults, serious injuries, and arrests that occur among college students. The authors review and discuss the risk factors, drinking patterns, and consequences that are relevant to the general student population. In addition, the authors highlight individuals at an increased risk of experiencing alcohol-related problems, such as Greek-letter social organization members and student athletes. The authors also discuss the interventions that attempt to reduce risky drinking and related problems in these subgroups as well as the future directions for research.     

The effects of creative,expressive, and reflective writing on career learning: An explorative study

This study investigates whether creative, expressive, and reflective writing contributes to the formation of a work-life narrative that offers both meaning and direction among students in higher education. The content of writing done by students who participated in a two-day writing course at the start (or in preparation) of their work placements and of a control group who did not take part in the course were compared. Writing samples were analysed using the Linguistic Index Word Count program (Pennebaker, Booth, & Francis, 2007) and an instrument based on Dialogical Self Theory (Hermans & Hermans-Konopka, 2010). Results show writing promotes the development of career narratives.