A Study of Blocking and Overshadowing in Filial Imprinting

The occurrence of blocking and overshadowing in filial imprinting was investigated in junglefowl chicks (Gallus gallus spadiceus). When subjects were exposed to a novel object in the presence of a familiar one, imprinting on the novel object was impaired in one of two experimental groups (Experiment 1). When subjects were exposed to two objects from the beginning, imprinting on each object was impaired (Experiment 2). These results suggest that phenomena resembling blocking and overshadowing in conditioning may occur in imprinting. The fact that overshadowing was much more prevalent and convincing than blocking is discussed by referring to processes involved in the formation of internal representations. It is suggested that processes connecting these representations to the executive system of filial behaviour may follow the rules of associative learning.     

Effectiveness of Two Cognitive Interventions Promoting Happiness with Video-Based Online Instructions

A 3-month experimental online study examined the short-term and 1 month follow-up effects of regularly practicing one of two cognitive interventions on subjective well-being. Participants were 435 self-selected adults (366 female, 69 male, aged 18–63) randomly assigned to one of three conditions: writing about best possible selves in the future (n = 135), making gratitude lists (n = 150) or writing to-do-lists as a control condition (n = 150). The study was fully self-administered and exercise instructions were given in online videos. Repeated-measures MANOVA revealed that both interventions significantly increased subjective well-being in comparison to the control condition. Effect sizes for the different components of subjective well-being ranged from r = .09–.13 (η² = .01–.02) for the 2 months intervention period. These effects were maintained until the 1-month follow-up. Enjoyment and interest regarding the exercise as indicators of perceived person-intervention-fit moderated the effect; participants of the happiness interventions who perceived a better fit showed greater increases in subjective well-being. These findings confirm previous research on these interventions and encourage further studies on online interventions, especially regarding possibilities to increase participants’ motivation and reduce dropout attrition.     

Functional Mobility in a Divided Attention Task in Older Adults With Cognitive Impairment

ABSTRACT. Motor disorders may occur in mild cognitive impairment (MCI) and at early stages of Alzheimer's disease (AD), particularly under divided attention conditions. We examined functional mobility in 104 older adults (42 with MCI, 26 with mild AD, and 36 cognitively healthy) using the Timed Up and Go test (TUG) under 4 experimental conditions: TUG single task, TUG plus a cognitive task, TUG plus a manual task, and TUG plus a cognitive and a manual task. Statistically significant differences in mean time of execution were found in all four experimental conditions when comparing MCI and controls (p < .001), and when comparing MCI and AD patients (p < .05). Receiver-operating characteristic curve analyses showed that all four testing conditions could differentiate the three groups (area under the curve > .8, p < .001 for MCI vs. controls; area under the curve > .7, p < .001 for MCI vs. AD). The authors conclude that functional motor deficits occurring in MCI can be assessed by the TUG test, in single or dual task modality.