Glucose effects on memory: behavioral and pharmacological characteristics

Recent findings indicate that post-training glucose injections can modulate memory storage for inhibitory (passive) avoidance training. Experiment I extended these findings to determine whether glucose, like other memory modulating treatments, enhances memory storage when administered after training with low footshock and impairs memory storage after high footshock training. In Experiment I, male Sprague-Dawley rats were trained in a one-trial inhibitory avoidance task using either a brief footshock (0.5 mA, 0.7 s) or slightly more intense footshock kept on until escape (0.7 mA, mean escape latency = 3.4 s). Immediately after training, each rat received a subcutaneous injection of glucose (100 mg/kg). When tested for retention performance 24 h later, the glucose-injected animals exhibited enhanced retention performance for low footshock training and impaired retention for high footshock training. Experiment II determined whether pretreatment with adrenergic antagonists blocked the effects of glucose on memory. Pretreatment with the alpha- or beta-adrenergic receptor antagonists, phenoxybenzamine, or propranolol, respectively, had no effect on acquisition or retention in animals trained with the brief footshock and did not affect glucose facilitation of that memory. In animals trained to escape footshock, phenoxybenzamine did not attenuate the amnesia produced by glucose. Propranolol-pretreated animals had impaired retention whether or not they received post-training amnestic injections of glucose; glucose had no effect on retention in these amnestic animals. These findings add further support to the view that glucose release after training and treatment may represent a physiological response subsequent to epinephrine release in modulating memory storage processing.     

What is agentic about the Spatial Agency Bias? How pragmatic relevance contributes to the spatial representations of actions

The mental imagination of (social) actions has been shown to follow a left‐to‐right trajectory, with the thematic agent associated with the left position (Spatial Agency Bias, Suitner & Maass in Advances in Experimental Social Psychology, 53, 2016, p. 245–301). For example, individuals asked to choose a picture that visualizes the sentence “Tom kicks George” tend to choose an image where the agent, Tom, is positioned on the left‐hand side rather than on the right‐hand side. However, as an alternative to the thematic role of the agent, such findings may reflect a mental representation following pragmatic relevance. Specifically, a pragmatic perspective holds that word order and syntactic functions are strategic devices to communicate that the element is important for the sentence. Thus, positioning in the described picture‐matching task may actually reflect the agent's pragmatic relevance instead of agency per se. As a test, we vary whether sentences are written in the active versus the passive voice. Results from five studies indicate that the passive voice results in the tendency to place the agent on the right‐hand side rather than on the left‐hand side of a picture. Instead, the acted‐upon person is positioned on the left‐hand side of a picture. A sixth experiment reveals that for the passive voice, the agent is still seen as more agentic than the receiver, but is considered less relevant. The findings are congruent with the proposed pragmatic relevance account. Implications for the Spatial Agency Bias as well as for building mental representations in general are discussed.     

Too exhausted to go to bed: Implicit theories about willpower and stress predict bedtime procrastination

While most people are aware of the importance of sleep for their health, well-being, and performance, bedtime procrastination is a pervasive phenomenon that can be conceptualized as a case of self-control failure (Kroese et al., Frontiers in Psychology, 5, 2014, 1). Two daily diary studies (N₁ = 185, N₂ = 137) investigated beliefs about willpower and stress as interactive predictors of bedtime procrastination. Beliefs about willpower capture whether people think of their willpower as limited resource that gets easily depleted (limited theory) or as something that remains regardless of previous acts of self-control (non-limited theory). Results show that after a stressful day, people with a limited versus non-limited theory procrastinate more on going to bed, while there is no difference in bedtime procrastination on less stressful days. Thus, ironically, limited theorists who should be more concerned with recovering their resources after a stressful day sleep less the following night.     

Individual and Dyadic Coping and Fear of Progression in Mothers and Fathers of Children with Hematologic Cancer

This study investigated the association of individual and dyadic coping strategies with fear of progression (FoP) in mothers and fathers of children with hematologic cancer. Parental couples (N = 44) whose children had been diagnosed with hematologic cancer were recruited at a university hospital and a rehabilitation clinic in Germany between 03/2017 and 08/2017. Data included parents' self-report on FoP (Fear of Progression Questionnaire—parent version, FoP-Q-SF/PR), individual coping (Coping Health Inventory for Parents, CHIP-D), and dyadic coping (Dyadic Coping Inventory, DCI). Statistical analyses were carried out for mothers and fathers individually as well as for parental couples using dyadic data analyses (e.g., actor-partner interdependence model, APIM). Individual and dyadic coping strategies were significantly correlated with FoP in mothers, but not in fathers. Fathers' evaluation of the couple's dyadic coping significantly predicted mothers' FoP. The more frequent use of familial integration (CHIP-D FAM) and maintaining social support (CHIP-D SUP) as well as a better evaluation of their partners' dyadic coping was significantly associated with lower FoP in mothers. Differences in individual and dyadic coping in parental couples were not associated with FoP. Individual and dyadic coping strategies should be addressed in the psychosocial care of mothers and fathers of children with hematologic cancer. Study results support the benefits of involving fathers in psychosocial interventions, for example, in couple-based interventions that acknowledge interpersonal effects of coping on FoP. Future research should further explore coping strategies applied by fathers of children with hematologic cancer for the regulation of FoP.     

Self-protection and growth as the motivational force behind majority group members' cultural adaptation and discrimination: A parallel mediation model via intergroup contact and threat

What motivates majority group members to adapt to or reject cultural diversity? Considering the relevance of personal values on our attitudes and behaviours, we inspected how self-protection and growth predict levels of discriminatory behavioural and cultural adaptation intentions towards migrants via intergroup contact and perceived intergroup threats, simultaneously (i.e., parallel mediation). Specifically, positive contact between groups is known for reducing prejudice through diminishing perceived intergroup threats. Yet current research emphasises the role of individual differences in this interplay while proposing a parallel relationship between perceived intergroup threats and contact. Also by inspecting cultural adaptation and discriminatory behavioural intentions, the present study examined more proximal indicators of real-world intergroup behaviours than explored in past research. Using data from 304 US Americans, structural equation modelling indicated a good fit for a parallel mediation model with growth relating positively to cultural adaptation intentions and negatively to discriminatory behavioural intentions through being positively associated with intergroup contact and negatively with perceived intergroup threats, simultaneously. The reverse was found for self-protection. These findings stress that personal values constitute a relevant individual difference in the contact/threats-outcome relationship, providing a motivational explanation for majority group members' experience of cultural diversity in their own country.     

Braking reaching movements: a test of the constant tau-dot strategy under different viewing conditions

Following F. Zaal and R. J. Bootsma (1995), the authors studied whether the decelerative phase of a reaching movement could be modeled as a constant tau-dot strategy resulting in a soft collision with the object. Specifically, they investigated whether that strategy is sustained over different viewing conditions. Participants (N = 11) were required to reach for 15- and 50-mm objects at 2 different distances under 3 conditions in which visual availability of the immediate environment and of the reaching hand were varied. Tau-dot estimates and goodness-of-fit were highly similar across the 3 conditions. Only within-participant variability of tau-dot estimates was increased when environmental cues were removed. That finding suggests that the motor system uses a tau-dot strategy involving the intermodal (i.e., visual, proprioceptive, or both) specification of information to regulate the decelerative phase of reaching under restricted viewing conditions. The authors provide recommendations for improving the derivation of tau;(x) estimates and stress the need for further research on how time-to-contact information is used in the regulation of the dynamics of actions such as reaching.     

The role of specific consequences in the maintenance of three types of questions

This research replicated and extended a study by Williams, Donley, and Keller (2000). In that study, children with autism received a box with an object inside and learned to ask “What's that?,” “Can I see it?,” and “Can I have it?” to have the name of the object, to see the object, and to get the object, respectively. The purpose of the present research was to determine if the three questions (a) were three independent repertoires of behavior, (b) constituted three instances of a single functional response class, or (c) belonged to a chain of behavior. The 3 boys with autism who participated responded independently to each question when the consequences for each question were altered. This indicates that the three target responses were three independent repertoires of behavior, each one reinforced and maintained with its specific consequences. Thus, this procedure serves to teach children with autism to ask questions with flexibility according to a variable context.     

Predicting stuttering from linguistic factors for German speakers in two age groups

Brown's factors [J. Speech Disorders 10 (1945) 181] predict the likely loci of disfluency in English-speaking adults who stutter. A word is more likely to be stuttered for these speakers if it is a content word, starts with a consonant, is positioned at the beginning of a sentence, and if it is a long word. These same factors were examined in native German-speaking children and adults who stutter. Speech data of 15 German adults and 17 children were coded according to Brown's factors. For the adult group, it was predicted that words starting with consonants would not lead to as much of an increase in disfluencies compared with English samples, because of cross-linguistic differences in syllable onset properties. It was predicted that stuttering would be more likely in later sentence positions in German because in German the verb is usually near the end of a sentence. There were no obvious reasons to expect differences on the two remaining factors, content words and word length. With children, it was hypothesised that Brown's factors that specify level of linguistic difficulty would not be such a good predictor of stuttering rate. Specifically, it was predicted that the difference in stuttering rate between function and content words would be lower in children. For the adults both word type (content/function) and word length increased stuttering rate significantly, whereas changes in stuttering rate for the other two factors were non-significant. It was also found that when word difficulty (based on a combined measure of all factors) increased, stuttering rate rose. With children, only the word-length factor was significant, and stuttering rate was not governed to the same extent by overall word difficulty. Conclusions are drawn as to the effect of linguistic and motor influences on stuttering. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to describe: (1) how linguistic factors affect stuttering rates in German; (2) the different patterns of adults and children who stutter and how language might influence this pattern; and (3) how to interpret these findings in light of a current theory of fluency failure.