Temporary inactivation of the dorsal entorhinal cortex impairs acquisition and retrieval of spatial information

We tested the effects of temporary inactivation of the dorsal entorhinal cortex on spatial discrimination using a conditioned cue preference (CCP) paradigm. The three phases of the procedure were: pre-exposure: unreinforced exploration of the center platform and two adjacent arms of an eight-arm radial maze; training: rats were confined to the ends of the two arms on alternate days – one arm always contained food and the other never contained food; testing: unreinforced exploration of the center platform and the two arms. Rats that received bilateral infusions of saline into the dorsal entorhinal cortex before the training trials or before the test trial spent significantly more time in the arm that previously contained food than in the arm that never contained food, demonstrating that they had acquired and were able to express information that discriminated between the two adjacent maze arms. In contrast, rats that received bilateral, intra-entorhinal infusions of muscimol, a gamma-aminobutyric acid_a (GABA_a) agonist, before either training or testing spent equal amounts of time in the two arms, indicating that they failed to acquire and were unable to express this information. Interactions between the entorhinal cortex and hippocampus in the acquisition and expression of the information required for this discrimination are discussed.     

Becoming self-directed: Abstract representations support endogenous flexibility in children

A fundamental part of growing up is going beyond routines. Children become increasingly skilled over the first years of life at actively maintaining goals in the service of flexible behavior, allowing them to break out of habits and switch from one task to another. Their early successes often occur with exogenous (externally-provided) goals, and only later with endogenous (internally-driven) goals – a developmental progression that may reflect the greater demands on selection processes inherent in deciding what to do. Three studies investigated the mechanisms supporting endogenous flexibility, using a verbal fluency task in which children generated members of a category and could decide on their own when to switch from one subcategory to another. Children’s verbal fluency related to their performance in a more constrained and well-established switching task (Experiment 1), suggesting that the more complex verbal fluency measure taps the flexibility processes of interest. Children’s verbal fluency was also linked to their abstract, categorical representations in both individual difference analyses (Experiment 2) and experimental manipulation (Experiment 3). We interpret these results in terms of the role of abstract representations in reducing selection demands to aid the development of endogenous control.     

Mobile phone use while driving: An investigation of the beliefs influencing drivers’ hands-free and hand-held mobile phone use

This study explored the psychological influences of hands-free and hand-held mobile phone use while driving. Participants were 796 Australian drivers aged 17–76 years who owned mobile phones. A cross-sectional survey assessed frequency of calling and text messaging while driving (overall, hands-free, hand-held) as well as drivers’ behavioural, normative, and control beliefs relating to mobile phone use while driving. Irrespective of handset type, 43% of drivers reported answering calls while driving on a daily basis, followed by making calls (36%), reading text messages (27%), and sending text messages (18%). In total, 63.9% of drivers did not own hands-free kits and, of the drivers that owned hand-free kits, 32% did not use it most or all of the time. Significant differences were found in the behavioural, normative, and control beliefs of frequent and infrequent users of both types of handset while driving. As expected, frequent users reported more advantages of, more approval from others for, and fewer barriers that would prevent them from, using either a hands-free or a hand-held mobile phone while driving than infrequent users. Campaigns to reduce mobile phone use while driving should attempt to minimise the perceived benefits of the behaviour and highlight the risks of this unsafe driving practice.     

Indirect peer aggression in adolescence and reproductive behavior

Evolutionary psychologists have suggested that indirect aggression during adolescence is a strategy to compete with same-sex peer rivals for resources, status, and mating opportunities. We collected survey data on 143 young adults to determine retrospectively, the amount of indirect aggressive behavior they perpetrated and the amount of indirect victimization they experienced in middle school and high school. We also collected information about reproductive opportunities such as age at first sexual intercourse and number of lifetime sex partners to determine whether aggression or victimization could be used to predict measures of reproductive opportunity. We performed a principal components analysis to develop factors from 16 aggression and victimization variables. Results indicate that females who reported indirect aggression toward peers had earlier ages at first sexual intercourse and females who were more victimized in adolescence experienced later ages at first sexual intercourse. We discuss these results in terms of intrasexual competition and evolutionary theory.     

On Guessing: An Alternative Adjusted Positive Learning Estimator and Comparing Probability Misspecification With Monte Carlo Simulations

Practitioners in the sciences have used the “flow” of knowledge (post-test score minus pre-test score) to measure learning in the classroom for the past 50 years. Walstad and Wagner, and Smith and Wagner moved this practice forward by disaggregating the flow of knowledge and accounting for student guessing. These estimates are sensitive to misspecification of the probability of guessing correct. This work provides guidance to practitioners and researchers facing this problem. We introduce a transformed measure of true positive learning that under some knowable conditions performs better when students’ ability to guess correctly is misspecified and converges to Hake’s normalized learning gain estimator under certain conditions. We then use simulations to compare the accuracy of two estimation techniques under various violations of the assumptions of those techniques. Using recursive partitioning trees fitted to our simulation results, we provide the practitioner concrete guidance based on a set of yes/no questions.     

Gender and priming differences in speed of processing of information relating to social structure

Previous research has shown that women and men’s different interactional contexts result in selective differences in retention of information (e.g., Gabriel & Gardner, 1999). This study tested the hypothesis that there should be broad gender-related differences in latencies of retrieval of information focused on groups or dyads, with women processing the latter more rapidly, and men processing the former more rapidly. Participants were given a diary reading task with explicit recall instructions. Results showed that although no difference was found in overall retention of items, women responded more rapidly to items referring to dyads, while men responded more rapidly to items referring to groups. In addition, a strong effect of the gender of the protagonist of the diary was found. Participants of both gender responded more rapidly to dyadic items when the protagonist was female but responded more rapidly to group items when the protagonist was male. These results indicate that gender differences in social structure result in differences in encoding and retrieval of broad classes of information that are not accountable for by selective retention.     

Culture, self-construal, and affective reactions to successful and unsuccessful others

Three studies examined whether cultural background and self-construal predict affective reactions to successful and unsuccessful others. Asian-Canadians and those with more interdependent self-construals had less positive affective reactions to an unsuccessful than a successful other, and less positive affective reactions to an unsuccessful other than did European-Canadians and those with less interdependent self-construals (Study 1). Priming self-construal in a sample of European-Canadians mimicked these cultural differences (Study 2), and this priming effect was moderated by cultural background (Study 3). Asian-Canadians primed with interdependence (but not independence) had less positive affective reactions to an unsuccessful than a successful target, whereas European-Canadians primed with independence (but not interdependence) had more positive affective reactions to an unsuccessful than a successful target.     

Reasons for Belief

Davidson claims that nothing can count as a reason for a belief except another belief. This claim is challenged by McDowell, who holds that perceptual experiences can count as reasons for beliefs. I argue that McDowell fails to take account of a distinction between two different senses in which something can count as a reason for belief. While a non-doxastic experience can count as a reason for belief in one of the two senses, this is not the sense which is presupposed in Davidson's claim. While 1 focus on McDowell's view, the argument generalizes to other views which take experiences as reasons for belief.