Attachment, Friendship, and Psychosocial Functioning in Early Adolescence

Fifth-graders' (N = 162; 93 girls) relationships with parents and friends were examined with respect to their main and interactive effects on psychosocial functioning. Participants reported on parental support, the quality of their best friendships, self-worth, and perceptions of social competence. Peers reported on aggression, shyness and withdrawal, and rejection and victimization. Mothers reported on psychological adjustment. Perceived parental support and friendship quality predicted higher global self-worth and social competence and less internalizing problems. Perceived parental support predicted fewer externalizing problems, and paternal (not maternal) support predicted lower rejection and victimization. Friendship quality predicted lower rejection and victimization for only girls. Having a supportive mother protected boys from the effects of low-quality friendships on their perceived social competence. High friendship quality buffered the effects of low maternal support on girls' internalizing difficulties.     

Imperfection,Indecision, and Hoarding

Hoarding disorder is a new DSM-5 disorder that causes functional impairment and affects 2 to 6% of the population (Frost and Steketee 2014). The current study evaluated a multiple mediation model with 243 undergraduate women in which indecisiveness (VOCI; Thordarson et al. Behaviour Research and Therapy, 42(11), 1289-1314, 2004) and decisional procrastination (DPS; Mann 1982) mediated the relationship between dimensions of perfectionism (F-MPS-B; Burgess et al. 2016a) and hoarding behavior (SI-R; Frost et al. Behaviour Research And Therapy, 42(10), 1163–1182, 2004) and excessive acquiring (CAS; Frost et al. Annual Review of Clinical Psychology, 8, 219–242, 2012). Multiple mediational analyses indicated a significant indirect effect for decisional procrastination, but not indecisiveness, in mediating evaluative concerns (but not striving) to SI-R Total, SI-R Clutter, SIR Excessive Acquisition, and both CAS subscales. Both mediators were significant pathways between evaluative concerns and SI-R Difficulty Discarding. These findings support a cognitive behavioral model of hoarding, suggesting that evaluative concerns produces problems in decision-making that influence acquisition, discarding, and clutter.     

A computational approach to modeling population differences

Four experiments were conducted to determine whether the Hyperspace Analogue to Language (HAL) model of semantic memory could differentiate between two different populations. An analysis of the differences in densities (or average distances between word neighbors in semantic space) in HAL matrices—generated from text corpora derived from younger and older adults—confirmed that HAL was able to distinguish between the two age groups. This difference was again detected when structured interview data were used to build the corpora. A third experiment, designed to test the specificity of HAL in detecting differences between groups, did not detect any difference in the densities of the memory representations when older adults generated both the test corpora. The final experiment, conducted on the language of adults with Alzheimer’s and normal adults, again demonstrated that HAL could discriminate between the two populations. These results suggest that HAL is capable of modeling, on the basis of changes in mean density, some of the differences between populations without modifying the model itself but, rather, by changing the text corpus from which the model creates its representations in semantic space.     

Age effects in a computational model of memory

Previous research demonstrates that semantic priming is relatively unaffected by age (Chiarello, Church, & Hoyer, 1985; Howard, 1988). To determine how age might affect representations in the HAL model of memory, the authors gathered text from older and younger adults and generated a global co-occurrence matrix for each. An analysis demonstrated that, as in humans, there was little difference in measures of semantic priming between memory matrices constructed from the two corpora. However, the authors discovered that semantic word neighborhoods generated by the older adult corpus were denser than corresponding neighborhoods derived from the younger adult corpus. This result has implications for changes in the semantic representation of words due to the aging process.     

An analysis of generalized imitation

An experimenter presented English words to three intermediate-level children and reinforced accurate imitation of these words. The experimenter also presented novel Spanish words, but the imitation of these words was never experimentally reinforced. One subject quickly ceased performing non-reinforced imitative responses. The other two subjects were exposed to a series of conditions designed to facilitate discrimination. Upon observing the first subject for one session they immediately ceased imitating Spanish demonstrations. For all three subjects, when reinforcement was delivered for responses other than imitation, all imitative responses eventually ceased. When reinforcement was reintroduced for English imitations there was an immediate resumption of such responses to their previous 100% level. The occurrence of non-reinforced imitations in this and previous studies was discussed as being a function of one or combination of four variables: (1) similarity acquiring conditioned reinforcing properties, or (2) instructional, (3) coincidental, or (4) conditional stimulus generalization.     

Decidability for branching time

The species of indeterminist tense logic called Peircean by A. N. Prior is proved to be recursively decidable. To the memory of Ivo Thomas     

The degree of control exerted by phobic and non-phobic verbal stimuli over the recognition behaviour of phobic and non-phobic subjects

Four groups of subjects comprised of one control group, two analogue phobic groups and one clinical phobic group were exposed to a dichotic listening experiment in which they were required both to shadow one message to the exclusion of the other and recognize the occurrence of target words appearing in both the attended and rejected messages. Target words were either phobic-relevant or neutral. It was found that the clinical phobic group recognized significantly more target words than any of the other groups. This difference was due to their superior recognition of phobic-relevant targets from the rejected message. The results were interpreted within a combined framework of Staats's (1968, 1975) social behaviour theory and the Rescorla and Wagner (1972) model of classical conditioning.     

Matching since Baum (1979).

Data from recent studies employing concurrent variable-interval schedules are reviewed. Subject species employed in different experiments have included rats, pigeons, and humans, and reinforcers have varied from food and shock avoidance to points exchangeable for money. Undermatching (a greater preference for the schedule of the concurrent pair that delivers the lower rate of reinforcement than the Matching Law predicts) has been preponderant in recent studies, irrespective of whether behavior has been measured in terms of response ratios or time allocation, with the possible exception of data produced by human subjects. Little difference in the degree of undermatching exhibited by response and time measures has been found, except in the results from a single laboratory, in which time-allocation measures have tended to undermatch less than response measures. Procedural features, such as type of manipulandum used and changeover delay, seem to have little effect on the degree of undermatching exhibited, but asymmetrical response manipulanda (such as lever and key) for the different concurrent schedules, or other asymmetries in the experimental situation, show up clearly in bias measures, in a manner consistent with previous analyses.     

The hippocampus, space, and viewpoints in episodic memory

A computational model of how single neurons in and around the rat hippocampus support spatial navigation is reviewed. The extension of this model, to include the retrieval from human long-term memory of spatial scenes and the spatial context of events is discussed. The model explores the link between spatial and mnemonic functions by supposing that retrieval of spatial information from long-term storage requires the imposition of a particular viewpoint. It is consistent with data relating to representational hemispatial neglect and the involvement of the mammillary bodies, anterior thalamus, and hippocampal formation in supporting both episodic recall and the representation of head direction. Some recent behavioural, neuropsychological, and functional neuroimaging experiments are reviewed, in which virtual reality is used to allow controlled study of navigation and memory for events set within a rich large-scale spatial context. These studies provide convergent evidence that the human hippocampus is involved in both tasks, with some lateralization of function (navigation on the right and episodic memory on the left). A further experiment indicates hippocampal involvement in retrieval of spatial information from a shifted viewpoint. I speculate that the hippocampal role in episodic recollection relates to its ability to represent a viewpoint moving within a spatial framework.