Age-trend-related differences in tasks involving conjunctive probabilistic reasoning

Conjunctive probabilistic reasoning has been studied at different ages to ascertain whether the conjunction fallacy is due to a task demand misinterpretation. Such a misinterpretation might occur because a task that requires a comparison between a superordinate class A and a subordinate class A&B is mistakenly interpreted as requiring a comparison between the two complementary subordinate classes of A (i.e., A&B and A¬B). Children (7- and 10-year-olds) and adults were required to make conjunctive probability judgments about problems for which explicit objective probabilities were provided. The total number of A items was kept constant and the frequencies of the A&B and of the A¬B items varied across problems. When the number of A&B items was smaller than the number of A¬B items, the frequency of congruent responses increased with age. When the number of A&B items was greater or equal to that of the A¬B items, the frequency of correct answers decreased. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

A mental number line in human newborns

Humans represent numbers on a mental number line with smaller numbers on the left and larger numbers on the right side. A left‐to‐right oriented spatial–numerical association, (SNA), has been demonstrated in animals and infants. However, the possibility that SNA is learnt by early exposure to caregivers’ directional biases is still open. We conducted two experiments: in Experiment 1, we tested whether SNA is present at birth and in Experiment 2, we studied whether it depends on the relative rather than the absolute magnitude of numerousness. Fifty‐five‐hour‐old newborns, once habituated to a number (12), spontaneously associated a smaller number (4) with the left and a larger number (36) with the right side (Experiment 1). SNA in neonates is not absolute but relative. The same number (12) was associated with the left side rather than the right side whenever the previously experienced number was larger (36) rather than smaller (4) (Experiment 2). Control on continuous physical variables showed that the effect is specific of discrete magnitudes. These results constitute strong evidence that in our species SNA originates from pre‐linguistic and biological precursors in the brain.     

Development and validation of the HIV Medication Readiness Scale

Excellent medication adherence (>95%) is required for optimal HIV treatment success. This study aimed to develop and validate a brief scale to assess psychological readiness for successfully starting and adhering to HIV medications. HIV-positive men and women (N = 142) from an HIV outpatient clinic completed the proposed HIV Medication Readiness Scale (HMRS) prior to starting HIV medications. The 10-item HMRS demonstrated high internal consistency (alpha = .90), test-retest reliability (r = .83), and sensitivity to change following a standardized 4-session psychoeducational intervention designed to increase readiness for successful adherence. Predictive validity was supported by higher readiness scores on the day starting HIV medications, predicting higher treatment adherence at 1-month follow-up. The HMRS is a brief, easy-to-use, clinically relevant tool that can assist in identifying people living with HIV at high risk of nonadherence, who might benefit from tailored readiness counseling prior to initiating HIV medications.     

How fish do geometry in large and in small spaces

It has been shown that children and non-human animals seem to integrate geometric and featural information to different extents in order to reorient themselves in environments of different spatial scales. We trained fish (redtail splitfins, Xenotoca eiseni) to reorient to find a corner in a rectangular tank with a distinctive featural cue (a blue wall). Then we tested fish after displacement of the feature on another adjacent wall. In the large enclosure, fish chose the two corners with the feature, and also tended to choose among them the one that maintained the correct arrangement of the featural cue with respect to geometric sense (i.e. left-right position). In contrast, in the small enclosure, fish chose both the two corners with the features and the corner, without any feature, that maintained the correct metric arrangement of the walls with respect to geometric sense. Possible reasons for species differences in the use of geometric and non-geometric information are discussed.     

Neural pathways mediating vaginal function: the vagus nerves and spinal cord oxytocin

The initial observations, made in our laboratory with Knut Larsson, of the ability of vaginocervical stimulation (VCS) to block withdrawal responses to foot pinch in rats has led to findings of multiple behavioral, autonomic, and neuroendocrine effects of this potent stimulus in rats and also in women. It has led to an understanding of: (1) the neuroanatomical and neurochemical basis of a novel and potent pain-blocking mechanism; (2) likely neuroanatomical pathways mediating both the Ferguson reflex and a specific autonomic response - the pupil-dilating effect of VCS; (3) a role for oxytocin as a putative central nervous system neurotransmitter that stimulates autonomic sympathetic preganglionic neurons within the spinal cord; and (4) a novel pathway that can convey sensory activity from the cervix, adequate to induce orgasm, via the vagus nerves. This latter pathway bypasses the spinal cord and projects directly to the medulla oblongata, and thus can convey genital afferent activity despite complete spinal cord injury at any level.     

Contents of Volume 58

Volume Contents

Contents of Volume 58