Psychophysics of associative learning: Quantitative properties of subjective contingency.

Allan and collaborators (Allan, Hannah, Crump, & Siegel, 2008; Allan, Siegel, & Tangen, 2005; Siegel, Allan, Hannah, & Crump, 2009) recently proposed to apply signal detection theory to the analysis of contingency judgment tasks. When exposed to a flow of stimuli, participants are asked to judge whether there is a contingent relation between a cue and an outcome, that is, whether the subjective cue-outcome contingency exceeds a decision threshold. In this context, we tested the following hypotheses regarding the relation between objective and subjective cue-outcome contingency: (a) The underlying distributions of subjective cue-outcome contingency are Gaussian; (b) The mean distribution of subjective contingency is a linear function of objective cue-outcome contingency; and (c) The variance in the distribution of subjective contingency is constant. The hypotheses were tested by combining a streamed-trial contingency assessment task with a confidence rating procedure. Participants were exposed to rapid flows of stimuli at the end of which they had to judge whether an outcome was more (Experiment 1) or less (Experiment 2) likely to appear following a cue and how sure they were of their judgment. We found that although Hypothesis A seems reasonable, Hypotheses B and C were not. Regarding Hypothesis B, participants were more sensitive to positive than to negative contingencies. Regarding Hypothesis C, the perceived cue-outcome contingency became more variable when the contingency became more positive or negative, but only to a slight extent. (PsycINFO Database Record

Integration of multiple memories in sensory preconditioning.

The present study demonstrates that humans' response to a single stimulus (S1) is determined by what follows S1's associates. The experiment used a sensory preconditioning (SPC) design where S1 was associated with both S2 and S3 on separate trials before establishing relationships between these latter stimuli with an outcome or its absence in a second phase. When S2 and S3 were associated with the same consequence, either an outcome or its absence, strong consequence-based responding to S1 was observed in a reaction time test. Participants responded quickly to indicate that the outcome was, or was not, predicted by S1. When S2 predicted the outcome and S3 did not, SPC was weaker although participants were not slower to respond to S1. Implications on the understanding of the mechanisms that allow for the response to S1 to emerge are discussed.

Maternal depression related to infant's wheezing.

OBJECTIVE: To assess whether maternal psychological status is related to infant's wheezing. STUDY DESIGN: In a case-control study conducted in Paris in cases aged less than 36 months suffering from wheezing and matched healthy controls, mothers filled a standardized questionnaire on child's health and the State Trait Anxiety Inventory form Y-B and the Beck Depression Inventory short form. Cases underwent also routine clinical and biological assessments. The statistical analysis used the propensity score analysis to control for selection bias. RESULTS: Hundred and thirty-eight wheezers and hundred and nine controls participated in the study. After adjustment for confounders, maternal depressive symptoms at the period of the survey according to the Beck Inventory were more significantly found in the cases than in others (p < 0.01). A trend was found for maternal depression during pregnancy. Among the cases, 10.6% suffered from severe asthma, 84.8% took inhaled corticosteroids (ICs), 17.4% had positive specific immunoglobulin E (IgE) to allergens and 11.5% hypereosinophilia. The more the mother was depressed according to the Beck Inventory, the more the infant's asthma was severe (OR = 4.25, 95% CI: 1.14, 15.9 between severe infant's wheezing and severe maternal depression). No relationship was observed between mother's depressive symptoms and ICs taken by the infant, allergic sensitization or eosinophilia. CONCLUSION: Our findings support the hypothesis of a link between maternal depression and infant's wheezing and its severity early in life independent of allergic status. Consequences of our study include the need to assess depressive symptoms in mothers of infants with asthma.