The effects of postconditioning revaluation of CS1 and UCS following pavlovian second-order electrodermal conditioning in humans

An experiment is described which uses various inferential post-conditioning revaluation techniques in order to clarify the associative substructure underlying Pavlovian electrodermal conditioning in human subjects. This study established a second-order skin conductance response (SCR) by pairing a CS₁ with an aversive 115 dB tone (UCS), and then pairing a different stimulus (CS₂) with CS₁. The second-order SCR survived post-conditioning extinction of the response to CS₁, but was abolished when (i) a post-conditioning habituation procedure resulted in a favourable revaluation of the tone UCS, or (ii) when subjects were given instructions which informed them that there would be no more UCS presentations. These results suggest that in the second-order electrodermal conditioning paradigm described, CR₂ is not mediated by S-R links--as it appears to be in second-order aversive conditioning in nonhuman animals--but is affected by manipulations which modify the subject's cognitions concerning the UCS.     

Killing and Letting-Die: Bare Differences and Clear Differences

Philosophical Studies -     

The social behaviours of inhibited children in and out of preschool

The goal of the present study was to explore the social behaviours of inhibited children in familiar social contexts, including: (1) free play with peers at preschool and (2) social activities at home and in the community. The initial participants were N =248 preschool children between the ages of 42 and 66 months. From this initial data, two smaller groups of inhibited (N =12) and uninhibited comparison (N =12) children were identified. These children were observed during free play at preschool and parents completed daily logs of children's social activities outside of school. Among the findings, inhibited children were observed to display more reticent (on looking, unoccupied) and anxious behaviours during free play preschool than uninhibited children. As well, inhibited children participated less in structured social activities outside school and were more likely to engage in dyadic play at home with a single friend as compared to their uninhibited counterparts.