Learning to like triangles: A longitudinal investigation of evaluative conditioning in infancy.

There is tentative evidence that infants can learn preferences through evaluative conditioning to socioemotional stimuli. However, the early development of evaluative conditioning and the factors that may explain infants' capacity to learn through evaluative conditioning are not well understood. Infants (N = 319; 50.2% boys) participated in a longitudinal study where an evaluative conditioning paradigm using socioemotional stimuli was conducted on two occasions (when infants were 7 and 14 months old, on average). We tested whether repeatedly pairing neutral stimuli (triangular and square shapes) with affective stimuli (angry and happy faces) affects infants' preferences for these shapes. At both timepoints, the majority of infants did not choose the shape that was paired with happy faces, indicating that, in general, learning through evaluative conditioning was not present. However, as expected, individual differences were evident such that infants who spent more time fixating on faces compared to shapes (face-preferrers) during the conditioning trials were significantly more likely than non-face-preferrers to choose the shape paired with happy faces, and this effect strengthened with increasing age.

Still connecting the dots: An investigation into infants' attentional bias to threat using an eye-tracking task.

An attentional bias toward threat has been theorized to be a normative aspect of infants' threat and safety learning, and an indicator of risk for internalizing psychopathology in older populations. To date, only four studies have examined this bias using the dot-probe task in infancy and the findings are mixed. We extended the literature by examining patterns of attention to threat in a culturally and linguistically diverse sample of infants aged 5-11 months old (N = 151) using all measures previously employed in the infant dot-probe literature. Given that an attentional bias toward threat is associated with higher risk of developing anxiety disorders later in life, we also examined how negative affect-an early correlate of later anxiety disorders-is related to attentional bias toward threat in infancy. This study was the first to use a consistent measure of negative affect across the whole sample. An eye-tracking dot-probe task was used to examine attentional bias toward threat (i.e., angry faces) relative to positive (i.e., happy faces) stimuli. Results showed that an attention bias to threat was not characteristic of infants at this age, and negative affect did not moderate the putative relationship between attention and emotional faces (angry, happy). These findings therefore suggest that attention biases to socio-emotional threat may not have emerged by 11 months old.

The role of the response-outcome association in the nature of inhibitory Pavlovian-instrumental transfer in rats.

Inhibitory stimuli can reduce animals' reward seeking in an outcome-specific manner or outcome-general manner. However, we do not understand the factors that determine which of these effects are produced. To address this, we carried out three experiments which examined whether instrumental training with one or multiple outcomes determined the nature of subsequently observed Pavlovian-instrumental transfer (PIT). Rats underwent Pavlovian training to produce inhibitors and excitors for two outcomes using a feature-negative procedure. In Experiment 1, these stimuli were tested for their effects on a single response trained with one of those outcomes in a PIT procedure. Here, stimuli trained as inhibitors and excitors were found to produce outcome-general effects on reward seeking (in addition to an outcome-specific effect for excitors). In Experiment 2, we trained two responses, one for each of the Pavlovian outcomes, and tested the effect of the stimuli on each response individually. This design also produced outcome-general inhibitory and excitatory PIT effects. Experiment 3 followed the procedure of Experiment 2, except for implementation of a shorter Pavlovian training phase and an additional choice test, where both responses were concurrently available. This procedure produced putative inhibitory effects that were also outcome-general. However, outcome-specific excitatory effects were observed, indicating that the general inhibitory results may not be attributable to the duration of Pavlovian training. Overall, this study suggests that variations in the number of response-outcome contingencies experienced by animals do not readily determine the specificity of putative inhibitors.