Friday, 4 October 2013

A couple of new publications to share

Wow, where has the time gone? In particular, what's happened to summer?!

It's Autumn and I'm already busy with the start of semester, grant and paper writing, and welcoming new students (PhD and UG) to the lab. So I just wanted to update the blog and share details of two recently published studies.

The first study is from a BIAL Foundation project and was published in Computers in Human Behavior. It's on conditioned suppression, which is a behavioural model of anxiety where a previously conditioned aversive cue (CS+) interupts or supresses appetitive, approach-oriented operant behaviour. We received funding to develop a virtual reality task with which to investigate conditioned suppression in humans. And the results are very promising! Here's the abstract of the study:

Virtual environments (VEs) provide an inexpensive way of conducting ecologically valid psychological research. The present study used a VE to demonstrate conditioned suppression, a behavioral model of anxiety, in a first-person perspective video game. During operant training, participants learned to shoot crates to find gold bars and thus score points in the game. Next, during Pavlovian conditioning, a colored light (i.e., conditioned stimulus: CS+) was followed by a white noise unconditioned stimulus (US) while a different colored light (CS ) was not paired with the US. Probe trials in a final testing phase were then used to assess suppression. We found significant suppression of accurate responding (shots hitting the designated targets) during the presence of the CS+ relative to the CS , both in terms of total hits and hits as a proportion of total shots. Importantly, this effect emerged despite the overall level of operant responding being undiminished during the CS+. Our findings are consistent with related studies examining human behavior in real environments, and demonstrate the potential of VEs in combination with a modestly aversive CS to allow a detailed behavioral profile of anxiety to emerge.

Greville, W. J., Newton, P. M., Roche, B., & Dymond, S. (2013). Conditioned suppression in a virtual environment. Computers in Human Behavior, 29, 552-558.

We currently have another paper under submission and another, multi-experiment paper in the works, so watch this space!

The other study is due out in the Quarterly Journal of Experimental Psychology and was conducted with people screened for spider fear and divided into high vs. low groups. Both groups were given the same symbolic generalization of avoidance task and each performed differently. Basically, the high spider fearful individuals showed greater behavioural avoidance and lower cognitive expectancy, whereas the opposite was the case for the low spider fearful people.

This could mean that, for someone with a fear of spiders, the world is a place where spiders could, potentially, be found, and that their avoidance behaviour modulates expectancies of spiders. Much, much more to be done on this important topic! Anyway, here's the abstract:

Overgeneralization of fear and threat-avoidance represents a formidable barrier to successful clinical treatment of anxiety disorders. While stimulus generalization along quantifiable physical dimensions has been studied extensively, less consideration has been given to symbolic generalization, in which stimuli are indirectly and arbitrarily related. The present study examined whether the magnitude and extent of symbolic generalization of threat-avoidance and threat-beliefs differed between spider-phobic and non-phobic individuals. Initially, participants learned two sets of stimulus equivalence relations (A1 = B1 = C1; A2 = B2 = C2). Next, one cue (B1) was established as a conditioned stimulus (CS +; threat) that signalled onset of spider images and prompted avoidance, and another cue (B2) was established as a CS– (safety cue) that signalled the absence of such images. Subsequent testing showed that phobics compared to non-phobics exhibited greater symbolic generalization of threat avoidance to threat cues A1 and C1 (indirect CS+ threat cues related via symmetry and equivalence, respectively), while all individuals showed non-avoidance to indirect safety cues A2 and C2. The enhanced symbolic generalization of threat-beliefs and avoidance behaviour observed in spider phobics warrants further investigation.
Dymond, S., Schlund, M. W., Roche, B., & Whelan, R. (in press). The spread of fear: Symbolic generalization mediates graded threat-avoidance in specific phobia. Quarterly Journal of Experimental Psychology. DOI:10.1080/17470218.2013.800124

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