Attention to Detail: The Generalization of Extinction
Tom Barry
Promoter: Prof. Dr. Dirk Hermans; Co-Promoter: Dr, Bram Vervliet
University of Leuven, Centre for Learning Psychology and Experimental Psychopathology
Background
Methods
Results
Conclusions
Treatment of Simple Phobia
Stimuli
Acquisition
GS Extinction
Despite the effectiveness of exposure
therapy in reducing fear to the objects of
simple phobias, evidence suggests that
fear can return.
Fribbles: ‘A’ (CS) fribbles had only the
body in common with ‘B’ (GS) whereas
X were a completely different species.
By the end of Acquisition, there was a
significant differential conditioning effect
in US expectancy (F(1,37)=308.82,
p<.001), SCR (F(1,45)=11.62, p<.05)
and FPS (F(1,43)=6.43, p<.05) with no
differences between groups (p>.05).
Extinction with a GS may be insufficient
at preventing fear to a CS; it is no more
effective than using a novel stimulus.
The Future
Post-treatment, the original fear learning
may be retrieved and begin to express
itself again (Rowe & Craske, 1998).
A
B
X
Return of Fear
Greater dissimilarity between the original
fear event and the stimuli in exposure
may prevent generalization of extinction
learning to other objects of fear more
like the original object of fear.
Where treatment stimuli have different
features to the original stimulus
(generalization stimuli; GS), there may
be a possibility that some stimulus
features maintain fearful value.
Previous Research
The few studies that have assessed
extinction with a GS on subsequent fear
to a CS, have used US expectancy and
skin conductance to assess the return of
fear. However, both of these measures
are not valence specific and may
instead represent the expectation of US
and not fear (Vervliet et al., 2005)
Research question
- Is extinction with a GS sufficient to
prevent fear to the original CS?
Extinction
By the final block of Extinction there
were no differences between groups on
any of the DVs and no differential
conditioning effect between CS types.
Measures
Skin Conductance Response (SCR)
Generalization of Extinction
Index of generalization computed:
Fear Potentiated Startle (FPS)
Trial-by-trial US expectancy ratings
Design & Procedure (N=48)
Acquisition: All groups 6 CS+ with US; 6
CS- no US (A stimuli)
Extinction (no US): 3 groups (n=16) AAA - 12 CS+/- (A)
Test Block - Final Extinction Block
Significant main effect of extinction
condition on the generalization indices
for US expectancy (F(2,45)=26.02,
p<.001) and FPS (F(2,41)=5.07, p<.05).
There was also a positive correlation
between the indices for US expectancy
and FPS (r=.36, p<.05).
ABA - 12 GS+/- (B)
AXA -12 X+/- (completely new stimuli)
Test (no US): All groups 3 CS+/-
B
X
Also, it should explore the role that
attention to different stimulus elements
has on generalization?
Implications
Clinical translation
Exposure treatment with a stimulus
other than the original CS may be
insufficient to prevent fear to the CS
during subsequent experience. After the
original fear learning has been retrieved
this may result in full clinical relapse.
References
Rowe, M. K., & Craske, M. G. (1998). Effects of
varied-stimulus exposure training on fear
reduction and return of fear. Behaviour Research
and Therapy, 36, 719–734.
p<.05
A
A
Research should now ask what the
effect of extinction with a GS can have
on fear towards other GS.
A
p<.001
Vervliet, B., Vansteenwegen, D., Baeyens, F.,
Hermans, D., & Eelen, P. (2005). Return of fear
in a human differential conditioning paradigm
caused by a stimulus change after extinction.
Behaviour Research and Therapy, 43, 357–371.
Funded as part of the KU Leuven Centre for Excellence - Generalization Research in Ill Health and Psychopathology: Transdiagnostic Processes and Transfer of Knowledge and a
Research Foundation - Flanders (FWO) Ph.D Fellowship Grant