Public Perceptions of Autism Treatments: Does Source Credibility Matter?

Background: Scientifically validated instructional strategies have been identified to improve behavioral symptoms associated with autism (see Wong, 2014 for a review), however families and practitioners often give credence to “fad” approaches that lack evidentiary support. Not only are fad treatments, such as sensory integration therapy and special diets, unlikely to be effective, but they may delay or even prevent individuals with autism from accessing evidence-based intervention that is more likely to produce favorable outcomes.

Objectives: To explore factors that can influence the public’s acceptance of autism treatments, specifically evidentiary support and source credibility.

Methods: Adults read a series of texts describing different autism treatments (N=379). The text presentation was based on a 2 x 2 within-subjects factorial design with treatment status (evidenced-based vs. fad) and credibility of the source in the text (credible vs. non-credible) as the independent variables. Thus, participants read about evidence-based treatments (EBP) presented by credible sources, EBP presented by non-credible sources, fad treatments presented by credible sources, and fad treatments presented by non-credible sources. Participants rated the degree to which they believed the treatment would be effective (believability); the extent to which they would either use or recommend the treatment to someone else (intentionality), and credibility of each treatment using a Likert scale. In a subsequent instruction manipulation condition, the text remained the same but participants were instructed to “pay attention to the credibility of the source providing information.”

Results:  Our analyses reveal an overall main effect of treatment status, t(377) = 12.56, p < .001 such that EBP were rated as more credible than fad treatments. We also identified a main effect of source credibility, t(377) = 8.33, p < .001, such that credible sources were rated as more credible than non-credible sources. Participants considered the credibility of the source only when explicitly instructed (instruction manipulation condition). Participants successfully differentiated between the credibility of EBP texts, t(129) = 5.61, p < .001, with EBP descriptions presented by credible sources (M = 3.85, SE = .07) receiving higher credibility ratings than those from a non-credible source (M = 3.33, SE = .08).  We also find that fad texts from a credible source (M = 3.68, SE = .04) received higher credibility ratings than those from a non-credible source (M = 2.81, SE = .08; t(129) = 6.27, p < .001. In this condition, participants’ ratings of EBP presented by a non-credible source did not differ from fad treatments presented by a credible source.

Conclusions: These results suggest that people do not naturally attend to source credibility when evaluating treatments described in print. Manipulation instructions to attend to the credibility of sources had the intended effect: credibility ratings of non-credible sources were reduced and credible sources increased regardless of EBP status. This also meant that credibility ratings increased even for fad approaches presented by credible sources (e.g., physicians presenting pressure/weighted vests), which may indicate a maladaptive over-correction effect.