No practitioner is completely objective. Every person brings previous experiences, education, values, beliefs and assumptions into professional practice. These mental shortcuts, known as cognitive biases, help people make decisions efficiently but can also influence judgement in ways that are inaccurate, unfair or inconsistent with evidence.
Biases are a normal part of human thinking and are not a sign of poor character or intentional discrimination. However, ethical practitioners recognise that unchecked bias may affect assessment, training, animal welfare decisions, occupational therapy recommendations, recruitment, supervision, funding recommendations and organisational leadership.
Recognising bias is therefore an essential component of reflective practice, cultural humility and evidence-informed decision-making.
The following biases are among the most relevant to occupational therapy and assistance animal practice.
Anchoring Bias
Allowing the first piece of information received to disproportionately influence all later judgement.
Example: Reading a referral stating a handler is “difficult” before meeting them and unconsciously interpreting subsequent interactions through this lens.
First Impression Bias
Forming a lasting opinion based on the first few minutes of interaction.
Example: Assuming a nervous applicant lacks confidence to handle an assistance dog when they are simply anxious during assessment.
Halo Effect
Allowing one positive characteristic to influence judgement in unrelated areas.
Example: Assuming a highly educated applicant will automatically provide excellent animal care.
Horn Effect
Allowing one perceived weakness to negatively influence overall judgement.
Example: Judging a handler as generally unreliable because they arrived late due to inaccessible transport.
Primacy Effect
Remembering and valuing information presented first more strongly than later information.
Recency Effect
Giving excessive weight to the most recent event while overlooking the person’s longer history.
Example: Allowing one poor training session to outweigh months of successful progress.
Contrast Effect
Evaluating someone relative to the previous person assessed rather than against objective standards.
Example: Rating an average handler very highly because they were assessed immediately after a very inexperienced handler.
Confirmation Bias
Seeking evidence that confirms existing beliefs while overlooking contradictory evidence.
Example: Noticing only behaviours supporting an initial opinion that a handler is unsuitable.
Availability Bias
Judging likelihood based on memorable previous experiences rather than objective evidence.
Example: Assuming a particular breed is unsuitable because one previous dog from that breed failed training.
Representativeness Bias
Assuming someone fits a stereotype because they resemble previous examples.
Example: Assuming every veteran with PTSD will require similar assistance animal tasks.
Framing Bias
Being influenced by how information is presented rather than the information itself.
Example: Viewing identical assessment outcomes differently depending on whether they are described as “80% successful” or “20% unsuccessful.”
Salience Bias
Paying disproportionate attention to information that is particularly noticeable or emotionally striking.
Belief Perseverance
Continuing to believe something despite clear evidence demonstrating otherwise.
Blind Spot Bias
Recognising bias in others while believing oneself to be largely objective.
Hindsight Bias
Believing an outcome was obvious after it has occurred.
Example: Saying, “I knew that partnership would never work,” despite limited evidence at the time.
Outcome Bias
Judging the quality of a decision solely by its outcome rather than the quality of the decision-making process.
Diagnostic Overshadowing
Incorrectly attributing new concerns to an existing diagnosis.
Example: Assuming anxiety is “just autism” rather than recognising a genuine welfare or occupational issue.
Premature Closure
Stopping the assessment too early after reaching an initial conclusion.
Search Satisficing
Finding one explanation and failing to continue looking for additional contributing factors.
Overconfidence Bias
Overestimating one’s own knowledge, judgement or expertise.
Automation Bias
Over-relying on technology, algorithms or standardised tools without applying clinical judgement.
Commission Bias
Preferring to take action even when observation may be more appropriate.
Omission Bias
Avoiding necessary action because inaction feels psychologically safer.
Fundamental Attribution Error
Overestimating personal characteristics while underestimating environmental influences.
Example: Assuming poor attendance reflects laziness rather than inaccessible transport, fatigue or caring responsibilities.
Attribution Bias
Making assumptions about why people behave in certain ways without sufficient evidence.
Affinity Bias
Feeling more positively towards people who share similar backgrounds, interests or experiences.
Similarity Bias
Preferring people who think or communicate similarly to ourselves.
In-Group Bias
Showing preference towards individuals perceived as belonging to one’s own group.
Out-Group Bias
Making less favourable assumptions about people perceived as different.
Authority Bias
Giving excessive weight to the opinions of senior professionals without critically evaluating the evidence.
Gender Bias
Making assumptions based upon gender identity or gender stereotypes.
Age Bias (Ageism)
Assuming capability based upon chronological age rather than individual assessment.
Disability Bias (Ableism)
Assuming disability automatically limits competence or quality of life.
Cultural Bias
Evaluating others according to one’s own cultural norms.
Language Bias
Confusing communication style or English proficiency with intelligence or competence.
Weight Bias
Making assumptions based upon body size or weight.
Socioeconomic Bias
Allowing income, occupation or education to influence perceptions of competence.
Attractiveness Bias
Allowing physical appearance to influence judgement.
Status Quo Bias
Preferring existing practices simply because they are familiar.
“We’ve always done it this way.”
Sunk Cost Fallacy
Continuing with a poor decision because substantial time or money has already been invested.
Example: Continuing to train an unsuitable assistance dog because two years of training have already occurred.
Escalation of Commitment
Persisting with an unsuccessful course of action despite increasing evidence that change is needed.
Groupthink
Prioritising group agreement over critical thinking.
Normalisation of Deviance
Accepting unsafe practices because they have become routine.
Survivorship Bias
Learning only from successful cases while ignoring unsuccessful ones.
Optimism Bias
Underestimating risks because of unrealistic optimism.
Negativity Bias
Giving excessive attention to negative information while overlooking strengths.
Loss Aversion
Avoiding change because potential losses appear greater than potential gains.
Breed Bias
Making assumptions about suitability based solely on breed.
Every dog should be assessed individually according to temperament, health and task suitability.
Rescue Versus Purpose-Bred Bias
Assuming one source of dogs is inherently superior without considering individual assessment.
Size Bias
Assuming larger dogs are always more capable or smaller dogs are less effective.
Colour Bias
Allowing coat colour to influence perceptions (for example, “Black Dog Syndrome” or assumptions about white dogs).
Handler Appearance Bias
Making assumptions based upon clothing, grooming or physical appearance.
Disability Stereotype Bias
Assuming certain disabilities automatically predict success or failure with an assistance animal.
Previous Team Bias
Allowing experiences with previous handlers or dogs to influence judgement about a new partnership.
Funding Bias
Allowing funding source or financial circumstances to influence recommendations.
Trainer Preference Bias
Believing one’s preferred training philosophy is always superior without considering evidence or individual circumstances.
Reputation Bias
Allowing an individual’s organisational reputation to outweigh objective evidence.
Therapy Dog Versus Assistance Animal Bias
Confusing the roles, rights or expectations of different categories of working animals.
Recognising bias is only the first step. Ethical practitioners actively implement strategies that reduce its influence on professional judgement.
Useful approaches include:
Before making significant decisions, practitioners should ask themselves:
By continually reflecting on these questions, occupational therapists strengthen fairness, improve decision-making and ensure that assistance animal services remain ethical, inclusive and evidence-informed.