Scientists have discovered the reason why we retain disgusting memories

Researchers have found that our disgusting memories are often associated with smells, tastes and touches to help protect us from disease.

Psychologists at Macquarie University in Australia, and Karolinska Universitet in Sweden, suggest that sensory cues elicit disgust intensely to help support our physiological immune system.

The study consisted of 216 university students who were asked to complete two surveys, one week apart.

In the first questionnaire, 127 participants were asked to detail their most memorable disgusting experiences.

The second questionnaire asked 89 students to fill in the same information, but using experiences that took place in the preceding week.

After recalling these experiences, participants were asked to rate how much each sense - smell, taste, touch, sight or sound - contributed to their effect.

The results showed that disgusting experiences are most commonly associated with smells, tastes or touch, known as the 'proximal' sense.

Researches have psychology hypothesised that the emotion of disgust supports our physiological immune system by making us averse towards sources of infection so that we avoid them.

Michael de Barra, a psychologist at Brunel University London who was not involved in the study, spoke to Newsweekabout the role disgust plays in evolutionary psychology.

"From an evolutionary perspective, the main function of disgust seems to be to prevent infection. It motivates avoidance of things that might cause illness.

"Infectious disease is a really important selection pressure in evolution: it's shaped behavioural disease avoidance strategies in many animals with examples everything from sheep to ants," he said.

It has been suggested that smell, taste and touch cues may be more intense elicitors of disgust because pathogens and toxins tend to enter the body at the nasal passages, the mouth, or skin.

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