Purpose – The purpose of this study is to explain how cognitive and emotional responses may influence decisions to purchase cause-related products. Design/methodology/approach – An experimental design clarifies how autonomic reactions determine altruistic choices in a simulated shopping environment. Eye-tracking and electrodermal response measurements were set to predict choices of hedonic vs utilitarian cause-related vs unrelated products. Findings – Emotional arousal, pleasure and attention to the cause-related bundle are associated with altruistic behaviour in hedonic choices. When facing utilitarian choices, customers focus on brand logo and donation amount while experiencing pleasure, but emotional arousal does not increase marketing effectiveness in this case. Research limitations/implications – The experiment may be replicated in the real-world shopping environment, but spurious influences will be difficult to control. Distracting cues such as background music and scents used to increase positive emotions may affect intensity of emotive and cognitive processes. Practical implications – The results highlight the prominence of automatic reactions in customers’ choices. In the present instance, managers’ effort should be directed to the raising of altruistic visual cues of the donation-based promotion and positive emotional responses through guilt reducing effects. Originality/value – The study pioneers the use of eye-tracking coupled with skin conductance measurement in experimental designs aimed at clarifying the role of autonomic reactions such as emotional arousal, pleasure and attention in the effectiveness of emotionally charged marketing campaigns.