When Less Is More: Evolutionary Origins of the Affect Heuristic

Abstract

The human mind is built for approximations. When considering the value of a large aggregate of different items, for example, we typically do not summate the many individual values. Instead, we appear to form an immediate impression of the likeability of the option based on the average quality of the full collection, which is easier to evaluate and remember. While useful in many situations, this affect heuristic can lead to apparently irrational decision-making. For example, studies have shown that people are willing to pay more for a small set of high-quality goods than for the same set of high-quality goods with lower-quality items added [e.g. 1]. We explored whether this kind of choice behavior could be seen in other primates. In two experiments, one in the laboratory and one in the field, using two different sets of food items, we found that rhesus monkeys preferred a highly-valued food item alone to the identical item paired with a food of positive but lower value. This finding provides experimental evidence that, under certain conditions, macaque monkeys follow an affect heuristic that can cause them to prefer less food. Conservation of this affect heuristic could account for similar ‘irrational’ biases in humans, and may reflect a more general complexity reduction strategy in which averages, prototypes, or stereotypes represent a set or group.

Too Good to Be True: Rhesus Monkeys React Negatively to Better-than-Expected Offers

“…We subsequently conducted an affective decision-making study with these monkeys as well as with free-ranging rhesus monkeys at the Caribbean Primate Research Center on Cayo Santiago in Puerto Rico [45]. We obtained the same general findings in the laboratory and field, suggesting that the laboratory conditions are not significantly biasing experimental results, and that the subjects in the current study are representative of rhesus monkeys in general [46].…”

When animals misbehave: Analogs of human biases and suboptimal choice

“…For instance, monkeys willingly ate a piece of sliced vegetable or a grape but when offered a choice between them, showed a clear preference for the grape over the vegetable slice. However, surprisingly, when they were offered a choice between a single grape and a grape plus a slice of vegetable, they reliably preferred the single grape (Kralik et al, 2012).…”

Edgcumbe. 2019 - The relationship between cognitive reflection and morality judgments are mediated by thinking dispositions.

“…Much like the evolutionary origins of moral values, intuitive and analytic thinking evolved in our early ancestors (Bekoff, 2001;Evans, 2006;Evans & Stanovich, 2013). Intuitive thinking is evolutionary ancient (Evans, 2010) as such we share this capacity for thinking in this way with other species (Brosnan et al, 2007;Kralik, Xu, Knight, Khan, & Levine, 2012). Non-human primates such as chimpanzees (Pan troglodytes) (Brosnan et al, 2007;Eckert, Call, Hermes, Herrmann, & Rakoczy, 2018) and rhesus macaque (Macaca mulatta) (Hayden, Heilbronner, Nair, & Platt, 2008;Kralik et al, 2012) have been observed to rely on intuitive thinking.…”

“…Intuitive thinking is evolutionary ancient (Evans, 2010) as such we share this capacity for thinking in this way with other species (Brosnan et al, 2007;Kralik, Xu, Knight, Khan, & Levine, 2012). Non-human primates such as chimpanzees (Pan troglodytes) (Brosnan et al, 2007;Eckert, Call, Hermes, Herrmann, & Rakoczy, 2018) and rhesus macaque (Macaca mulatta) (Hayden, Heilbronner, Nair, & Platt, 2008;Kralik et al, 2012) have been observed to rely on intuitive thinking. Moreover, non-primate species, of which we share a common ancestor, have demonstrated a capacity for intuitive thinking too, for example, pigeons (Fantino, Kanevsky, & Charlton, 2005).…”