A modified version of the dimensional change card sort task tests cognitive flexibility in children (Homo sapiens) and cotton-top tamarins (Saguinus oedipus).

Abstract

A modified Dimensional Change Card Sort (DCCS) task was used to test cognitive flexibility in adult cotton-top tamarins and children aged 19 months to 60 months. Subjects had to infer a rule from the experience of selecting between two cards to earn a reward, and the pairs of stimuli defined the rule (e.g., pick blue ones, not red ones, or pick trucks, not boats). Two different tests measured subjects’ ability to shift to a reversal of the rule (intradimensional shift) and to shift to a new rule defined by a dimension previously irrelevant (interdimensional shift). Both adult tamarins and children aged 49–60 months were able to learn the initial rule and switch to a reversal and to a rule based on a different dimension. In contrast, the two younger groups of children, aged 19–36 months and aged 37–48 months, could switch when a reversal was imposed but took significantly longer to learn a new rule on a former irrelevant dimension. Experiment 2 presented a wider set of novel stimuli which shared some features with the original set to further explore the basis of rule learning. The result was that tamarins and 52- to 60-month-old children both chose novel stimuli that fit the rule and had no a priori associative strength, suggesting a rule application not solely based on associative strength. Importantly, novel items introduced some risk for choice, and children showed themselves to be risk-averse, whereas tamarins were risk-prone within a novel context.

Rules and metarules: Adult cotton-top tamarins (Saguinus oedipus) and 5-year-old children (Homo sapiens) can master both.

“…In this issue's featured article, Neiworth et al (2022) report that they have conducted exactly this kind of comparative study: They examined cognitive flexibility in adult cotton-top tamarins (Saguinus oedipus) and human children in three age groups (,3 years, 3-4 years, and 4-5 years) as they participated in a modified version of the DCCS (Figures 1 and 2). Neiworth et al (2022) reasoned that cotton-top tamarins, which live in socially cohesive monogamous family groups, and in which both parents and adult offspring share caring for young infants, are likely candidates to possess cognitive flexibility. A body of work with this endangered primate (e.g., Neiworth et al, 2001Neiworth et al, , 2002Neiworth et al, , 2009Neiworth, 2013) has shown that they demonstrate relatively heightened social awareness compared to other nonhuman primates.…”

“…If the hypothesis of shared processes supporting cognitive flexibility and social awareness is correct, tamarins might be expected to master interdimensional shifts in an abstract task such as the DCCS. On the other hand, Neiworth et al (2022) noted that tamarins display other aspects of cognition that suggest limited rule-shifting capacity.…”

“…The first challenge was to develop a procedure that presents the same challenge to make interdimensional and extradimensional shifts to both species. Neiworth et al (2022) used a training procedure with both monkeys and children to instill the initial discrimination between pairs of cards displaying images of red or blue trucks or boats, touching one card in order to gain a reward. Then experimenters invited the children to play the choice game with pairs of cards "with a secret."…”

“…And like children under 5 years old, monkeys failed to learn a new rule that required using a previously irrelevant dimension, or (in the case of monkeys only) learned it only after hundreds of trials (vs. a maximum of 60, as the tamarins did in the experiment described earlier). As Neiworth et al (2022) point out, "it would be useful to manipulate familiarity, associative strength, framing of the task in terms of winning or losing a reward, and risk . .…”

“…Thus, intradimensional shifts are mastered by younger children, but interdimensional shifts are not. Developmental psychologists have noted a similar timeline of change for children’s use of different perspectives about the same objects or events, as in the use of different labels for the same object, an aspect of language, and in understanding other’s knowledge or beliefs, an aspect of social cognition (reviewed in the study by Neiworth et al [2022]). Three-year-olds master rules (blue is correct; square is correct); 5-year-olds master metarules (one dimension is correct now; the correct dimension can change in the next moment).…”