In cognitive tests, animals are often given a choice between two options and obtain a reward if they choose correctly. We investigated whether task format affects subjects' performance in a physical cognition test. In experiment 1, a two-choice memory test, 15 marmosets, Callithrix jacchus, had to remember the location of a food reward over time delays of increasing duration. We predicted that their performance would decline with increasing delay, but this was not found. One possible explanation was that the subjects were not sufficiently motivated to choose correctly when presented with only two options because in each trial they had a 50% chance of being rewarded. In experiment 2, we explored this possibility by testing eight naïve marmosets and seven squirrel monkeys, Saimiri sciureus, with both the traditional two-choice and a new nine-choice version of the memory test that increased the cost of a wrong choice. We found that task format affected the monkeys' performance. When choosing between nine options, both species performed better and their performance declined as delays became longer. Our results suggest that the two-choice format compromises the assessment of physical cognition, at least in memory tests with these New World monkeys, whereas providing more options, which decreases the probability of obtaining a reward when making a random guess, improves both performance and measurement validity of memory. Our findings suggest that two-choice tasks should be used with caution in comparisons within and across species because they are prone to motivational biases.When the cognitive abilities of animals are assessed with cognitive tests, subjects are often presented with two options to choose from and rewarded with a food item if they choose the correct option. This two-choice task format has been used to test, in a range of animal species, a variety of cognitive abilities such as memory (e.g. delayed response tasks in ). One test that has extensively used the two-choice format in particular with a wide range of animal species is the object choice task. This task tests for sociocognitive abilities by assessing a subject's ability to use an experimenter's gestural cues (e.g. gaze, point, touch) in order to locate a reward that is hidden under one of usually two containers. The tested species include primates (all four great apes and some Old and New

A Photovoice pilot was conducted with a sample of youth living with sickle cell disease (SCD), in order to further understand their lived experience and examine the acceptability, feasibility, and utility of this method for use in this population. SCD is an inherited genetic condition whose primary symptom is severe pain. Youth were able to reflect on their experiences with SCD using Photovoice and the adapted SHOWeD method. Parents and youth found Photovoice to be valuable for children and adolescents with SCD. Emerging themes included the impact of SCD, coping with the disease, and the importance of family and support.