Motivation in cognitive tests and its outcome on test performance in pigs

Animals may vary in their motivation to participate in cognitive and behavioural tests, and this can result in a poor test performance despite their actual cognitive abilities. This suggests a potential interaction between motivation and competence. Our aim was to investigate the motivation of pigs to perform cognitive tasks and to understand whether their motivation relates to their cognitive performance. Furthermore, as environmental enrichment may influence motivation, we compared pigs that were housed in either barren (B) or enriched conditions (E) and of which half experienced a switch in those housing conditions (EB: enriched to barren; BE: barren to enriched). Male and female pigs (Sus scrofa domesticus, n = 128) were tested from 9 to 17 weeks of age for their motivation to voluntarily leave their siblings and move to the test arena. A motivation score was given (0-7, where lower scores represent higher motivation) and the duration to move to the test arena was recorded. Performance in a spatial cognition task (16-hole holeboard) was assessed through trial duration and reference and working memory. The cognitive tests consisted of an acquisition, reversal, and long-term memory phase, resulting in approximately 80 trials per pig. Data were analysed using mixed models that accounted for housing, sex and BW. Pigs were, in general, highly motivated to partake in cognitive tasks. Both the motivation score (P < 0.001) and duration to move to the test arena (P = 0.001) decreased over repeated tests, indicating that pigs became more motivated over time. Housing conditions did not influence the motivation score during the acquisition phase (P = 0.524), but during the reversal phase, enriched pigs were more motivated (P = 0.014) and moved faster (P = 0.003). Lighter pigs were more motivated than heavier pigs during the reversal phase (P = 0.016) and were faster to reach the test arena during the acquisition (P = 0.015) and reversal (P = 0.001) phase. The motivation score and duration to move to the test arena had no effect on reference and working memory scores, but more motivated pigs had a shorter trial duration (P < 0.001). The switch in the housing conditions did not affect motivation scores, but EE pigs, who remained in enriched conditions throughout the whole experiment, were more motivated and faster to go to the arena than BB pigs (which remained in barren conditions). In conclusion, these findings suggest that while individual and environmental factors influence pigs' motivation to participate in cognitive tasks, motivation alone does not predict cognitive performance.