A larger brain confers a benefit in a spatial mate search learning task in male guppies

Abstract

Lay SummaryDoes a large brain make you smarter? If you are a guppy male searching for a female in a maze, it does. The association between brain size and smartness is a debated issue, largely due to the lack of experimental data. We compared guppies artificially bred for large and small brains and found that large-brained males learned the route through a spatial maze faster. These results thus support a link between brain size and smartness.

Increased juvenile predation is not associated with evolved differences in adult brain size in Trinidadian killifish (Rivulus hartii)

“…Despite a growing body of work illustrating a connection between predator‐induced mortality and the evolution of vertebrate brain size (van der Bijl et al., 2015; Burns & Rodd, 2008; Edmunds et al., 2016; Kotrschal et al., 2012b, 2015b; Shultz & Dunbar, 2006a; Walsh et al., 2016), we found that increased rates of juvenile mortality are not associated with evolutionary shifts in adult brain size. In contrast to much work illustrating a connection between juvenile mortality and evolutionary shifts in adult characteristics (Reznick & Endler, 1982; Sparkes, 1996a; Wellborn, 1994), one potential implication of our results is that mortality experienced early in life may not alter selection on adult brain size.…”

“…There are clear fitness benefits associated with a larger brain as brain size is positively correlated with increased intelligence, cognition, learning capability, population persistence, and decreased susceptibility to predation (Sol & Lefebvre, 2000; Tebbich & Bshary, 2004; Shultz & Dunbar, 2006a; Sol, Szekely, Liker, & Lefebvre, 2007; Sol, Bacher, Reader, & Lefebvre, 2008; Overington, Morand‐Ferron, Boogert, & Lefebvre, 2009; Barrickman, Bastian, Isler, & van Schaik, 2008; Amiel, Tingley, & Shine, 2011; Reader, Hager, & Laland, 2011; Kotrschal et al., 2013b; MacLean et al., 2014; Kotrschal et al., 2015a; Kotrschal, Corral‐Lopez, Amcoff, & Kolm, 2015b; Benson‐Amram, Dantzer, Stricker, Swanson, & Holekamp, 2016; but also see Drake, 2007). Key hypotheses, such as the expensive tissue hypothesis (i.e., expensive metabolic cost of brain tissue) (Aiello & Wheeler, 1995; Isler & van Schaik, 2009) and energy trade‐off hypothesis (increased encephalization leads to trade‐offs with other functions) (Isler & van Schaik, 2006a,b, 2009; Navarrete, van Schaik, & Isler, 2011; Tsuboi et al., 2015), recognize that brain tissue is costly and that fitness trade‐offs likely underlie increased encephalization (Aiello & Wheeler, 1995).…”

“…Selection for larger brains in captive populations of guppies is associated with increased cognitive function and declines in susceptibility to predation (Kotrschal et al., 2013a,b, 2015b). However, work on natural fish populations in other species yielded the opposite trajectory of evolution.…”

Brain size predicts problem-solving ability in mammalian carnivores

“…Although there is circumstantial evidence suggesting an association between problem-solving ability and brain size, experimental evidence is extremely rare. To experimentally assess the relationship between brain size and any cognitive ability across a number of species in a standardized way is challenging because of the unique adaptations each species has evolved for life in its particular environment (17). In this study, we investigate whether largerbrained animals do, indeed, exhibit enhanced problem-solving abilities by conducting a standardized experiment in which we present a novel problem-solving task to individuals from a large array of species within the mammalian order Carnivora.…”

Problem-solving performance and reproductive success of great tits in urban and forest habitats

“…For example, risk sensitivity might be reduced by habituation to humans (Geffroy et al 2015), whereas being less competitive might be less costly in cities due to altered distribution and abundance of food sources such as bird feeders (Shochat et al 2006;Tryjanowski et al 2015), although the latter hypothesis received little empirical support so far (Bókony et al 2010). A further proposed cost of cognitive skills is the development and maintenance of energetically expensive brain tissue (Kotrschal et al 2013(Kotrschal et al , 2015; urban birds might afford not paying some of these costs if instead they have more opportunities to explore and learn about their environment and practice various tasks. It has been suggested that experience with diverse foraging substrates in urban habitats enhances motor diversity and thereby problem-solving performance (Diquelou et al 2015).…”