Social Facilitation Revisited: Increase in Foraging Efforts and Synchronization of Running in Domestic Chicks

Abstract

Social influences on foraging efforts were examined in domestic chicks by investigating the frequency of runs made to feeders and the amount of pecking to gain food. Single or paired chicks foraged in an I-shaped maze equipped with a millet feeder on each end, that distributed one or two grains at variable intervals. Regardless of when the grain(s) were dispensed, chicks ran back and forth between the feeders. Analyses of their movement patterns revealed: (1) running patterns were not directly synchronized with the dispensing of grain(s), (2) running distance was longer in paired chicks than in single chicks, (3) paired chicks partially synchronized their runs between feeders, and (4) social effects were immediate but cumulative after repeated blocks. We further examined the social effects on running by dividing the I-maze into two parallel lanes separated by a transparent wall, so that kleptoparasitic interference of food did not occur. Again, the chicks increased their running speed and were even more synchronized with their partner's movements, indicating that food competition alone was not responsible for increased foraging effort. The number of pecks to get grains was also assessed under conditions where the food tray was gradually replaced, from an easy one to more difficult ones. When tested in the separated I-maze, paired chicks pecked more in the difficult food situation without increase in the number of gained grains. Results suggest that (i) social facilitation leads to increased foraging efforts and (ii) the presence of a conspecific is alone may lead to enhanced foraging efforts in chicks. These findings are discussed in terms of possible ecological background of social facilitation.

Selective contribution of the telencephalic arcopallium to the social facilitation of foraging efforts in the domestic chick

“…In a previous study, we revealed that Arco lesions resulted in handling‐cost aversion in a binary choice task, in which the larger option was accompanied by more pecks (Aoki et al ., ). In present study, we focused on the foraging effort involved in approaching a food patch (Ogura & Matsushima, ; Ogura et al ., ), and found that chicks paid extra effort, even when it was not accompanied by extra food gain.…”

“…Choice impulsiveness in chicks can be conditionally enhanced by competitive training experiences (Amita et al, 2010), and this enhancement might involve the suppression of striatal neuronal activities, as elicited by the presence of the accompanying forager (Amita & Matsushima, 2014). Furthermore, foraging effort (Ogura & Matsushima, 2011) and operant peck latency (Amita & Matsushima, 2011) are socially facilitated in a reversible and contextual manner. Based on the 'drive' theory (Zajonc, 1965), we initially hypothesized that ascending dopaminergic pathway is involved in the social facilitation.…”

Striatal and Tegmental Neurons Code Critical Signals for Temporal-Difference Learning of State Value in Domestic Chicks

“…In the reward period, some aspects of state value are supposed to be quickly updated. Similarly, in another task in which chicks actively forage between two feeders placed at opposite ends of an I-shaped maze (Ogura and Matsushima, 2011; Ogura et al, 2015), chicks quickly changed their stay time when the profitability of the feeders changed (Xin et al, under review). Chicks behave as if the state value is flexibly updated, particularly in the final consumption phase when food reward is just to be gained.…”

Behavioural and pharmacological effects of fluvoxamine on decision-making in food patches and the inter-temporal choices of domestic chicks

“…Effects of FLV on work efforts (running for feeders) were examined (experiment-4) according to the procedure described elsewhere [27]. Briefly, chicks were habituated to the I-maze on days 7 and 8, and then allocated to two groups in a counter-balanced manner based on body weight; one group for FLV and another for vehicle treatment.…”

“…An I-shaped maze (88 cm long and 12 cm wide) was used for testing each chick's foraging efforts (experiment-4); see [27] for details. Briefly, the maze was equipped with a pair of terminal feeders, each of which supplied a grain of millet at variable intervals (mean = 15 sec, uniformly ranging 10-20 sec) for 30 times (therefore 60 grains in total).…”