The Development of Postnatal Turning Bias is Influenced by Prenatal Visual Experience in Domestic Chicks (Gallus gallus)

Abstract

Recent research supports a significant role for prenatal sensory experience in the development of lateralized postnatal visual discrimination in birds, but little is known about its potential effect on the development of lateralized postnatal motor behaviors. Therefore, the present study examined the effects of prenatal visual experience on the development of spatial turning bias in domestic chicks. Control tests with maternally naive, domestic chicks in a standard T maze revealed a left-side turning bias in 90% of subjects. Such large population biases are considered unusual in nonhuman species. Chicks were exposed to one of three prenatal conditions: both eye systems exposed to enhanced visual experience, right-eye system exposed/left-eye system occluded, or left-eye system exposed/right-eye system occluded. Results revealed a significant lack of population turning bias in all experimental subjects except those that received right eye stimulation prenatally. These results suggest that unilateral prenatal visual experience to the right eye/left hemisphere is a significant contributor to the lateralization process in domestic chicks.

Asymmetrical hatching behaviors: The development of postnatal motor laterality in three precocial bird species

“…These and other motor lateralities have been demonstrated in many diverse species such as fish (Bisazza, Cantalupo, Capocchiano, & Vallortigara, 2000;Bisazza, Sovrano, & Vallortigara, 2001;Facchin, Bisazza, & Vallortigara, 1999), newts (Green, 1997;Marzona & Giacoma, 2002), toads (Bisazza, Cantalupo, Robins, Rogers, & Vallortigara, 1996, birds (Casey & Martino, 2000;Regolin, Vallortigara, & Zanforlin, 1995), rats (Diaz-Palarea, Gonzalez, & Rodriguez, 1987), primates (Westergaard & Suomi, 1996), and humans (Bracha, Seitz, Otemaa, & Glick, 1987;Bradshaw & Bradshaw, 1988). Previous research has demonstrated that the development of turning biases in bobwhite quail (Casey & Lickliter, 1998) and domestic chicks (Casey & Karpinski, 1999) may be influenced by prenatal visual experience. However, as with footedness, turning biases can also be influenced by postnatal lateralized eye preferences and perceptual discrimination processing.…”

“…So important is this stereotypical bodily orientation and the canalizing influence it has on subsequent sensory experience and motor behavior (Bekoff, 1995;Casey & Karpinski, 1999;Casey & Lickliter, 1998;Rogers, 1982;Rogers, 1990;Rogers, 1997;Rogers & Workman, 1989) that alternative embryonic orientations most often result in a failure to hatch and subsequent death inside the egg (Asmundson, 1938;also, see Byerly & Jull, 1932 for inherited problems that might limit hatching and survival rates.) As this is the only behavioral sequence that will afford successful hatching, and is essentially the same for all members of the species, and occurs at a time of great plasticity in the chick's nervous system (Rogers, 1991(Rogers, , 2002, it is reasonable to propose that these lateralized and coordinated motor movements have a significant effect on the development of postnatal motor laterality at both the individual and population level.…”

Comment on “Number-space mapping in the newborn chick resembles humans’ mental number line”

“…As noted previously, there is nevertheless a strong a priori reason to expect motor and perceptual biases under the conditions used in this study [e.g., (4,6,9)]. Evidence of side bias is also detectable in Rugani et al For example, the average absolute deviation from 50/50 responding across all 10 trials for each chick was 12.7% T 1.1%, indicating that most chicks exhibited some degree of bias (t = 11.5, P < 0.00001).…”

“…This Comment will focus on a critical flaw in the study's design and statistical analysis. I argue that Rugani et al failed to measure, model, or control for the significant side biases displayed by precocial birds, including the domestic chicks used in their study (2)(3)(4)(5)(6)(7)(8)(9).…”

“…For example, chicks show significant bias for turning left at the intersection of a T maze (4,6,9,11), in addition to task-dependent preferences for foot and eye use (2,3,5). Such biases are sculpted by normally occurring pre-and perinatal experience, including both differential exposure of the hemispheres to audiovisual stimulation prenatally (4,7,11,12) and the repetitive turning movements necessary for chicks to successfully hatch from the egg (6, 9). As a consequence, as many as 67 to 90% of domestic chicks display significant side biases in tasks requiring a locomotor response (4,6,9).…”