Infant temperament and feeding history predict infants' responses to novel foods

Highlights

• Temperament and feeding history were examined as predictors of novel food reactions.

• Infant temperamental approach predicted acceptance of the novel food.

• Temperament and solid food exposure interacted to predict novel food responses.

• Maternal responsiveness predicted infants' acceptance and rejection behaviors.

Abstract

The purpose of the present study was to investigate whether infant temperament and previous feeding history were associated with infants' acceptance and rejection of a novel food at 12 months of age. Mother–infant dyads (n = 89) were video-recorded during a novel food (hummus, cottage cheese) feeding task. Infants' reactions (acceptance and rejection behaviors) and maternal responsiveness and affect during the interaction were coded from the recordings by teams of coders. Mothers reported on their infants' temperamental approach via the Infant Behavior Questionnaire-Revised (IBQ-R) and their infants' feeding history (previous exposure to solid foods and exclusive breastfeeding). Regression analyses revealed that infants rated lower on approach showed less acceptance of the first offer of novel food than infants rated higher on approach. Additionally, low approach infants who were previously exposed to a greater number of solid foods showed fewer rejection behaviors in response to the later offers of food. Exclusive breastfeeding for 4 months did not appear to have an effect on acceptance or rejection. Finally, greater maternal responsiveness was related to the infants' acceptance of the new food whereas lower maternal responsiveness was associated with rejection of the novel food. These results suggest that the acceptance and rejection of new foods by infants is dependent upon their temperament and previous exposure to solid foods, as well as the manner in which mothers present the novel food.

Introduction

Human infants, like other omnivores, are faced with a dilemma when trying novel foods: they must accept the new foods to ensure dietary variety, but they also risk the possibility of ingesting toxic substances. In order to protect themselves from harm, young infants respond to bitter and sour tastes with negative facial expressions indicating initial rejection of these flavors (Rosenstien, Oster, 1988, Steiner, 1977). More recent research by Forestell and Mennella (2007) revealed that the majority of infants display facial expressions of distaste, such as squints, brow movements, and upper-lip raises, when eating a novel vegetable (i.e. green beans). However, this study also showed that infants exhibit clear individual differences in their facial expressions that predicted variability in acceptance of the new food (Forestell & Mennella, 2007). These findings are important because they highlight that infants display individual differences in their responses to novel foods. The present study investigates two factors that may contribute to these individual differences: infant temperament and feeding history.

Infant temperament is defined as individual differences in emotional and behavioral reactivity and regulation (Rothbart, Bates, 2006, Rothbart, Derryberry, 1981). Temperamental differences appear early in life and can account for why individuals respond differently to the same stimuli (Goldsmith et al., 1987). In particular, the temperamental dimension of approach, which characterizes individual differences in infants' responses to novelty, might be related to the ease or difficulty infants have in accepting new foods. Infants who are high on the dimension of approach tend to show positive affect and physically approach novel stimuli, but infants who are low on the dimension of approach tend to show negative affect and withdraw from novel stimuli (Rothbart & Bates, 2006).

Empirical works by Schaffer et al, 1972, Rothbart, 1988, and Putnam and Stifter (2002) indicate that infants tend to approach novel stimuli to a varying degree until the second half of the first year of life. After this time, infants develop the ability to inhibit their approach tendencies and may show hesitation in response to novelty. However, there are individual differences in infants' inhibition of approach; some infants do not become wary in novel scenarios and continue to exhibit approach behaviors, even exhibiting positive affect to novelty (Putnam, Stifter, 2002, Rothbart, 1988). If infants respond in the same way to new foods as they do to other novel stimuli, it is likely that there will also be individual differences in their responses to novel foods. On the extreme ends, some infants may show positive affect and accept novel foods readily, while other infants may show negative affect and reject novel foods.

To date, only one study has examined the relationship between infant approach and food acceptance. Forestell and Mennella (2012) had mothers of infants ranging from 4–9 months feed their infants a green vegetable (i.e. green beans) and rate their infants' temperamental approach. The results of the study showed that when controlling for past exposure to vegetables, higher scores on the approach dimension of temperament were related to greater consumption of green beans, a longer duration of feeding, fewer lip raises and nose wrinkles while eating the food, and higher ratings by the mother on how much she thought her infant liked the food (Forestell & Mennella, 2012). The present study aims to expand upon Forestell and Mennella's results in four ways: (1) by examining whether approach is also related to infants' responses to a novel food; (2) by determining whether approach also predicts infants' behavioral responses to a new food (i.e. acceptance and rejection); (3) by testing whether temperamental approach predicts infants' responses to a new food after infants have developed inhibition of approach (i.e. at 12 months); (4) by examining the interaction between the infants' levels of approach and their feeding history, another predictor examined in the present study.

Repeated exposure to novel foods has consistently emerged as one strategy that can increase acceptance of new foods. Research has shown that infants increase their consumption of a novel food after repeated exposures to that food (e.g. Forestell & Mennella, 2007; Gerrish, Mennella, 2001, Sullivan, Birch, 1994). These increases in consumption have been shown to be particularly strong for breastfed infants (Sullivan & Birch, 1994). Additional work has also shown that very few exposures are required to increase consumption: infants in one study doubled their intake of a new food after only one exposure to that food (Birch, Gunder, Grimm-Thomas, & Laing, 1998). However, as Forestell and Mennella (2007) suggest, consumption of a food does not necessarily indicate liking for that food. In their study, infants showed increased consumption of a food after repeated exposure, but the infants' facial expressions, which indicate like or dislike of the food, did not change. This result suggests that few exposures may be required to increase consumption of a novel food but that significantly more exposures are required to increase liking for that food (Forestell & Mennella, 2007).

In addition to the consistent body of work highlighting the importance of repeated exposures for novel food acceptance, other work examines variables that are associated with infants' responses to the first exposure of a new food. For example, Gerrish and Mennella (2001) and Lange et al. (2013) showed that previous exposure to a variety of foods led to increased acceptance of a novel food on the first exposure. Similarly, Mennella, Nicklaus, Jagolino, and Yourshaw (2008) found that repeated exposure to a variety of fruits increased acceptance of a novel fruit, but not a novel vegetable. Finally, Maier, Chabanet, Schaal, Leathwood, and Issanchou (2008) found that offering three vegetables for three consecutive days each did not increase consumption of a new vegetable (i.e. peas), whereas alternating the three vegetables daily did increase consumption of the new vegetable. Together, these results suggest that exposure to a variety of flavors may lead to increased acceptance of new foods. However, this effect may be dependent on the similarity between the variety of foods and the novel food (Mennella et al., 2008; see Birch et al., 1998 for a similar finding) and how often the various foods are rotated.

Another aspect of an infant's feeding history that may be related to novel food acceptance or rejection is exposure to breast milk. However, there are mixed results on this topic. One study found no differences between breastfed and formula-fed infants on their initial intake of a novel food (Sullivan & Birch, 1994), whereas another study showed that breastfed infants ate more calories of a novel fruit (i.e. peaches) than did formula-fed infants (Forestell & Mennella, 2007). Differences in results between the studies may be attributed to differences in mothers' consumption of the novel food while lactating. Forestell and Mennella (2007) found evidence to show that breastfeeding may only offer an advantage to infants if the tastes of the target food are transmitted to the infant through breast milk. Additional research on the relationship between breastfeeding and infants' acceptance of novel foods is needed.

The purpose of the present study was to investigate whether infant temperament and feeding history were associated with acceptance and rejection of a novel food, hummus or cottage cheese, at 12 months of age. We had three primary goals for the study. First, we examined whether infant temperament predicted infants' responses to the novel food. High approach infants tend to show more positive responses to novel stimuli (e.g. Rothbart & Bates, 2006), so we predicted that high levels of approach would be associated with more acceptance behaviors and less rejection of the new food. Conversely, we expected infants rated lower in approach to show less acceptance and more rejection behaviors in response to the novel food.

The second goal of this study was to examine the relationship between infants' previous feeding history and responses to the novel food. Since exposure to a variety of foods has been shown to increase infants' acceptance of a novel food (Gerrish, Mennella, 2001, Lange et al, 2013), we hypothesized that exposure to a greater number of solid foods would be associated with more acceptance and less rejection of the novel food in the present study. Also, although research on the relationship between breastfeeding and acceptance of novel foods has yielded mixed results (e.g. Forestell, Mennella, 2007, Sullivan, Birch, 1994), we predicted that infants who were exclusively breastfed for at least 4 months would be more accepting and less rejecting of the novel food than infants who were exclusively breastfed for less than 4 months. Finally, since the duration of exclusive breastfeeding may affect the rate at which the mothers introduce their infants to solid foods, both feeding history variables were included in the same analyses to examine the effects of each variable above and beyond the effects of the other variable.

The third goal was to examine the combined effects of temperament and feeding history on infants' responses to the novel food. Low approach infants are unlikely to accept novel foods because they tend not to show positive responses to novelty (Rothbart & Bates, 2006). However, it is possible that exposure to a greater number of solid foods and/or exclusive breastfeeding for at least 4 months may help low approach infants accept a new food due to their familiarization with a variety of flavors. Conversely, since high approach infants tend to accept novel stimuli, it is likely that they will show more acceptance behaviors and less rejection regardless of the number of solid foods they previously tasted or the duration they were exclusively breastfed.

Finally, when testing each of the above hypotheses, we examined the infants' responses to both the first and subsequent offers of a novel food during the infants' first exposure to the food. The first spoonful of a new food is the only offer that is completely novel to the infant, so it is possible that infants' reactions to this first spoonful will differ from their responses to subsequent spoonfuls of the food. However, previous research has focused on differences in infants' responses across feedings instead of within the infants' first experience with the food. For this reason, no hypotheses could be made regarding differences in infants' responses to the first versus later spoonfuls of novel food in the present study.