Relationship between food habituation and reinforcing efficacy of food

Reinforcing value and habituation are two processes that have been used to study eating behaviors, but no research has examined their relationship, how they relate to energy intake, and whether they respond in a similar manner to food deprivation. Twenty-two female subjects were randomized to food deprived or non-deprived conditions, and assessed for food reinforcement, habituation to food and ad libitum eating. Results showed food reinforcement and habituation are correlated (r = 0.62, p = 0.002) and both independently predict energy intake. Hierarchical regression showed that the rate of habituation accounted for 30 percent of the variance in eating (p = 0.008), and adding food reinforcement increased the amount of variance accounted for up to 57.5 percent (p < 0.05). This suggests that both processes may influence energy intake in a meal.     

Observing stimulus sources that signal food or no food

Pigeons were given a choice between observing a stimulus source that was uncorrelated with food or one that was informative. The informative source was either positive, in which a stimulus change signalled food, or negative, in which change signalled no food. If observing is supported by the reduction of uncertainty, the negative as well as the positive source should be preferred to the uncorrelated source. On the other hand, if observing requires support by conditioned reinforcement, the negative source should not be preferred to the uncorrelated source. Two keys served as stimulus sources in a discrete trial procedure. The keys were lighted together, remained on for a variable length of time, and went off together. A key could change color 1 sec before going off. In the uncorrelated source, the change occurred equally often on trials ending with or without food. In the positive information source, the change occurred only on food trials, whereas in the negative information source, it occurred only on no-food trials. All stimulus changes and food delivery were response independent. As measured by orientation and autoshaped pecking, the positive information source was preferred to the uncorrelated source. However, the uncorrelated source was preferred to the negative information source. The latter result does not support the view that observing behavior is reinforced by the reduction of uncertainty. The positive and negative information sources reduced uncertainty equally but only the positive source provided a signal that could act as a conditioned reinforcer by virtue of its relation to food.     

Defective food concepts

Our aim in this paper is to employ conceptual negotiation to inform a method of rethinking defective food concepts, that is concepts that fail to suitably represent a certain food-related domain or that offer representations that run counter to the interests of their users. We begin by sorting out four dimensions of a food concept: (i) the data upon which it rests and the methodology by which those data are gathered; (ii) the ontology that sustains it; (iii) the social acts that serve to negotiate and establish the concept; (iv) and the aims and values that it fosters. We then discuss the conditions that make a food concept defective, pointing out four types of defects—fragility, polarization, incoherence, and schizophrenia—which we illustrate by means of two specific examples: local food and healthy food.

     

Local effects of delayed food

Five pigeons were trained on a procedure in which seven concurrent variable-interval schedules arranged seven different food-rate ratios in random sequence in each session. Each of these components lasted for 10 response-produced food deliveries, and components were separated by 10-s blackouts. We varied delays to food (signaled by blackout) between the two response alternatives in an experiment with three phases: In Phase 1, the delay on one alternative was 0 s, and the other was varied between 0 and 8 s; in Phase 2, both delays were equal and were varied from 0 to 4 s; in Phase 3, the two delays summed to 8 s, and each was varied from 1 to 7 s. The results showed that increasing delay affected local choice, measured by a pulse in preference, in the same way as decreasing magnitude, but we found also that increasing the delay at the other alternative increased local preference. This result casts doubt on the traditional view that a reinforcer strengthens a response depending only on the reinforcer's value discounted by any response-reinforcer delay. The results suggest that food guides, rather than strengthens, behavior.     

Aversive CSs suppress lever pressing for food but not the eating of free food

Forty rats received CER acquisition, half “on the baseline” (response lever present), half “off the baseline.” During initial CER extinction, Ss received: (a) normal CER extinction (lever available), (b) free food during CSs only (no lever), (c) free food during non-CSs only (no lever), or (d) free food during both CS and non-CS periods (no lever). While normal extinction Ss were highly suppressed in the presence of the CS, all free food groups readily ate but did not differ in eating latencies. On subsequent CER extinction trials on the baseline, those Ss which received free food during the CSs were no less suppressed than other Ss. These data offer no support for Estes' (1969) reciprocal inhibition explanation of CER and punishment, nor do they support a fear interpretation of CER.     

Through the eyes of dieters: Biased size perception of food following tempting food primes

Why do some dieters succeed in controlling their diet while others do not? This research focused on a perceptual process—size perception of food objects—that may moderate the success of dieters in self-control dilemmas. We assessed successful and unsuccessful dieters' size perception of palatable food (Study 1) and diet-food (Study 2) after pre-exposing them to tempting food primes. Dieters perceived palatable food as bigger when primed with tempting food (vs. control prime), regardless of self-regulatory success in dieting (Study 1). Palatable food thus looms larger for both unsuccessful and successful dieters when in a “hot” state. In contrast, the perceived size of diet-food was increased by a tempting food prime only for successful dieters, but decreased for unsuccessful dieters (Study 2). These results are interpreted in terms of differences in the mental accessibility of competing goals (eating enjoyment vs. dieting) in successful vs. unsuccessful dieters. Indeed, when the dieting goal was made accessible for all dieters by a diet prime, even unsuccessful dieters perceived diet-food as bigger (Study 2). This research provides insight into a perceptual process that may be detrimental or beneficial in resolving self-control conflicts in the domain of eating and dieting behavior—and probably other domains of self-control as well.     

From world hunger to food sovereignty: food ethics and human development

The role of Amartya Sen's early work on famine notwithstanding, food security is generally seen as but one capability among many for scholars writing in development ethics. The early literature on the ethics of hunger is summarized to show how Sen's Poverty and Famines was written in response to debates of past decades, and a brief discussion of food security as a capability follows. However, Sen's characterization of smallholder food security also supports the development of agency in both a political and an economic sense. Economic agency is discussed and tied to longstanding literatures on the moral significance of farming within political economy. Finally, while the newly emergent literature on food sovereignty includes many themes, it is shown to be re-articulating arguments that stress smallholder's economic agency as a development goal. This pattern of argument thus provides a way to reconcile at least some of the claims being advanced under the banner of food sovereignty with the human development approach, while also restoring food ethics to a more central place in the overall discourse of development ethics.     

Using food redistribution to reduce packing in children with severe food refusal

Positive- and negative-reinforcement-based procedures typically have targeted acceptance for children with severe food refusal; however, these procedures do not always result in successful swallowing. Once acceptance is achieved, some children expel the food repeatedly or pack (hold or pocket) it in their mouths for extended periods of time. This study evaluated the effects of using food redistribution with a bristled massaging toothbrush to reduce packing and increase consumption in 4 children with severe feeding disorders. Packing was reduced for all children. In addition, latency to clean mouth (the duration of time from acceptance to food no longer being present in the child's mouth in the absence of expulsion) for 2 children decreased when the food-redistribution procedure was used. Results are discussed in terms of the potential operant functions of the food-redistribution procedure.     

Explaining unexplainable food choices

In recent years, psychologists have started to investigate the downstream consequences of nonconsciously activated behaviour (acting in an ‘explanatory vacuum’). Results have shown that when such behaviour is norm‐violating, people experience a need to confabulate reasons for this behaviour. The present paper aims to add more convincing evidence for this assumption. Study 1 addresses this question by replicating Study 2 of Adriaanse, Weijers, De Ridder, De Witt Huberts, and Evers ( 2014 ) while adding a condition in which people are post hoc provided with an explanation for their behaviour. Study 2 addresses this question by explicitly demanding an explanation for a nonconsciously steered choice. Both studies were conducted in the context of eating behaviour. Results of both studies were indicative of confabulation as a downstream consequence of nonconsciously steered eating behaviour (Study 1) or food choice (Study 2). Future research should address the potential of confabulated reasons spilling over to next occasions.     

An evaluation of simultaneous and sequential presentation of preferred and nonpreferred food to treat food selectivity

In the current investigation, we compared two methods of food presentation (simultaneous vs. sequential) to increase consumption of nonpreferred food for 3 children with food selectivity. In the simultaneous condition, preferred foods were presented at the same time as nonpreferred food (e.g., a piece of broccoli was presented on a chip). In the sequential condition, acceptance of the nonpreferred food resulted in presentation of the preferred food. Increases in consumption occurred immediately during the simultaneous condition for 2 of the 3 participants. For 1 participant, increases in consumption occurred in the simultaneous condition relative to the sequential condition, but only after physical guidance and re-presentation were added to treatment. Finally, consumption increased for 1 participant in the sequential condition, but only after several sessions. These results are discussed in terms of possible mechanisms that may alter preferences for food (i.e., establishing operations, flavor-flavor conditioning).