EFFECTS OF A PROCEDURE DERIVED FROM THE OVERCORRECTION PRINCIPLE ON MANIPULATED AND NONMANIPULATED BEHAVIORS

Positive practice overcorrection has been shown to be effective in reducing stereotypic self-stimulatory behaviors displayed by retarded and autistic individuals. In addition, the procedure also may increase the occurrence of appropriate behavior through intensive practice. In the present study, several stereotypic and one appropriate behavior (appropriate toy play) displayed by two autistic children were measured before and during treatment by a positive practice in appropriate toy play overcorrection procedure. Overcorrection was introduced for each of the targeted inappropriate behaviors in succession for both children. Results showed that overcorrection reduced all stereotypic behaviors displayed by both children. In addition, one subject displayed marked increases in the behavior practised during overcorrection, appropriate toy play, relative to its baseline rate of occurrence. The results indicate that for some individuals, overcorrection may be effective in teaching and motivating appropriate forms of behavior as well as in reducing stereotypy.     

Scaling pigeons' choice of feeds: bigger is better.

Preferences of hungry pigeons among 10 grains and pellets were analyzed using a Thurstone scaling procedure. The recovered scales were positively correlated with size of the feed. The correlations improved when the Thurstonian assumption of equal-sized discriminal dispersions (Case V) was replaced with the assumption of proportional-sized dispersions (Case VI), as entailed by Weber's law. The correlations weakened when the experiments were conducted with the pigeons close to their free-feeding weights, where the probability of sampling alternative grains increased. In the final experiment, exposure to a large pellet shifted the preferences between two smaller pellets.     

Free birds aren't fat: Weight gain in captured wild pigeons maintained under laboratory conditions

Nine feral pigeons, 5 from an urban setting and 4 from a rural setting, were captured and maintained for 42 days under free-feeding conditions comparable to those arranged for laboratory subjects. On average, birds increased their body weights by 17% over this period. The range of increase across birds was 9 to 30%. These findings suggest that the food deprivation arranged for laboratory pigeons, which is characteristically 80% of free-feeding weights, may in some sense be less severe than it first appears.     

Food word processing in Chinese reading: A study of restrained eaters

Food-related attentional bias refers that individuals typically prioritize rewarding food-related cues (e.g. food words and food images) compared with non-food stimuli; however, the findings are inconsistent for restrained eaters. Traditional paradigms used to test food-related attentional bias, such as visual probe tasks and visual search tasks, may not directly and accurately enough to reflect individuals' food-word processing at different cognitive stages. In this study, we introduced the boundary paradigm to investigate food-word attentional bias for both restrained and unrestrained eaters. Eye movements were recorded when they performed a naturalistic sentence-reading task. The results of later-stage analyses showed that food words were fixated on for less time than non-food words, which indicated a superiority of foveal food-word processing for both restrained and unrestrained eaters. The results of early-stage analyses showed that restrained eaters spent more time on pre-target regions in the food-word valid preview conditions, which indicated a parafoveal food-word processing superiority for restrained eaters (i.e. the parafoveal-on-foveal effect). The superiority of foveal food-word processing provides new insights into explaining food-related attentional bias in general groups. Additionally, the enhanced food-word attentional bias in parafoveal processing for restrained eaters illustrates the importance of individual characteristics in studying word recognition.     

Resurgence of time allocation

The resurgence of time allocation with pigeons was studied in three experiments. In Phase 1 of each experiment, response‐independent food occurred with different probabilities in the presence of two different keylights. Each peck on the key changed its color and the food probability in effect. In Phase 2, the food probabilities associated with each keylight were reversed and, in Phase 3, food was discontinued in the presence of either keylight. The food probabilities were .25 and .75, in Experiment 1, and 0.0 and 1.0 in Experiment 2. More time was allocated to the keylight correlated with more probable food in Phases 1 and 2, and in Phase 3 resurgence of time allocation occurred for two of three pigeons in Experiment 1, and for each of four pigeons in Experiment 2. Because time had to be allocated to either of the two alternatives in Experiments 1 and 2, however, it was difficult to characterize the time allocation patterns in Phase 3 as resurgence when changeover responding approached zero. In Experiment 3 this issue was addressed by providing a third alternative uncorrelated with food such that in each phase, after 30 s in the presence of either keylight correlated with food, the third alternative always was reinstated, requiring a response to access either of the two keylights correlated with food. In this experiment, the food probabilities were similar to those in Experiment 1. Resurgence of time allocation occurred for each of three pigeons under this procedure. The results of these experiments suggest that patterns of time allocation resurge similarly to discrete responses and to spatial and temporal patterns of responding.     

FOOD ETHICS: A CRITIQUE OF SOME ISLAMIC PERSPECTIVES ON GENETICALLY MODIFIED FOOD

This article critiques some Islamic approaches to food ethics and the debate over genetically modified (GM) food. Food ethics is a branch of bioethics, and is an emerging field in Islamic bioethics. The article critically analyzes the arguments of the authors who wrote in favor of genetically modified organisms (GMOs) from an Islamic perspective, and those who wrote against GMOs, also from an Islamic perspective. It reveals the theological and the epistemological foundations of the two main approaches. Moreover, it provides an attempt to critique what is perceived as an exclusivist and legalistic trend adopted by some authors. It argues that an alternative approach that acknowledges the priority of reason in ethics and is at the same time rooted in Islamic tradition would be more inclusive and constructive.     

Differential effects of approach bias and eating style on unhealthy food consumption in overweight and normal weight women

Objective: The current study aimed to examine the effects of approach bias for unhealthy food and trait eating style on consumption of unhealthy food in overweight and normal weight individuals.

Method: Participants were 245 undergraduate women aged 17 – 26 years. They completed an Approach–Avoidance Task, the Dutch Eating Behaviour Questionnaire (to assess restrained, emotional, and external eating), and a taste test to measure consumption of unhealthy food.

Results: An external eating style predicted increased consumption of unhealthy food. Among overweight participants, external and emotional eating style individually moderated the relationship between approach bias for unhealthy food and subsequent consumption. Specifically, approach bias was positively related to consumption in high external and emotional eaters, but negatively related to consumption in low emotional eaters. These interactions were not observed among normal weight participants.

Conclusion: Practically, the results suggest that overweight individuals who are external or emotional eaters may benefit from interventions that aim to modify approach bias towards unhealthy food cues to reduce problematic eating behaviour.     

肥胖成因的解释——基于食物奖赏研究的视角

肥胖的形成和发展受生物、心理和社会因素的共同作用,其中食物奖赏对肥胖的产生有重要的作用。食物是一种自然奖赏,它指机体天生对食物的渴望和依赖。食物奖赏包括"wanting"、"liking"以及"learningreinforcement"三个成分,每个成分由相应的神经通路表征。食物奖赏调控机体的摄食行为并以此调控体重变化。目前,关于肥胖与食物奖赏关系的理论模型主要有刺激—敏感化理论、奖赏过度理论以及奖赏不足理论。采用横断面设计、前瞻研究设计和纵向被试内重复测量设计,使用食物图片线索和直接给予美味奶昔的技术方法,人类脑成像研究从不同侧面为以上三个理论模型提供了证据。除此之外,食物奖赏还受基因的调控。目前,研究者关注较多的是多巴胺D2受体基因Taq IA rs1800497的多态性和FTO基因rs9939609的多态性对食物奖赏及体重改变的调控。     

DYNAMICS OF CHOICE: RELATIVE RATE AND AMOUNT AFFECT LOCAL PREFERENCE AT THREE DIFFERENT TIME SCALES

To examine extended control over local choice, the present study investigated preference in transition as food‐rate ratio provided by two levers changed across seven components within daily sessions, and food‐amount ratio changed across phases. Phase 1 arranged a food‐amount ratio of 4:1 (i.e., the left lever delivered four pellets and the right lever one pellet); Phase 2 reversed the food‐amount ratio to 1:4, and in Phase 3 the food‐amount ratio was 3:2. At a relatively extended time scale, preference was described well by a linear relation between log response ratio and log rate ratio (the generalized matching law). A small amount of carryover occurred from one rate ratio to the next but disappeared after four food deliveries. Estimates of sensitivity to food‐amount ratio were around 1.0 and were independent of rate ratio. Analysis across food deliveries within rate‐ratio components showed that the effect of a small amount was diminished by the presence of a large amount—that is, when a larger amount was present in the situation (three or four pellets), the value of a small amount (one or two pellets) became paltry. More local analysis of visits to the levers between food deliveries showed that postfood visits following a large amount were disproportionately longer than following a small amount. Continuing food deliveries from the same source tended to make visits less dependent on relative amount, but a discontinuation (i.e., food from the other lever) reinstated dependence on relative amount. Analysis at a still smaller time scale revealed preference pulses following food deliveries that confirmed the tendency toward dependence on absolute amount with continuing deliveries, and toward dependence on relative amount following discontinuations. A mathematical model based on a linear‐operator equation accounts for many of the results. The larger and longer preference following a switch to a larger amount is consistent with the idea that local preference depends on relatively extended variables even on short time scales.     

FUNCTIONAL ANALYSIS AND TREATMENT OF MULTIPLY CONTROLLED INAPPROPRIATE MEALTIME BEHAVIOR

Functional analyses identified children whose inappropriate mealtime behavior was maintained by escape and adult attention. Function‐based extinction procedures were tested individually and in combination. Attention extinction alone did not result in decreases in inappropriate mealtime behavior or a significant increase in acceptance. By contrast, escape extinction alone resulted in a decrease in inappropriate mealtime behavior and an increase in acceptance. However, inappropriate mealtime behavior did not decrease to clinically acceptable levels. A combined extinction technique (i.e., escape and attention extinction) resulted in a decrease in inappropriate mealtime behavior to clinically acceptable levels and high and stable acceptance.