Pictorial gaze cues do not enhance long tailed macaques’ performance on a computerised object location task

The perception of pictorial gaze cues was examined in long-tailed macaques (Macaca fascicularis). A computerised object location task was used to explore whether the monkeys would show faster response time to locate a target when its appearance was preceded with congruent as opposed to incongruent gaze cues. Despite existing evidence that macaques preferentially attend to the eyes in facial images and also visually orient with depicted gaze cues, the monkeys did not show faster response times on congruent trials either in response to schematic or photographic stimuli. These findings coincide with those reported for baboons tested with a similar paradigm in which gaze cues preceded a target identification task (Fagot and Deruelle 2002). When tested with either pictorial stimuli or interactants, non human primates readily follow gaze but do not seem to use this mechanism to identify a target object; there seems to be some mismatch in performance between attentional changes and manual responses to gaze cues on ostensibly similar tasks

Testing cognitive performance of socially housed monkeys: possibilities and limitations of the study of social influences on age-related cognitive decline

In both humans and monkeys not all individuals show the same rate of age-related cognitive decline. One important factor to influence the rate of decline is extended exposure to elevated levels of glucocorticoids, which play a central role in the response to stress. Furthermore, studies with humans have suggested that the social environment influences such exposure to glucocorticoids. However, the complex social structure of human society complicates the investigation of the effects of the life time social environment on cognitive decline. The stable social structure of many monkey species does allow this investigation. The colony of long-tailed macaques (Macaca fascicularis) of the Utrecht University is especially suited for this. The social dominance relations of the females are stable and have been known for decades. Moreover, a low dominance status has been related to exposure to elevated levels of glucocorticoids. We aimed to confirm previously found results supporting the hypothesis that a history of low dominance is related to an acceleration of age-related cognitive decline. Fourteen female monkeys of various age and dominance classes were tested in a four-choice discrimination-reversal test. Subjects were temporarily isolated from their group based on voluntary co-operation, and tested with a computer operated touch screen. The results do not support this hypothesis. A number of theoretical and methodological issues are discussed in relation to this result. Further analyses revealed that high dominance status was related to relatively low levels of attention, which in turn were related to poor cognitive performance. This finding confounded the possibility to find the hypothesised effect. In an additional study the social groups were exposed to a loud noise to assess individual differences in the temperamental aspect of anxiety, which were then related to differences in behaviour and performance in the previous cognitive test. More anxious subjects paid less attention to the task and had a poor performance. However, this effect was found only for the experimentally naïve subjects. In the second part of this thesis the effects of stimulus parameters on cognitive performance are investigated. We hypothesised that biologically relevant 2-dimensional stimuli are more easily discriminated than pictures that the animals has no prior associations with. Also, bright and contrasting colours may improve performance compared to dull colours. In a relatively difficult cognitive task bright colours and high levels of contrast enhanced performance, while no such effect was found in a similar but less difficult task. Biological relevance of stimuli did not influence performance. This thesis underlines the possibilities and difficulties that testing individual cognitive performance of socially housed monkeys offer. Social dominance relations and individual characteristics strongly influence cognitive performance and complicate the study of other differences in cognitive abilities. Moreover, the parameters of the stimuli are important to consider in the design of a study as these may profoundly affect performance in more difficult tasks. It is recommended that in future studies a situation should be created in which the test is an integrated part of the animals' daily foraging behaviour, allowing larger sample sizes and longer study periods

A social cost-benefit analysis of meat taxation and a fruit and vegetables subsidy for a healthy and sustainable food consumption in the Netherlands.

Background: Implementation of food taxes or subsidies may promote healthier and a more sustainable diet in a society. This study estimates the effects of a tax (15% or 30%) on meat and a subsidy (10%) on fruit and vegetables (F&V) consumption in the Netherlands using a social cost-benefit analysis with a 30-year time horizon. Methods: Calculations with the representative Dutch National Food Consumption Survey (2012-2014) served as the reference. Price elasticities were applied to calculate changes in consumption and consumer surplus. Future food consumption and health effects were estimated using the DYNAMO-HIA model and environmental impacts were estimated using Life Cycle Analysis. The time horizon of all calculations is 30 year. All effects were monetarized and discounted to 2018 euros. Results: Over 30-years, a 15% or 30% meat tax or 10% F&V subsidy could result in reduced healthcare costs, increased quality of life, and higher productivity levels. Benefits to the environment of a meat tax are an estimated €3400 million or €6300 million in the 15% or 30% scenario respectively, whereas the increased F&V consumption could result in €100 million costs for the environment. While consumers benefit from a subsidy, a consumer surplus of €10,000 million, the tax scenarios demonstrate large experienced costs of respectively €21,000 and €41,000 million. Overall, a 15% or 30% price increase in meat could lead to a net benefit for society between €3100-7400 million or €4100-12,300 million over 30 years respectively. A 10% F&V subsidy could lead to a net benefit to society of €1800-3300 million. Sensitivity analyses did not change the main findings. Conclusions: The studied meat taxes and F&V subsidy showed net total welfare benefits for the Dutch society over a 30-year time horizon

Evaluation of foods, drinks and diets in the Netherlands according to the degree of processing for nutritional quality, environmental impact and food costs.

Objective: This study investigates nutritional quality, environmental impact and costs of foods and drinks and their consumption in daily diets according to the degree of processing across the Dutch population. Design: The NOVA classification was used to classify the degree of processing (ultra-processed foods (UPF) and ultra-processed drinks (UPD)). Food consumption data were derived from the Dutch National Food Consumption Survey 2012–2016. Indicators assessed were nutritional quality (saturated fatty acids (SFA), sodium, mono and disaccharides (sugar), fibre and protein), environmental impact (greenhouse gas (GHG) emissions and blue water use) and food costs. Setting: The Netherlands. Participants: Four thousand three hundred thirteen Dutch participants aged 1 to 79 years. Results: Per 100 g, UPF were more energy-dense and less healthy than unprocessed or minimally processed foods (MPF); UPF were associated with higher GHG emissions and lower blue water use, and were cheaper. The energy and sugar content of UPD were similar to those of unprocessed or minimally processed drinks (MPD); associated with similar GHG emissions but blue water use was less, and they were also more expensive. In the average Dutch diet, per 2000 kcal, ultra-processed foods and drinks (UPFD) covered 29% (456 g UPF and 437 g UPD) of daily consumption and 61% of energy intake. UPFD consumption was higher among children than adults, especially for UPD. UPFD consumption determined 45% of GHG emissions, 23% of blue water use and 39% of expenses for daily food consumption. UPFD consumption contributed 54% to 72% to daily sodium, sugar and SFA intake. Conclusions: Compared with unprocessed or minimally processed foods and drinks, UPF and UPD were found to be less healthy considering their high energy, SFA, sugar and sodium content. However, UPF were associated higher GHG emissions and with less blue water use and food costs. Therefore daily blue water use and food costs might increase if UPF are replaced by those unprocessed or minimally processed. As nutritional quality, environmental impacts and food costs relate differently to the NOVA classification, the classification is not directly applicable to identify win–win-wins of nutritional quality, environmental impact and costs of diets