Studies in Vision: IV. The Interactions of Rods and Cones in After-Sensations

Fixed-ratio (FR) size was increased for pigeons (N = 6), while the number of eating responses at reinforcement was either held constant or increased. Also, FR size was held constant while the number of eating responses at reinforcement was increased. Major findings were as follows: (a) when eating responses were held constant, higher FR requirements led to stable key rates and postreinforcement pauses; (b) allowing more eating responses at successively higher FR requirements led to stable key rates and postreinforcement pauses; (c) at high FR requirements which produced low key rates, increasing the number of eating responses at reinforcement increased key rates; and (d) eating response rates varied systematically with key rates.     

Chimpanzees (Pan troglodytes) transfer tokens repeatedly with a partner to accumulate rewards in a self-control task

There has been extensive research investigating self-control in humans and nonhuman animals, yet we know surprisingly little about how one’s social environment influences self-control. The present study examined the self-control of chimpanzees in a task that required active engagement with conspecifics. The task consisted of transferring a token back and forth with a partner animal in order to accumulate food rewards, one item per token transfer. Self-control was required because at any point in the trial, either chimpanzee could obtain their accumulated rewards, but doing so discontinued the food accumulation and ended the trial for both individuals. Chimpanzees readily engaged the task and accumulated the majority of available rewards before ending each trial, and they did so across a number of conditions that varied the identity of the partner, the presence/absence of the experimenter, and the means by which they could obtain rewards. A second experiment examined chimpanzees’ self-control when given the choice between immediately available food items and a potentially larger amount of rewards that could be obtained by engaging the token transfer task with a partner. Chimpanzees were flexible in their decision-making in this test, typically choosing the option representing the largest amount of food, even if it involved delayed accumulation of the rewards via the token transfer task. These results demonstrate that chimpanzees can exhibit self-control in situations involving social interactions, and they encourage further research into this important aspect of the self-control scenario.     

Perceived Ability to Cope With Trauma Among U.S. Combat Veterans

The Perceived Ability to Cope With Trauma (PACT) scale measures perceived forward-focused and trauma-focused coping. This measure may also have significant utility measuring positive adaption to life-threatening trauma, such as combat. Our objective was to examine perceived ability to cope with trauma, as measured by the PACT, and the relationships between this perceived ability and clinically pertinent information (anxiety, depression, posttraumatic stress disorder [PTSD]) among U.S. military veterans. Data were provided from 71 combat veterans, consisting of 47 veterans with PTSD and 24 veterans without PTSD who had subthreshold symptoms of the disorder. All veterans completed standardized clinical interviews as well as a battery of well-validated self-report symptom measures. We found that veterans with PTSD had significantly lower PACT scores than veterans without PTSD; those without PTSD self-reported more ability to engage in forward-focused and trauma-focused coping than those with PTSD. Importantly, we also showed relationships between the PACT scores and indices of psychological difficulties as both Forward Focus and Trauma Focus coping scores negatively correlated with PTSD, depression, anxiety, and alexithymia. Finally, the Forward Focus PACT scale improved prediction of PTSD severity over combat exposure alone. The PACT, especially the Forward Focus scale, appears to be a useful measure of perceived positive coping ability with trauma in combat-exposed veterans who report symptoms of traumatic stress, extending the utility of the measure from normative to clinical populations. The importance of adopting forward-focused coping is discussed.     

Living Out of the Past: Dilthey and Heidegger on Life and History

This essay examines continuities and transformations in Heidegger's appropriation of Dilthey's account of life and the accompanying picture of history between the end of World War One and Being and Time . The essay also judges the cogency of two conclusions that Heidegger draws in that book about history, viz, that historicity qua feature of Dasein's being both underlies objective history and makes the scholarly narration of history possible. Part one describes Dilthey's account of life, Heidegger's criticism that this account objectifies life, and Heidegger's appropriation of those aspects of Dilthey's account - temporality, movement, and wholes - that do not result from objectification. Part two focuses on how Heidegger reworks the idea that life is movement by reconceptualizing movement as a happening (and not a stream) and by replacing Dilthey's lived experiences with actions. Part three examines how Heidegger takes over from Dilthey the idea that something is historical if and only if the past is part of its present, also attending to the type(s) of past that these thinkers consider to be part of life. A final section judges the cogency of the two aforementioned theses, defending the claim that the historicity of life is the condition of the objective nexus of actions and events called history and criticizing the thesis that the historicity of a historian's life makes the writing of history possible.     

Restorative biological processes and health

Research on psychological influences on physiology primarily focuses on biological responses during stressful challenges, and how those responses can become dysregulated with prolonged or repeated exposure to stressful circumstances. At the same time, humans spend considerable time recovering from those challenges, and a host of biological processes involved in restoration and repair take place during normal, non-stressed activities. We review restorative biological processes and evidence for links between psychosocial factors and several restorative processes including sleep, wound healing, antioxidant production, DNA repair, and telomerase function. Across these biological processes, a growing body of evidence suggests that experiencing negative emotional states, including acute and chronic stress, depressive symptoms, and individual differences in negative affectivity and hostility, can influence these restorative processes. This review calls attention to restorative processes as fruitful mechanisms and outcomes for future biobehavioral research.     

Monkeys exhibit prospective memory in a computerized task

Prospective memory (PM) involves forming intentions, retaining those intentions, and later executing those intended responses at the appropriate time. Few studies have investigated this capacity in animals. Monkeys performed a computerized task that assessed their ability to remember to make a particular response if they observed a PM cue embedded within an ongoing learning-set (LS) task. At a break in the LS task, monkeys selected one of two icons indicating that they had or had not encoded the occurrence of the PM cue (the latter icon resumed the LS task). Critically, during this response period, the PM response icon appeared after a delay during which monkeys could self-initiate the PM response prior to receiving any external prompt. Monkeys selected the PM and LS icons when each was the optimal response, illustrating that they could encode, store, and respond appropriately to a stimulus event in the future. Critically, some monkeys self-initiated the PM response prior to that icon's appearance, indicating that they could retrieve the PM and act on their intention to make that response without the aid of a prompt. These monkeys appeared capable of using PM in this task. Thus, this capacity appears not to be limited to humans.     

On the relations between distinct aspects of psychological distance: An ecological basis of construal-level theory

Construal-level theory's basic assumption of a positive relationship between psychological distance and abstractness of mental representations presupposes a unitary distance construct. Although prior research testifies to convergent influences of temporal, spatial, social and reality (probability) distance, there is no direct evidence for the integration function of all four major distance aspects assessed within the same study with reference to the same target objects. Does high (low) distance in any aspect imply high (low) distance in all other aspects, or are discounting effects (e.g., high temporal distance rendering high personal distance obsolete) sometimes apparent in negative correlations? In pursuing this question, we obtained strong and regular positive correlations between all four distance aspects, across judges and judgment targets, regardless of whether freely construed future episodes or really experienced past episodes were judged. Existing ecological correlations seem to account for the positive relationship between time, space, probability and temporal distance.