Sexy Stripper Game: the motivating effects of anticipated sexual reward. Rodney Birjmohun Student number: 9964371 Poppy Watson Supervisor University of Amsterdam Glossary Abstract 2 Introduction 3 Method 5 Results 10 Discussion 15 References 17 1 Abstract In the current study we investigated whether anticipated sexual reward (sexual stimuli) would bias the motivation to pursue financial rewards. This general Pavlovian-to-instrumental- transfer (PIT) was assessed by using a computerized PIT-task in which participants had to press on two response keys, at certain moments in the presence of Pavlovian sexual stimuli, in order to gain financial (instrumental) rewards. The hypotheses (1) that a general PIT effect would be observed by increased overall response rates and (2) that the general PIT effect would be greater for Pavlovian stimuli that predict rewards of greater magnitude, were both confirmed. We also found an unexpected result, which states that less-appetitive anticipated sexual stimuli biases responses towards rewards of lower financial magnitude. Additionally, we examined individual differences in the strength of the PIT-effect, by relating the behavioral data to data about sexual attitudes and watching online pornography, acquired by corresponding questionnaires. A positive correlation between addictive porn watching and strength of PIT was found. The societal relevance of this study is of most importance, considering the abundance of cues in the modern environment, signaling the availability of sexually rewarding encounters such as internet pornography and dating apps such as Tinder. 2 Introduction Cues that have previously been associated with rewarding outcomes, can bias responding towards those rewards and also influence the rate of responding for other rewards (Corbit & Balleine, 2005, 2011). Previous research has shown that this Pavlovian-to-instrumental transfer (PIT) effect, consists of an excitatory motivational transfer, generated from Pavlovian conditioning, on to instrumental learning; thereby influencing the choice and/or response rate for rewards as learned in the instrumental setting (Corbit, Muir & Balleine 2001; Dickinson & Balleine, 2002). The PIT effect is of interest because previous research has suggested that reward- paired cues can trigger responding for outcomes that are currently not desired (Corbit & Balleine, 2005, 2011). Watson and colleagues (2014) for example, showed that cues that had been previously paired with chocolate, triggered responding on a key that yielded chocolate, even when participants were no longer desiring chocolate and had stopped responding for chocolate in the absence of cues. In line with this, alcohol dependent persons show stronger PIT than non-clinical persons (Garbusow et al., 2016). The PIT-effect is thought to be particularly important in maintaining drug-seeking behavior when an addicted person is exposed to environments previously linked to substance abuse (Sanchis Segura & Spanagel, 2006). In their studies, Corbit and Balleine (2005, 2011) have shown that there are actually two kinds of PIT; a specific form and a general form. In specific PIT, the rewards gained in the Pavlovian setting are similar to those gained in the instrumental setting. The excitatory effect of the Pavlovian stimuli enhances the response rate for the same reward in the instrumental setting. In general PIT, the rewards gained in the Pavlovian setting are different from the rewards gained in the instrumental setting. Nonetheless it has been shown that the excitatory effect of the Pavlovian stimuli, enhances the response rate for different rewards in the instrumental setting (Corbit & Balleine, 2005, 2011). In the case of general PIT, it is argued that anticipation of the rewarding outcome, activates a central motivational drive, which then elevates all ongoing reward-related responses (Balleine & Baldassar, 2016). Both forms of PIT are argued to be of importance in understanding how reward-paired cues in the environment can trigger maladaptive food and drug-seeking behavior (Garbusow et al., 2016, Watson et al., 2014). Corbit and Balleine (2005, 2011) demonstrated the PIT effect in two studies with rats. Responses (e.g. lever presses) were trained towards different food rewards (e.g. pellets and sucrose). Outcome specific PIT as well as general PIT was observed in the tested animals, when they clearly showed an invigorated response rate when a Pavlovian sound associated with a third food outcome (e.g. polycose) was played, even though this third food outcome was not previously associated with a lever. However, in these two studies it is of importance to give notice to the fact that although a general PIT effect was found, it was not “trans motivational”, because the general (third) outcome was another type of food. In the current 3 study we wanted to investigate how strong a general PIT effect would manifest itself in a context with different (trans motivational) outcomes. In humans, the PIT effect has been demonstrated with both food and financial rewards. In their study, Hebart & Glascher (2014) showed that different Pavlovian cues (predicting an aversive sound, no outcome and sandwiches), biased the response rate for financial rewards (money could be earned by shooting a sufficient amount of times at a space ship, in a computer game, by pressing a response key). Responses went up for the appetitive cue (sandwiches), but went down for the aversive sound cue, compared to baseline (no outcome). In this study it can be stated that a trans motivational (from food and sound to money) general PIT effect had been demonstrated. However, it has to be noted that there was only one response key available for the gaining of the financial reward. An interesting point in this case may have been overlooked; that is the opportunity to make a choice. In the current study we investigated how the general PIT effect would establish itself in a context where participants could respond for both a high and a low financial reward (instead of just one reward). In line with appetitive stimuli of food, different stimuli that can also be considered as appetitive are sexual stimuli. To this date, PIT has not been investigated in the context of sexual stimuli, although the modern environment gives many reminders of sexual available situations, like chatting and dating, in which it is not uncommon to pay money for certain services (e.g. online chat sites, dating sites, pornographic sites). Cashwell et al. (2016) report that in a sample of 337 students, 16,9 % showed scores of sexual addiction within the clinical range. We therefore suggest that this warrants further research and has societal relevance. Snagowski, Laier, Duka & Brand (2016) claimed in their paper that they were going to investigate the PIT effect in the context of pornographic images (Pavlovian cues). Disappointingly, the researchers merely established classical conditioning, in which the participants learned the relationships between pornographic images and neutral images. Subsequently, the participants rated the neutral images as more sexually than before the Pavlovian training phase. This can’t be specified as PIT, as there was no instrumental responding measured during this task. As the above makes clear, general PIT has not been systematically studied and there are a number of outstanding questions, regarding a) whether all ongoing reward-related responses are elevated to the same degree and b) whether the general PIT effect is greater for Pavlovian stimuli that predict rewards of greater magnitude. These questions were addressed in the current research. Specifically, we investigated how cues previously associated with sexually relevant outcomes (stripper pictures), can invigourate responding for financial rewards (i.e. general PIT). PIT has not yet been investigated in the context of sexual stimuli although the modern environment contains many reminders of the availability of sexual encounters. A computerized PIT task was used to assess general PIT. The task consisted of an instrumental and a Pavlovian training phase, followed by the transfer test phase. Four Pavlovian cues (black and white patterns) were related to four different 4 outcomes; two financial (high, low, outcome specific PIT) and two erotic (preferred, non- preferred, general PIT). The two financial rewards could be earned during the instrumental training phase by pressing on two different keys, each related to the higher or the lower financial reward. We systematically varied the reward magnitude of both the Pavlovian outcomes (preferred and non-preferred strippers) and also the instrumental outcomes (high and low financial rewards), to gain insight into the parameters of the general PIT mechanism. We expected a trans motivational general PIT effect, from sexual associative stimuli to financial rewards. We expected to find (1) a general-PIT effect: stimuli previously associated with sexually excitatory stimuli, should cause response rates to increase for financial rewards, relative to a baseline condition in which there are no stimuli presented. (2) Relative to the baseline condition, “preferred” strippers should increase response rates more than “non-preferred” strippers. (3) All ongoing responses (for both high and low financial outcomes) should be elevated to the same degree. Outcome specific PIT was also assessed, but merely as a control condition, as for this form of PIT has already been intensively investigated (Corbit & Balleine, 2005, 2011, Watson et al., 2014). We