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 furthermore investigated how individual differences in attitudes towards sexuality (including internet pornography, sexual liberalism and online dating) related to the strength of the PIT effect. Taking into consideration the stronger PIT demonstrated by alcohol addicts (Garbusow et al., 2016), a stronger sexual preoccupation, obsession or addiction, should promote stronger PIT. Therefore we also expected that (4) higher scores on the sexual attitudes questionnaires (indicating more use of internet pornography and more liberal attitudes towards sexual contact), should correlate positively with the general PIT effect.

Method

Participants For this study, 50 male participants in the age of 18 years old and above, were recruited via the University of Amsterdam. The advertisement highlighted that only heterosexual males were required and furthermore stated that the study involved earning “stripper points” in order to see a striptease show at the end of the experiment. Participants received € 10 or a study participation point and an additional bonus payment, depending on their performance during the training and test phases in the experiment. A G-Power analysis determined the sample size needed for a reliable result. For a repeated measures ANOVA, a priori, with given α= .05, β= .95 and an effect size of .25, the required sample size was calculated to be exactly 50.

Stimuli and materials A computerized PIT task, similar to the one used by Watson et al. (2014) was programmed in Presentation and presented on a desktop computer. The task consisted of an instrumental

5 and a Pavlovian training phase, both followed by a rating test of desirability to see a striptease show from a preferred or a non-preferred stripper. The sexy stripper game is outlined in detail below (see procedure and Figure 1). Various striptease videos were used in the task (duration: 2.5 minutes), always presented full screen. Various images were used in the task - approximately one-fifth of the screen size and were always presented in the middle of the screen., These included, images of female strippers, four black and white patterns used as Pavlovian stimuli and two squares representing the financial outcomes – one purple with the text 2C (2 cents) and one blue 5C (5 cents) written in it. The number of key presses (vigour key presses) and reaction time (RT) of the first key press, for both high and low financial rewards, were recorded on each trial.

Striptease desire questionnaire At two times during the experiment, A Likert scale was used to measure the desire to watch a preferred or a non-preferred stripper perform a striptease show. Participants were asked to rate their desire on a 10 cm Likert scale with anchors “very much” and “not at all”.

Brief Sexual Attitudes Scale The strength of the sexual attitudes was assessed by the Dutch version of the Brief Sexual Attitudes Scale (BSAS). The BSAS consisted of 23 different statements about sexual attitudes, on which the participants had to give their answer on a five-point Likert scale, ranging from (1) strongly agree to (5) strongly disagree. The questionnaire is divided into four subscales: permissiveness, birth control, communion and instrumentality. Previous research has shown the reliability and the validity of the BSAS; Cronbach’s alpha = .86 (Hendrick et al., 2006). The Dutch version only contains the subscales permissiveness and instrumentality. Total scores are not useful, but scores on the subscales are (Hendrick et al., 2006).

Cyber Pornography Use Inventory The Cyber Pornography Use Inventory (CPUI) was especially developed to assess online pornography use and was based on the principle of addiction; an inability to stop the behaviour, being obsessed with the behaviour and the deriving negative consequences of it (Delmonico & Miller, 2003). It consists of 40 items which had to be answered on a 7-point Likert scale, ranging from (1) strongly agree to (7) strongly disagree, or from: never to always. A factor analysis of the CPUI has shown a reliability of α > .80 on three identified factors: addictive patterns, guilt regarding online pornography use and online sexual behaviour-social (Grubbs et al. 2010). 6

Procedure Participants were first asked to read an information brochure and if they agreed, sign an agreement for the use of their research data (informed consent). The PIT task was then started on a computer and presented to the participants who went through the following phases.

1. Warm Up Phase: to heighten participants’ motivation in the task and increase their interest in the stripper stimuli, the experiment started with the participants watching a two and a half minute striptease (from a stripper who was not presented further in the task).

2. Stripper Preference Phase: Participants then saw the images from four different strippers and were asked to click with the mouse on the images of the two strippers they most preferred. One of these strippers was then assigned during the task as the ‘preferred stripper’ and one of the other (non-selected) pictures was assigned as the ‘non-preferred’ stripper.

3. Instrumental Training Phase: participants were told that they could earn money by pushing on two response keys. One key (“L”) was assigned to 5 cents and the other one (“J”) to 2 cents (counterbalanced across participants). A purple box appeared in the center of the screen and the participants were told that the box contained a financial reward of 5 cents or 2 cents. Participants were told that only one reward was available and they were told to sample both response keys, using only one finger, until they won that reward (the image of 5 cents or 2 cents was then shown in the box for 1 second, with an ITI of 1,5 seconds). Participants were also told that they should learn the relationship between the keys and the financial outcomes and that they would be tested on this. The number of presses needed to eventually bank the financial reward, was between five and 15 presses and was determined by a variable ratio schedule of 10. The instrumental training phase consisted of four blocks in which the two financial outcomes could both be banked three times, in random order (24 trials in total). At the end of the second and the fourth block, an instrumental query block was inserted, which consisted of four trials. This is where participants were tested on their knowledge of the relationship between the response keys and the financial outcomes. On each trial, one of the two images of the financial outcomes was presented and the participant had to press the key that during the training trials produced that specific outcome. After participants pressed one of those keys, they immediately received feedback on their choice. The words “correct” or “incorrect” appeared on the screen for two seconds and was followed 7 by a 1,5 seconds ITI. Each financial outcome was presented in random order.

4.Striptease Desire Questionnaire 1. Participants completed the questionnaire, rating their desire to see each of the two strippers perform a striptease.

5. Pavlovian Training Phase: This phase consisted of 8 trials in which participants passively viewed the screen and were told to try and learn the relationship between the four black and white patterns and the four outcomes (non-preferred stripper, preferred stripper, 2 cents and 5 cents) and are told that they will be tested later on. They did not need to push any keys, but just watch the screen. They still earned the money when it appeared or a stripper point when a stripper appeared. During each trial, one of the four Pavlovian cues was presented for two seconds and was then overlaid with the picture of a stripper or an image of a financial reward, with a duration of one second. The ITI was 1,5 seconds. After these 8 trials the active Pavlovian training phase began. Participants saw one of the four Pavlovian stimuli appear in the center top of the screen and had to select with the mouse the correct outcome from four smaller outcome pictures which were presented at the bottom of the screen in a 2 x 2 matrix. The four outcome pictures were presented in a random location within the matrix on each trial. After participants made their selection, they immediately received feedback on their choice. The words “correct” or “incorrect” appeared on the screen for two seconds, along with the correct outcome picture and the words “this was the right answer”. The active Pavlovian training phase consisted of eight blocks, during which, each of the four cues were presented twice in random order, for a total of 64 trials.

6. Striptease Desire Questionnaire 2. The stripper rating phase was repeated.

7. Transfer Test Phase: Participants were informed that just as before, during the instrumental training phase, they could earn 2 cents and 5 cents by pressing the response keys when the purple box appeared. They were told that the procedure and the relationship between the buttons and the financial outcomes are the same as before (see point 3 above), but that occasionally pictures will appear on the screen; these could be ignored and they should pay attention to the purple box, as this indicated that they could start responding to bank the financial rewards. In this phase, participants did not see their winnings until the end of the last block. The purple box appeared on 1/5 of trials, without any stimuli (baseline trials). Each of the four Pavlovian stimuli were also shown on 1/5 of trials, with the purple box overlaid.

8 8. Final Questionnaires: After the test phase, participants completed the BSAS and the CPUI questionnaires.

1. Instrumental training

Left Key 

Right Key 

2. Pavlovian Training

3. Transfer test

Left Key Press?

Right Key Press?

Fig 1. Procedure. Participants learned the relationship between two response keys and financial 9 outcomes (2 cents and 5 cents). They then learned the relationship between four Pavlovian and both sexual outcomes (pictures of strippers) and financial outcomes. After this they did the transfer test in which Pavlovian cues occasionally appeared with the purple box overlaid.

Results

Participants In total, six participants were excluded because they did not pass the final test of instrumental knowledge, testing the relationship between the keys and the two financial rewards. Data analysis proceeded with 43 participants, between the ages of 18 and 46 years (mean = 25,9 years; SD = 8,2 years).

Stripper rating phases (manipulation check) After the participants chose their two favorite strippers, they rated their desire to see a striptease from both a preferred and a non-preferred stripper at two later moments (T1 after the instrumental training phase and T2 after the Pavlovian training phase) during the task. A repeated measures ANOVA for Time (T1, T2) and Stripper (preferred, non-preferred), showed a main effect of Stripper, F (1, 42) = 48,001, p < ,001. No main effect of Time was found. There was a marginal interaction between time and stripper, F (1, 42) = 3,961, p = ,053. As can be seen in Figure 2, this indicates that the participants rated the preferred stripper significantly higher than the non-preferred and they rated the preferred stripper marginally higher at last rating moment (T2) compared to the first (T1).

10 Desire to see a striptease from the non- preferred and the preferred stripper 90

80 70 60 50 40 T1 30 T2 20 Desire to see striptease in % in striptease see to Desire 10 0 Non-preferred Preferred Stripper

Figure 2. Stripper ratings. T1 refers to the rating moment after the instrumental training phase and T2 to the rating moment after the Pavlovian training phase.

Instrumental training phase (manipulation check) During the last block of the instrumental training phase, the average accuracy of knowledge of the relationship between the two response buttons and the financial outcomes, was 100 %.

Pavlovian Training Phase

A repeated measures ANOVA on RT, with variables Block (1-8), Outcome type (stripper/money) and Value (high/low), showed a main effect of Block, F (3,718, 133,835) = 15,244, p < ,001. No effect of Outcome type was found, F (1, 36) = 1,050, p = ,312. The analysis showed a main effect of value, F (1, 36) = 11,226, p = ,002. Participants were significantly faster at responding for higher than lower values (preferred vs. non-preferred and 5 cents vs. 2 cents), as can be seen in Figure 3. There were no further significant effects.

The same repeated measures ANOVA was repeated for the accuracy data, showing a main effect of Block, F (3,272, 137,418) = 10,494, p < ,001. No main effect was found for Outcome, F (1, 42) = ,260, p = ,613. A marginally significant effect was found for Value, F (1, 42) = 3,529, p = ,067 indicating that participants were more accurate for the high value outcomes (preferred stripper and 5 cents). See also Figure 3.

11 Percentage correct answers on the Pavovian query 100

95 Non- preferred 90 Preferred 85 Reward 2c 80

Percentage Percentage correct answers Reward 5c 75 1 2 3 4 5 6 7 8 Block

Figure 3. Pavlovian trials. Average time in ms. for correct trials and accuracy of answers only on Pavlovian training trials during eight blocks.

Transfer Test Phase General PIT effect: To investigate whether a general PIT effect occurred the total number of presses (vigour of key pressing, collapsed across both keys) was entered into a repeated measures ANOVA with within subject variable of Cue (no-stimulus, non-preferred stripper, preferred stripper). This analysis showed a marginally significant effect of Cue: F (1,732, 72,732) = 2,974, p = ,065. As can be seen in Figure 4, participants pushed significantly more vigorously during the preferred stripper stimulus relative to the baseline cue (no stimulus) condition, F (1, 42) = 4,270, p = ,045. There was no significant difference in response vigor during the non-preferred stripper stimulus relative to the baseline cue, F (1, 42) = 1,859, p = 0,180. This finding was in line with the expectations.

12

Figure 4. Vigour key presses. Average total vigour key presses for stripper stimuli and baseline condition (no stimulus). *p = ,045, compared to baseline.

Outcome-specific PIT: To analyze the outcome specific PIT effect and to examine how the stripper cues increased responding on the two keys separately, we calculated the percentage of presses on the two response keys and inserted the percentage of pressing on the 5 cent key into a repeated measures ANOVA, with a within subject variable of Cue (baseline, non-preferred, preferred, 2 cents, 5 cents). This analysis revealed a main effect of Cue F (17,434, 873,725) = 19,954, p < ,001. As can be seen in Figure 5, relative to the baseline (no stimulus) condition, the percentage of presses on the 5 cents key was reduced during the cue signaling the 2 cents reward, F (1, 42) = 28,263, p < ,001 and increased during the cue signaling the 5 cents reward, F (1, 42) = 13,411, p = ,001 (i.e. an outcome- specific PIT effect). This analysis also revealed that the non-preferred stripper stimulus reduced responding on the 5c key (and instead increased responding on the 2c key), F (1, 42) = 6,174, p = ,017, while there was no significant difference in responding on the 5c key between baseline and the preferred stripper cue, F (1, 42) = 1,784, p = ,189.

13

Figure 5. Average % presses on the 5 cents key. The 50 % line indicates an equal amount of presses on the 2 cents and the 5 cents key.

Data Questionnaire We calculated the general PIT effect for all participants, by taking the total vigour presses for the preferred stripper stimuli and subtracting the total vigour presses during baseline (no stimuli). After assessing for the normality of the distributions, we correlated this score with the BSAS and the subscales of the CPUI (porn addiction and feelings of guilt after watching porn) questionnaire. We used the Spearman correlation, as the general PIT effect was not normally distributed (skewness = 1,418 and kurtosis = 5,425). As predicted, there was a significant positive relationship between porn addiction and the mean general PIT effect, r = ,400, p = ,028. See Figure 6 for the corresponding scatterplot. No other significant correlations were found.

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Figure 6. Correlation general PIT effect and porn addiction. r = ,400.

Discussion

In this study, the general motivating effect of anticipated sexual reward on responding for financial rewards was investigated. As expected we found that relative to a baseline (no stimulus) condition, participants pushed the reward keys more vigorously in the presence of cues previously associated with stripper images. Closer examination of this effect, showed that the difference in presses between the baseline condition and the stripper stimuli conditions, was due to the “preferred stripper” stimuli. The hypotheses, (1) that a general PIT effect would be observed as indicated by increased overall response rates and (2) that a “preferred stripper” stimulus would increase response rates on the two financial reward keys more than a “non-preferred stripper” stimulus, were therefore confirmed. In addition, this study was the first to examine the biasing effect of the general PIT stimuli on different response keys. We found that whereas participants pushed more on the 5 cents key than on the 2 cents key during the preferred stripper stimuli, presentation of the non-preferred stripper stimulus caused participants to reduce responding on the 5 cents key and instead respond more on the 2 cents key. This unexpected result was not in line with the hypothesis that all ongoing responses would be elevated to the same level by the general PIT cues and will be discussed in more detail below. Furthermore, the Porn Addictive subscale of the CPUI showed a significant correlation with the mean general PIT effect of the participants, suggesting that those who more compulsively watched pornography, showed increased vigor of responding in the presence of the stripper stimuli. This finding was in line with the expectations and will also be discussed further below.

The current study was the first one to investigate general PIT in the context of sexual stimuli. Based on previous research and the theory of the central motivational drive which elevates all reward-related responses (Balleine & Baldassar, 2016), we expected a general PIT effect to occur whereby sexual stimuli, which are particularly motivating, increasing responding for financial rewards. In the animal studies of Corbit & Balleine (2005, 2011), the researchers 15 found an outcome specific PIT effect as well as a general PIT effect. Although different rewards were used in the transfer phase in order to assess general PIT, these rewards were simply different types of food. The findings were however promising and worth investigating in a broader perspective. The trans motivational PIT effect was first demonstrated by Hebart & Glascher (2014), who found a general PIT effect in humans for appetitive stimuli (sandwiches) on financial rewards and an aversive general PIT effect (diminished response rates) for aversive stimuli (sound), also on financial rewards. We replicated this trans- motivational general PIT effect whereby a stimulus predictive of the “preferred stripper” boosted response rates for financial reward and furthermore discovered an unexpected mechanism in which the “non-preferred stripper” stimuli invigorated pressing on the 2 cents key. A possible explanation for this might be that an overlap of outcome specific PIT and general PIT exists. This means that the “non-preferred stripper” stimuli, somehow get related to the lower financial reward, by they are both ‘low value’. When we look at Hebart & Glascher (2014), a similar mechanism might be identified. Appetitive stimuli invigorated response rates, when on the other hand aversive stimuli diminished response rates. This study had however only one response key, therefore leaving the possibility of choice out. The current study had two response keys and therefore possibly created an alternative path on which general PIT, generated from non-appetitive stimuli (non-preferred strippers) could be directed upon, by a way of choice. Non- or less-appetitive stimuli, therefore may not necessarily diminish response rates, once an alternative choice is given. Interesting enough, the choice generated from unattractive stimuli seems to be polarized to the more unattractive reward. This new finding needs to be investigated more intensively in future research.

The present study also found a positive correlation between porn addiction and the strength of PIT. The CPUI was based on the principle of addiction (Delmonico & Miller, 2003). Garbusow et al. (2016) demonstrated that alcohol dependent persons show a stronger PIT effect than non-clinical persons. People with a previous alcohol dependency who were exposed to an environment in which substance use and abuse took place, showed not only specific goal directed behaviour but also general directed behaviour; aiming on satisfying a need in general and not particularly the need for alcohol. The study of Watson et al. (2014) showed that even when food (chocolate) was no longer desired, people still kept responding for it when the anticipated stimuli context was activated. This general PIT effect was found by demonstrating that the anticipation of cashew nuts increased responding for different food outcomes. Both studies point out that an inability to stop the alcohol, food or general goal seeking behaviour exists, in the context of anticipated stimuli. Our present study found results which are in line with the findings of Garbusow et al. (2016) and Watson et al. (2014). Participants who reported a stronger addictive pattern of viewing porn, also show stronger general PIT in the presence of anticipated sexual reward. The novelty of the current findings however is the trans motivational character of the general PIT effect (from sexual stimuli to financial rewards). The present study demonstrated that the previous findings may underestimate the degree to which people who are vulnerable to substance abuse may be triggered by less salient triggers and these can still bias response choice through mechanisms that are not well understood.

There are certain aspects of this study that need to be looked upon closer or maybe have to be improved in future research. First, In the context of general PIT, in the current study, strippers and money were considered to be independent; meaning that if a general PIT 16 effect occurred, this would be considered as trans motivational. The question is however, to what extend strippers and money are independent, as for it is a well known fact that in the sex industry, people pay money in order to see a stripper perform a striptease show. Future research should assess to what extent participants associate sex with money. For if a strong association would be found, then the possible overlap between outcome specific PIT and general PIT could be a more natural explanation. Second, when we look at the video’s and the photographs of the strippers that were used, it is clear that the stimuli used were relatively dated. This may have limited how sexually arousing the participants found the stimuli and therefore reduced the influencing effect on behavior. If this was the case, it is possible that in future experiments, a stronger general PIT effect could be found if participants are exposed to sexual stimuli that are up to date and readily accessible e.g. similar to what would be found on the internet.

To summarize, the present study provided evidence that anticipated sexual stimuli, can bias motivation for responding for financial rewards. This trans motivational PIT effect showed increased motivation of participants to pursue salient reward when appetitive cues were signaled. Perhaps the most interesting finding was, that participants also showed an increased motivation to pursue the smaller reward when non-appetitive cues were signaled. Even though this PIT effect is considered to be general of character, a certain overlap seems to exist with outcome specific PIT, for high-value and low-value cues biased responding towards high and low value rewards, that were different in nature. These results open a much broader perspective in which general PIT should be investigated. When we consider the positive correlation between porn addiction and strength of PIT, the societal relevance of this study immediately stands out. The internet environment, not only on computers, but also on mobile phones, offer many cues of sexual stimuli and availability of websites and apps that provide a wide variation of possible engagement in sexual contact. The importance of further research is therefore obvious, for people need to be aware of these psychological mechanisms which can interfere in the choices they make, even though their focus might not be directed upon making that specific choice.

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